Mixed Bag of Rain, Wind, and Potentially Severe Weather to End Wednesday

As of 1:30pm, it looks like there might be tropical depression off the North tip of the Yucatan, although even though satellite animations show a definite very tiny 'swirl', it is moving around a broader scale cyclonic circulation toward the SSE.  Otherwise, jet stream level winds are spreading the denser cirrus and cirrostratus clouds across much of the peninsula, with heavier rainstorms (some rotating) over the lower 3/4th of the Keys where Miami Doppler Estimated rainfall totals so far show rainfall totals ranging from 3-14 ", but most is in the 4-7" range. Already, the Keys is experiencing a rain event, and more 'events' of subtopical origin could occur elsewhere in the state through early Wednesday.

NOW: What appears to be a diffusing warm front over far South Florida is working slowly northward piece meal as high pressure stretches from the western Atlantic across the north half of the state in the mid-levels. High pressure should retreat slowly as an approaching trough works eastward from the north and central Plains, further developing east of the Rockies across Kansas, Oklahoma, and Texas by sunset.
Image below is for midnight. 

The low pressure area near the Yucatan should remain in the same general location through tonight and begin to lift north prior to daybreak, Tuesday. The series of diffuse warm fronts lift north with it as does the rain chance.
It appears the best chance of rain outside of South Florida later today will be near the east coast toward East Central along an axis of instability as the warm front works north. Some showers have already formed and dissipated toward South and Central Brevard and inland, but have since diffused under the canopy of thicker high clouds.

 After 48 hours of model runs and a lot of changes with them, the general outlook posted here on Saturday sums up to be pretty much the same thing as posted then. 


Two Tiered system with several imbedded impulses and vortmaxes to impact the state mostly from sunrise Tuesday through Wednesday in various shapes and forms, with differing results depending on where one is located.


Rain showers most likely to approach the east coast to inland by late afternoon Central toward sunset, with the chance working northward by Tuesday morning. This will not be a continuous rain by any means, but some thunder could be thrown in for good measure, most likely elevated.

TUESDAY: Chance of a tropical storm developing. However, any bone fide tropical storm to form does not appear will actually make land fall as one. The NAM is showing a warm core low to form up through 20,000 ft, but the system is quickly torn as the approaching cold front from the WNW moves in. In doing so, the surface low is displaced from the upper level core which progresses east while the surface low lifts toward the Florida Big Bend. Actually, the NAM shows the warm 500mb core to cross Central Florida along with a developing warm front from the west as the low moves to the NE. This is shown further down in the post.


Using the CIMMS tropical cyclone site as a reference, the Ocean Heat content near the Loop Current could play a critical role in development of this storm system. It is important to note that whether or not this system is named, the results of the impacts could come out to be quite similar either way. In this image the red on the top of the image is dry air, while the colors in the Eastern Gulf are the warmest ocean temperatures west of Tampa. Models have been showing actual storm tracks varying from Dead Central to the Big Bend in direction, but what might happen in reality is that there will be two storm systems with different characteristics tracking along with them both.

INVEST of interest north of Yucatan is circled in dark red. To the NE of that "I" is the warmest Gulf water/Heat Energy. North of this location is dry air at the moment. This will move out later tonight. A storm could form 'of name' in this area, or at least all the parameter formidable for storm formation will explode with energy either way. 

Below are some model tracks for a potential surface low, if one truly forms. My take, or opinion, is that if a truly tropical low is to form it would only remain tropical or subtropical by taking a track across Central to South Central Florida. Otherwise, models indicate it will become rapidly absorbed into the much larger scale trough by Tuesday late afternoon if it continues to be guided more northerly to NNE as the GFS/NAM indicate. 

This is why it is interesting why the NAM is showing the warm core aloft  to move across Central while the surface low takes off more toward the NE and the Big Bend region or more toward the south north of Tampa Bay. See image below, and the orange warm core across Central , west of Orlando, on Wednesday morning at 2AM. I did not draw that it, it is model derived.

I'm thinking the biggest concern with the system in the rotating storm (tornado) department will come with that core / trough couplet and the associated wind fields as they appear will cross the state from SW Florida near Cape Coral area and across the state , exiting the east coast from Central Volusia south toward Indian River county from near sunrise Tuesday toward just after dark. 


Meanwhile, the parent and more substantial low will track toward Cedar Key through the Big Bend and interact with the approaching cold front bringing larger rainfall totals from Gainesville and North to Jax and along I-10  toward Tallahassee in a short amount of time.


WEDNESDAY: The front should be clear of Central Florida by mid-late afternoon. Whether there will be much rainfall with it is still up for debate. As of yesterday there appeared there would be a period of heavier rain across Central as the front temporarily locked up, but now it appears it will go through with nothing more than cloudiness and light rain. There is clearly much more to be learned and followed as the events unfold, and so far this one particular aspect of the system seems to be of minor concern (based on the morning GFS at least).


THURSDAY-FRIDAY: Very cool ... coldest mornings since early spring, with lows in the mid40s through the 50s as far South as Far South Florida. Overall, Thursday will be the coldest from sunrise to sunset, with Friday being the day that the most of the state   being simultaneously cooled from north to south.


SATURDAY: Winds should start to swing slightly onshore by morning along the east coast making for a noticeable warm up. The models (GFS) has been consistent with hanging the trough at the mid levels behind over Central or South Central Florida in all cases, thus rapid air mass modification with the onshore return flow and eventually low topped showers reaching the coast by Sunday or Monday. The GFS in the last run is holding off on the showers until Monday now, but impacting the coast to 20 miles inland for 2 days. Previous runs indicated showers could move in as soon as early afternoon Saturday, so this too will have to be re-evaluated late week.


