AREA FORECAST DISCUSSION…updated for aviation/long term sections
NATIONAL WEATHER SERVICE TALLAHASSEE FL
616 AM EDT MON Aug 13 2012

.NEAR TERM…[THRU TODAY]
A stationary FRONT stretched from the Florida panhandle coastal
waters to just south of Tallahassee and then northeast across SE
Georgia. A much drier airmass has filtered into the region behind
the front. DEW points have dropped into the lower to MID 60s just
north of our CWA AS of 06z. Will show only slight POPS for today
south of the CURRENT placement of the front with the exception of
Dixie county where PoPs are at 30%. With the drier airmass and
increased INSOLATION, MAX TEMPS today will REACH” onClick=”return popup(this, ‘notes’)”>REACH the mid 90s at
most inland locations.

&&

.SHORT TERM…[TONIGHT THRU WEDNESDAY]
The MEAN upper TROUGH across the eastern CONUS will become more
amplified as a SHORTWAVE drops into the southeastern states tonight
into Tuesday. This will help push the next cold front into the
southeastern states. The front is forecast to enter our forecast
area either Tuesday NIGHT or Wednesday as additional shortwave
energy further amplifies the trough. Deep layer MOISTURE makes a
quick return to our region with PW`s increasing to around 2 inches
by tuesday afternoon and remaining at these levels through
Wednesday. Will adjust PoPs up to CHANCE/good chance category all
zones for both Tuesday and Wednesday. Max temps will be at or just
above seasonal levels.

&&

.LONG TERM [Wednesday Night through Monday]…
The large scale longwave pattern commences with a trough over NRN
Plains and another broad ERN LOW AMPLITUDE trough with axis down Ern
seaboard and the WRN extension of the Bermuda RIDGE across SE
region. At the surface, main features are the axis of the surface
ridge extending from the WRN Atlc to across the CNTRL Gulf and a
low off the New England coast with cold front extending S then SW
across Cntrl GA. This will keep onshore FLOW and abundant low
level moisture in place.

During the rest of the period, models in good agreement with upper
features. ERN trough moves offshore allowing for brief semi-zonal
flow but by Fri UPSTREAM trough amplifies and digs SEWD with axis
into ERN Gulf. Wavy troughiness and will exist over local region
into weekend while impulses help to drive a front SEWD thru at least
SAT. At surface, models diverge but in better agreement than 24hrs
ago. As the upper trough digs, GFS lifts ridge axis NWD and develops
an area of low PRESSURE in the WRN Gulf and steers it and deeper
tropical moisture with locally heavy RAINFALL NEWD toward the FL
Panhandle during weekend. Conversely, ECMWF shifts ridge axis SWD,
and shows no such Gulf low development. But both models now show
upper flow at base of trough largely parallel to front on Sun and
stalls front just north of CWA keeping CWA in warm sector.

Will go with daytime POPs of low-mid SCT on Thurs increasing to mid
sct then HIGH sct Fri and Sat down to low-mid sct Sun and low sct on
Mon. Generally WDLY sct-low sct pops at night. This could be higher
especially if GFS turns out to verify. With local area in the warm
CLOUDY sector, MIN temps will persist at 2 to 4 degrees above CLIMO
and max temps around climo thru the period. (AVG inland Min/Max is
70/91 degrees).

&&

.AVIATION [Through 12z Tuesday]…
With drier AIR moving in, mainly VFR conditions are expected to
prevail except for predawn hours. MVFR vsbys in areas along and
ahead of the front mainly at VLD thru 13z. CONVECTION is expected to
be quite limited today and too low to include in TAFS. Onshore winds
5 to 10 mph will decrease to CALM after sundown. MVFR vsbys LIKELY
and mainly AL/GA terminals 09z-12z Tues.

&&

.MARINE…
The subtropical ridge is forecast to remain south of the waters
through much of next week. This will keep light west to southwest
flow and minimal SEAS in place over the coastal waters outside of
convection.

&&

.FIRE WEATHER…
Although, the airmass will continue to dry out today and inland
Florida relative humidities may drop to below 35 percent for one or
two hours, DISPERSION and ERC values will be below critical levels.
The airmass will begin to moisten up again on Tuesday and there are
no red flag concerns thru the upcoming work week.