"Heavy - Strong Storms' Possible Again Today

 

A Strong Storm Encroaches in on US1 and SR528 In Cocoa Late Monday Afternoon

TODAY: Similar set up to yesterday with little change in the overall synoptic (larger scale) pattern. At the lower levels not much else has changed either, other than the day looks like it will start out not 'quite as cloudy' as it was Monday (given, it is still dark out at the time of writing) based on Infrared Satellite Imagery. Given what occurred yesterday (and continuity) the atmosphere should sufficient de-stabilize with sufficient moisture already now in place to set the stage for another round of heavy storms with gusty winds in the stronger storms - with occasional to frequent lightning at times (perhaps small hail in the strongest cores).

A mid-level trough just to the west of the state combined with a ridge across Far South Florida results in W-SW steering across Central/North Florida. At the immediate surface the wind is forecast to be from due south though a bit more of an easterly component is possible along the immediate coast from US1 and east. All this means that storm motion outside of the effects of outflow boundaries translates to storms moving in from the SSW-W depending on the situation.

The only 'issue' is in regard to timing, with the RAP consistently inferring activity will be 'hitting the coastal regions' between 2-3pm this afternoon, whereas even the RAP derived HRRR does not show this to be the case, nor does the 4KM NAM or the GFS, but rather those models point to the 4-6pm time frame, then lasting (and weakening) as it gets dark going to the mid-evening hours. Will side with continuity, and hence speak 'late afternoon' for the better 'time-frame' for activity. Temperatures aloft are still 'cool' without much to speak of over-head wind-wise - but 25-35kt wind aloft translates to surface gusts in the 40-60mph range related to the strongest of storms . Storm motions might be a bit slower today, so other than wind the bigger 'hazard' would be localized flooding in the prone areas that have already received a healthy dose in the past week.

WEDNESDAY: One more day of the current patter, with again storms favoring the region north of Lake Okeechobee to I4 for greatest coverage , including the immediate east coast. Again, the favored area appears to be near I4 south toward Osceola /Brevard Counties for mid-late afternoon storms to move even more slowly toward the east. 

THURSDAY-FRIDAY: Pattern change. Though steering decreases even more, moisture remains across much of the state. South Florida more likely to get in on the 'action' by this time frame...and timing of rainfall, especially near the East Coast could get tricky. There are 'hints' that come Friday morning (for example ) some areas along the east coast could see showers/storms just offshore that might migrate onto the coast early to mid-morning time frame so will just have to be watching for these subtle changes in upcoming days.

WEEKEND: GFS consistent infers a drying out phase across the state as the high pressure surface ridge lifts north and deeper easterly flow ensures eliminating any chance of sea breeze convergence but for perhaps along the immediate west coast and across the Panhandle region. Beyond the Tuesday time frame there is not enough agreement between models to bother going into - though worth noting the last GFS the came out showed yet another tropical system lifting north toward the northern Gulf Coast region.

Pattern Change Commences! Risk of a Strong Storm Today/Saturday

 

Early Morning Thunderstorm Offshore Canaveral (June 1, 2017) 

TODAY: A long awaited (and monitored) pattern change began yesterday subtly and coming into more full swing today and through the weekend. A strong 'heat ridge' building over the Desert Southwest up into the SW Rockies will continue to build northward and in response a  deepening Trough Aloft will ensue all along the U.S. East coast with Florida near the base of this upper-mid level troughing action.

In response, the high pressure ridge axis that had been 'north' of Florida providing for the on-going onshore (easterly) flow has been shunted southward to south of Central Florida this morning with morning Southwest -West winds now in place (for a change from the easterly winds that had been in place).

This overall scheme will remain in place through the weekend and well into next week. That being  -- the ridge axis at the low levels situated/positioned well south of Central to even South Florida leaving the state in southwest to westerly flow as well as 'storm steering' flow from the 'west' (in general), so any activity that can form over the state will press from west to east during the course of the day. The question will be, 'is there enough moisture to generate storms and if so where will that moisture be?".

TODAY: Though  there 'could' be strong storms today along the east coast, it appears the potential will be limited to a rather small area(if so) where Upward Vertical Velocities (VVs) will be maximized along the predominating westerly flow as it meets an East Coast Sea breeze that is not expected to make a whole lot of leeway inland (not much beyond I-95 or so, today. 

