Severe Thunderstorm Warning 19, NWS Tallahassee, FL

Area Forecast Discussion
National Weather Service Tallahassee FL
112 PM EDT Tue Mar 20 2018

.AVIATION [Through 18Z Wednesday]...

VFR conditions will prevail through the period at our TAF sites,
though IFR cigs will remain in place near 40J/CTY for the next few
hours with thunderstorms in that area. Winds are still out of the
southwest ahead of the cold front at ECP/TLH/ABY/VLD, with more
westerly winds already at DHN. Gusts of 20-30 kts are expected
this afternoon and again Wednesday.

&&

.PREV DISCUSSION [1230 PM EDT]...

.NEAR TERM [Through Today]...

A cold front is moving eastward toward our northwestern areas,
currently stretching from far southern MS through east central AL
with a 997 mb surface low residing near Atlanta. A cluster of strong
to severe thunderstorms continues to track eastward just to the
southeast of the low pressure center from eastern AL into central
GA, but only a few light showers are present farther south along the
front. Despite a nearly saturated boundary layer with dewpoints from
the mid 60s to lower 70s across our area and ample instability (up
to 1500-2500 SBCAPE), very dry air is present from 700-500 mb across
much of our area along with some surface-based CIN, which is
currently preventing showers and thunderstorms from developing
across our area.

As the front moves eastward across our area during the morning and
early afternoon, remaining CIN is projected to erode and some
scattered showers and thunderstorms will develop along/southeast of
the front. The aforementioned CAPE values around 2000 J/kg combined
with very strong effective bulk shear up to 50-60 kts will maintain
favorable conditions for supercells; however, persistent dry air at
mid levels may continue to suppress convection for most of our area.
Latest CAM guidance only shows scattered light-moderate showers from
now through 15Z, but does sFhow the potential for a few stronger
cells across the FL Big Bend (mainly south and/or east of
Tallahassee) during the late morning and early afternoon. All severe
hazards are possible if thunderstorms develop in this environment.
Chances of showers and thunderstorms will end across most of our
area by the afternoon, although the southeastern FL Big Bend could
still see scattered strong/severe thunderstorms at this time near
the front. High temperatures will range from near 70 in our
northwestern areas to upper 70s/lower 80s in our eastern areas.

.SHORT TERM [Tonight Through Thursday]...

By this evening, the cold front will be off to the east of the
region, but with a strong pressure gradient, expect gusty WNW
winds to continue for a couple of hours after sunset before
diminishing. With strong cold advection, overnight lows will dip
into the low to mid 40s.

On Wednesday, another breezy day is expected under sunny skies.
Temperatures will struggle to warm above the mid to upper 60s,
which is a few degrees below normal for this time of year. High
pressure by Wednesday night will still be sufficiently far back to
the NW that winds should prevent temperatures from dropping too
low as some of the coldest guidance suggests. Nevertheless, while
lows should generally be in the lower 40s, a few sites may drop
into the upper 30s.

By Thursday afternoon, high pressure will settle over the region
with winds becoming light and cold advection ending. Temperatures
will warm into the upper 60s to lower 70s with another sunny day.

.LONG TERM [Thursday Night Through Tuesday]...

After a cool start on Friday in the lower 40s, temperatures will
begin a warming trend that will continue on through the weekend.
Dry conditions are expected through at least Sunday. By Sunday
night, a backdoor cold front will approach our NE zones and
depending on the set of guidance, may even pass through much of
the forecast area on Monday, however confidence in this portion of
the forecast is quite low. For now have followed persistence from
the last few model cycles, which showed the cold front passing
through some of our NW zones and then stalling. Only a slight
chance of rain accompanies this front on Monday.

.MARINE...

Hazardous marine conditions are expected beginning today and
continuing through Wednesday. Winds will increase rapidly today
behind a cold front. Winds to gale force, mainly in gusts, are
expected over the marine area this afternoon and evening. Then, an
extended period of advisory level winds and seas will continue
through Wednesday night. Thereafter, high pressure builds over the
marine area as light winds and generally low seas returns.

.FIRE WEATHER...

Dispersion values could reach 100 this afternoon and Wednesday
afternoon as strong northwesterly winds develop behind a cold front.
RH values will not reach critical thresholds today, but will likely
dip to 25-30 percent on Wednesday afternoon. Due to recent rains,
however, it may be difficult to reach ERC thresholds in FL, fuel
moisture in GA, and KBDI criteria in AL. As a result, red flag
conditions may not be met on Wednesday despite meeting RH and wind
criteria.

.HYDROLOGY...

In North Florida, generally 2 to 4 inches of rain occurred with
this recent storm system, though locally heavier totals near 6 to
7 inches were seen in portions of the Southeast Florida Big Bend.
Lighter amounts were common in Southwest Georgia and Southeast
Alabama.

This rainfall has resulted in some notable rises on area rivers in
North Florida, though with many starting this event so low,
flooding is not anticipated at most river points. The Steinhatchee
River bears watching over the next 36-48 hours. Significant rains
in Southeast Lafayette County have led to sharp rises on the
river at US-19, which may approach minor flood stage late Tuesday
night and into Wednesday.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is requested. Spotters should safely report
significant weather conditions and/or damage by calling the office or
tweeting us @NWSTallahassee.

&&

.PRELIMINARY POINT TEMPS/POPS...

Tallahassee   44  70  39  69  40 /   0   0   0   0   0
Panama City   49  68  45  68  47 /   0   0   0   0   0
Dothan        42  66  39  65  42 /   0   0   0   0   0
Albany        43  66  37  64  41 /   0   0   0   0   0
Valdosta      45  67  39  67  39 /   0   0   0   0   0
Cross City    45  70  36  69  37 /   0   0   0   0   0
Apalachicola  49  69  44  68  47 /   0   0   0   0   0

&&

.TAE WATCHES/WARNINGS/ADVISORIES...
FL...Wind Advisory until 11 PM EDT /10 PM CDT/ this evening for
     Calhoun-Central Walton-Coastal Bay-Coastal Dixie-Coastal
     Franklin-Coastal Gulf-Coastal Jefferson-Coastal Taylor-
     Coastal Wakulla-Gadsden-Holmes-Inland Bay-Inland Dixie-
     Inland Franklin-Inland Gulf-Inland Jefferson-Inland Taylor-
     Inland Wakulla-Jackson-Lafayette-Leon-Liberty-Madison-North
     Walton-South Walton-Washington.

     High Rip Current Risk through late tonight for Coastal Bay-
     Coastal Franklin-Coastal Gulf-South Walton.

     High Surf Advisory until 8 AM EDT /7 AM CDT/ Wednesday for
     Coastal Bay-Coastal Gulf.

GA...Wind Advisory until 11 PM EDT this evening for Baker-Ben Hill-
     Berrien-Brooks-Calhoun-Clay-Colquitt-Cook-Decatur-Dougherty-
     Early-Grady-Irwin-Lanier-Lee-Lowndes-Miller-Mitchell-
     Quitman-Randolph-Seminole-Terrell-Thomas-Tift-Turner-Worth.

AL...Wind Advisory until 10 PM CDT this evening for Coffee-Dale-
     Geneva-Henry-Houston.

GM...Small Craft Advisory until 2 PM EDT this afternoon for Apalachee
     Bay or Coastal Waters From Keaton Beach to Ochlockonee
     River FL out to 20 Nm-Coastal Waters From Ochlockonee River
     to Apalachicola Fl out to 20 Nm-Coastal waters from
     Suwannee River to Keaton Beach FL out 20 NM-Coastal waters
     from Mexico Beach to Apalachicola FL out 20 NM-Coastal
     waters from Mexico Beach to Okaloosa Walton County Line FL
     out 20 NM-Waters from Suwannee River to Apalachicola FL
     from 20 to 60 NM-Waters from Apalachicola to Mexico Beach
     FL from 20 to 60 NM-Waters from Mexico Beach to Okaloosa
     Walton County Line FL from 20 to 60 NM.

