"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".

Sunday, July 22, 2012

Unusually Warm This Morning, Storms and Shower Issue at Hand

Water Vapor Image showing moisture at mostly mid-upper levels.
The more color, the deeper the moisture.
Highlights on animation show what appears to be a vorticity max or upper level low like feature near Lake Okeechobee lifting slowly northward (the red "V"). Ridge axis (blue) to move little today ,if not strengthen in positioning. Note 'speed max' lower right.  
TODAY: Will quickly compare model guidance for reasons that will become apparent further on in this quip. The North American Model (NAM) and short term Rapid Refresh (RAP/RR) are showing zero rain today except along the west coast mainly. On quite the contrary, the GFS is holding fast to several runs prior with deep moisture reaching as far north as the secondary ridge axis shown in the image above by the small blue 'zig zag'  across far Southern Volusia County. It has depicted this scenario consistently, then again, the NAM has depicted the zero rain scenario consistently as well. 

The Storm Prediction Center and the MLB NWS are in agreement closer to the GFS (and possibly the Euro which I do not have access to) which would favor thunder and showers south of the northern most orange line, or mostly from near Melbourne and South across the state. For now, will side with this line of reasoning given the swirl evident near the Big Lake lifting north. It appears the NAM and RAP are looking at warm upper-level temperatures capping off rising motions (as opposed to cold air aloft), thus preventing rain storms and thunder from forming. In short, we are at the mercy of which witch is which, so in playing the 'Wild Card Shrug' will side in agreement although this in my mind is questionable. There is no doubt the west side will see activity later today, it is the east 3/4 of the state that is questionable. When will we know to go from Two Pair and play a potential full house? Apparently not until after noon time when the tables turn and supposedly the cooler air moves in. But better yet, in about an hour or so morning sounding data will be coming in to reveal the true nature of the atmosphere in place over the state 'aloft'. Unfortunately, we still do not know what conditions reside out over the Atlantic and Bahamas (which is upstream for the state in the current flow pattern).

Otherwise, it is very warm prior to sunrise with 80F on the porch and 81F at Melbourne, and warmer readings further South. St Pete is reading 81F with a dewpoint of 80F which is close to morning readings of "insane' on the thermometer/dewpoint scale if there were such a scale to read . Guidance is showing high instability already in place to persist all day long , with values of Convective Available Potential Energy (CAPE) already akin to late afternoon values, unusually so. Not surprisingly then, it is very humid at this hour since CAPE includes the low level moisture (dewpoint) variable from the equation from which the value is derived.
Big Thunder activity north of Cuba moving WNW

Later today, the GFS has been consistent on picking out a mid-to lower level wind speed max rounding the base of the Atlantic High Pressure Bubble (the axis shown by jagged blue above) with the arrows shown in the first image in the lower right toward the state. These winds will advect straight off the north Bahamas toward Central Brevard shortly after sunset, thus there is a chance that some showers or even thunder could move ashore into Brevard after 9pm tonight for a time due helicity curls off the islands. Whether they will make it onshore (as well as the exact positioning of those winds tonight ) will determine if in fact rain is realized toward the Cape Canaveral area.

MONDAY/TUESDAY: Given the already major question, "Exactly where is the best moisture heading this morning?"!   means as well, "Where will it then be early in the week as well?". Point in case, if the GFS is correct , better rain chances most areas on Monday with the offices showing a 60-70% rain chance, whereas the NAM with its output showing ZERO rain chance! :-0  (aghast emoticon exclamation). Will stick with the GFS at this early hour, meaning much better rain chances with thunder Monday. The ridge axis shown in the first image is then to drop South to the south end of Lake Okeechobee overnight Monday night with a flip flop in low level winds and steering currents from WSW or SW toward the ENE-NE. The moisture bubble gets trapped over Central and North Florida resulting in isolated thunderstorms forming mid afternoon through early evening which would be able to move off the east coast north of Ft Pierce or Vero Beach (more likely) while The Far South remains mostly dry.

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