NATIONAL WEATHER SERVICE TALLAHASSEE FL
355 AM EDT Thu May 29 2014
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 a 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
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.
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
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.
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.
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.
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.
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
FL...Flash Flood Watch through this evening for Central Walton-Holmes- Inland Walton-South Walton.
AL...Flash Flood Watch through this evening for Coffee-Geneva.