     Small Craft Advisory from 5 AM Wednesday to 5 AM EDT Thursday
     for Apalachee Bay or Coastal Waters From Keaton Beach to
     Ochlockonee River FL out to 20 Nm-Coastal Waters From
     Ochlockonee River to Apalachicola Fl out to 20 Nm-Coastal
     waters from Suwannee River to Keaton Beach FL out 20 NM-
     Coastal waters from Mexico Beach to Apalachicola FL out 20
     NM-Coastal waters from Mexico Beach to Okaloosa Walton
     County Line FL out 20 NM-Waters from Suwannee River to
     Apalachicola FL from 20 to 60 NM-Waters from Apalachicola
     to Mexico Beach FL from 20 to 60 NM-Waters from Mexico
     Beach to Okaloosa Walton County Line FL from 20 to 60 NM.

     Gale Warning until 5 AM EDT Wednesday for Apalachee Bay or
     Coastal Waters From Keaton Beach to Ochlockonee River FL
     out to 20 Nm-Coastal Waters From Ochlockonee River to
     Apalachicola Fl out to 20 Nm-Coastal waters from Suwannee
     River to Keaton Beach FL out 20 NM-Coastal waters from
     Mexico Beach to Apalachicola FL out 20 NM-Coastal waters
     from Mexico Beach to Okaloosa Walton County Line FL out 20
     NM-Waters from Suwannee River to Apalachicola FL from 20 to
     60 NM-Waters from Apalachicola to Mexico Beach FL from 20
     to 60 NM-Waters from Mexico Beach to Okaloosa Walton County
     Line FL from 20 to 60 NM.

&&

NEAR TERM...Lahr
SHORT TERM...Godsey
LONG TERM...Godsey
AVIATION...Nguyen
MARINE...Godsey
FIRE WEATHER...Lahr
HYDROLOGY...Godsey

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TALLAHASSEE FL
1113 AM EDT TUE MAR 20 2018

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

0300 PM     TSTM WND DMG     2 NNW CAIRO             30.90N 84.22W
03/19/2018                   GRADY              GA   PUBLIC

            LARGE PINE DOWN ON VEHICLE ON HWY 84 ABOUT
            1.5 MILES WEST OF CAIRO, GA.

1045 AM     LIGHTNING        1 W GOVERNORS SQUARE MA 30.44N 84.27W
03/19/2018                   LEON               FL   COUNTY OFFICIAL

            LIGHTNING STRIKE AT COMFORT INN CAUSED FIRE
            AND ROOF DAMAGE.

&&

Special Weather Statement
National Weather Service Tallahassee FL
209 PM EDT TUE MAR 20 2018

FLZ029-034-134-201845-
Coastal Dixie FL-Inland Dixie FL-Lafayette FL-
209 PM EDT TUE MAR 20 2018

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN LAFAYETTE AND DIXIE
COUNTIES UNTIL 245 PM EDT...

At 209 PM EDT, National Weather Service doppler radar indicated a
strong thunderstorm near Cross City, moving northeast at 45 mph.

Half inch hail and winds in excess of 40 mph will be possible with
this storm.

Locations impacted include...
Cross City, Horseshoe Point, Fowlers Bluff, Suwannee, Branford,
Horseshoe Beach, Shamrock, Cross City Airport, Shired Island, Old
Town, Hines, Jonesboro, Grady, Hatch Bend, Eugene, Fletcher, Yellow
Jacket, Guaranto Springs, Fletcher Springs and Fanning Springs.

A tornado watch remains in effect until 700 PM EDT for Big Bend of
Florida.

LAT...LON 2929 8322 2953 8345 3006 8304 2996 8293
      2989 8292 2990 8290 2986 8288 2981 8293
      2972 8296 2970 8294 2963 8297 2958 8295
      2959 8294 2940 8302 2937 8307 2934 8307
      2930 8316 2929 8317
TIME...MOT...LOC 1809Z 238DEG 38KT 2964 8318

42-DVD