"But seeing they could not See; hearing they could not Hear"
“The views expressed herein are those of the author and do not necessarily represent those of the National Weather Service or affiliate/related organizations. Please consult .gov sites for official information”

"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, November 23, 2011

Several Weather Changes Next 7 Days - Gentle Intro to Winter

In blue are generalized cool front locations as noted in the time-phased image shown. Coverage of showers at any one time will not be extensive and will be mostly associated with the front itself upon approach and passage

TODAY: Cool front across the Panhandle to make slow progress into Central Florida from early afternoon through sunset. A prefrontal trough associated with the radar echoes shown in the image above  is damping out, as such are the showers. Increasing cloud coverage to spread across Central (some already in place), with breaks in the clouds to allow highs today to reach the upper 70Fs to around 80F or so. Warmest S. Florida by a few degrees , not significantly so. Using a combination of morning RUC and NAM, the RUC appears a little fast. Likewise, perhaps the NAM is too slow. In combination, it appears another diurnal pre-frontal trough will form across the CDL (Central Diving Line) Zone this afternoon with daytime heating and hold tight, allowing the cold front itself to play 'catch-up". This will for whatever can be mustered up with cloud breaks as the front progresses only slowly SE ward from North Florida to provide a focus for rain to happen chance.

Suspect much of North Central will be stabilized/hampered by greater cloud coverage from the pre-existing trough that is moving out this morning, and so rain there should be limited to sprinkles and a few spits. Further south toward Dead CDL, cloud coverage will be less extensive. West winds all day, possibly becoming WNW behind a pre-frontal trough North Central (and prior to the actual front).  Winds from surface to well aloft will be mostly unidirectional (from the same direction) with height, and instability will be severely hampered by cloud cover and be mostly surface based due to mulit-layered clouds. Thus, the better chances of rain today/tonight appears will occur along and south of the secondary pre-frontal trough from Brevard County, possibly part of Orange/Seminole and south toward Miami (with time overnight as the front moves in that direction).  If there is to be any thunder at all, it should be elevated type harboring mostly incloud or cloud to cloud lightning, but not feeling very strong on any of said activity. If so, Brevard to Martin County within 20 miles of the coast.

The image above shows general locations will the front should be today through early Thursday. It currently appears that a "diurnal frontal stall cycle' will occur near I-4 to Dead Central during the mid-late afternoon, with no clear delineation as to exactly where the front is located until after dark once that cycle is complete. From that aspect, the front will be free to plow through toward the Straits by sunrise if not before.  Best chance of showers appears to be when convergence/low level winds sync with the time phased diurnal cycle combined with the fronts location near Central as high pressure builds east across the Deep South region toward Georgia. This puts the best covergence/abrupt wind shift on the east side of the state toward Southern Volusia / Brevard region around 8pm as the front will be close to there.  All in all, most people today will not receive rain under partly to mostly cloudy skies and west to West Southwest winds around 10-18mph this afternoon. At some points (or points), skies will be cloudy, but for residents across South Central and South that will occur after sunset.

TONIGHT/THANKSGIVING DAY: Front to press south and be followed by a NNE-NE wind by sunrise most locations (after veering overnight from the NW).  Sunrise should yield a Thanksgiving Day with lows in the lower 60Fs and 50Fs north Florida, warming to the mid-upper 60Fs toward Central and upper 60Fs to lower 70Fs South Central to South. Cool and breezy day with winds from the NE at 15-22mph, gusts toward 28mph. Looks like possible Lake Wind Advisory conditions and Small Craft Advisories might be required. Stratocumulus clouds, but not extensive to follow by mid-late afternoon. Not all that much warming during the day, perhaps up it about 5 degrees from morning lows as already modified cool air advection sweeps across the state from off the Atlantic.  In short, breezy and cool with some clouds. For Friday, NAM continues with bringing in rain showers most of the east coast by morning or shortly thereafter with a nearly saturated atmosphere from the surface to 5000 ft. This seems like 'overplay", and if even so, having a hard time rationalizing anything but more clouds as opposed to showers.

BEYOND: Next front to impact the state beginning Sunday through Monday. Rainfall appears will be more likely most areas with this front, only 4 days later. But hold on, yet another front could follow in due time within another 3-4 days if not less. This next front could manifest anything from widespread showers to isolated thunder, maybe even severe. If so (the latter), it would most likely be for the North Half of the state. Good wind shear but meager  thermal instability being the ever present liability as we approach the last quarter of the year, aka Winter.

As noted yesterday, much cooler from Tuesday and through the first week of December, except maybe for a day or two before the second front comes in to re-enforce Winter's Urgent Calling Card. So far, it doesn't appear it will be extremely cold, just very cool to almost cold (in the mornings) for a prolonged period. Slow and easy...  for easier adjustment without a profound shock to the system.

No comments: