"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".

Monday, September 19, 2011

Slow Transition to Moisture Laden Southeast Flow Emerging Through Wednesday

A slightly better chance of thunderstorms today toward Ocala and interior Volusia/Flagler and in the Gainesville area. Also along the SW Coast. Coast showers could re-appear within 1 hour of sunset (very isolated) along the Central to Southeast Coast...more numerous the NE Coast toward JAX and SE Georgia.

TODAY: Not much change in the line of thinking from yesterday's post. An inverted trough has appeared, temporarily as almost a very weak close surface low over Brevard County. This feature will move inland with the sea breeze and daytime heating as a weakly defined, inverted thermal trough to act as a focal point for more thunderstorms than the past few days over the interior (which isn't saying much). Lightning was observed near noon time in North Brevard as the showers, moving generally toward the NNW moved inland from Central Brevard.  There is a small chance of an isolated shower or two re-appearing within one hour of sunset along the beaches most anywhere while the activity over the interior should dwindle rapidly after sunset. Northeast Florida seems the most likely candidate for that early evening activity, although one or two is possible Central.

TUESDAY: Another slice and dice day of where/when the renegade showers will occur. Most likely before 11AM along the east coast, progressing into the interior by shortly after noontime and re-emerging as thunderstorms from early afternoon, and peaking in strength between 4:30-7pm. in other words, much like today.

WEDNESDAY and Beyond: The NAM has been consistent (for a change) at showing a region of higher moisture (PWAT) air over the SW Atlantic to progress WNW toward Florida during the course of the next 48 hours. For two consecutive runs one can actually trace the rain field areas it depicts approaching systematically toward the east coast of Florida for arrival by late Wednesday afternoon. The GFS is far less as obvious, but both do show a broader coverage of atmospheric moisture for a greater coverage of showers and some thunderstorms, but by no means will every one be seeing rain. All in all, it might seem more like a typical summer day albeit just a tad cooler by a few degrees. Favoring the west side late in the day for the heavier storm activity. Thursday looks similar.

Elsewhere, during the next few days a frontal boundary will be inching eastward toward the State. It is moving at such a snail's pace as it rams into the ridge running down the Appalachians as noted in the image above (with yet more in the Atlantic)..that it can barely reach Central Florida before being stretched thin (Saturday/Sunday time frame).  For comparison's sake, were this a 'normal' frontal boundary in mid-winter it would be through the state by Tuesday night from its current location, which is  down the Mississippi River Valley area.  It still appears the boundary will make it to Central Florida or thereabouts, and be able not to progress much further. That is at the surface. Just above the surface the upper level supporting trough lags well if to emphasize this is not a 'big temperature dropper', but rather a focal point for showers/thunder.

Beyond Saturday we are already into the time frame of greater unreliability and tremendous variations from run to run, although the GFS has been fairly consistent in having this boundary merge with a broad area of low pressure over the Caribbean.  In fact, the morning run now cuts the remaining frontal boundary off into a close surface to upper level low pressure area encompassing most all of Florida by the middle portions of next week. This is highly unlikely as well as any other extended outlook has and ever will be. But the implications, or rather, the tendency for this model to want to evolve into some sort of transformation of low pressure areas off and on again for over a week near or over Florida in the extended can't be completely ignored. There is a brief drying period during the transformation, but the gist has been that no big temperature dropping frontal systems appears yet to be fully in the making for a big cool off for anywhere beyond the Panhandle and Northern portions of the state into October. That too, could change. But not within the next week when fall begins on September 22nd at 5:05AM. Last year, our first fall like day arrived almost simultaneously with the passage of Tropical Storm Nicole (September 31st). From October 1st and beyond, summer or any semblance of summer ceased to exist.

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