Severe Thunderstorm Warning 71, NWS Tallahassee, FL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
251 AM EDT Sun Mar 24 2013

...Squall Line will likely generate Severe thunderstorms and locally
heavy rain through this morning...

.Mesoscale Update... With our 00 UTC sounding at TAE showing such a
strong saturated inversion between 987 and 968 mb with both temps
and dewpoints rising from 59 to 64 degrees, it was becoming very
difficult to discern whether we would be able to break through the
inversion to mix the instability down to the SFC if and when the
expected squall line developed and approached from the west. In
fact, this temperature inversion continued up to 67 degrees at 925
mb (though not saturated with a dewpoint of 61). Therefore, with so
much uncertainty, and still a solid severe weather potential
indicated in the hi-res models (combined with the very steep
mid-level lapse rates), we coordinated with SPC and NCEP to launch a
06 UTC special sounding. Based on some of the preliminary data, we
have made quite a bit of progress in eroding this inversion. It is
still present between the Sfc and 946 mb, but is now only 3 degrees
(64 T and Td at the Sfc to 67 at the top of the inversion. With it
quickly eroding above that level, chances now appear quite good
that the strong instability will indeed mix down to the Sfc out
ahead of the squall line. In fact, as of 200 am EDT, the initial
parcel from our sounding launch point has already reached T=67,
Td=67, and both continue to rise at steady rate as the Sfc Low off
to our west continues to deepen.

With the 06 UTC TAE sounding now complete, modified the Sfc Parcel
to the expected High of T=85, Td=68, to get a PWAT= 1.54", an LI=
-7.4, a CAPE= 2577 J/KG, a wet bulb zero height of 10819 ft below a
FZL of 14019 ft, and a whopping 627 m^2/s^2 0-3 km Helicity! If
these and other significant Severe Weather parameters in this
sounding are reached or approached with the squall line or any
discrete supercells, ALL modes of Severe Weather will clearly be
possible!

&&

.NEAR TERM [Today]...
Severe storms are expected to develop later this morning with the
severe threat initially over the FL Panhandle zones shifting to our
FL Big Bend and GA zones after sunrise. As mentioned above, we do
expect storms will get rooted in the boundary layer. Mid level lapse
rates will steepen to about 7.5 deg/km. Shear will also increase
with 0-6 km bulk shear increasing to 55-60 kt and CAPE surging to
1500-2000 J/kg. All modes of severe weather will be possible with
this round of convection, including hail, severe wind gusts and
tornadoes. Local confidence grids had severe probs up around 20%
with tornado probs at 5%. These are both impressive. We expect the
convection to push east of the area by around 18Z. However, the cold
front will trail behind enough to allow temps to soar into the mid
80s. This should be the warmest day we have seen since November 3.
It will also be a breezy afternoon with frequent gusts up around 30
mph.

&&

.SHORT TERM [Tonight Through Tuesday]...
Upper trough over Ern Conus will gradually deamplify and move Ewd
thru the period. Assocd H5 low will move from WV ewd into Atlc by
sunrise Monday. This will leave a very tight nearly zonal flow
over SE region. At surface, low invcnty of Mid-Atlc coast at 12z
Mon will exit the coast early Mon. In its wake, a large ridge with
an unseasonably cold/dry dome of high pressure will move from the
Plains towards the Ms River Valley on Monday and approach local
region on Tuesday. So, in the wake of cold front a much cooler and
drier airmass will filter in. Expect breezy and gusty conditions
thru the period.

With clearing skies, temps Sun night will drop to around 40 SE AL to
near 50 SE Big Bend. Despite full sunshine, Monday's highs will be
about 20 degrees cooler than Sunday's, near 60 SE AL to mid 60s SE
Big Bend. Under increasing cold air advection, min temps Monday
night will drop into the mid 30s. Highs on Tuesday drop to the upper
50s SE AL to low 60s SE Big Bend.

&&

.LONG TERM [Tuesday Night through Friday]...
The extended period will be dry with below seasonal temperatures
through Thursday night. High temperatures will range from
the upper 50s northern zones to lower 60s across north Florida on
Wednesday. Max temps moderate to the mid to upper 60s Thursday and
around 70 to the lower 70s on Friday. A widespread light freeze is
possible Tuesday night. Min temps will be in the mid to upper 30s
Wednesday night and then around 40 Thursday night.

&&

.AVIATION...
[through 06Z Monday] LIFR to VLIFR conditions will continue this
morning north of the warm front with intermittent light showers in
the warm advection regime. Convection is expected to fire after 09Z
and some of the storms will be severe. The best window for
thunderstorms at the TAF sites is 10-16Z. During that time, ceilings
could improve to MVFR. After the convection ends, the primary impact
will be westerly winds that will frequently gust to around 25 knots.
Skies will clear in the evening, but winds will remain gusty as they
veer to the northwest.

