The threat for severe storms has left our area, pushing East and Southeast, but we’re still expecting some rain overnight, along with some strong winds and much cooler temperatures.

Saturday morning lows will drop into the upper 30s in many areas with afternoon highs only in the upper 50s!

The biggest threat for severe storms is just to the north of Ozark today. However, we cannot completely count out the potential for damaging winds and hail as a fast-moving cold front moves through our area later.

Be aware of quickly changing weather close to you, especially after midday.

Here’s the ;atest from the National Weather Service…

MESOSCALE DISCUSSION 0151
   NWS STORM PREDICTION CENTER NORMAN OK
   0556 AM CST FRI FEB 24 2012
  
   AREAS AFFECTED...CENTRAL/ERN AL...CENTRAL/NRN GA...AND UPSTATE SC
  
   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
  
   VALID 241156Z - 241330Z
  
   A TORNADO WATCH IS BEING CONSIDERED FOR ISSUANCE FROM PARTS OF
   CENTRAL AND ERN AL THROUGH CENTRAL/NRN GA INTO UPSTATE SC...AND
   POTENTIALLY INTO WRN NC.  PROBABILITY OF WW ISSUANCE BY 13-14Z IS
   60-70 PERCENT.
  
   IN ADDITION TO A CONTINUATION OF TSTM DEVELOPMENT ALONG A COLD FRONT
   ADVANCING THROUGH NRN AL...REGIONAL RADAR IMAGERY/LIGHTNING DATA
   SHOWED AN INCREASE IN TSTM ACTIVITY ACROSS CENTRAL AL/WRN GA SINCE
   1045Z.  COLD AIR ADVECTION ABOVE 850 MB HAS RESULTED IN A WEAKENING
   OF THE CAP THAT WAS EVIDENT ON THE 24/00Z BHM/ATL SOUNDINGS AND NOW
   ERODED PER 12Z BHM SOUNDING.  THUS...GIVEN A MOIST WARM SECTOR /PW
   VALUES RANGING FROM 1-1.5 INCH/ AND LAPSE RATES NEAR 7 C/KM...THE
   MUCAPE IS ALREADY NEAR 1000 J/KG.  DESPITE A LACK OF STRONGER HEIGHT
   FALLS ACROSS THE DISCUSSION AREA TODAY...UPWARD VERTICAL MOTION
   WITHIN THE RIGHT ENTRANCE REGION OF A 150+ KT UPPER JET IN THE TN/OH
   VALLEYS IS EXPECTED TO SUPPORT FURTHER TSTM DEVELOPMENT ENEWD FROM
   THE ONGOING ACTIVITY.  THIS SCENARIO IS SUPPORTED BY MOST SHORT TERM
   MODELS WHICH SUGGEST A CONTINUED INCREASE IN TSTM DEVELOPMENT THIS
   MORNING FROM AL THROUGH CENTRAL/NRN GA TO UPSTATE SC/NC.
  
   STRENGTHENING WSWLY DEEP LAYER WIND FIELDS /60-70 KT AT 700 MB AND
   80-100 KT AT 500 MB/ WILL MAINTAIN STRONG BULK SHEAR FOR ORGANIZED
   STORM DEVELOPMENT.  STRAIGHT HODOGRAPHS SUGGEST SPLITTING SUPERCELLS
   WILL BE POSSIBLE WITH LOW LEVEL SHEAR SUFFICIENT FOR TORNADO
   DEVELOPMENT...IN ADDITION TO DAMAGING WINDS AND HAIL.
  
   ..PETERS.. 02/24/2012
  

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
900 PM EST Wed Feb 22 2012
SYNOPSIS...
AT UPPER LEVELS...
The large scale longwave pattern is highlighted by a LOW-AMPLITUDE
TROUGH/CUTOFF low over Baja CA and and the northeast portion  of the
country, with a similarly low-amplitude RIDGE over PAC NW and
Rockies. This Baja low is expected to MEANDER slowly EWD over
northern Mexico through Friday. Another SHORTWAVE over PAC nw will
amplify AS it continues to dig east-southeast, reaching the Ohio
River Valley by early Friday.

AT LOWER LEVELS...
A broad diffuse HIGH PRESSURE ridge extended north of the Bahamas
through the southern Florida peninsula. Generally lower pressure was
found to the northwest OF CWA. In between, warm FRONT near the
coast. This combination has SET up broad southerly low-level FLOW
over much of the Southeast.

On Thurs, an H5 Trough lingers over N FL with WSW flow and 40kt JET
over area. warm front should lift new during days enhanced by jet.
This should lead to BREEZY to WINDY conditions approaching WIND
ADVISORY criteria, particularly over the northern third of our
forecast area.

