Area Forecast Discussion
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461
FXUS62 KTAE 121023
AFDTAE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
623 AM EDT Sat Apr 12 2014

.Aviation...
[Through 12z Monday] VFR conditions will prevail today with winds
generally SE near or below 10 kt this afternoon and mostly clear
skies expected across our region.

&&

.Prev Discussion [357 AM EDT]...

.Near Term [Through Today]...
A surface ridge of high pressure will remain in place today, keeping
conditions mild and pleasant. Afternoon highs are expected to top
out in the lower to middle 80s away from the immediate beaches this
afternoon. A sea breeze is expected this afternoon given the cool
shelf waters and land temps in the 80s, keeping the beaches a bit
cooler.


.Short Term [Tonight Through Monday]...
Tonight...a large scale pattern change begins with increasing
amplification and marked by a positively tilted trough over Wrn
states and weak ridging over Ern states with very weak gradient over
Gulf region. At surface...persistent high off Carolina Coast with a
ridge Swwd across Gulf region. This translates to generally onshore
flow sfc-H7 with WLY above aloft. Increasing low level moisture
brings area PWATS up to around 0.9 inches and provide a favorable
environment for at least patchy fog and lower ceilings. This will
maintain inland lows in the mid 50s.

Sunday and Sunday night...Patchy fog should linger past sunrise. The
longwave pattern will undergo further amplification/strengthening
as Ern ridge pushed offshore in response to Wrn trough deepening
Ewd. Broad cyclonic flow evolves across Cntrl Conus with multiple
shortwaves serving to deepen trough thru the night. This generates
cyclogenesis over the Plains with cold front extending Swd from LWR
MS Valley into TX by sundown weakening and shunting SE ridge back
into Atlc. Area soundings show that mid/upper flow backs to SWLY
while lower level Sly flow strengthens. Rainfall should hold off
until Monday except for possibly small chance of rain Wrn/SE
counties towards sunrise. With local area in warm sector ahead of
next system... expect inland highs from 81 NW to 85 east. Very mild
lows around 60 with a good chance of fog/or low clouds developing
after midnight.

Monday...Longwave trough deepens as it pivots ewd. Closed low forms
over Srn Hudson bay and vigorous shortwave moves across SE region.
Assocd surface low moves from Plains to NE region with cold front
approaching Wrn counties by sundown. Ahead of cold front...guidance
implies that a line of convection will develop which would precede
front and move across during the day. PWATS increase to about 1.5
inches with local gradient further tightening for fast SW steering
flow. At this time...models differ so confidence of chances of
timing and possibility of severe as well as max temps not high. GFS
noticeably faster and somewhat weaker. If ECMWF verifies then
chances for strong to severe weather increase. Forecast will split
the difference. Expect highs from near 80 N to 84 SE. 60-30%
NW-SE POP shwrs/tstms gradient. Will keep out any enhanced wording
for now.


.Long Term [Monday Night Through Friday]...
Guidance is in general agreement with a trough developing over the
central portion of the country early next week. However, there are
still timing/strength difference in the handling of the two main
shortwaves that will be responsible for generating the trough. The
GFS is a little weaker and keeps the best instability and shear out
of phase through Tuesday, resulting in a lesser severe threat. The
00z ECMWF was a little more bullish on the potential for strong to
severe storms. Regardless of the severe threat, it does appear that
another round of significant rainfall will impact the region into
Tuesday.

Thereafter, the pattern is forecast to become a bit less
progressive, with a ridge building off the east coast and surface
high pressure nosing down the eastern seaboard. This will result in
a more easterly to northeasterly flow pattern, and the potential for a
few showers to move back into the region late in the work week.


.Marine...
Benign conditions will persist through tonight as high pressure
remains in place. By late Sunday into Monday onshore winds and waves
will begin increasing ahead of our next weather system. Another
round of showers and thunderstorms are expected ahead and along
a cold front expected to cross late Monday. In its wake...advisory
level offshore winds and seas are expected Tuesday night into
Wednesday.


.Fire Weather...
Low level moisture will continue to slowly increase through the
weekend with RH values remaining above critical levels. Dispersion
values greater than 75 are possible across portions of the area this
afternoon, mainly west of a Tallahassee to Albany line away from the
coast. Dispersions near 75 are possible again on Sunday afternoon.


.Hydrology...
Most rivers have reached their peak and should begin to fall. The
only exceptions should the Choctawhatchee River at Bruce and
Ochlockonee River at Havana. A new flood warning was also issued
for the Withlacoochee at Valdosta. The next chance of rainfall is
on Monday into Tuesday. The system currently appears progressive
enough to prevent excessive rainfall, but rainfall amounts may be
enough to temporarily halt some of the river falls.

The most up to date, specific river forecast information can be
found on the AHPS page at
http:/water.weather.gov/ahps2/index.php?wfo=tae.

&&

.Preliminary Point Temps/PoPs...

Tallahassee   83  56  83  61  82 /   0   0   0  10  40
Panama City   78  63  76  65  76 /   0   0   0  10  50
Dothan        82  57  83  61  79 /   0   0   0  10  60
Albany        84  56  83  61  80 /   0   0   0  10  60
Valdosta      85  55  84  61  82 /   0   0   0  10  40
Cross City    85  55  83  61  82 /   0   0  10  20  30
Apalachicola  77  64  74  65  76 /   0   0   0  10  40

&&

.TAE Watches/Warnings/Advisories...

FL...None.
GA...None.
AL...None.
GM...None.

&&

$$

NEAR TERM...DVD
SHORT TERM...BLOCK
LONG TERM...CAMP
AVIATION...DVD
MARINE...BLOCK
FIRE WEATHER...DVD
HYDROLOGY...BLOCK






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