&&

.MARINE...
Dense fog expected overnight early this morning especially ern
waters. Onshore flow will increase through today along an
approaching squall line and parent cold front. Small Craft
Advisory winds and seas are expected. Strong offshore flow will
develop later today from W-E in the wake of a cold front with
advisory conditions persisting at least across the offshore
segments through Monday evening before subsiding.

&&

.FIRE WEATHER...
Drier air will arrive behind a cold front with minimum RH of 20-25%
on Monday. Winds will also remain elevated and it appears likely
that our Southeast AL zones will meet their red flag criteria. A
watch will be issued. It will be nearly as dry on Tuesday, but winds
will be lower and red flag criteria are unlikely to be met on that
day.

&&

.HYDROLOGY...
Latest radar estimates and local obs show that widespread 2 to 3
inches have fallen south of I-10 in N FL and adjacent GA with
lesser amounts elsewhere across the local area. An additional 1 to
2 inches is possible thru Sunday morning if squall sets up just
right. Because this event is expected to be of relatively short
duration (about 24 hours) and current rather high flash flood
guidance, widespread flooding is not anticipated with this system.
However, localized flooding in the usual flood prone areas is
possible.

Additionally, widespread rainfall of this amount will likely push
several area rivers back to action stage with a few of the faster
responding basins potentially reaching minor flood stage by early
next week. This includes the Sopchoppy River 13.98 feet forecast to
rise to 25.97 feet at 1am Mon. Two rivers are forecast to rise to
minor flooding stage. They are the Aucilla at Lamont, 8.23 feet
forecast to rise to 10 feet at 1am Tues, and the Withlacoochee River
at Valdosta, 9.36 feet forecast to rise to 13.7 feet at 1 am Mon.

&&

.PRELIMINARY POINT TEMPS/POPS...
Tallahassee   85  43  64  35  62 / 70  10   0   0  10
Panama City   77  47  65  41  59 / 50  10   0   0  10
Dothan        80  41  61  34  59 / 50  10   0   0  10
Albany        81  42  61  33  58 / 70  10   0   0  10
Valdosta      82  45  63  34  61 / 80  10   0   0  10
Cross City    80  49  64  36  63 / 80  10   0   0  10
Apalachicola  78  48  64  43  59 / 60  10   0   0  10

&&

.TAE WATCHES/WARNINGS/ADVISORIES...
FL...HIGH RIP CURRENT RISK Walton...Bay and Western Gulf counties
     through early Monday.
GA...None.
AL...FIRE WEATHER WATCH from Monday afternoon through Monday
     evening for Coffee-Dale-Geneva-Henry-Houston.
GM...DENSE FOG ADVISORY until 10 AM EDT this morning for the
     eastern waters.
     SMALL CRAFT ADVISORY until 8 PM EDT Monday for all waters.

&&

NEAR TERM/AVIATION/FIRE WX...WOOL
LONG TERM...BARRY
MARINE/SHORT TERM/HYDROLOGY...BLOCK
MESOSCALE...GOULD

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TALLAHASSEE FL
348 AM EDT SUN MAR 24 2013

ALZ065>069-FLZ007>019-026>029-034-108-112-114-115-118-127-128-134-
GAZ120>131-142>148-155>161-GMZ730-750-755-765-770-775-250900-
COFFEE-DALE-HENRY-GENEVA-HOUSTON-INLAND WALTON-CENTRAL WALTON-
HOLMES-WASHINGTON-JACKSON-INLAND BAY-CALHOUN-INLAND GULF-
INLAND FRANKLIN-GADSDEN-LEON-INLAND JEFFERSON-MADISON-LIBERTY-
INLAND WAKULLA-INLAND TAYLOR-LAFAYETTE-INLAND DIXIE-SOUTH WALTON-
COASTAL BAY-COASTAL GULF-COASTAL FRANKLIN-COASTAL JEFFERSON-
COASTAL WAKULLA-COASTAL TAYLOR-COASTAL DIXIE-QUITMAN-CLAY-
RANDOLPH-TERRELL-DOUGHERTY-LEE-WORTH-TURNER-TIFT-BEN HILL-IRWIN-
EARLY-MILLER-BAKER-MITCHELL-COLQUITT-COOK-BERRIEN-SEMINOLE-
DECATUR-GRADY-THOMAS-BROOKS-LOWNDES-LANIER-
APALACHEE BAY OR COASTAL WATERS FROM KEATON BEACH TO OCHLOCKONEE
RIVER FL OUT TO 20 NM-
COASTAL WATERS FROM APALACHICOLA TO DESTIN FL OUT 20 NM-
COASTAL WATERS FROM  OCHLOCKONEE RIVER TO APALACHICOLA FL OUT TO
20 NM-
COASTAL WATERS FROM  SUWANNEE RIVER TO KEATON BEACH OUT 20 NM-
WATERS FROM APALACHICOLA TO DESTIN FL FROM 20 TO 60 NM-
WATERS FROM  SUWANNEE RIVER TO APALACHICOLA FL FROM 20 TO 60 NM-
348 AM EDT SUN MAR 24 2013 /248 AM CDT SUN MAR 24 2013/

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST ALABAMA...
SOUTHWEST AND SOUTH CENTRAL GEORGIA...THE FLORIDA BIG BEND AND
PANHANDLE...AND THE ADJACENT GULF COASTAL WATERS.