BEYOND: It appears that perhaps two backdoor cold fronts could move through next week toward next weekend with little change in winds other than some wind surges from the NE to ENE, and a break in showers between them. Timing is difficult and changes with every run when these will occur. The latest morning run shows a very showery day for all of coastal NE-East Central Florida on Halloween. Lows and highs likely remaining the 70Fs round the clock.


TROPICS could could continue from north of Central America north through much of the Caribbean....through the end of the month.


STORM IMPACTS:
RAIN: Largest rainfall totals outside of the Keys (ongoing) will be along the cold front/Gulf low merger over North and parts of North Central Florida. Although totals will not be as high as what was experienced with the last event, the rain will fall in a much shorter amount of time. Areas further south toward Central and South Central will not receive as much rain most assured as before, but already filled retention areas and high ground water could easily result in a resurrected flood threat despite the lower rainfall totals over a large area. Areas across Central will likely not experience the bigger totals due to fast shower/storm motion, but training could amount to much higher localized rainfall. Parts of SE Florida might also deal with some flooding threats in the more fabled, flood prone areas.


WIND: Strong winds of 35-55moh (at least) could occur near the Big Bend toward Brooksville and swath across North and North Central Florida from JAX to northern Volusia County, but possibly as far south as Central Brevard. The strongest winds forecast are actually just above ground at 2000 - 10,000 feet, but in heavy down pours these winds could translate to the surface .   Trees will be able to fall in these stronger winds more easily now with loosened/weakened soils in place, and additional rainfall will further aggravate the situation. The other way of looking at it though, is that the last system likely cleared up many of the already loosened or rotten fronds and branches.


STORMS: This entire event looks more to be a function of wind shear and kinematics rather the thermodynamics. Only the South 1/2 or 5/9th of the state are ever indicated to be have appreciable unstable conditions. Regardless, there appears to be a tornado threat at different times from SW Florida near Naples and along a swath extending ENE ward along and ahead of what could be the remains of any tropical type features that might be directed across the state as   a north/south running warm front or trough toward all of Brevard and portions of Volusia and Indian River Counties. This would include Sarasota, Lakeland, near Naples, Cape Coral, Polk, Osceola, Orange/Seminole Counties, parts of Lake and Volusia Counties. But this is just for starters. 


Even if instability is lacking, this system appears could act more like a tropical system with warm air aloft, and as such it will all be about the wind directions aloft and bulk shear between various levels of the atmosphere. Thus, if it comes to the point that warnings are deemed necessary, a tornado would be possible even without vast amounts of lightning. Another way of thinking of it is, any storm with more than an occasional rumble might be a big trouble maker . 


The reality in my mind is that things will unfold probably nothing like what I'm imaging or how the model rain fields are shown, nor in the way they are expected to form. The truth, or some semblance of it will evolve as things happen. Thus, early Tuesday through midnight Tuesday night so far seems to be the time for extra precautions to be at the first and forefront.


This systemh as the potential to go down in the annuls of Florida's meteorological history , if for nothing more than a case study....the Keys are likely already on their way for breaking a rainfall total record, and other records could be on the way to be broke almost anywhere. 

Potentially Volatile Period Monday-Wednesday Awaits a Verdict

Full Moon and Jupiter Prior To Sunrise Friday

OVERALLTODAY: Short lived cold frontal impacts quickly modifying today, with the boundary along the northern Florida Straits. Breezy NE-NNEwinds will gradually veer to ENE-E on Monday through mid-day.


Rain and some isolated thunder has been on going across the Keys today, with totals already over 1" in some locations. This activity is expected to continue through tomorrow and gradually lift northward into Dade, Broward , and Southern Palm Beach Counties later today through Sunday afternoon bringing some larger rainfall totals to mainly Collier, Dade, Broward and at least the southern 1/2 of Palm Beach County.


Meanwhile, low pressure in the northern Great Lakes is expected to lift north toward James Bay and merge with another low pressure area trekking across Southern Canada through Tuesday. This second low pressure area will gradually aid to develop a stern cold front appendage across the North and Central Plains States after interacting with the Lee of the Rocky Mountain chain on Monday which will head toward the Deep South on Tuesday.


Further south, our old cold front, after having made a visit to the tropics, will be lifting north in response to the approaching trough out West,   as what I'll refer to as a modified sub-tropical warm front (for purposes here only). Sub-tropical in the sense that it will be transporting tropical moisture with it from the Caribbean. Low pressure in the far SW Caribbean appears will drift WNW-NW in the next 48 hours, but never congeal into a certified tropical system, at least not at this point.  


As this modified cold front turned sub-tropical warm front lifts north, so too does the rain chance into South Central Florida on Monday afternoon through evening. After 24 hours worth of various depictions (which have varied vastly), the GFS is back to where it started, only about 6-12 hours faster with the moisture and rain return northward.


SUNDAY: For the region north of Palm Beach county Sunday will be much like today, with continued high clouds and perhaps more mid-level clouds and a few lower clouds. Further south, rain showers and thunderstorms will continue, with several inches total anticipated as the boundary lifts north. Winds to remain from the NE-ENE but gradually veer toward the East on Monday and E-ESE with the approaching boundary.

TODAY: Green shows best chance of showers and thunder today. Yellow is the cold front of yesterday morning. Arrows point to anticipated lift of the boundary through Monday, with more northward motion from the east than from the west side. Low pressure in the SW Caribbean, low pressure near Lake Superior, and High Pressure which is generating the winds of today and Sunday over the Deep South combined with low pressure to the south. 

MONDAY: The GFS of 8AM has sped up both the approach of the warm front as well as that of the developing cold front in the Plains. Thus, since this is the first run of this nature, timing remains uncertain in regard to when the rain will reach Dead Central (mainly only at the coast initially until the cold front moves closer).  But all in all, the GFS and morning North American Model (NAM) match close enough that rain will work up to Southern Brevard by Monday afternoon with some reaching North Brevard by shortly after sunset. Meanwhile, rain will continue over South Florida but begin to decrease as the boundary lifts north. Just how far north this rain will proceed is another big question. Previous runs had the boundary clearing completely all of Florida, but with the now faster  approach of the cold front of the morning GFS, it never gets much further north than Southern Volusia County (??!) 


MONDAY NIGHT/TUESDAY: Potential  for volatile weather across any portion of Central Florida. To Be Re-Evaluated Through Sunday Morning.


The latest NAM and GFS agree in general on some of the wind fields that eventually are to unfold, but the timing differs by as much as 12 hours with the GFS being the faster for a change and more turbo-charged.


This is quite a surprise, so not sure exactly what to make of it yet. The ECMWF, per discussions, is not as dynamic with the depth of the approaching trough. This , in turn, would have a considerably assuaging effect on the outlook for this time frame (less potent).  Winds to become more ESE-SE-SSE on Monday night as the warm front lifts north and meets the gradually lifting out divergent southern branch jet stream winds. Showers increase, with the potential for thunder along the east coast from Ft. Pierce to Port Canaveral by sunrise.


Meanwhile, the GFS is forming a disturbance along the boundary in the SE Gulf which greatly impacts the southern Tampa Bay region toward Sarasota. Thus, the focus shifts from South Florida to Central Florida on Monday no matter which model of preference or timing is chosen.


With the faster approach of the morning GFS run, the bigger impact is now toward Tampa rather than the Big Bend area. 


The greater concern other than the astounding 9+ inches of rain the GFS forecasts on the West Coast is the  increasingly veering of winds with height. The latest GFS has a disturbance accompanying (or rather, responsible) for these winds to develop a  swath from near South Tampa Bay, across the state toward North Brevard during daylight Tuesday. On the other hand, the NAM is faster at this point, developing it overnight into Tuesday morning. In either case, wind profiles are supportive for what could be a tornado watch, lasting or varying in location for up to 18 hours anytime from post Midnight Tuesday morning through Tuesday afternoon.  The one ingredient missing during the time of favorable wind profiles is instability and only mediocre lapse rates. But given the wind fields shown, and the large loop in the hodograph (left ,below),  and using Orlando as a central point of reference..... :

...the chance of a tornado threat seems to be a viable option to investigate in greater detail with subsequent releases/versions of the NAM and GFS models. Accompanying which would be very heavy rain in thunderstorms and rainstorms working across the state. Thus, this is nothing like the event of last weekend.


WEDNESDAY: The actual cold front will essentially absorb the warm front, stretching out a mid level trough across North Central Florida. It looks like there could be yet another form of rain resultant from isentropic lift along and behind a rapidly moving but very shallow and potent  warm front turned cold front heading into the late Tuesday through Wednesday time frame.


 Again, timing remains a big issue at this point, but this was shown to occur in yesterday morning's run (but not shown in subsequent runs). So who knows. One run showed literally no rain event anywhere. But already, South Florida's (so far, just the Keys) event seems to be in the works.


THURSDAY: The cold front could sweep through, as is shown in several runs, but it will shallow, brief, and a bit  more 'potent' in the temperature department compared to what we are used to. On the other hand, like this last front it looks relatively brief, with a wind shift to the NNE to NE by Saturday morning. Even this temperature potency of lows in the 40Fs and 50Fs to South Florida is debatable, the GFS has tended to over extend itself with the previous two fronts in the long range.  In the mean time, the mid-level trough never really clears the state as high pressure builds rapidly behind this potentially dynamic system quite quickly well to the north of Florida.


FRIDAY: By this time, we might be talking about a wind surge moving in on northeast Florida and working down the coast, eventually engulfing the entire east coast by late Saturday. ..with rapidly modifying temperatures in tow. If the GFS is correct (which it seldom is this far out in time so far this season), mid-level temperatures are very cool aloft, but upper level temperatures are relatively warm. The net affect is considerable cloudiness and brief, low topped rain showers working down the coast with time during the course of next weekend.


By the next Saturday time frame I quit looking since  reliability in the model decreases logarithmically in the "Great Beyond", and next Saturday is getting beyond even that.    

Skies Clear Sky Most of Florida, But Forecast Remains Murky

Thursday Late Afternoon. A Storm moved up the A1A Corridor from near Patrick AFB to the tip of the Cape, buidling northward along what appeared to be a weak sea breeze boundary combined with a forward flanking line of towering clouds and a separate updraft. The area in the center is what remains of a gust front that was absorbed by the newer updraft. To the left of this low cloud 'blob' is what appeared to be a shear funnel, not created by rotation within any part of the storm but by conflicted stirring behind the gust front and ahead of the heavy rain shaft's (barely visible to the left in this image) ouflow.

