"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, April 19, 2012

Showers, Isolated Thunder after 5pm Through Mid Evening / Possible Severe Saturday

Forecast GFS Plot for Saturday near sunset. Low in Eastern Gulf, with
possible two warm front like boundaries, and cold front extending south. Purple arrow crosses the cold front and toward South Florida. That indicates strongest jet stream winds. See below for more information

TODAY: Old frontal boundary remains and decays far north Florida as shown below. Although light showers and some thunder are occurring now, it appears the best or potentially most likely time that storms will either increase in number OR in strength will be after 6-7pm toward the interior with a trend toward the east side due to lifted condensation levels dropping off at or near sunset. Often, the magic hour is around 6pm in the summer, so given the time of year 5pm might be closer to transition from showers to more thunder. However, given that the atmosphere is not really all that unstable, the drop off hour might not result in much activity since instability will also drop off with lower sun angle. Otherwise, most areas will be dry tonight across the state..but a 35 -50 % coverage at some point in time when all is said and done might not be too far off the mark. Naturally, the other % wonders what one is talking about as they sit high- and - dry. A storm or two could have stronger wind gusts and a brief spit of tiny hail, but really am not considering the possibility at this time.
Latest satellite presentation on the visible spectrum with comments for rain shower sor  possible "orange thunder"  up until nearly mid-night
FRIDAY: 'Space saver'. More like today with greater likelihood of thunder further south.

SATURDAY: As noted previously, it appeared as of later yesterday the big trough to kick on by over the weekend could drop further south than was being depicted which indeed proved to be a valid assumption . However, the latest GFS of this morning seems to correlate well with the ECMWF now, with the NAM being odd man out by about 75 miles further south (at most). 

Every mile counts though especially when  under the guise of potential severe weather. Without going into great depth, the strongest upper level winds appear will eject around the base of the trough into south Florida and the Keys, but the better wind profiles for rotation will be closer to North Central, with winds becoming more unidirectional (all from the same direction with height) further south. However, there may be more than one ripple  of energy running through the base of the trough, so for now  nearly a state wide chance of strong to severe storms is possible. The GFS implies best chance to severe and possible tornado to be dead Central, with heaviest rains further north.  Image is for 8pm ala GFS mode. Worst weather now appears to occur late morning through sunset on Saturday.

Same Image as a top of blog post for 8pm Saturday night
  SUNDAY: Continued clouds, wrap around rain and possible thunder continues mainly north 1/2 of state until late afternoon, possibly ending sooner. All rains should be over with by sunset or shortly thereafter. NOT a state wide rain day though, so some will not get wet.

BEYOND: Other than maybe one day of brisk onshore winds, high pressure follows low pressure..and dry air ensures. Just take a big BIC eraser across the state and forget about plotting rain on there that is measurable for much of next week the way it is looking now.Cool inland lows most of the week, cooler that recent days...with mainly 60Fs to near 70F some of the coastal areas some of the time prior to and near sunrise. Otherwise, afternoons will be a bit cooler, but nothing to be concerned over. All in all, looks like a nice week ahead going into mid week.

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