As the above upper level shortwave digs and amplifies, surface
CYCLOGENESIS should commence from the Dakotas tonight into the
eastern Great Lakes by Friday. An accompanying cold front trailing
to the southwest will also SURGE southeastward across much of the
central and eastern US, reaching the eastern Gulf Coast on Friday
and will LIKELY be our next STORM system. Until that cold front
passage occurs, there will be periodic chances of RAIN and storms
with breezy south to southwest winds.

There is better model consensus today on the timing of the cold
front, reaching roughly the I-65 corridor just northwest of our area
shortly after SUNRISE, and pushing into the southeast part of our
area (near Dixie County) by 00z Saturday. This places the arrival of
the front squarely in the DIURNAL timeframe, and that`s when the
highest (approx 60%) POPS were concentrated. as the upper level
trough and cold front move SEWD and phase with lingering H5 Trough
over local area. The main concern then is related to potential
severe weather which remains a possibility and will dealt with in
more details on next AFD.

&&

.SHORT TERM [REST OF TONIGHT THRU EARLY THURSDAY]...
Analysis during wed AFTN/early EVE was due to upper shortwave
moving ewd across NB most Apalachee Bay. At surface weak warm front
from SRN la ESE thru the warm gulf CURRENT to our west and then
across and shelf waters of Gulf of MEX. This combination provided
enough lift for ample rain and SCT thunderstorms especially over SE
Big Bend and Apalachee Bay. However, activity waned last FEW hours
as initial shortwave moved ewd reaching E coast by 9PM with some
drying in its WAKE. Also, earlier large scale warm and MOISTURE
ADVECTION shifted NWD. However, AT 9PM another albeit weaker
shortwave was moving ENE across Apalachicola Bay generated showers
across se Big Bend and adjacent waters. Have updated ZFP to lower
pops thru 06z with MAX 60% over water down to less than 20 PCT NRN
tier counties. (ALTHO some light DRIZZLE a good bet over CWA).
satellite PIX implies a few more impulses may move in from waters
later tonight so cant drop pops too much. For 06z-12z, 0-40% NW-SE
GRADIENT with ISOLD tstms across mainly coastal counties and
waters.

Aside from rain chances overnight, tonight will be the first of a
couple of MUGGY nights out ahead of the main system expected to
arrive on Friday. Strengthening surface winds and CLOUD cover and
passing impulses will likely limit dense FOG development across the
region, however, the potential for low STRATUS will be high. Best
CHANCE of fog will be near the coast and e/se of a line from
Tallahassee thru Valdosta and Cross City and adjusted GRIDS
accordingly.

&&

.AVIATION..(thru 00Z Thursday)
Ongoing moist AIR advection from the gulf will keep ceilings in the
IFR/LIFR RANGE for most of the area overnight. Expecting fog to
impact all terminals starting at 3z near the coast and near 5z
further inland, with significantly reduced VIS between 1 to 2SM at
TLH,VLD,and ECP. 40kt winds near 2000ft will keep wind SHEAR wording
in the TAFs from 3z to 14z. Winds will pick up to around 20 KTS
gusting to 30kts region wide tomorrow afternoon and MVFR ceilings
will linger into the afternoon as well.

&&

.MARINE...MID eve buoys showing 10-15kts. winds expected to increase
from w-e overnight with se winds 15-20kt likely with SEAS building
to 4-5 feet offshore. thus will keep SCEC headlines.

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
354 PM EST Tue Feb 21 2012
SYNOPSIS...
The long wave pattern is continuing to progress. The RIDGE that was
over the SE US yesterday has moved east over the MID-Atlantic.
Currently over our region is a SHORTWAVE TROUGH that brought some
light RAIN this morning and some CLOUDY skies. Besides a FEW light
showers this morning, today has been a CALM day in terms of weather.
IR and visible imagery show mid-upper level clouds. RADAR is QUIET
with a few leftover showers on the outskirts of the forecast area.
The trough should continue to progress eastward, but more slowly
than yesterday`s ridge AS it will begin lifting and our region
will begin to see more zonal FLOW until a second LOW approaches
Thursday NIGHT. This low could render some weather on Friday.

&&

.NEAR TERM [Today and Tonight]...
Heavy CLOUD cover and light rain from this morning have made us
lower today`s forecast HIGH today to the mid to upper 60s. Skies are
expected to clear for a little bit with a short break in the cloud
cover. With light southerly winds overnight and high MOISTURE from
RAINFALL and ADVECTION by said winds, FOG is expected across most of
the area starting early tomorrow morning and continuing into the
afternoon. Model forecast soundings and statistical guidance
indicates that the fog could be dense in spots.