TODAY: Cold front moved through dead central sometime between 530AM-6:30AM, but it is not exactly clear. Based on a thin line of lower clouds it might have been closer to 8:00AM. These clouds seem to be more closely associated with the frontal trough at 925mb (2000 ft) rather than at the surface...and that is lagging ever so slightly behind. The mid and upper level troughs are even further behind. The prefrontal trough of yesterday over North Florida now traces the northern part of the Florida Straits.

8:15AM and estimated front position or zone. The boundary is now stretching from Fort Pierce to Port Charolette. Note the higher clouds over South Florida. They could be in an out of these clouds the remainder of the day, with some lower clouds over the Keys at this time. As of last hour they seemed to be thinning out a bit.

Little fanfare with the front except blue sky, ever so slightly drier air, and a wind shift which could be considered something to celebrate for those north of the front. Temperatures tonight are not expected to make much of a drop, and folks at the beaches might not be able to even tell the front went through by morning, if ever other than that there is no chance of rain.


The front is expected to make it as far south as the current position of the pre-frontal trough along the Florida Straits where it will remain through the first half of Saturday at least.


SATURDAY: Very pleasant Day for most of the state, but high clouds could move in for much of the peninsula. This will be about the only driving factor to make the weekend less than perfect. South Florida could have the most cloud cover, way South Florida. The Keys areas seems most likely to get in on the rain chances through Saturday and early Sunday, with the slight chance working slowly north with time as the frontal boundary relaxes, nearly washing out, and lifts back north uniformly across an even latitude .


SUNDAY: Looks very similar to Saturday with the ever present chance of High Clouds but otherwise pleasant with an ENE-NE breeze at the beaches shortly after sunrise.


MONDAY: Boundary slowly working north now, with a rain chance emerging along with it. It is a bit hard to say whether high clouds would reduce that chance, but in consistency with the matching GFS and NAM this far out in time, it could rain near the coast as far north as Sebastian Inlet prior to sunset and further north toward Southern Volusia by sunrise Tuesday. The remainder of the state is in on the rain chances by day's end as another frontal boundary approaches.


BEYOND TUESDAY: Here's where we enter the murky waters in the forecast from how I see it. Models are fairly similar but there are some differences that are significant. Based on the GFS and somewhat the ECMWF, tropical moisture will be drawn northward and across all of the state ahead of the next front.


The latest GFS is showing a potential rain event setting up toward Apalachicola (the Big Bend), but other heavy rain areas could amount almost anywhere working toward Wednesday/Thursday time frame, while other areas could be bone dry.


The big question comes: What will happen with this front? The GFS has more often than not had the surface front clear to the Florida straits, but leaves the mid-level trough behind across Dead Central which sets up for an isentropic lifting mini-rain event across Central. The GFS has been most consistent with having this mid level trough hang up across Central..it is what happens below that level that will make the difference of when/where/how any potential rain event can or will occur heading toward the end of next week. On the other hand, the last 2 of 4 runs has hand the front blast through with a quick burst of the coldest air this fall season, but it only lasts 18 hours. This looks very suspicious. Models over played this cold front of today, so I'm inclined to think they are over playing the next one as well.


Either way, there could be a slippery, wet road ahead for almost anywhere in the state between next Tuesday through the following Tuesday.


TROPICS: So far, only the NAM is showing any significant tropical development. It has been going a bit 'over board' in the tropical development realm all season beyond 24-36 hours, so disregarding for now.


But there is a part of it that may need closer consideration. If the low pressure area over and near the Yucatan Peninsula expands as shown by this model (but does not organize a concentrated center), this would be the impetus to prevent the next front mid next week from cleanly clearing the state at all levels of the atmosphere. 


 The other option per the latest ECMWF is that much of this area of low pressure is ejected northward ahead of the next front, soaking the Big Bend and likely putting a big 'squash' on any chance of tropical development in this area toward the Yucatan for quite some time to come. It would also mean a big reduction in the rain chances heading toward next weekend. Based on a loosely consistent GFS, I'm more prone to side with its trend, and to ignore any big chance of a substantially long term ,drying frontal passage in the later portions of next week.


Much to be determined still and to be on alert for. Either way, the GFS is now showing rainfall totals up to 9" inches once again, only in a different location than the event of late last week, with other areas across the state varying from 1" to as much as 6" over a one week period. If there is one thing we can learn, if it is showing 9" somewhere (and within 72 hours no less) , chances are it could be much more than that. Or, there could be a major 'event' to unfold, the origins of which or why remaining unknown. 


 It is interesting that the model run of last night showed a low pressure bubble just off the Space Coast in 192 hours, that looked identical to the event of last Sunday evening, but with much less wind/impacts.  In other words, we could be dealing with a mid-level trough, resulting in sub-tropical parameters mixed with completely non-tropical factors resulting in rains wide spread for quite some time...or, we could be looking at a big cold down.  

Scattered Showers / Slightly Better Chance of Thunder Through 11pm

Going back and forth today in regard to where there is a better chance of rumbles, with two regions (North vs. South) with the dividing line running from near Sebastian to South Tampa Bay... later North of the line and earlier onset south of that line.

TODAY OVERALL: Low pressure is becoming more focused now at all atmospheric levels from Central Wisconsin to the arrow head of Minnesota. A much larger trough encompasses the Eastern Third of the U.S. with what appears to be 3 distinct vorticity lobes rotating through Mississippi, Alabama, and Georgia per satellite imagery.  Only surface observations reveal what appears to be the true cold front by wind fields and dew point temperatures. A weaker surface low reflection which is barely closed is rotating up the east coast and is now located just off NYC. There are two other small indiscernible weak circulations scattered about within the large scale upper level trough, which is slightly negatively tilted.


Over Florida, the pre-frontal cold front is located as shown above per observations and satellite imagery. There is another boundary running from South Tampa Bay toward Sebastian Inlet, with a weak ridge running just north of that boundary to Southern Volusia County. Thus, sinking air with this feature should hold off  showers until much later today as it slowly erodes and the prefrontal trough approaches across Dead Central.


Further South, much less cloud cover (and daytime heating) could lead to showers almost anywhere, but the most favored area should be close to the east coast as peak heating ensues toward 1-2pm  from just south of Vero to Northern Dade County.


Short term models, namely the RUC and High Resolution Rapid Refresh are split with where the better thunder chance will be. The HRRR favors the southern zone , whereas the RUC favors the more northern zone toward sunset with the prefrontal trough. This post thus will account for both, since each area has both pros and cons  for the rumble department.  Otherwise, showers could easily occur in both.


BEST GUESS: Sea breeze development could easily occur today, but is not expected to be a big player today since it will be quite light and remain close to the coast (within 5 miles, maybe a bit more toward SE Florida).  The RUC has a big CAPE (instability) hole over East Central near the coast, but that might be because of earlier cloud cover which is breaking up, so disregarding. Either way, instability is not all so tremendous. The driving factors today appear will be respectable mid-level lapse rates as the 700 -500mb heights fall with the incoming trough during peak heating. Heating being, where there is cloud breaks. This is another factor to consider.


The other factor will be some lower to mid-level vorticity rotating through the much broader scale synoptic features. The earlier NAM and the GFS favored dead Central (namely Brevard and Indian River counties) late with these features, showing good vertical velocity providing lift.  Not expecting strong storms as of yet due to lack of surface based instability ..but as we work toward dark strong wind fields in the 20,000 ft level to the jet stream could create more than one active thunderstorm from Ormond beach toward Port St. John as the prefrontal trough moves in. But at this time appears to sketchy to highlight.


The prefrontal trough is generally 10-14 hours ahead of the actual front, and it should be across Dead Central between the hours of 7pm -11pm. The actual front will be sliding across the Panhandle tonight and a few showers and thunder could occur with that feature where better moisture ahead of it exists further north.


TOMORROW: By sunrise the prefrontal trough will be near Southern Dade County with the actual front across Dead Center, give or take 2-3 hours. The front is then expected to reach the pre frontal trough location by late day. Moisture with the latter feature is lacking, so no rain is expected with it. 


SEE CAPTIONS:

WEEKEND: Both features should align along the north Florida Straits. The latest 2AM GFS has rethought its position, and now has these boundaries back further north to where it first had figured they'd be 2 runs earlier.  Thus, the Keys and perhaps including the Key Largo area will be in and out of the rain chances over the weekend (at least as far as the local forecast goes). Elsewhere, surface winds will be quick to shift onshore behind the cold front, which really is hardly  even a cool front. Temperatures are not expected to fall as much as previously ascertained, thus the coastal areas will hardly notice a difference south of Cape Canaveral on Sunday morning, with dew points evening out across the South Half of the state by the end of the day. Overnight lows and daytime highs perhaps 2-4 degrees cooler than the past two days at best, if even that from Lake Okeechobee region and south. Most notable away from the coast is where the cooling will be recognized. It will be brief though.


BEYOND: Another frontal boundary and upper level trough will enter the Deep South working into Monday/Tuesday time-frame. Ahead of this feature the  earlier front of tonight/tomorrow will be drawn back north as a modified, subtropical warm front (not an officially recognized term) and moist air (with PWAT 2" +) in its wake as it lifts toward Georgia. Rain chances increase all areas during the day Tuesday, so that by evening most any where could receive rain. Timing , yet to be fully determined..


Meanwhile, a large and slightly organized area of low pressure is visible over the Yucatan. Between this broad feature which extends into the Southern Gulf and most of the Caribbean as well as what will become two frontal boundaries from Central Florida (by next weekend) it gets very messy. The GFS has been consistent for the most part for an inverted warm frontal like trough to extend from the region near the Yucatan to extend NEward across at least the South Half of the state if not further north, with rain chances re-emerging along and south of the boundary through  next weekend and into  the following week. 


It appears this could all culminate in a rain event for South Florida, namely from West Palm Beach to Ft Myers and South, but not of the magnitude of the previous event that occurred north of this region last week. Even so, some areas near Cutler Ridge can flood easily, and the area is already saturated from the previous event of late.


There might also come a time in association with the second front mid-next week the chance for stronger storms will need to be looked into. With this features comes Deep SSE-South  moist flow and divergent jet stream level winds hedging on departing left exit region winds, aiding in lift. Not sure which. This is one week out already though, so more to determine surely lurks.   
    

The 10-911 " No Name Storm" Of October 9, 2011

"We've been  on the beach in a storm with no name, it felt good to get out in the rain;


In the  storm,  we can't remember the name, but the pressure dropped down and the wind blew insane" 


Events over Florida of October 7-9, 2011, leading up to....

Storm 10-911 (10-9-11) !

 Some of the events that led up to the final escapade that prompts the question, "Should this storm have been named?" when all was said and done.


The initial weather pattern  leading up to the time in question was expected to be a wind/rain event as first noted by the Melbourne, Florida National Weather Service extended forecaster on Duty, Mr. T. Cristaldi (and followed up later the same morning here) was not a tropical or even sub-tropical one. 


