"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".

Friday, August 3, 2012

Interior Strong Thunder Possible, Muggy Messy Weekend

Green shows rain chance zones heading into red, where isolated strong storms are possible due to mid level dry slot preceding a tropical wave (much like a dip before an ocean wave) and cold air aloft along the Lake , east coast sea breeze, and west coast sea breeze meeting places
TODAY: Will not go into extraneously extensive detail as guidance continues to attempt a resolve to what could occur this weekend in regard to a tropical wave and timing of it being realized up the east coast.

In the next image a general idea can be seen of what is going on out and up there this morning. The mid-level trough of the past several days as expected is lifting out as a tropical wave moves in from the SE to replace it. The moisture field associated with the wave is deep, up to 10,000 ft at least, but preceding it is a dry slot in the mid levels although the lower levels remain quite moist as can be felt upon stepping outside. Cold air aloft remains though, so between the colder air, instability, and Lake and Sea breezes coupled with outflow boundaries from showers and eventually storms the saga of rain and showers today could continue well past dark over the interior and toward the west coast as steering is shifting now toward the interior and west side from  the south- south -east to north during the course of the day.

This is for 10,000 feet, with the darkest green being the greatest moisture at that level. It is also deep to the surface in these same locations below in the lower levels of the atmosphere. Note the dry slot though of white. The area WNW-NW toward interior Volusia could see some good rains and west of there, as steering is slow, thus, some big rainfall totals could be realized somewhere today by the time mid-evening comes
Tropical wave seen above over the Bahamas. Without going into great detail there is two options becoming apparent per the NAM and ECMWF. 850mb vorticity (center) is shown consistently to approach Brevard County on Saturday with a closed mid -level low working downward toward the surface but circulation is weak. With cooler air aloft,  for even in rainshowers over the weekend (particularly the first one of the day for any location) winds could be strong in and near them, but once an area is worked over by rain cooled air, that is no longer much of a factor except near the vort max.  The NAM goes too far likely, showing nearly a 'dry eye' center near South Central Brevard by Sunday with rain all around it but not heavy. Point being, winds across the Bahamas may generate a self-induced weak surface low just as westerly winds downstream of the Rocky Mountains create a downstream trough over Kansas and Oklahoma. Timing will become factorless on the rain chances but best chances will be mid-morning through mid-evening Saturday and Sunday, with the greatest chances of rain over the weekend commencing within 3 hours of sunrise and working west across the state. Cloudy and muggy mainly on Saturday and into Sunday, keeping the highs in to the mid 80s on average, but warmer depending on when it rains elsewhere and when or the extent of cloud cover. Winds from the SE by then going into Sunday behind the wave with moisture continuing.

On the other-hand, the GFS refuses to give creedance to any low pressure development by all means, but does imply a mid-level vort lobe. Either way, best rain chances appears over the weekend with partly to mostly cloudy skies, and humid and muggy 24/7.

BEYOND: Continued backwash moisture into Monday, with perhaps another 'wave' of moisture moving in well north of the other tropical disturbance, the 'storm', passing well south of Florida. The extent to which that system wraps up will determine our outcome into mid week weatherwise. The less wrapped up it is, the better chances of rain here will be.  

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