&&

.SHORT TERM [Wednesday through Friday Afternoon]...
Plenty of weather concerns in the short term period, as nearly 48
hours of low-level warm advection and associated various rain
chances will be followed by the arrival of a strong cold FRONT on
Friday. We edited the GRIDS today out through 00z Saturday to ensure
a more smooth transition of weather elements into the previous
long-term forecast from last night.

First, model preferences. Differences have re-emerged from what was
a fairly good consensus amongst the 21.00z model suite. This seems
to be largely tied to two features: (1) the upper-level CUTOFF low
that is centered near 28N/117W or just west of Baja California, and
(2) an elongated PV ANOMALY / axis of SHEAR VORTICITY north of a
strong JET streak in the Gulf of Alaska. The general theme amongst
the models is that the shear vorticity will consolidate and dig
southeast into the Plains by Thursday as the jet streak develops
eastward along the NE rim of the Eastern Pacific ridge. This is
expected to lead to low-level CYCLOGENESIS in the Great Lakes or
Ohio River Valley on Thursday, and will aid in driving a deeper cold
AIR mass southeast behind a surging cold front. The new 12z GFS is
much faster with this cold front, pushing it through our area by 18z
Friday, whereas the global model consensus (and prior 00z GFS) was
much slower. In collaboration with surrounding WFOs, TAFB, and HPC,
we have decided to go with the slower cold front timing, with most
weather elements a blend of 21.00z GFS, 21.12z NAM, and 21.00z
ECMWF. There are also major differences in how the models handle the
Baja low, with potential implications for the long term period
(weekend and beyond). That will be sorted out on the overnight shift
by the long term forecaster.

For tomorrow, there is good agreement on a quick round of rain with
a fairly sharp N-S POP/QPF GRADIENT, with highest values south. This
seems to be forced largely in the low levels as isentropic ascent
kicks in as a response to a subtle shortwave trough ejects east from
the Rockies to the east coast in fast, nearly-zonal flow. Arguing
for greater rain coverage is the added benefit of being in the right
entrance region of a 120-130kt upper level jet streak. High-res
model guidance is in excellent agreement that showers will affect
mostly our marine and Florida zones, entering the western half of
our area mainly 14-18z, and then moving quickly east and diminishing
by early Wednesday evening. The various 4km WRF models all indicate
some small amounts of CAPE with some weak-moderate UPDRAFT
velocities out over the Gulf, so THUNDER was added over the water.

The earlier prospects of SCATTERED thunderstorms on Thursday seem to
have dwindled on the latest model guidance. As we are LIKELY to warm
into the upper 70s and potentially near 80 degrees, we should see at
least a weak sea-breeze CIRCULATION develop by the afternoon. 12z
model guidance does seem to support this notion with some light QPF
(0.01-0.05") amounts hugging the coastline during the day. Forecast
soundings don`t indicate much INSTABILITY, with LCL-300mb lapse
rates almost at moist ADIABATIC levels. The SREF model MEAN SBCAPE
is around 300 j/kg with a few members up around 600-800 j/kg. There
will also be quite a bit of WIND shear, with 0-6km bulk shear around
60 knots. Therefore, the threat of strong to severe thunderstorms is
non-zero. One potential flaw is strong WAA in the 900-800mb layer
just atop the boundary layer, particularly in the afternoon. This
could limit updraft strength and keep CONVECTION mostly as shallow
showers. Given the amount of shear, there are a wide RANGE of
convective possibilities on Thursday, so stay tuned!

It looks like we will see a lull for most of Thursday Night as
overnight storms would tend to fire to the northwest of us along the
cold front in the Mid-South. With the strong WAA regime and likely
increase in low cloud cover, it should be a warm night with lows in
the mid 60s. For Friday, severe weather is a possibility and we are
currently outlooked in the Day 4-8 OUTLOOK" onClick="return popup(this, 'notes')">OUTLOOK with severe probabilities
at or above 30%. More details on this in the coming days, but the
main points with this forecast update are: (1) the timing of the
greatest severe weather threat appears to have shifted into the
daytime on Friday, (2) a DIURNAL timing of the storms would probably
favor a bit more instability, (3) regardless of eventual timing the
ATMOSPHERE will be highly sheared. While there are differences in
the models regarding timing and some MESOSCALE details, they all
agree that there will be an arc of thunderstorms along the front.

