AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
835 PM EST Thu Dec 22 2011


SHORT TERMĀ  (Friday through Saturday NIGHT)...
There is likely to be a band of showers at the beginning of the
period (Friday morning) that will slowly sink south across the area.
This should be the remnants of the showers and thunderstorms that
will be ongoing along and behind the surface cold front this
afternoon and tonight. This front will slowly stall out and lose its
character. The fast-moving shortwave trough associated with the
frontal system today will be moving off to the northeast, with the
overall upper level FLOW pattern rather unchanged (large RIDGE over
the Caribbean, Bahamas and south Florida, and WSW flow aloft).
Therefore, there should be very little upper level support to get
the front much past our forecast area. As NVA sets in aloft and
mid-upper level heights rise slightly into Saturday, the rain
showers should gradually diminish. By Saturday we should have partly
CLOUDY skies with a drier period, before the next shortwave ejects
to the east. To sum it up, tomorrow should be relatively cloudy with
some periodic light showers, followed by drying Friday Night and a
dry and pleasant forecast for Saturday. With no major model
differences of note, a broad consensus was used. No THUNDER was
included in the sensible weather as model forecast instability is
either non-existent or below 100 j/kg.

.LONG TERM (Sunday through next Thursday)...
The large scale longwave pattern commences rather amplified
highlighted by ridging over WRN states...large positively tilted
trough across much of rest of country with axis from Great Lakes
SWWD into Old MEX with nearly CUTOFF low over SW most TX/Old Mex
border, and a strong H5 ridge over S FL with an ANTICYCLONE
centered over the Bahamas. Impulses assocd with low will lift and
move rapidly into NRN stream trough across Great Lakes and combine
with shortwave diving from Canada into East Coast to begin to
deepen NE trough and suppress FL ridge SEWD. At surface, low over
Nrn GA with warm front EWD into Atlc and trailing cold front
across Wrn CWA. Local forecast area remains under an ACTIVE SWLY
flow aloft, as well as a broad warm sector with SLY low level flow
ahead of front with OVERRUNNING rain behind locally yielding a
continuation of ample MOISTURE return and beneficial mainly
STRATUS precip and embedded showers to begin the period. Also with
DEW points into the mid 60s and a slow moving front, the strong
possibly of FOG exists especially at night. With DEEPENING ERN
trough, Front will finally move THRU in fits and starts during
Sunday but will have no upper support and so no threat for strong
to severe storms.

However, forecast remains tricky as models continue to diverge on
timing of impulses and how fast to bring front across so which model
wins out will noticeably impact POPS/TEMPS. Beginning Monday, the
GFS much more bullish on drying us. ECMWF much slower with frontal
passage and keeping post frontal moisture around so overall
confidence past Sunday remains not HIGH until I see better model
agreement. Best forecast is that the TX upper cutoff low will
continue to lift NEWD, fill and open into a wave with flow across SE
region becoming more zonal. However, the above Canadian shortwave
with phase with one moving across Gulf to further carve out a trough
along the NE Coast especially if ECMWF verifies. Either way, in WAKE
of front, brief drying commencing on Monday from NW-SE. However, yet
another albeit weak shortwave tracks ewd across mainly FL zones and
coastal waters on Tuesday and brings a small CHANCE of rain. Then, a
large area of CP high PRESSURE builds SWD thru the Plains and into
SE states promoting STABLE conditions, a drier airmass and cooler
temperatures for remainder of period.

Will go mid SCT pops SAT night thru Sun. low sct FL zones on Tues,
otherwise WDLY sct or below rest of period. In warm sector...MIN
temps remain around 5 to 10 degrees above CLIMO thru at least Sat
night dropping to slightly above climo rest of period. MAX temps
will hover around climo Sun-Tues than increase to up to 5 degrees
above climo Wed and Thurs. AVG inland min/max temps around 40/63
degrees).