Temperatures aloft today are 'cool' but not overly cold nor is there upper level shear (either directional or speed shear). 

Hence, any 'strong storms' today will be relying on nearly  and exclusively 'Upward Forcing" at the lower to mid-levels in accompaniment with surface based 'Instability' and any low level 'helicity' / localized spiraling actions providing additional upward forcing. 

Over the course of the past 24 hours the 4KM NAM model and now the shorter term RAP model runs are showing localized vorticity and helicity actions up and down the Florida East Coast, especially from near Indian River county northward toward JAX Beach in Northeast Florida once the sea breeze attempts to move in -- in accompaniment with peak instability at prime time (mid-late afternoon) to occur along to east of Brevard County toward southern Volusia Countiesin the same areas.

Though a sea breeze should be able to form today, it won't make a 'whole lot' of inland progress. This 'onshore flow' will advect the greater instability just offshore into and across the coast line accompanied by what might amount to a rather 'side-shore type Sea Breeze' beneath an otherwise prevailing southwest flow resulting in strong convergence along the sea breeze front during the mid-late afternoon hours atop moderate surface based instability. 

First showers to develop won't be much - but outflow boundaries from them as they collapse will add to the development of other activity along the prevailing sea breeze front merges resulting in even greater upward forcing along where low level helicity/vorticity has set up at the Sea breeze front itself. 

Storms that go up along the boundary and are forced eastward will meet these other parameters resulting in at least some good 'lightning' activity today - so 'beach goers and boaters beware!'.

Thus, expect the 'greatest hazard today' might well be but frequent lightning (and maybe some small hail ) and strong (sub-severe) wind gusts.

SATURDAY: The same scenario will be setting up but temperatures aloft will start to cool a bit more as the heat ridge over the Desert Southwest continues to build, and hence the trough along the US East Side deepens.

 A frontal boundary will sink down toward Highway 10 and eventually to somewhere between I-10 and I-4 by Monday/Tuesday providing for even greater moisture and more widespread activity. In any case, Saturday is showing by the NAM to have even stronger storms than today in roughly the same area, but that is yet to be put in 'concrete' and we'll just have to play it on a Day-By-Day basis as situations develop.

SUNDAY and BEYOND: Greater coverage might be expected Sunday-Tuesday with even more strong storms becoming likely to even 'spot/pulse severe' popping up in the headlines for future posts. 

Of course, more specific locations have yet to be, nor can be, determined at this point in time, but suffice it say this pattern change which will last through at least mid-late week next week favoring the interior to east coast for mid-afternoon to early evening storms.  

Also watch for 'early on-set' days ahead, meaning days when storms might form and move into Central/East Florida during the late morning (along the west side of the state) and press eastward - increasing in coverage into the noon to early afternoons time frame. 

Seeing signs now of early-mid morning activities that could commence off the Florida West Coast mainly near to north of Tampa up toward Cedar Key that would form especially along the aforementioned frontal boundary and press eastward along the I4 corridor toward the DAB (Daytona Beach) area first off  ..then spread southward into Central Florida for the mid-late afternoon hours, but again, there is a number of scenarios at hand and possible.

TROPICS: Animation example of activity related to the 

"Central America Gyre' which often produces Tropical Storm Activity into the Gulf of Mexico area in 'June' and again in 'October' time frames.

TROPICS: Deep moisture looms well south of Cuba and across Central America awaiting to be drawn north. Over the course of the past week long range model guidance has continually shown a NAMED STORM system to form in this area of what would be the 'Central America Gyre" but it has all been in the 'long range' time frame and keeps getting pushed out in time - the location too of a named system lifting north has varied from anywhere from the Brownsville, Texas area to as far east as Central Florida and then everywhere else in between. 

Suffice it say however, that should a storm system lift northward even well west of Florida it appears that deeper atmospheric moisture through the upward column could eventually find it's way into Florida. 

Oft times such moisture if TOO MUCH of a 'good thing' offsets storm activity resulting in more of a cloud cover situation rather than heavy storms/rainfall which the 'official forecasts' inevitably will predict. 

Regardless, this pattern change we will be experiencing TODAY and through the weekend and into next week is bringing on a change the state has not seen since early-mid summer last year.