.LONG TERM [Friday Night through next Tuesday]...
On a more positive note, the cold front and associated
thunderstorms will be exiting quickly to our east Friday evening
setting up a dry...although cooler weekend period. A more zonal
upper level pattern over-TOP surface high PRESSURE building in
from the west supports near zero rain chances Saturday and Sunday.
The airmass arriving is quite chilly through. The late February
sun is getting stronger, so still anticipate highs into the 60s,
however a chilly night looks to be in store for Saturday night. As
of now have gone with WIDESPREAD mid/upper 30s away from the
immediate coast, with normally colder spots down near freezing by
SUNRISE. This will also need to be monitored closely, as the
eventual position of the surface high Saturday night will
determine if a more widespread light FREEZE will be possible.
Seasonal conditions with rebounding TEMPS then expected for the
early portion of next week.

&&

.AVIATION [through 18z Wednesday]...
12Z model guidance is showing lower CIGs and VISBYs for the BR Wed
morning and conditions deteriorating earlier for ABY and DHN than
forecast at the 12Z TAF issuance. BR setup time remains similar to
the last issuance, beginning around 04Z, deteriorating near 09Z, and
improving at 16Z, earlier at ECP and VLD. Model agreement is quite
strong on low VSBY, but weak on CIGs, especially after 14Z. Expect
VFR conditions until around 04Z Wed when conditions FALL to MVFR.
At 09 conditions will fall further to IFR, then return to MVFR
around 15Z.

&&

.MARINE...
Generally quiet marine forecast until at least Wednesday. A
NOCTURNAL SURGE of southerly winds could REACH" onClick="return popup(this, 'notes')">REACH SCEC headline
levels Wednesday Night, subsiding briefly on Thursday, before
ramping up ahead of a cold front Thursday Night into Friday. We
went entirely with a SEAS forecast based on the SWAN model, as the
WW3 (based on the 12z GFS) seems to be: (1) too fast with frontal
timing, and (2) too weak with surface winds. The winds were a
blend of the ECMWF and NAM models which bring the front through
the coastal waters on Friday afternoon. Ahead of the front this
gives SSW winds around 25 KT with seas building to 7-9 feet. The
combination of the rapid ramp-up in wind-waves, plus longer period
SWELL originating from the 15-20kt SSW flow Thursday to Thursday
Night is expected to build surf heights to ADVISORY levels on
Friday (6ft or so), with dangerous rips likely.

&&

.FIRE WEATHER...
High relative HUMIDITY values keep us well above criteria level
across the region through the end of the work week. Relative
humidity is forecast to decrease to around 30 percent on Saturday
across the area for several hours, so Florida may reach red flag
criteria, but it`s too early to see ERC values, or to be certain of
what the winds will do.

Pensacola  1.82″
Andalusia  1.94″
Albany  2.13″
Pine Level  2.17″
Crestview  2.51″
Troy  2.74″
Wicksburg  2.75″
Dothan  3.25″
Geneva  3.70″
Marianna  4.75″
Bonifay  5.00″
Chipley  5.90″

Biggest total we could find, from a trained spotter, was in Walton County, near Eucheeanna, Fl. (SE of De Funiak Springs), 7 inches!

Overview:

A potent upper level disturbance will move across Southern Texas tonight and lead to the development of a strong low pressure area along theCentral Gulf of Mexico. This low pressure will move northeastward acrossAlabamaand into theSouthern Appalachiansby Sunday morning. Warm and moist air will be drawn northward and inland along theGulfCoastahead of this low pressure area. This will create an environment favorable for the development of strong to severe thunderstorms on Saturday afternoon into early Sunday morning.

Impacts:

Our computer models have come into a little better agreement today regarding the timing and progression of this storm system. However, there still is some uncertainty with respect to how much instability will be present across the region. While this complicates the forecast slightly, our confidence is increasing that there will be severe weather occurring on Saturday into Sunday morning across a good portion of the region.

The latest computer models indicate that a few strong to severe storms are now possible late Saturday afternoon as a warm frontal boundary lifts north through the region. This portion of the event still remains the most uncertain as the necessary instability may be lacking. Later Saturday evening and early Sunday morning, a squall line is expected to surge eastward across the region. Sufficient instability is anticipated to be available Saturday evening and into the overnight hours, especially across Southeast Alabama,Southwestern Georgia, and the Florida Panhandle making another round of severe weather likely. Lesser instability is anticipated to be present across the Florida Big Bend and into South Central Georgia, resulting in lower chances of severe weather late Saturday night and into Sunday morning.

* As the warm front lifts northward on early Saturday afternoon isolated tornadoes and damaging wind gusts will be possible.

* As the squall line moves through the area Saturday evening and into Sunday morning, more widespread damaging winds are anticipated. Isolated tornadoes will still be possible.

