UPDATE: Slight interesting change required for this morning's post. These changes follow at the end so as to preserve the original thinking. Please see the UPDATE at the end. Original post: The word for the day seems to be "mum" around the offices today. And no wonder, the models are all over the place, so save yourself the time of looking and wait until 11AM to start viewing the latest runs. Although it will be entertaining to see the differences between 00z and the new 12z just for kicks. It's amazing how each run or even the short term RUC varies with every successive output. I should know, I've been up ALL night to watch meteors...
The Problem: How far south and how strong will the surface and upper level trough axises be this afternoon. That's it in a nut shell. Where exactly will they be - or in some cases, IF they will be -- puts steering currents, moisture at various levels, instability or lack there of, all over the boards. At least on this blog all info is unofficial and my job isn't on the line (although my reputation is..and actually, I care more about that). So for now it's what I call the "take your initial gut feeling and run with it because you can be more realistic by 1pm" forecast.
Initial Forecast: This morning the surface front/trough lies on a line running from Cross City to Jacksonville then right along the east US coast to N. Carolina and beyond with high pressure behind it centered essentially over Nashville, TN. The trough will move very little today and gradually weaken during the course of the next 36 hours. CLOSE inspection of the vapor loop reveals a defined mid-level circulation centered over Tampa as of 8:30am which seems to be inching at a snail's pace toward the NE. The upper level trough is deepening into the N. GOM just south of Pensacola and seems to have no inclination to stop digging.
So what?: What this means is that East Central Florida may very well be in the frontal/ascent region (rising air) of the upper level trough. Moisture is coming in both from the SE and SW. And we have a kicker in place (the circulation over Tampa). The latest sounding as of 3 hours ago shows a sudden jump in moisture which coincides nicely with all the aforementioned..to a level that is higher than it ever was yesterday with actually a respectable cooling at 500mb from the past couple of days (and that's all within the past 6 hours). So it seems the wheels are in motion for good rain/storm coverage today. The fly in the ointment is that the RUC wants to blow all this out of the water at the most critical time of the day (around 2pm) surface to mid-level winds wise. For now, that is being disregarded.
This is what: Not unlike other days, there will be some initial development of cumulus and perhaps a good rain shower close/over the rivers in the 10:30am - 12pm time frame. These may actually move little or even drift NE-NNE ward. Then there should be a break in the early afternoon with spotty showers and storms developing across the entire peninsula between 1-3pm and increasing in coverage until dark. Highest coverage will be over the central part of the state due to (1) that region being under the ascent (2) moisture convergence (3) the circulation now over Tampa passing within the proximity.
There could be some prolific lightning makers today as well and some strong downdrafts especially if the moisture levels increase more and the temperature aloft cools a smidgen more, both of which is what appears to be in progress as I type. Motion will be based more upon boundaries collisions and propagation more than anything else (what can we expect, it's August in Florida...and the Panhandle doesn't count) but general motion will be toward the ENE-NE. Expect the main show to occur earlier than yesterday around 4-5pm with the Gulf Coast Breeze making further penetration eastward today no matter what transpires. Stuff made it as far east yesterday as the Brevard/Osceola County line and I see no reason why it won't make it to at least US1 today. Activity shouldn't have a problem exiting the immediate coast from N. Brevard and points north...whereas from Vero Beach South the main show might be over right as things get cranking on a Vero - Yeehaw Junction Line and points north.
UPDATE: Only changes are (1): the noon sounding is yet even more unstable, more moist, and cooler aloft as was the forecast presumption this morning, thus storms this afternoon could be quite vigorous. I plan on eyeing The Great Outdoors - Fish Camp - Kenansville zone, but might need to be advised that the additional surge during collisions might force things further east than seems feasible at this time, thus I'll be on the alert to not stray too far out of position for a race back to the coast. And (2)the little spiral over Tampa seems to be dropping SIGNIFICANTLY to the SSW and is now W. of Key West and still dropping. This may have a big impact on tonights or tomorrow mornings model runs, but it seems at this time that no matter what happens the results will be generally the same. Tropical wave to approach S. Florida by early Saturday morning and exit the area by very early Sunday. Impact on East Central Florida will be greater the further south one gets..but even still it should only mean in increased chance of rain showers and clouds. Saturday could pan out to be a very nice day further north than Ft. Pierce. Friday looks much more like Wednesday was all over again with slightly greater coverage.