Flood and Damaging Winds in Georgia, April 1 to 3, 2016

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
415 PM EDT FRI APR 1 2016

...Threat of severe weather and flooding continues from this
afternoon and into early Saturday...

.Near Term [Through Tonight]...

A well-defined convective line has made steady progress to the
east in our forecast area during the day, and at 20Z extended
roughly from Fitzgerald, to Moultrie, to Quincy, to Youngstown, to
Panama City Beach. In other words, the line roughly bi-sected the
forecast area from southwest to northeast. A modest cold pool has
developed behind the line as stratiform rain continues to fall
as far as 150 miles rearward of the main convection. Temperatures
in the northwest part of our area have fallen into the mid-60s.
The environment ahead of the line was characterized by moderate
instability with temperatures in the upper 70s to around 80
degrees and dewpoints in the low 70s. In other words, there is
plenty of fuel for the storms to continue their eastward
progression, and since about 15Z (with the stronger cold pool) the
storms have been more progressive (even though individual cell
motions are generally to the northeast). We adjusted the
temperatures to fit the current trends, which were cooler than
models were indicating behind the main squall line.

The basic message of the forecast is somewhat clear in the near
term: a large area of rain and thunderstorms will continue to
gradually shift southeast with time from this afternoon through
the overnight period, and should generally clear out of most of
the area by sunrise Saturday. However, the details matter in this
case as they could affect both flooding and severe weather
potential. Many of the high-resolution models show the storms
beginning to slow their progress and weaken late this afternoon,
with another round of storms forming and pushing into the area
overnight. This has the effect of producing a westward "wobble" in
the average position of the convective line overnight on the model
simulated 1-hr rainfall and reflectivity. In some ways, this makes
sense, as the stronger synoptic forcing is still situated well to
our west. This is evident in the cooling IR satellite cloud tops
and increasing lightning near coastal Louisiana in an area of
stronger upper level divergence. Global models generally show a
maximum in QG convergence in that area this afternoon, and shift
it into our area overnight. Sometimes in these situations when
stronger forcing has yet to arrive from the west, we can see the
warm sector retrograde a bit and a second round of rain and storms
that will affect areas that have already received heavy rainfall.

For these reasons, we have maintained the Flash Flood Watch in all
the areas it was previously in effect, even if rain rates have
slowed in parts of southeast Alabama and adjacent areas. Even
though the storms have been increasingly progressive this
afternoon, a secondary wave of convection could produce additional
flash flooding tonight. Regarding the severe weather threat, deep
layer shear is quite strong at the moment, but low-level shear is
fairly weak. The low-level shear is forecast to increase
overnight, notably in the 00-03Z timeframe. The expanding low-
level hodographs and continued moderate instability in the warm
sector ahead of the advancing storms should support a continued
threat for damaging winds and isolated tornadoes overnight.

.Short Term [Saturday Through Sunday Night]...

Most models have the cold front sweeping clear of the area quite
early in the morning, with chances of rain quickly diminishing.
Given that there has been a southeastward bias in model precip
forecasts thus far today, we did not clear rain out as fast as
some models indicate on Saturday, but the heaviest rain rates
associated with thunderstorms should be mostly clear of our area
by 15Z. In the wake of the front, slightly cooler and drier
conditions are expected with highs in the low-mid 70s and lows in
the upper 40s.

.Long Term [Monday Through Friday]...

Early in the week northwesterly flow will develop aloft due to the
upper trough axis along the eastern seaboard. This is expected
to lead to drier and more seasonable conditions through the first
half of the work week. Highs are expected in the upper 70s and
lows are expected in the upper 40s and lower 50s through
Wednesday. Another cold front is expected to rapidly pass through
the area on Thursday. Winds will gain a southerly component ahead
of the front, bringing humid from the Gulf of Mexico air into the
area. There will also be a chance of showers and the possibility
of a few thunderstorms associated with this front. After the front
passes, there should again be northwesterly flow promoting drier
and cooler conditions.

&&

.Aviation...

[Through 18Z Saturday] Strong to severe thunderstorms will move
through the region this afternoon and evening. A steady rain
will move in behind the storms. Mainly MVFR CIGS are expected this
evening and overnight with a few pockets of IFR CIGS. VFR
conditions will return tomorrow morning.

&&

.Marine...

We issued a Small Craft Advisory for areas west of Apalachicola
from later tonight through Saturday morning. Model forecast wind
speeds were close to 20 knots in those areas. After a brief lull
during the afternoon in which northwest winds should be around 15
knots over most of the coastal waters, the winds will veer
slightly to the north and increase to advisory levels again on
Saturday Night. An advisory has not been issued for that timeframe
quite yet. After that, winds and seas should quickly subside as
high pressure builds into the region.

&&

.Fire Weather...

Widespread showers and thunderstorms will further wet fuels.
Therefore, even though much drier air will arrive so a few days
starting Sunday, red flag criteria will not be threatened.

