"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".

Wednesday, July 7, 2010

Retrogression To Yield Rain Chance Progression

(Image: Very typical view one would expect to see any given summer day..but not today)
Strong high pressure over the Mid-Atlantic region is the key player today for most if not all of the eastern U.S. seaboard, resulting in continued very hot conditions for our friends in the NE U.S....shifting south toward the mid-Atlantic states in coming days.

Accompanying the high pressure system in the broad scheme of things is a low pressure system WSW of Bermuda. This system has been retrograding toward the WSW-SW during the past few days and will continue to do so through Thursday. Meanwhile, a large low pressure system revolves up by James Bay with an accompanying trough of low pressure to begin developing down into the Great Lakes and eventually into the northeast states in coming days. The retrograding low in the Atlantic will eventually approach the N. Carolina coast as we work into Friday and merge with the developing low pressure trough from Canada as the nuisance high pressure system plaguing the N.E. U.S. weakens slightly and retrogrades toward the Mid-West states as we look toward the weekend.

Closer to home, it appears that a weak inverted trough near the surface is lined up right along Florida's east coast this morning. There was a small pocket of mid-level moisture accompanying this trough and as a result some very small rain showers eked on-shore just north of West Palm Beach during the early morning hours but are rapidly diminishing. KSC sounding came in very dry for this time of year at 1.35"...with an easterly flow from the surface as high up in the atmosphere as heaven. Hark the herald angels sing.

TODAY: As was briefly mentioned yesterday, it still appears we could get a 'wind surge' of sorts in the mid-levels by mid-afternoon which will likely not manifest itself to the casual observer at all...but could be accompanied aloft by a patch of thin clouds and maybe some distant light rain showers well off shore in the Atlantic which radar might or might not even pick up (if that even happens). It will be a dry day though and sunny for the most part and pretty much entirely. Actually, it looks like about the only place in the state that could get any truly measurable rain will be along Florida's Southwest Coast maybe as far north as Sarasota. Temperatures along the coast will run in the upper 80s and inland in the low-mid 90s.

THURSDAY/FRIDAY: Slow transitioning period. About the only highlight for this period will be warmer temperatures by a few degrees, particularly inland...with highs running in the upper side of the mid-90s. During this time, particularly Friday, the retrograding low which will be near the N. Carolina coast by later Friday will be merging with a low pressure trough extending from Canada. The two will work in tandem and force the high pressure that has been over this same area lately to re-evolve/retrograde further west. Thus, the heat in the N.E. states will finally dissipate. At the surface, a weak frontal boundary will be entering the Southeast states (but much further north of Florida). A very small rain chance enters the picture for Friday during this evolution of events...mainly for the inland areas.

SATURDAY/SUNDAY: Back to normal. Rain chances increase to the 40-50 percent range (at least that's what we'll probably be hearing through the media)....but most of that chance will be away from the coastal least initially. Particularly on Sunday a combination of a high pressure ridge axis extending east/west across south Florida and the approaching but waning frontal boundary could actually provide folks east of U.S. 1 with a chance of thunderstorms as well.

MONDAY-WEDNESDAY: High pressure ridge axis directly overhead (Central Florida) with a weak flow/moist environment pattern in other words, a typical summer pattern both in thunderstorm activity and temperatures.

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