"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".

Thursday, February 23, 2012

Warm, Breezy, Chance of Showers (Thunder?) North Central

Note annotations: This pre-sunrise satellite image (infrared) shows few clouds this morning. Ironically, the COOLEST temperatures this morning are found over SOUTH FLORIDA, in a very stable atmosphere with weak   to calm winds in that area. Stirring of the atmosphere further north is keeping temperatures  in the upper 60Fs with a few low 70Fs north. Green and orange show where it 'could' briefly shower or even thunder after noon - 5pm.
TODAY: Low pressure crossing the Tennessee River Valley region (in general terms) will continue moving off toward the E-ENE today . Despite its far distance from Florida, the pressure gradient at the low levels associated with its distant passage combined with high pressure to the south of the state will increase the winds toward the 1-10 corridor. Upper level as well as mid-level winds remain strong, and these will be able to translate to the surface with daytime heating and colder air aloft associated with those winds to a smaller portion over direct Central. The greatest atmospheric moisture to work with today at all levels is centered across the state along I-4 toward Central as well (SR 528).

SW winds are already in place prior to sunrise, and expect that with sunshine (heating) they will increase in the 20-29mph range (in gusts) along the water ways. Coolest temperatures as a result will be found along the outer barrier islands of Brevard and Volusia down stream of this wind due to the projection of surface wind blowing across cooler waters of the rivers (which are most wide in this area). Regardless, we can still see some highs Central and South toward 78F (barriers) toward the low and maybe mid-80Fs (South Central / South interiors toward the east side of the state).

There is very little in triggering mechanisms or boundaries to set storm or shower activity off as of this morning, but instability is already in place along with very respectable bulk of speed shear between atmospheric levels. This shows up nicely on all model guidance as well as Melbourne's Local Data Integration System (LDIS). Sufficient instability and this bulk speed shear coupled with a marginal amount of directional shear (which could act as triggering mechanism in the presence of ample moisture and lift with daytime heating), could set off some showers or even thunder, closer toward I-4 in particular.  This area will need to be watched, just in case, for surprises as was noted yesterday, although none has been depicted or strongly anticipated as of this hour.


Yesterday evenings activity propagated southward even though activity was moving west to east. This propagation was likely caused by leading outflow from previous activity meeting unsettled atmospheric conditions under less cloudy sky conditions not directly downstream of upper level winds.

FRIDAY: Atmospheric moisture will be pulling out later today, thus ending the rain chance altogether. As noted yesterday, Friday appears to be the most warm day of all (especially the south half of the state). No rain chance and continued breezy, with a frontal boundary approaching the panhandle early on. This boundary, although timing remains a bit flaky, I still expect will have very little impact on the state south of I-4. Regardless, it does appear that it will cross Central near Midnight Friday night, accompanied by continued breezy WNW winds becoming N during the day Saturday. Cloudy conditions possible on Friday, especially later on in the day toward evening Central.

SATURDAY: With frontal passage over night Friday a brief course of cold air advection follows. Highs on Saturday not likely to breach the lower to mid-60Fs Central and north, warmer South. Winds becoming ENE after midnight Saturday night. Little temperature changes very close to the coast overnight, so that Sunday may dawn with a low in the lower 60Fs east of US1 many locales.

SUNDAY: Frontal boundary will be stretched out across the Florida Straits. Meanwhile, recall the upper low south of California in previous posts?  This appears still to fill as a mere trough and then be carried eastward by the jet stream winds toward and across the Southern Tier of States .  The net affect will be to lift moisture associated with the frontal boundary northward in a buckling type fashion . Thus, on Sunday it will likely become partly to mostly cloudy with a chance of some showers later in the day as this moisture lifts north and winds become E-ESE.

THROUGH TUESDAY: Shower chances and most cloudy skies at times. Location of showers is not discernible due to the fact that there is not focus or apparent triggers with great certainty. Although, a vorticity max is being indicated to cross the peninsula "somewhere" later on Monday. This all in prelude to the next typed front to enter the picture toward mid-late week. Thus, it could be a bit cloudy and a little cooler through Wednesday or Thursday with highs in the lower 70Fs and lows in the 60Fs with cloudiness over night precluding lower temperatures (acting as a blanket).    

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