Flash Flood Warning 31, NWS Tallahassee, FL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
355 AM EDT Thu May 29 2014

...A FLASH FLOOD WATCH is in effect for Walton...Holmes...Geneva
and Coffee Counties through this Evening...

.Near Term [Through Today]...

The large scale regional pattern continues to show local area
between upper cutoff low centered over Nrn LA this morning and ridge
over Wrn Atlc. This reflected in area soundings with weak capping
and marginal buoyancy but with deep Sly flow to upper levels and
PWATs around 1 3/4 inches allowing a continued plume of deep
moisture with modest forcing to advect from Gulf waters Nwd over our
area. At 4 AM EDT...Per dual-pol EOX/EVX radar its been raining up
to 3 inches last hour in Okaloosa County and slowly edging towards
Walton County with more than 1 inch in last hour. Based on radar
trend and model guidance, we decided to issue Flash flood watch
until 00z this eve for Walton, Holmes, Geneva and Coffee Counties and
next shift will possibly have to expand watch Ewd.

During the rest of today, upper low will remain quasi-stnry with a
few impulses with PVA rotating ENE across the Gulf region further
eroding downstream ridge. Models show dew points 65 degrees well
inland to low 70s at coast. Weak steering flow will allow early
start of Gulf seabreeze which will be enhanced by passing impulse
and increasing diffluence allowing for somewhat lower H5 temps than
yesterday to generate ample showers and Tstms. Per CAM and HI RES
reflectivity plots, best rain chances will be over the Wrn Panhandle
and Wrn Geneva and Coffee to start the day then over Ern Panhandle
and rest of SE AL mid morning, spreading SW GA and Wrn Big Bend by
midday then Newd with another local max along the I-75 corridor late
aftn into early eve with enhancement from meeting of the Gulf and
Atlantic seabreezes. With light steering flow, locally heavy rains
and flooding remain a concern. Inserted heavy rains in WX GRID for
Wrn CWA.

If all sets up accordingly strong storms with ample lightning, small
hail and gusty winds a good bet with outflow/seabreeze interactions.
And, with just enough low level shear below 20kt H85 Jet...isold
pulse severe storms with wet microburst and damaging wind gusts
looking promising especially if aided by passing impulse and diurnal
heating. Will go with 70-10% SW-NE POP gradient in morning, 50-70%
in aftn with lowest across Cntrl CWA and waters. Temperatures
generally in the upper 80s but will be highly dependent on rain
coverage with lower max temps likely in the Panhandle where
thunderstorms will kick off earlier.

&&

.Aviation...
[Through 06Z Friday]...

MVFR ceilings thru 14Z from TLH westward to DHN with brief IFR
possible towards sunrise. Some MVFR VIS restrictions may be possible
in the pre-dawn hours at ABY, DHN, and VLD. Thunderstorms with heavy
rain will begin to impact ECP and DHN in the morning hours and later
in the afternoon for sites further east and continue thru 02Z at
VLD.

&&

.Prev Discussion [317 AM EDT]...

.Short Term [Tonight Through Saturday]...
The combination of deep moisture with weak southerly flow and weak
upper level forcing aided by an upper level low west of the area
will keep PoPs in the 50-60% range during both Friday and Saturday
afternoon. Although the upper level low will weaken with time, the
atmosphere should still be unstable enough each afternoon with
mesoscale forcing given the sea breeze boundary and any other
leftover boundaries to allow for a decent coverage of convection
across the area. The typical decrease in coverage is expected during
the nighttime hours. Temperatures will be close to their seasonal
averages.

.Long Term [Saturday Night Through Thursday]...
At the start of the period the upper level ridge is located near
the Great Lakes. The ridge will be too far to our north to
suppress afternoon thunderstorms for the weekend. Starting Monday
drier air moves in from the east bringing PoPs down. Temperatures
will be near climatology with highs near 90 and lows in the 60s.

.Marine...
The pressure gradient over the western waters will be a little
tighter today, resulting in southerly winds around 15 knots. High
pressure is then expected to build back over the waters for the
weekend, keeping winds closer to 10 knots.

.Fire Weather...
With a little cooler afternoon temperatures and higher low level
moisture levels through the next few days, relative humidity
levels will stay well above critical thresholds. No fire weather
concerns are anticipated through the middle of the upcoming work
week.

.Hydrology...
Some locally heavy rainfall is possible across the far western
portions of the area today, especially in and near Walton county. A
widespread heavy rain does not look likely at this time, so the
larger rivers are not expected to see any flooding at this time.

&&

.Preliminary Point Temps/PoPs...

Tallahassee   85  67  89  67  90 /  50  30  60  30  50
Panama City   82  71  87  71  88 /  60  40  50  30  50
Dothan        86  68  90  68  93 /  60  30  50  40  50
Albany        89  68  90  68  92 /  50  30  50  40  50
Valdosta      86  66  90  67  90 /  60  40  50  40  50
Cross City    87  67  88  66  89 /  50  30  50  40  50
Apalachicola  82  71  86  69  86 /  40  30  50  20  50

&&

.TAE Watches/Warnings/Advisories...

FL...Flash Flood Watch through this evening for Central Walton-Holmes-
     Inland Walton-South Walton.

GA...None.
AL...Flash Flood Watch through this evening for Coffee-Geneva.

GM...None.

&&

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

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TALLAHASSEE FL
625 AM EDT THU MAY 29 2014

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0615 AM     HEAVY RAIN       1 N FOX HILL            30.84N 86.29W
05/29/2014  M3.05 INCH       WALTON             FL   MESONET

            3.05 INCHES OF RAIN IN 3 HOURS AT WUNDERGROUND SITE
            KFLDEFUN5

&&

DVD