Area Forecast Discussion
Issued by NWS
FXUS62 KTAE 052047
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
347 PM EST Wed Mar 5 2014
.Near Term [Through Tonight]...
A robust area of convection along a quasi-stationary boundary draped
across the Gulf has not been modeled well. The only models that have
an acceptable representation are the frequently updating hires
models. Even then, most incorrectly place the convection spatially.
This convection will play an important role in the PoP forecast
overnight, especially across the southeast third of our forecast
area. Expect the mid-level warm anomaly generated by the convection
to move northeast away from the convection in the southwesterly flow
regime. As it does so, it will spread an area of mid-level
isentropic ascent (and showers) over the southeast Big Bend. There
is a low layer of dry air that the mid-level showers will have to
fall through, so it is unclear just how much rain will reach the
surface, but it should remain rather light.
On the heels of that disturbance, an area of mid level ascent has
been moving steadily across the northern Gulf today. This area of
ascent/moisture was forced as continued southwesterly flow spread
over cooler mid/upper level air in the wake of last nights/this
mornings disturbance. As this area of ascent moves over the
persistent thermal trough (oriented northeast to southwest across
Georgia and Alabama), the two features will link up and surface
cyclogenesis and low layer isentropic ascent will commence. Expect a
large area of rainfall to spread from southwest to northeast across
the Tri-State region beginning after midnight. Overnight QPF amounts
will likely range from a half inch along the Panhandle coast, to a
quarter of an inch or less further northeast. Overnight lows will
hold steady in the 40s area wide.
.Short Term [Thursday Through Friday Night]...
Primary weather maker for the next couple of days over our area will
be the pronounced upper low now over the srn high plains as it
ejects rapidly enewd across the Gulf of Mexico as an open wave
through Friday. Models have been consistent with this feature and
associated surface low which is expected to develop over the
northeast Gulf and shift along a near stationary front extending
from near Cedar Key towards JAX during the day, keeping our area
is cool, e-ne flow. Rain chances will steadily increase through
the day with categorical PoPs CWA-wide as perhaps several bands
of showers move across the area. Primary area/band of storms
should move enewd through the afternoon with moderate to heavy
rainfall in the stronger cores. Although this activity will remain
elevated atop cool/stable surface air in place, it is not out of
the question for a few rumbles of thunder. However expect most of
the tstm activity will remain over the water or off to our s-se
where modest instability will be in place over the FL peninsula.
Pattern will remain unsettled into Friday as second round of
lighter showers will likely accompany main upper low/mid level trough as
it shifts over the area through Friday morning. Clearing will
shift from west to east across the tri-state region through the
day Friday. Most locations could see 1.5-2 inches of
rain with this event.
All in all expect continued cloudy, wet and cool
conditions for this time of year through Friday morning, with
general clearing and gradual warming as we get into the weekend.
With the clouds, rain and cool air entrenched north of the main
front/low track into Friday, have pushed max Ts down a bit Thu and
Fri with highs well below normal into the weekend. In fact it
would not be surprising if our northern counties fail to get out
of the 40s tomorrow.
.Long Term [Saturday Through Wednesday]...
We should finally see some warming to around normal levels for the
weekend as pattern becomes more zonal. Unsettled weather will
move back into the area by mid week ahead of yet another system.
There remain differences between the operational GFS and Euro
with this next system as the Euro phases with a nrn stream
impulse and GFS does not. However, both bring another shot of rain
during the mid week period. Expect highs to return to the 70s Sat
through mid week.
[Through 18Z Thursday]
KDHN and KECP have scattered to VFR this afternoon, while all other
terminals range from MVFR to the southwest, lowering to IFR further
northeast. Expect ceilings to collapse to IFR at all terminals once
again tonight. Moderate rain will spread from southwest to northeast
beginning after midnight.
Expect moderate east to northeast winds will increase tomorrow to
exercise caution levels as a surface low develops just south of the
area, with an increasing offshore component late Thursday into
Friday as the surface low moves across north FL. Much lower winds
and seas are expected this weekend. Rain chances and possibly an
a few thunderstorms can be expected tomorrow with weather clearing
from west to east through the day Friday.
Red Flag conditions are not expected over the next several days,
though dispersions will remain low through Friday.
We`re expecting 1 to 2 inches of rain from through Friday, with
isolated, locally higher amounts possible. Because these amounts
will be spread out over a few days, the threat of flash flooding
appears low. However, this represents a fairly large volume of
water for our local rivers to absorb, and we expect flow/stage
increases going into next work week. Despite these rises, however,
the latest SREF/GFS/CMC ensemble guidance (MMEFS) continues to
suggest forecast sites will remain below flood stage at this time.
They do, however, forecast several points to be in "action" state
by next week, meaning that some of our rivers could be "primed"
for flooding if we get another round or two of soaking rain
.Preliminary Point Temps/PoPs...
Tallahassee 45 55 42 59 40 / 90 90 70 30 0
Panama City 49 56 45 59 49 / 100 90 70 10 0
Dothan 44 50 39 59 43 / 80 80 70 20 0
Albany 42 48 40 57 40 / 70 90 70 40 0
Valdosta 43 51 41 59 42 / 70 90 70 40 0
Cross City 49 61 48 63 42 / 100 90 60 30 0
Apalachicola 51 59 46 59 48 / 100 90 70 20 0