&&

.Hydrology...

Local rivers are rising as heavy rain moves into the region. Most
area rivers were already high with the exception of the
Suwannee. Flooding is occurring on the Ochlockonee, Apalachicola,
Withlacoochee, and Choctawhatchee Rivers in Florida. Most rivers
will continue to rise this weekend and early next week. The
Kinchafoonee Creek and the Chipola River need to be monitored and
a warning may be issued later.

Several inches of rain has already fallen over Southeast Alabama
today. Light to moderate rain will continue to soak the region this
evening and overnight with heavy rain possible within thunderstorms.
Expect another two to four inches of rain with higher amounts in
thunderstorms.

The Flash Flood Watch remains in place for most of the region
through Saturday morning.

&&

.Preliminary Point Temps/PoPs...

Tallahassee   66  74  48  73  48 /  90  50   0   0   0
Panama City   62  70  52  70  54 / 100  40   0   0   0
Dothan        57  69  46  70  47 /  90  10   0   0   0
Albany        60  70  46  70  45 /  90  20   0   0   0
Valdosta      67  73  48  72  47 /  90  60   0   0   0
Cross City    71  77  49  75  49 /  50  80  10   0   0
Apalachicola  66  73  51  71  54 /  80  60   0   0   0

&&

.TAE WATCHES/WARNINGS/ADVISORIES...
FL...Flash Flood Watch through Saturday morning FOR Calhoun-Central
     Walton-Coastal Bay-Coastal Franklin-Coastal Gulf-Coastal
     Jefferson-Coastal Wakulla-Gadsden-Holmes-Inland Bay-Inland
     Franklin-Inland Gulf-Inland Jefferson-Inland Wakulla-
     Jackson-Leon-Liberty-North Walton-South Walton-Washington.

     High Rip Current Risk through Saturday morning FOR Coastal Bay-
     Coastal Franklin-Coastal Gulf-South Walton.

GA...Flash Flood Watch through Saturday morning FOR Baker-Ben Hill-
     Berrien-Brooks-Calhoun-Clay-Colquitt-Cook-Decatur-Dougherty-
     Early-Grady-Irwin-Lee-Miller-Mitchell-Quitman-Randolph-
     Seminole-Terrell-Thomas-Tift-Turner-Worth.

AL...Flash Flood Watch through Saturday morning FOR Coffee-Dale-
     Geneva-Henry-Houston.

GM...Small Craft Advisory from 2 AM to 2 PM EDT Saturday FOR Coastal
     waters from Apalachicola to Destin FL out 20 NM-Waters from
     Apalachicola to Destin FL from 20 to 60 NM.

&&

NEAR TERM...LAMERS
SHORT TERM...LAMERS
LONG TERM...LAMERS/KING
AVIATION...MCDERMOTT
MARINE...LAMERS
FIRE WEATHER...WOOL
HYDROLOGY...MCDERMOTT

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TALLAHASSEE FL
232 PM EDT FRI APR 01 2016

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

0226 PM     FLASH FLOOD      3 S RHOADES             31.22N 86.17W
04/01/2016                   COFFEE             AL   911 CALL CENTER

            WATER COVERING ROADWAY

&&

MCDERMOTT

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TALLAHASSEE FL
233 PM EDT FRI APR 01 2016

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

0226 PM     FLASH FLOOD      2 NW WICKSBURG          31.23N 85.65W
04/01/2016                   HOUSTON            AL   911 CALL CENTER

            WATER COVERING ROADWAY

&&

MCDERMOTT

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TALLAHASSEE FL
234 PM EDT FRI APR 01 2016

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

0226 PM     FLASH FLOOD      2 WSW DOTHAN            31.21N 85.43W
04/01/2016                   HOUSTON            AL   911 CALL CENTER

            WATER COVERING ROADWAY

&&

MCDERMOTT

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TALLAHASSEE FL
235 PM EDT FRI APR 01 2016

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

0226 PM     FLASH FLOOD      2 SE PINCKARD           31.29N 85.53W
04/01/2016                   DALE               AL   911 CALL CENTER

            ROAD CLOSED DUE TO FLOODING

&&

MCDERMOTT

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TALLAHASSEE FL
237 PM EDT FRI APR 01 2016

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

0226 PM     FLASH FLOOD      PINCKARD                31.31N 85.55W
04/01/2016                   DALE               AL   911 CALL CENTER

            ROAD CLOSED DUE TO FLOODING

&&

MCDERMOTT

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TALLAHASSEE FL
324 PM EDT FRI APR 01 2016

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

0230 PM     FLASH FLOOD      SLOCOMB                 31.11N 85.59W
04/01/2016                   GENEVA             AL   PUBLIC

            SOCIAL MEDIA PICTURE OF FLOODING IN SLOCOMB. ROADWAY
            COMPLETELY COVERED WITH WATER

&&

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