"But seeing they could not See; hearing they could not Hear"
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"From its chamber comes the whirlwind, and cold from the scattering winds." - Job 37:9.

"The wind blows to the south and turns to the north; round and round it goes, ever returning on its course".

Saturday, March 24, 2012

Strong to Near Severe Storms Possible Esp. East Coast

Annotation for the 4pm time frame based on the Rapid Update Cycle (RUC) Weather Forecast Model. This image shows 'precipitable water' (PWAT) air, sum total moisture amount in certain levels of the atmosphere, in brief. The purple shows where it is 'possible' some stronger storms could occur; although, further north central could experience storms a bit further inland from the coasts as well. The 'blue' "Severe?" is a questionable area of interest from Southern Volusia to coastal Central Brevard for sole reason that the North American Model and RUC are showing rather strong upward vertical velocities along I-95 East Central Brevard specifically, as has been the case for 48 hours for the most part in previous runs.
For continuity, this shows the location of the upper level 500mb low today. Recall this low originated toward northern New Mexico several days ago. We can see also the next trough approaching the Western U.S., with a 'ridge' in between the two, much and not unlike two waves on the ocean. Those along the ridge are 'riding high' with nicer weather today in regard to rainfall. This is a forecast valid for 4pm EDT.

TODAY: A frontal boundary mostly defined as far as Florida is concerned by drier air behind it is  well to the north of Central and barely in the Panhandle yet still. This boundary will be across Dead Central around noon time Sunday as it stands now, give or take an hour or two.

Westerly winds today across much of Central and North Florida through noon time. Expecting , as yesterday's post mentioned, that perhaps a side shore up-river wind could develop from South Central toward  Volusia by mid afternoon. Steering for rain to move from today should be generally from the west around 12mph South Central and Central and faster further north toward Ormond and JAX due to closer proximity of the 500mb low shown above.  Vertical Velocity values from the 925mb (2000 ft) up through 700mb (10,000 ft) are coming in very respectable on the latest morning RUC model, as was  mathematically theorized by the NAM for the past two days near Central and parts of Southern North Central, especially near the coast. 

With a side shore wind (if indeed this manifests which is the BIG player today in regard to potential severe weather)  *possibly a bit 'gusty' and only apparent EAST of US1*, storms crossing the rivers from Volusia toward possibly Southern Brevard could acquire some local enhancement as they approach the coast. Temperatures well aloft are more than cold enough to provoke greater upward buoyancy, although surface based convective instability is not overly impressive, although ample.

Else where, some stronger storms due to greater winds aloft are possible toward Ocala, Orlando and north to JAX/GNV as well as south toward Northern Osceola County, into areas around Sanford for example toward Mims/Titusville, Oak hill, Scottsmore, and south perhaps as far south as Cocoa Beach to Satellite Beach. The jury is out regarding further south toward West Palm Beach or toward Martin County, but have not included this area in the graphic due to lack of greater moisture availability for strong storm generation south of Brevard County in this post.

Forecast soundings continue to show temperatures aloft as noted yesterday, and NAM forecasts from overnight indicated a shallow inverted 'V" type which would indicate a potential for Cold air to drop through a shallow dry layer enhancing surface wind gusts. Small hail is possible as well, but 'severe category' hail is unlikely due to lack of greater instability, but it could come close, hence the 'severe' annotation for 1" hail in one storm or two..and stronger wind gusts toward 58 mph... It appears the highest rainfall totals are possible over North Central along and near I-4 and north as well as a bit south. Rainfall totals though are not necessarily equivalent to storm strength, as those areas could be receiving rain prior to the time that the atmosphere could become most unstable. Thus, the greater VVs are further south.

SUNDAY: The "dry front" will be close to Dead Central sometime around 11AM-noon, with a chance of showers any time after midnight along and ahead of it across North Central and Central. The front will then proceed southward during the day with dry air following on NW winds. Clearing from North to South late morning through mid-afternoon.

Chance of Storms on Sunday will be greatest along the East Half of the State from Palm Beach County to Miami, and some of those could be strong as well, especially into Broward, southern Palm Beach County, and Dade..possibly toward Key Largo.

BEYOND: The upper (and mid-level low not shown) will be pulling off to the east, and so far guidance appears to indicate another 850mb trough will swing overhead with greater moisture stacked up along that as well., possibly another very shallow boundary underneath. Winds becoming NE-ENE-E overnight Monday into Tuesday at 12-20mph during the day and perhaps cloudy with a chance of showers some time on Tuesday, ending by the time we wake up Wednesday morning. No rain is foreseen beyond toward next weekend at least...although this time frame needs to remain open-minded for greater scrutiny in the next few model runs.

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