As noted, a blocking pattern was to set up with high pressure over the Mid-Atlantic that was to be reinforced from a secondary high pressure area from Canada.  Meanwhile, low pressure was mounting in areal coverage from the Florida Straits and into the Caribbean along and south of the old cold front that brought the state the first hint of fall on October 1st.


It was posted here originally that I thought it looked like an OMEGA BLOCK was going to set up, but that quickly changed to resemble a REX BLOCK as noted by the NWS office. Technically,I'm not sure either case was absolutely true because for these blocks to form in 'text book fashion' both areas would be cut off from the main Northern Hemispheric circulation. It was quite close though, and even that could be up for debate.


In this case, the low pressure area was far enough south to not be part of the circulation, whereas the high pressure had nearly cut off with a large trough well to the east . Recall there was also a trough approaching from the west that nearly cut off in the upper levels toward the SW U.S. That would have made for an Omega Block. So, and only from the perspective of this writing for entertainment purposes, I'm thinking of it as a "Modified OMEGA/REX Block". This term does not exist to my knowledge technically  ..but it harbored both aspects of an Omega and a REX Block, but not completely.


It was within this block  that Florida found itself within a tightening pressure gradient portion of it that brought the high winds. On the other-hand, the weather over the Great Lakes and most of the NE states was gorgeous where it had been previously wet and cool for a long duration when a cut off Low had established in this area just 10 days earlier. In fact, it was not until that cut off low (a blocking pattern as well), moved well off the U.S. NE Coast that the newer pattern could establish over the SE States.  


 The deepening easterly flow from the surface to 700mb was discussed in depth early on, and was described in posts as "Phases I, II, and III) early in the week to midweek as they unfolded ..it was when the flow became deep enough (or higher up in the atmosphere) that heavier rains and squalls began in full, Phase III.


Despite all this wind and rain, it was not a case for 'naming' the events that were on going. Not until there is a closed low pressure area at the surface does the 'naming' come into consideration.


Such a low appeared to take shape toward the NW Bahamas on the evening of the 8th. The old frontal boundary (cold front of one week earlier) lifted north, pivoting from the west side and lifting north on the east side.  As the boundary lifted north the pressure gradient (between high and low pressure) increased across Central Florida leading to the events of Sunday, as anyone who was in  Florida can relate too. Unusually high tides, minor beach erosion, rising waters and waves on the intracoastal waterways, and squally weather continued. Along 528 between Cocoa Beach and Merritt Island it can still be seen where the river breached the banks and flooded over where no barricades had been previously put in place. Water is still over the banks in a few spots where the shore was eroded on this Wednesday, October 12, 2011.    


OCTOBER 9 - The Day in Question: It was on this day toward early afternoon that a tightly confined and consistent cluster of strong thunderstorms moved north to NW off the Florida East Coast which developed offshore Vero Beach. Winds in this location increased in that area, and power outages began to filter in. It lofted NW- WNW to almost West toward Brevard County. The NWS in Melbourne issued high wind and Flood warnings especially for that point in time, and had been issuing lower key statements prior to the warnings in their Blog updates. TV news stations were put on alert and the NOAA Weather Radio was emitting the warnings as well.

It first appeared it would impact areas as far south as almost Ft. Pierce to north of Brevard, but as time went on the area of interest shown above lifted further north and parallel to the coast inching only closer westward with time as it reduced in size. The blue lines were drawn in at the time in order to point out that it was a coastal event, per the rain at the coast that was creeping west with time.


However , the area offshore lifted north more and more,  then started to take a hard left (toward the west)

At this point, I was listening to Led Zeppelin's Song, "When The Levee Breaks"

It started taking on more striking features on radar during this time, almost like banding around a tropical storm, but there was no center of circulation visible on radar or satellite imagery. It also increased in strength for a 'blob' with almost no lightning to abudant lightning after 4pm  -9pm. The HRRR model was showing what looked like a  "SuperCell Thunderstorm" at one point to cross exactly where the 'center of circulation' eventually crossed many hours later. That was about the 15Z run of that model, but cannot say for certain. It becomes available on line several hours after the fact.  At this point, the system was being more regarded as a potential low end tornado threat rather than a tropical one, as SPC also had this area under a "See Text" for a 2% Tornado Risk and strong wind risk . A second blog post was issued on this day as the new and evolving events began to unfold. Both the early and mid-afternoon posts are available (the image (below) included in the later post):


 http://highspeeddirt-steve.blogspot.com/2011_10_09_archive.html

The Green Area Shows Where the Storm Prediction Center (SPC) based in Norman, Oklahoma had issued the small tornado and wind threat. In blue was the modified version, unofficial for purposes of the blog posts, posted in the morning of the 9th. The SPC version was published earlier in the day, whereas the blog post was not issued until several hours later when the sun had been up a while and conditions to the south were improving conditions  

It was near 11pm the lightning activity began to cease..as the remaining convection moved ashore on the north end of Port Canaveral, toward the Kennedy Space Center, to along SR 3 in North Brevard near the Haulover Canal. At this point the boundary I've referred to as a warm front (not completely technically correct) was near or just south of Melbourne , Florida...and the pressure gradient was very tight along a narrow passage just north of that boundary where it met the strong high pressure to the north. But.....

The lightning ceased, and surface air temperature around Cape Canaveral at my place fell to nearly 68F degrees, almost the coolest it had been since early spring  and one degree shy of the coolest morning yet this fall season. Then after approximately 10 minutes of uneventful weather,  an interesting thing occurred in Cape Canaveral as I observed. The wind began to pick up again, from almost due north this time. I big change from the ENE-NE wind of the past two days. It seemed like more a fluke, perhaps outflow from the remaining storms to the north (?), but it increased steadily. A closer look at radar, and an interesting feature became visible within radar range of MLB's WSR-88D Doppler Radar.

An "eye like feature"  to the ENE of Melbourne clearly was showing what looked like counterclockwise circulation as if around a central core of low pressure when viewed in animation mode (using weathertap.com) similar to that of a tropical cyclone's eye.  If there was a circulation , just like the HRRR model implied for a supercell (a rotating thunderstorm,) it was now just offshore but not as  a rotating thunderstorm.  Realize the supercell thunderstorms do not have an 'eye', the entire storm rotates.


Something else was apparently rotating as it lifted NW then turned WNW and into North Cocoa Beach toward Cape Canaveral. A look at the Radial Velocity revealed:

The strongest inbound winds are shown in the darkest blue just off the tip of the Cape and heading toward the north end of Port Canaveral. The red is outbound winds relative to the radar's location.

 Rhe air pressure on my home weather station (but who knows how well it can be trusted) indicating a RAPID fall in pressure from 29.82" to 29.70" in less than an hour.


Also note the 00Z Forecast from the North American Model (NAM) for this time frame for 2AM. It is 'slow', but does show the closed low roughly east of Sebastian Inlet:

Actual data that appeared from the Local Data Integration System (LDIS), a conglomerate Space Flight Group/NWS effort. Compare the image above and below, and note they both picked up a 'low', but it does not look like a Tropical Storm at all. But, it is a low, with tropical storm force winds on the north side.

As this apparent circulation approached the temperature rose from 68-69F to 74-75F degrees on my porch , even while it was raining. This should have been a cold, outflow like wind from storms to the north, but it was not. It was warm wind. 


Wind shifted in MLB to westerly while my location in Cape Canaveral just south of the Port had due North Winds estimated at 35G67mph (tops) in one quick squall. The prevailing mode was more closer to an estimated  30G48mph at my location...which lasted 50 minutes.  Rainfall of 2.67" was received in only 50 minutes and the storm total was 2.75" for the 90 minute period, although with how strong the wind was at this time I can't be certain that total rainfall was not even more. Rain was over-flowing the rain eaves above, which I've only witnessed on 3 previous events in 5 years. Radar estimated rainfall did not catch the high rainfall in Canaveral from what I could see on Weathertap at all, and I'm not sure if Melbourne's radar picked it up either. It is possible it was below the radar beam, since it all appeared to be very low level activity for the majority of the time. In fact, at times we could see the Full Harvest Moon in brief cloud breaks.

On Shore Centered Close to Port Canaveral shortly after midnight

And the latest LDIS Plot at the same time as this radar image above is below. Note how tight the isobars are shown here AROUND THE CENTER, and not depicted as a tight pressure gradient between two opposing much larger non-tropical systems. It was during this time the weather station outside registered a barometric pressure of 29.47".

It is only for this odd mesoscale feature that I'd think the system would have a potential to be named.54ft towers near the north end of the Cape measured a few gusts from 75-81mph as well.


It is important to note that most of the strongest winds worthy of rating this as a named storm occurred only in gusts, but might have been sustained toward the Port and further north toward the Haulover Canal or off the east coast. A cruise ship leaving harbor (I saw it going out to sea later in the afternoon as the system was approaching) relayed they encountered 'great difficulty', more so than expected.


Despite these winds measured on land, we'll never know how strong the winds were offshore as well due to lack of denser buoy data. The items of interest in my mind that would give this final 'obscurity of meteorology' the potential to be name worthy are:


 1) The rapid drop in surface pressure (not related to pressure gradient winds) 


2) The abatement of lightning as the system could have become warm core to higher altitudes which is not favorable for lightning activity, but denotes a tropical system;


 3) The rise in temperature at ground level despite the fact the wind was coming from the north in my location, and from the direction that cooling outflow from earlier thunderstorms would have come from ;


4) Even as the moon appeared in full, the wind continued sustained est'd around 30mph with gusts to 45mph with horizontal rain.


5) It might be that the strongest measured winds at 54 ft were a result of both a tight, low level circulation and pressure gradient winds combined.


If this were to be named, perhaps it would be the first "hybrid sub-tropical storm gone near extra-tropical"  all within the course of 4-6 hours.  

From the perspective of a Storm not to be forgotten in the annuls of meteorological research and history, perhaps it should be named for historical purposes. Would naming the storm affect those looking for recovery from insurance companies (for better or worse)? 


Names are not dealt out solely  for the purpose but other factors both pro and con abound for why or why not it could be named.  Post-event naming has occurred in the past.


The series of bizarre events leading up to the night of '10-911!' are not truly defined well enough to argue either way, nor is the availability of data surrounding the system during this time in-depth enough. It is within the hands of our scientists at the National Hurricane Center in collaboration with NWS Employees to decide (if they are even giving this storm event a second look).

Will we, the witnesses, be forgotten like salt spray in the wind once the storm's flood waters absorb back into the ground and vaporize into the air as the beaches recover?    