Based on the latest data, the Storm Prediction Center has kept the entire region within a Slight Risk for severe weather for Saturday into Sunday morning. The associated severe weather probabilities with this event are still relatively high in western portions of our region at 30 percent with lower values of 15 percent further to the east along the Interstate 75 corridor and into the Florida Big Bend. Of course, there still remains some uncertainty and this outlook may change as the event approaches on Saturday.

Rainfall amounts are expected to be heaviest acrossSoutheast Alabamaand into the Florida Panhandle where 2 to 3 inch totals are anticipated. Lesser amounts are expected further southeast with areas in the Florida Big Bend seeing around 1 inch of rainfall from this system.

We’re expecting heavy rain and numerous intense storms to move through our area 2 times on Saturday. The first time will begin around midday and continue through the early part of Saturday evening. The second surge looks to be after 10pm and continuing into early morning Sunday.

The Slight (30%) chance for Severe Storms in our area means we’re concerned about the likelihood of multiple Tornadoes and Damaging winds.

Tornado Watches and Warnings will be issued.

Make plans now to keep up with quickly changing weather conditions near you this weekend.

Here’s the latest information from the NWS Severe Storm Center in Oklahoma…

   NWS STORM PREDICTION CENTER NORMAN OK
   1217 AM CST FRI FEB 17 2012
  
   VALID 181200Z - 191200Z
  
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM EXTREME SERN TX THROUGH
   SRN PORTIONS OF THE GULF COASTAL STATES...
  
   ...SYNOPSIS...
  
   A PROGRESSIVE SPLIT FLOW REGIME WILL CHARACTERIZE THE SYNOPTIC
   PATTERN SATURDAY. PRIMARY FEATURE OF INTEREST IS CUTOFF UPPER LOW
   LOCATED OVER THE NRN GULF OF CALIFORNIA AS OF LATE THURSDAY EVENING.
   THIS FEATURE WILL ACCELERATE EWD IN RESPONSE TO AN UPSTREAM WAVE
   APPROACHING THE PACIFIC NW. MODEL CONSENSUS IS THAT THIS TROUGH AXIS
   WILL BE LOCATED FROM CNTRL TX INTO NERN MEXICO EARLY SATURDAY AND
   WILL SUBSEQUENTLY ADVANCE INTO THE CNTRL GULF COAST STATES SATURDAY
   NIGHT. CYCLOGENESIS WILL COMMENCE OVER SERN TX SATURDAY MORNING IN
   VICINITY OF BAROCLINIC ZONE AND WITHIN DIVERGENT EXIT REGION OF
   UPPER JET ROUNDING BASE OF THE TROUGH. THIS LOW WILL LIKELY DEEPEN
   AS IT DEVELOPS NEWD INTO THE SERN STATES...REACHING AL OR GA LATE IN
   THE PERIOD.
  
   ...GULF COASTAL STATES...
  
   OBSERVATIONAL DATA INDICATE A RESERVOIR OF UPPER 60S DEWPOINTS OVER
   THE CNTRL GULF SOUTH OF A QUASISTATIONARY FRONT. RETREATING HIGH
   PRESSURE AND STRENGTHENING LLJ ASSOCIATED WITH DEVELOPING CYCLONE
   SHOULD CONTRIBUTE TO INLAND ADVANCE OF THE FRONT INTO SRN PORTIONS
   OF THE GULF COAST STATES. HOWEVER...ISENTROPIC ASCENT NORTH OF THE
   WARM FRONT WILL RESULT IN AREAS OF WIDESPREAD CLOUDS AND RAIN EARLY
   IN THE PERIOD FROM ERN TX INTO THE LOWER MS VALLEY WHICH COULD
   POTENTIALLY LIMIT BOUNDARY LAYER DESTABILIZATION AND SLOW THE NWD
   PROGRESS OF THE FRONT. NEVERTHELESS...AT LEAST WEAK INSTABILITY WITH
   300-500 J/KG SBCAPE SHOULD DEVELOP INLAND DUE PRIMARILY TO NWD
   ADVECTION OF HIGHER DEWPOINTS.
  
   STORMS MAY INCREASE IN INTENSITY ALONG WARM CONVEYOR BELT AND
   PRE-FRONTAL CONFLUENCE BANDS INITIALLY ACROSS SERN TX COASTAL AREA
   WHERE WIND FIELDS AND VERTICAL SHEAR WILL STRENGTHEN WITH THE
   APPROACH OF THE UPPER TROUGH. ACTIVITY WILL SUBSEQUENTLY DEVELOP
   THROUGH THE GULF COASTAL STATES WARM SECTOR DURING THE DAY AND
   OVERNIGHT WHERE MOISTENING BOUNDARY LAYER WILL CONTRIBUTE TO
   POTENTIAL FOR NEAR SURFACE BASED CONVECTION. STRONG EFFECTIVE DEEP
   SHEAR AND LARGE HODOGRAPHS ACCOMPANYING THE STRENGTHENING LLJ WILL
   PROMOTE A RISK OF LEWP/BOWS AND EMBEDDED SUPERCELLS. DAMAGING WIND
   AND ISOLATED TORNADOES WILL BE THE MAIN THREATS WITHIN THE EXPECTED
   HIGH SHEAR/LOW CAPE ENVIRONMENT.
  
