AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
731 AM EDT MON JUL 9 2012
UPDATE...Aviation discussion below for the 12Z TAFs.
NEAR TERM [Through Today]...Primary large scale features across
the CONUS this morning are the amplified RIDGE over the western
states and the broad TROUGH which has settled across the Great
Lakes eastward to New England. Across the southeastern states, a
weakening ridge is in place across the Carolinas south to
northeast Florida, with a weak upper LOW centered over southern
Mississippi. At low levels, the surface ridge axis is situated
just south of the Florida Panhandle and Big Bend.

Through today, this overall pattern is not forecast to change a
whole lot, with generally light southwesterly low-level FLOW
expected across the forecast area. This pattern would typically
foretell an ACTIVE seabreeze day for the Panhandle and Big Bend,
with POPS in the HIGH CHANCE to LIKELY category. However, with the
lingering upper ridge in place and the upper low just a little too
far west to provide much of an increase in deep layer MOISTURE,
expect PoPs to remain below CLIMO for this seabreeze regime. Will
go with 30s and 40s for PoPs, with highest chances along the I-10
corridor from Tallahassee westward.

Temperatures will remain warm, especially over the eastern zones,
which remain more heavily influenced by the upper ridge.


&&

.SHORT TERM [Tonight Through Wednesday]...A couple of factors will
combine to gradually increase PoPs over the next several days. At
the upper levels, the ridge should gradually weaken and slide
east, allowing the weak trough to the west to inch closer to the
forecast area. In addition, a weak inverted trough is forecast to
move into the eastern Gulf by early Tuesday, and introduce some
additional deep moisture. These factors should lead to better RAIN
chances for Tuesday and Wednesday (closer to climo for the low-
level flow regimes). High temperatures should also pull back a FEW
degrees owing to lower heights and additional CLOUD cover.


&&

.LONG TERM [Wednesday NIGHT through next Monday]...
The large scale extended forecast remains relatively consistent
during the last few days. The period begins with ridging over west
half of Conus, very broad MID/upper trough from WRN Great Lakes EWD
into Canadian Maritimes with axis from ERN Great Lakes SWWD across
Wrn Gulf. Looking east, a Bermuda high was noted with axis SWWD
across NE Gulf. The trough continued to become increasingly detached
from the NRN branch of the JET stream. At surface, stalled FRONT
from the Carolinas through CNTRL GA/AL with eroding ridge across NE
Gulf/N FL. All this places local area under deep SLY flow regime.

Beginning on Thurs, trough begins to dig SSW with low developing
across SRN OH Valley by late Thurs night into early Fri. Then,
Bermuda High/Wrn Atlc ridge begins to expand WNW across the region
THRU Mon allowing low to lift NWD then retrograde into the SRN
Plains. At surface, ridge initially breaks down due to trough
strengthening but then AS upper ridge expands WNW, the front begins
to lose its character and surface ridge moves back NWD. Thus local
airmass remains sufficiently moist as deep onshore flow brings a
plume of moisture across local area for much of period leading to
UNSETTLED forecast. Highs PWs combined with slow moving storms and
deep later could lead to locally heavy RAINFALL especially thru SAT.
Deeper later moisture begins to lift further NWD with the ridge
beginning Sat EVE.

Will go with high SCT pops Thurs-Sat AFTN, otherwise low-mid sct Sun
and Mon aftns and each night. With area in warm sector both MIN and
MAX TEMPS will linger at or slightly above climo thru the period.
AVG inland climo is 71/92 degrees.

&&

.AVIATION...
VFR conditions will prevail at the terminals through most of the
forecast period (12Z Tuesday). The only exception will be the
possibility for a brief period of MVFR VISIBILITY at DHN, ABY and
VLD after 09Z. Convective coverage today is not quite high enough to
justify tempo groups in the TAFs. However, 30-40% coverage means
that there will be SCATTERED storms around and pilots should be
prepared for amendments to the forecast. The most likely place to
see storms today will be ECP this morning and DHN this afternoon.

&&

.MARINE...
Light west to southwest winds today and Tuesday will gradually
shift to the south and southeast by the end of the week as a weak
tropical wave moves across the central Gulf of Mexico. No
headlines are anticipated at this time.

&&

.FIRE WEATHER...
A moist onshore flow will keep relative humidities well above
critical levels thru the work week. Thus no red flag concerns are
anticipated.