First Hurricane of 2011, Serene Irene - Showers/Thunder Mainly North Central Today

This charts shows Precipitable Water in the atmosphere. Over South Florida it is lowest..but not all that low. The moisture there is mostly contained within the cumulus cloud level...same with the I-10 Corridor.
You will see in the next image a strange 'anomaly' from the Norm.

TODAY: Interesting day can POTENTIALLY be in store.  A 700mb trough axis is expected to stroll into Central Florida on its last and most southern gasp today. Moisture is expected to pool along that boundary atop a  potentially relative very unstable low level atmosphere. Winds all the way up to heaven are less than 10mph and less than 5mph below 10,000 ft everywhere..so steering is non-existent. Believe, therefore, showers/thunder will first be promoted right as or before the weak sea breeze forms in the orange shaded area very close to along the 'magic dividing line' of North vs. South Central Florida...roughly from Cape Canaveral to North Tampa Bay. Thunder is questionable though without boundary mergers before 3 or 4pm.  


Light stirring currents at the low levels over the Merritt island Wildlife Refuge conflicting with each other and a developing sea breeze (or prior on the north side) could promote good rain shower upward lift underneath upper level divergence.  There are two negatives though. Moisture at cumulus cloud top height should be greater and I don't know how long the upper level divergence will remain in place.

In this image, I've written that divergence might increase as the trough at 700mb (about 10,000ft up) bottoms out There is already some deep layer moisture convergence going on over Central Brevard into Osceola County based on another plot I just looked at. But who knows just how deep......Could we end up with an axis of showers and maybe thunder all the way out to sea by early afternoon along the 700mb trough axis..OR..just a cloud deck!!? Given the high instability shown..I ran with the showers theory..but could be wrong easily.

SOUTH HALF OF STATE: Very little moisture above cumulus cloud level and has been decreasing since early morning. It is interesting that the GFS brings more in..but I see it no where on ACTUALS..at least note through early afternoon. Thus, expecting mostly quick showers along either coast and near the Lake along the Lake Breeze.  Thunder could occur along the sea/lake breeze merger in Martin/St. Lucie County area though and maybe toward the SW Coast later today if more moisture works in as depicted by the GFS.


NORTH HALF: Most unstable atmosphere today over all of North Central Florida. There is forecast to be an interesting moisture gradient in the mid-levels just south of the Magic Dividing Line almost all day. In fact, very little is to change today other than the south and far north drying out aloft and sea breezes forming during the mid-afternoon hours. Before then, they should cling to the coast and be quite light.


Very 'huggy' today on the intracoastals. Warm, Muggy, humid, and close, with heat indices in the 105 -112F range. This leaves this area for thunderstorms. Believe the sea breeze collision will occur toward the interior of the state..and some could roll off shore or to the shore as far south as North Merritt Island toward dusk if not later (other than earlier activity potential)..but outside of boundaries forcing such motion...most should be along and west of US1 except for in Volusia and North Brevard over the Intracoastal.


 It is with that activity that a waterspout could form given such a subtle nature like none I've seen this year aloft to the wind fields at literally every altitude prior to and during the sea breeze front development. If so, the most likely area would be near Pads A/B, the Refuge, and surrounding areas toward Canaveral Air Force station (less likely though). and perhaps near Daytona Beach. This is under the assumption that showers can form though first off. That mid level moisture might end up being a cloud deck instead to OFFSET showers rather than abet them. So, we'll see what surmounts to probably nothing. Just wanted to throw that in for good measure.


Thunder is most likely late today as the sea breezes and rain shower outflows merge..since the outflows could have a good push to them given that there is no conflict winds of substantial velocity to negate any forward motion of created OFBs (outflow boundaries).  Storms could continue until after dark toward Orlando in any area not already worked over...OR..where a shower occurs early and can recover its instability during the mid afternoon.


TOMORROW: Haven't really looked heavily into tomorrow, but from what I saw earlier and last night...it will be a similar scenario since the 700mb trough is expected to pull out during that time. South Florida should see some increasing moisture too by then, but we'll jump that hurdle when we come to it. In any case, there is nothing expected to occur that would prompt greater urgency than what is happening in the tropics.


TROPICS: Hurricane Irene was proclaimed this morning. I'm expecting it will oscillate between Hurricane and Storm until it reaches the Coast of the Dominican Republic then Cuba (if it does get there) at which point I'm thinking it will go back to storm..it all depends on how close it traverses to the northern coast..or for that matter..over it or inland from it..in which case it would go back to Storm.  