   ..DIAL.. 02/17/2012

DAY 3 CONVECTIVE OUTLOOK 
   NWS STORM PREDICTION CENTER NORMAN OK
   0220 AM CST THU FEB 16 2012
  
   VALID 181200Z - 191200Z
  
   ...THERE IS A SLGT RISK OF SVR TSTMS SAT AND SAT NIGHT ACROSS MUCH
   OF THE CNTRL AND ERN GULF STATES THRU THE S ATLANTIC COAST STATES...
  
   ...SYNOPSIS...
   MODELS CONTINUE TO DISPLAY CONSIDERABLE VARIABILITY CONCERNING SHORT
   WAVE DEVELOPMENTS WITHIN AT LEAST A COUPLE OF DISTINCT BRANCHES OF
   STRONGER FLOW THAT PERSIST ACROSS NORTH AMERICA.  HOWEVER...A
   SIGNIFICANT SHORT WAVE IMPULSE LIFTING OUT OF THE NORTHERN MEXICAN
   PLATEAU ON FRIDAY APPEARS LIKELY TO CONTINUE ACCELERATING EAST
   NORTHEASTWARD ACROSS THE GULF COAST STATES REGION ON SATURDAY.  THIS
   IS EXPECTED TO SIGNIFICANTLY SUPPRESS SUBTROPICAL RIDGING CURRENTLY
   PRESENT...AND CONTRIBUTE TO SURFACE CYCLOGENESIS ALONG A STALLED
   SURFACE FRONT ACROSS THE NORTHWESTERN GULF OF MEXICO BY 12Z
   SATURDAY.
  
   ALTHOUGH AT LEAST SUBTLE DIFFERENCES EXIST AMONG THE MODELS
   CONCERNING THE SPECIFICS OF THIS EVOLUTION...PARTICULARLY TO THE LEE
   OF THE SOUTHERN APPALACHIANS...MOST GUIDANCE GENERALLY INDICATES
   THAT A DEEPENING SURFACE LOW WILL MIGRATE INLAND ACROSS THE CENTRAL
   GULF COAST INTO NORTHERN/CENTRAL GEORGIA BY LATE SATURDAY EVENING.
   THIS IS EXPECTED TO BE ACCOMPANIED BY A STRENGTHENING SOUTHERLY 850
   MB JET IN EXCESS OF 50 KT...ACROSS THE WARM SECTOR OF THE
   CYCLONE...AS A STRONGLY DIFLUENT WEST/SOUTHWESTERLY 500 MB JET
   STREAK...SHIFTING WITH THE UPPER TROUGH...STRENGTHENS IN EXCESS OF
   90 KTS.
  
   ...CNTRL/ERN GULF STATES INTO THE S ATLANTIC COAST STATES...
   DESPITE LINGERING UNCERTAINTY CONCERNING BOUNDARY LAYER
   DESTABILIZATION EVIDENT IN THE MODEL DATA...GIVEN THE STRENGTH OF
   THE DEVELOPING SYSTEM...IT APPEARS THAT A RELATIVELY MOIST BOUNDARY
   LAYER PRESENT OVER THE GULF OF MEXICO SHOULD ADVECT INLAND WITHIN
   THE WARM SECTOR OF THE LOW.  EVEN IF MID-LEVEL LAPSE RATES DO NOT
   STEEPEN SUBSTANTIALLY...AS COLDER MID-LEVEL AIR PROBABLY WILL REMAIN
   DISPLACED TO THE WEST...SUFFICIENT CAPE IS EXPECTED TO SUPPORT
   VIGOROUS CONVECTIVE DEVELOPMENT.  IN THE PRESENCE OF WIND PROFILES
   EXHIBITING LARGE CLOCKWISE CURVED LOW-LEVEL HODOGRAPHS AND STRONG
   DEEP LAYER SHEAR...THIS SHOULD PROVE FAVORABLE FOR AN ORGANIZED
   STORM CLUSTER...OR CLUSTERS...AS WELL AS DISCRETE SUPERCELLS.
  