For a personal video now posted on YouTube, See:   

http://www.youtube.com/watch?v=uZX74NxHBZw


 Meteorologist, Stu Ostro, from The Weather Channel, has   posted a discussion regarding this event (link below):


http://www.weather.com/blog/weather/8_25746.html


Crown Weather Services, Rob Lightbown, was also concerned about the potential for an event to unfold, and his daily weather update for this day reflected that fact early in the morning. His feature/main page is located below, and is updated most every morning as tropical weather season is in progress, as need be: 

http://www.crownweather.com/

The National Weather Service out of Melbourne issued prompt and due warnings, in any event. So there is no argument either way that people were not warned for tropical storm like conditions in the areas that were impacted on this day.


And Thanks to Weathertap.com, whose services have been always necessary and reliable
and to Twisterdata.com, where the weather model data provided at this site proves beneficial innumerable times .


STORM: 10-911

Similar To Tuesday, With Showers and Isolated Thunder Near the East Coast Late Afternoon

Weak Trough that was over the Eastern Gulf Yesterday crossing South Central Florida early Afternoon accompanied by some brief showers. The trough is washing out, with another one off the west coast to replace the previous one.
More showers along the second trough toward North Florida currently. 

IN GENERAL : The mid-level low that was just east of Panama City is lifting north toward the Great Lakes and being absorbed into a larger upper level trough moving across the Northern Plains heading into Friday. The weak surface reflection is riding up the eastern sea board and toward the New England Coast through Saturday and will also be absorbed by the larger system. This will all occur during the next 3 days over the Great Lakes region, with portions of the Eastern Sea board receiving some heavier rain and thunderstorms. This large low pressure area will be slow to move out, as it now appears the primary frontal boundary might occlude.  


For Florida, the weak trough that was off the West Coast is sliding through Central and South Central Florida at noon, and setting off some rain showers along the way. It appears it is weakening with time and might fizzle altogether by late afternoon. Another similar trough seems to be more associated with the mid-level low, and that is to move toward the peninsula slowly today. Not sure if it will even play in though with weather over Florida locally.


There is moderate instability showing up now on the LDIS plots in the Eastern Gulf  from near Brooksville north of Tampa Bay toward Ft Myers. This is expected to wash across the state through afternoon and reach the east coast a bit stabilized by that point in time due to lower sun angle and no outstanding other parameters at play under a zero convectively inhibited atmosphere south of the Beach Line.  Thus, much of the instability will escape freely into the atmosphere, but what remains appears will be limited to Central Brevard and South to Miami..with a secondary area closer to the secondary trough approaching Eastern North Florida toward Ormond Beach.


A light East Coast Sea breeze has developed and expect it to not get much further west than I-95 today. Otherwise, much is similar to yesterday. Cirrus clouds moved in as expected, but are not nearly as dense as feared they would be, thus the sun is shining about 50/50 across the state.  Some thunderstorms possible near and east of I-95 late afternoon through mid-evening, possibly or mostly occurring just offshore.


THURSDAY: A pre-cold frontal trough will cross the state tomorrow, with another chance of conditions similar to today, although activity might be more showers and starting earlier in the day and maintaining through dark. There might not be a sea breeze tomorrow, and if so, it will remain within 5 miles of the coast.  Much still needs to be determined for tomorrow concerning cloud and shower coverage. If showers hold off until at least mid-afternoon and sunshine can work in, thunder storms could become a bigger reality, but at this point it looks like 'shower mode '.


FRIDAY: The actual cold front , at last, gets here. This is the same front that was generating snow over the Rockies before the Big Rain event even started over Florida. Recall, we were in a Blocking Pattern that prevented the front from continuing to the eastern sea board for several days beyond the norm. The front will cross Central around mid-morning and reach South Florida after or near Sunset. There is not much if any activity associated with it as it seems, primarily because as of the 12z GFS run, it appears that jet stream cirrus might be streaming out ahead of it from the Yucatan region. The front will get about as far south as the previous front, the Florida straits.


SATURDAY/SUNDAY: Not much cold air with this front, with morning lows briefly in the mid-50s inland and remaining in the low 70Fs closer to the coast. Afternoon highs in the low-mid 80Fs (about 2-3 degrees cooler than the past 2 days) is about it. The front will begin to work back north to Central Florida by late Monday, and as such does the rain chance .  Weekend looks worse over all for the Keys and perhaps far south Florida.


MONDAY- EARLY WEDNESDAY:   It appears they front will retrograde  back to Southern Volusia sunrise to sunset of Monday, with rain chances beginning most anywhere south of Volusia County by mid afternoon through dark. The boundary continues north and the remainder of the state gets in on the rain chances heading into Tuesday. 


These days look like a 'mini-event' of what happened the last few days ago, but will behave not at all like it. Not as much wind, but still plenty of rain fall. Flooding might become an issue in those areas that already received too much previously which is pretty much everywhere except a few locations that lucked out with that last event. The bigger problem with the rain will be for those areas that drain poorly and are still water logged. Not looking at big rainfall totals, SO FAR..at least, not as high as the EPIC totals of the previous event. But nonetheless..2" or more is not entirely out of the question, especially near the coast .


THURSDAY: The 36-48 hour event will end with another cold frontal passage. This second front, as noted previously, could become KEY to what the weather over and near Florida will be like by next weekend. The GFS has varied on the southern extent of the boundary, varying from over Cuba to stalling over Central Florida. In turn, that also affects where any possible tropical activity can form in the SouthWest Gulf, across the Yucatan, and into the Caribbean Sea mainly well south and west of Cuba. Simply too soon to say if there will be another Tropical Storm to form, but the GFS is implying it now with every model run (every 6 hours), but varies vastly on where it will form, how strong it will be, and where it will go..anywhere from SW Texas to Off the Florida East Coast. That is a Big IF.