The model guidance since late yesterday has been in very close agreement with its future course..although not being exact (as would be expected further out in time)..they remain clustered tightly. Thus, we should be able to rely closely on the weighted mean average of the forecast tracks...which has been portrayed by the Official Hurricane Tracking, Watch, and Warning Center in Miami.  


Presented below is the latest as of 9:15AM this morning. What this exactly  shows will be described in the following paragraphs below, as well as future implications-- and naturally, assumptions (both pro and con) for the weather wary or weary traveler or homesteader.

WHAT HAVE WE HERE?

Description:
1. Orange is dry air. The storm is near the center...brown circles show vorticity (wind energy) along the SOUTH side of the storm..Thus, it is not in the dry air...which is the SAL that had been in place for quite a while. It looks like the dry air is trying to wrap around the storm...but will it? If so, and that dry air gets entrained (pulled into) the system..it would weaken, especially since it is approaching more land. Thus, do not expect any more strengthening, or if so..only minor strengthening with the land near by.


2. The Solid White line is the official Forecast Track. At time, it approaches the Florida East coast where you will see all those other colored lines. Those lines represent forecast tracks from Consensus / Ensemble models as well as the main squeeze dynamical models. 


The latter want to take the storm further offshore from the coast. The eventual track hinges on the strength of low and high pressure to the north and east of the system. I see why the models want to relax the eastern push at this time. However, is it simply momentary with respect to the bigger picture in time? Say..by this time tomorrow? In other words, based on last nights projections and those of over night/morning..we could pretty likely see a hurricane within that broader cone of error within the outer yellow lines. Bear in mind, the easterly more side of the cone where the lines merge the most has been favored now since yesterday..and given the pattern we have been in for a month now...don't see that changing anytime soon.


3. Again the brown lines. It looks like the air from which the storm might be deriving some of its energy is moist..not dry, air..no reds or oranges. So perhaps it can hold its own...ALL depending on the track the storm takes in relation to the hilly land mass..but the most tall hills and mountains are over Haiti and Central...it all plays out to all things equal.


4. Finally, what happens once the storm clears the landmasses of the DR and Cuba is anyone's guess. Please refer to the Hurricane Center for the latest guidance and read word for word the "Discussion" Link after clicking on the little Irene Icon on the start page.  In a nut shell, I will say this. The center wrote this morning that they are playing the storm strength on the conservative side...in their forecast of sustained winds of 100-110 mph as the storm approaches the coast of West Palm Beach (but off shore).


They  are  also tackling the issue of the track at that point in time down the road..as well as if the storm stays further from shore..the possibility that Irene could become a major hurricane. Believe that would not occur until it gets north of Ft. Pierce if it t'were to be..but who knows. It strengthen TWICE now more than expected..so who's to say anything other than..be on alert.


5. Listen to advisories..but for the latest..watch the web...


SCENARIO: If the forecast goes EXACTLY as planned at this moment up through the next 60 hours...believe evacuations will be in order up and down the A1A Corridor from Miami to  Canaveral...as a precaution. I won't go into possible ramifications under certain scenarios at this point since it would be pure 'alarmist mode rhetoric' . But, do consider the provided list of yesterday once again.


Other suggestions: Keep gas tank full as of at least tonight. 


Have plastic zip lock bags on hand to store documents or jewelry. 


Ensure medications are in supply enough to last through September 5th at least...and consider having empty containers to store water.


These can be put in the freezer, so that if there is a prolonged power outage its contents can hold longer, and as it melts it also serves as drinking water. 


In case I forget and something more threatening looms...fill the tub with water. This can be used to flush the toilet in case the plumbing goes out (namely for the barrier islands).


It's a worn out cliche..."STAY TUNED"..rather "STAY ATTUNED" seriously to official outlets. I've said my peace already twice here...it's all up to the reader to play it smart and thrifty, or to live on the edge of stupidity ..especially if nothing changes by this time Wednesday.


Final note: It was written this storm could become a major hurricane. If so, the first most likely case for that to be true would be if it stays further from the coast. Bear in mind, so far it is expected to encompass a very large area within 72 hours and beyond due to the fact that outflow all around the system looks very good. In which case, were a major hurricane to take shape and be further offshore, the shear size could come close to outweighing the further distance from the coast in regard to winds along A1A at least. It would be better though from this perspective in regard to any storm surge threat up intracoastals or at the coast is concerned.