   IT CURRENTLY SEEMS MOST PROBABLE THAT ONE LARGE MESOSCALE CONVECTIVE
   SYSTEM COULD EVOLVE NEAR OR JUST EAST OF THE LOWER MISSISSIPPI
   VALLEY BY MID DAY SATURDAY...BEFORE ADVANCING EASTWARD ACROSS THE
   EASTERN GULF STATES THROUGH THE REMAINDER OF THE AFTERNOON AND
   EVENING.  THIS PROBABLY WILL BE ACCOMPANIED BY THE RISK FOR DAMAGING
   WINDS AND TORNADOES...WITH PERHAPS A MORE SIGNIFICANT TORNADIC
   THREAT IN DISCRETE SUPERCELL DEVELOPMENT THAT APPEARS POSSIBLE JUST
   AHEAD OF THE LINE.
  
   SEVERE STORMS WILL REMAIN POSSIBLE SATURDAY NIGHT EASTWARD INTO THE
   CENTRAL/EASTERN CAROLINAS...BUT THE DETAILS ARE LESS CLEAR AS THE
   SURFACE CYCLONE EITHER MIGRATES NORTHWARD THROUGH THE PIEDMONT...OR
   REDEVELOPS EASTWARD ACROSS THE COASTAL PLAIN.
  

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
905 PM EST Sun Feb 12 2012

DISCUSSION...00 UTC surface analysis shows a 1031 MB HIGH centered
across Northwestern Alabama. The PRESSURE GRADIENT across the South
was continuing to relax AS this high pressure area spreads eastward
with winds becoming near CALM across much of the region. With these
lighter winds tonight and clear skies temperatures have plummeted
into the MID and upper 30s across much of the region with a FEW
locations already at the freezing mark by 01z.

Vapor imagery and 500 mb analysis shows the large cold TROUGH that
was in place across the Eastern CONUS now shifting to a position
more across the Canadian Maritimes. SHORTWAVE ridging was spreading
eastward across the Central CONUS and into the Southeast. Some
Pacific MOISTURE was streaming across the Gulf of Mexico and this
has led to the development of an area of CLOUD cover across the
Central Gulf Coast States.

The primary forecast concern tonight again is with the temperatures.
The forecast is complicated by the arrival of some cloud cover from
the west. Model data shows a gradual and slow moistening of the
500-300 mb layer across the southern half of the region by morning
and this would LIKELY serve to limit how far temperatures would drop
overnight. Feel very confident about winds being essentially calm
overnight, so with the very dry and cold airmass that is in place,
temperatures away from the cloud cover should easily be in the lower
20s by morning based on the latest observations and model data. After
watching TEMPERATURE trends over the last couple of hours, have
decided to adjust temperatures up slightly in the Florida Big Bend,
but still keep minimum values in the lower 20s as it is expected the
cloud cover will have some but not much of an effect on temperatures
before SUNRISE. Aside from that adjustment, not additional changes
are planned with the forecast this evening. Have a great NIGHT!

&&

.AVIATION...VFR conditions will are expected to prevail through the
TAF period with mainly light winds. However, mid and upper level
cloudiness appear to be increasing from the southwest well ahead of
the model guidance, but this will be more of a concern to overnight
LOW temperatures than to Aviation concerns.

&&

.MARINE...Winds and SEAS will continue to diminish this evening and
into the overnight hours as high pressure moves nearer to the marine
area. Expect low winds and seas to persist into Monday before
increasing again on Tuesday.

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE TALLAHASSEE FL
400 PM EST Fri Feb 10 2012
...Much colder weather arriving this weekend...
SHORT TERM (Tonight through Sunday NIGHT)...

A MID/upper level shortwave trough will pivot rapidly eastward along
the northern Gulf coast. Decent swath of synoptic support/QG forcing
ahead of this energy will overspread the area this evening. This
area of forcing is already supporting a large area of showers across
southern LA/MS. Global and HI-res model consensus agrees that this
area of showers will expand rapidly into our region this evening.
The QG forcing will align with upper level JET energy to support the
highest SHOWER concentration over the southern half of the
area...and especially coastal areas eastward through the SE Big
Bend. These areas are highlighted with high end 70% POPS, and an
argument could easily be made for higher CATEGORICAL PoPs. POP
GRADIENT will decrease to the north down to 40-50% up toward KDHN
and KABY. Still do expect some of the showers to reach this far
north, however some guidance members insist that the main area of
showers will be more broken in nature north of the FL border. Even
across the far south...this will be a high PoP...low QPF event, with
highest RAINFALL amounts LIKELY remaining under 1/4 inch. This will
be a quick hitting event AS the last of the organized showers are
expected to be exiting the Suwannee River Valley/I-75 corridor by
around 09Z. Surface based CAPE is essential NIL, and even elevated
INSTABILITY is lacking. Showalter indices are all positive and will
not include THUNDER mention. Low temperatures in the 40s.