.DAY ONE...TODAY AND TONIGHT...
SEVERE STORMS ARE EXPECTED TODAY ACROSS MUCH OF THE REGION AND
CONVECTIVE WATCHES ARE ANTICIPATED. LARGE HAIL...DAMAGING STRAIGHT
LINE WINDS AND TORNADOES WILL ALL BE POSSIBLE. THE SEVERE WEATHER
THREAT WILL PEAK DURING THE MORNING AND BE OVER BY EARLY
AFTERNOON. WIDESPREAD FLOODING IS NOT FORECAST. HOWEVER...PONDING
OF WATER IN POOR DRAINAGE AREAS WILL BE POSSIBLE...ESPECIALLY OVER
SOUTH CENTRAL GEORGIA AND THE EASTERN FLORIDA BIG BEND. WINDS AND
SEAS OVER THE MARINE AREA WILL BE AT SMALL CRAFT ADVISORY LEVELS
THROUGH TONIGHT. THERE IS ALSO A HIGH RISK FOR RIP CURRENTS AT
AREA BEACHES.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY...
THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. WINDS AND
SEAS WILL REMAIN AT ADVISORY LEVELS ACROSS THE NORTHEAST GULF
THROUGH MONDAY WITH CAUTIONARY CONDITIONS LINGERING UNTIL TUESDAY
NIGHT. A LIGHT FREEZE WILL BE POSSIBLE WEDNESDAY MORNING ACROSS
INLAND LOCATIONS.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION IS REQUESTED.

FOR ADDITIONAL INFORMATION...VISIT THE NATIONAL WEATHER SERVICE
WEBSITE ON THE INTERNET AT WEATHER.GOV...THEN CLICK ON YOUR AREA
OF INTEREST ON THE NATIONAL MAP.

18-WOOL

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TALLAHASSEE FL
724 AM EDT SUN MAR 24 2013

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

0710 AM     TSTM WND DMG     PRINCES STILL           30.80N 84.25W
03/24/2013                   GRADY              GA   911 CALL CENTER

            MULTIPLE TREES DOWN IN GRADY COUNTY.

&&

WALSH/EVANS

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TALLAHASSEE FL
812 AM EDT SUN MAR 24 2013

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

0750 AM     TSTM WND DMG     2 NNW TALLAHASSEE       30.46N 84.29W
03/24/2013                   LEON               FL   TRAINED SPOTTER

            PINE TREE BLOWN ONTO TRUCK.

&&

CAMP

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TALLAHASSEE FL
851 AM EDT SUN MAR 24 2013

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

0720 AM     TSTM WND DMG     2 E BLOXHAM             30.39N 84.60W
03/24/2013                   LEON               FL   LAW ENFORCEMENT

            TREE BLOCKING BLOXHAM CUTOFF. TIME ESTIMATED BY RADAR.

&&

CAMP

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TALLAHASSEE FL
852 AM EDT SUN MAR 24 2013

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

0826 AM     TSTM WND DMG     BOSTON                  30.79N 83.79W
03/24/2013                   THOMAS             GA   AMATEUR RADIO

            PINE TREE DOWN AND BLOCKING OUTSIDE, EASTBOUND LANE OF
            US84 1/4 MILE WEST OF HALLMAN ROAD.

&&

JSE

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TALLAHASSEE FL
853 AM EDT SUN MAR 24 2013

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

0750 AM     TSTM WND DMG     3 NNW TALLAHASSEE       30.48N 84.31W
03/24/2013                   LEON               FL   LAW ENFORCEMENT

            TREES BLOCKING EASTBOUND LANES OF I10 AT MILE MARKER 199.
            TIME ESTIMATED FROM RADAR.

&&

CAMP

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TALLAHASSEE FL
909 AM EDT SUN MAR 24 2013

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

0826 AM     HEAVY RAIN       BOSTON                  30.79N 83.79W
03/24/2013  M4.47 INCH       THOMAS             GA   AMATEUR RADIO

            STORM TOTAL RAINFALL IN PAST 24-30 HRS.

&&

JSE