Saturday:
Cold front will quickly pass east of the forecast area Saturday
morning with a much cooler and drier airmass arriving on BREEZY NW
winds. 850mb TEMPS will FALL below 0C over most areas by the end of
the day. Despite the strength of the cold AIR...excellent DIURNAL
mixing in the post-frontal environment will keep things seasonable
for afternoon highs. Looking for highs to RANGE from the lower 50s
north and west of a Dothan to Albany line, and range upward to the
lower 60s over the SE Big Bend zones. As mentioned above it will be
quite breezy for those with outdoor plans. NW winds sustained
between 15 to 20 mph with gusts near 25 mph common.

Saturday Night:
The cold air will arrive quickly with the setting of the sun. At
this time expecting temperatures by SUNRISE on Sunday to be
generally in the upper 20s...with middle 20s possible across the far
north. CURRENT statistical guidance shows lower/middle 20s for
many locations, however, MOS guidance almost always is too low in
these events with respect to the initial ADVECTION FREEZE...and have
taken this BIAS into account. This will only prevent a hard freeze.
Still anticipate a WIDESPREAD freeze even right down to the coast.
Combine these temps with a steady northerly breeze and WIND chill
reading will reach the upper teens to lower 20s. Will continue to
monitor the situation in case a wind chill ADVISORY becomes
necessary for early Sunday morning.

Sunday/Sunday night:
High pressure will settle southeast from the TN valley toward the
forecast area. The airmass in place and less efficient mixing
will result in a cool day. High temps will struggle into the lower
50s by the late afternoon. The close proximity of the high CENTER
will cause any light afternoon winds will go nearly CALM quickly
during the evening. These calm conditions combined with very dry low
levels suggest temps will fall quickly after SUNSET. Expect to see
normally colder areas fall below freezing potentially by late
evening, and SET up a long duration freeze. This appears to be the
night in which hard freeze conditions will be more likely. Low temps
for normally colder areas may drop into the lower 20s...with most
locations away from the immediate coast falling into the middle 20s.
As is usual with radiational cooling...the immediate coast and more
urbanized inland centers (such as downtown Tallahassee) should end
up a FEW degrees warmer, but still below freezing.

&&

.LONG TERM (Monday through next Friday)...
We`ll see another cold day to start the extended period with
possibly another widespread hard freeze Monday morning mainly east
of the Apalachicola/Chattahoochee Rivers. Surface high pressure will
be centered over the southeast CONUS with nearly zonal FLOW aloft on
Monday. The high will rapidly move east making way for the next low
pressure system that will bring a weak cold front with RAIN chances
to the region on Tuesday. This front will stall over or just south
of our FA late Tuesday/early Wednesday and then lift north as a warm
front Wednesday/Wednesday night as a stronger low pressure system
begins to develop over the southern plains. Showers/thunderstorms
will begin to overspread the region during the Thursday/Thursday
night time frame with the front forecast to push into the CWA on
Friday. After below NORMAL temps for Monday, the rest of the
extended period will have above seasonal temps.

&&

.MARINE
A weak area of low pressure will pass south of the forecast waters
this evening. In the WAKE of this low, winds will increase from the
Northwest later tonight and are forecast to reach advisory levels
Saturday morning. These advisory level conditions will continue
through Sunday morning. A period of GALE force gusts is possible
Saturday night and this potential will need to be monitored closely.
Winds and SEAS will decrease below headline criteria later Sunday
into the early portion of next week.

&&

.Aviation (through 18Z SAT)...Although VFR conditions should prevail
through the bulk of this TAF period, gradually lowering Vfr level
cigs will predominate the FCST for the remainder of this afternoon
and throughout much of the evening hours. Widespread light rain is
also expected to develop from SW to NE across the terminals, with
possible periods of moderate rain and MVFR level VIS this evening at
TLH, ECP, and VLD. Although some VFR level clouds could linger
behind the cold front for a while, Saturday should be dominated by
clearing skies, much cooler temps, and very gusty NW winds.

&&

.FIRE WEATHER...
Much cooler and drier air will be building in from the northwest on
Saturday on gusty Northwest winds. This very dry air combined with
sustained 15 mph or greater winds and Dispersions greater than 75
will result in a Red Flag WARNING for all of the Florida Big Bend
and Panhandle on Saturday. However, even though relative HUMIDITY
values will be extremely low over the SAME area on Sunday, will hold
off on a Fire Weather WATCH until future ERC values can be
determined. Over Southeast Alabama and Southwest and South Central
Georgia, will issue a Fire Weather Watch for Sunday for expected
long durations of relative humidity below 25 percent.