Small Craft Advisory 52, NWS Mobile, AL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOBILE AL
400 AM CST SAT DEC 10 2010

.SHORT TERM (TODAY AND TONIGHT)...BIG CHANGES EXPECTED LATER THIS
AFTERNOON AND TONIGHT IN RESPONSE TO A STRONG COLD FRONT APPROACHING
FROM THE WEST. AHEAD OF THE FRONT NUMEROUS SHOWERS WITH EMBEDDED
THUNDERSTORMS CAN BE EXPECTED MOVING INTO WESTERN SECTIONS OF THE
CWFA EARLY THIS EVENING...SHIFTING EASTWARD QUICKLY THROUGH TONIGHT
AS MAIN UPPER TROF DIGS OVER THE MID TO LOWER MS RIVER VALLEY
OVERNIGHT. STRONG STORMS COULD DEVELOP AHEAD OF THE FRONT AFFECTING
PARTS OF SOUTHEAST MS AND EXTREME SOUTHWEST ALABAMA MOSTLY THIS
EVENING. WITH GOOD VERTICAL SHEAR...0-3 KM HELICITIES RANGING FROM
200 TO 400 M2/S2 COMBINED WITH MARGINAL CAPES AT AROUND 500 J/KG A
FEW STORMS COULD BECOME STRONG OR SEVERE...ESPECIALLY OVER WESTERN
SECTIONS OF THE CWFA OR GENERALLY WEST OF THE I-65 CORRIDOR
STRETCHING SOUTHWARD OVER THE GULF. A WEAK WARM FRONT IS ALSO NOTED
ACROSS WESTERN AND SOUTHERN SECTIONS OF THE CWFA THIS EVENING AND
OVERNIGHT...GENERALLY STRETCHING FROM CENTRAL MS TO THE AL COAST BY
00Z SHIFTING EASTWARD IN THE VICINITY OF THE I-10 CORRIDOR MOSTLY
THIS EVENING. THE STRONGER CONVECTION SHOULD BE IN THE VICINITY OF
THIS BOUNDARY AND SOUTHWARD. WILL CONTINUE TO MONITOR THIS SEVERE
THREAT THROUGHOUT THE DAY AND UPDATE WHEN NECESSARY. AS FOR TEMPS
WILL UNDERCUT THE COOLER MAV GUIDANCE A TAD FOR TODAYS HIGHS DUE TO
INCREASING CLOUDS AND INCREASING WINDS FROM THE SOUTH COMBINED WITH
THE COOLER NEAR SHORE WATERS...THEN STAY CLOSE TO THE MAV GUIDANCE
FOR MINS OVERNIGHT. DUE TO THE STRONG NORTHERLY WIND FLOW ON SUNDAY
A WIND ADVISORY MAY BE NEEDED FOR SOME LOWER PARTS OF THE CWFA. STAY
TUNED FOR FURTHER UPDATES. 32/EE

A DEEP UPPER LOW WILL MOVE NORTHEASTWARD FROM NEAR THE OHIO RIVER
VALLEY ON SUNDAY TO THE EASTERN GREAT LAKES ON MONDAY AND DEEPEN
FURTHER.  THIS SETS THE STAGE FOR THE STRONGEST DEEP LAYER COLD AIR
ADVECTION INTO THE FORECAST AREA IN THE WAKE OF THE COLD FRONT
PASSAGE SO FAR THIS SEASON WITH A 50 KNOT 850 MB FLOW...NEAR 70 KT
850-500 MB FLOW...THROUGH SUNDAY NIGHT THEN GRADUALLY ABATING
THROUGH MONDAY NIGHT AS THE ARCTIC DOME OF HIGH PRESSURE BUILDS INTO
AND THEN SETTLES OVER THE AREA.  HIGHS ON SUNDAY CONTINUE TO BE
CHALLENGING BUT PREFER GOING NEAR THE COOLER MAV SOLUTION AS THE NAM
IS THE ODD MEMBER OUT AND TOO SLOW ON THE FRONT/MOVEMENT OF COLDER
AIR INTO THE REGION COMPARED TO THE CLOSE AGREEMENT AMONG THE
GEM/ECMWF/GFS/UKMET.  THE RAINS WILL BE MOSTLY EAST OF THE AREA
SUNDAY MORNING EXCEPT FOR OVER THE EASTERN PORTION OF THE OFFSHORE
WATERS.  MAY SEE SOME WRAP AROUND DRIZZLE OVER THE NORTHERNMOST
COUNTIES SUNDAY MORNING BUT OTHER THAN THE MARINE AREA SUNDAY
MORNING HAVE GONE WITH A DRY FORECAST THROUGH MONDAY NIGHT.
1000-850 MB THICKNESSES DROP TO 1260 M INLAND TO 1275 M NEAR THE
COAST BY SUNDAY NIGHT PER BLEND OF ECMWF/GFS...THEN MODERATE
SOMEWHAT THROUGH MONDAY NIGHT.  BOTH SUNDAY NIGHT AND MONDAY NIGHT
WILL BE VERY COLD...MONDAY NIGHT SLIGHTLY MORE SO AS THE ARCTIC HIGH
SETTLES OVER THE AREA WITH WINDS BECOMING LIGHT.  LOCAL HARD FREEZE
CRITERIA OF 20 DEGREES LOOKS TO BE MET OVER THE NORTHWESTERN PORTION
OF THE AREA SUNDAY NIGHT AND THE ENTIRE INLAND AREA MONDAY
NIGHT...AND POSSIBLY OVER THE INTERIOR PORTION OF THE COASTAL
COUNTIES AS WELL.  IN ORDER TO HIGHLIGHT THIS ARCTIC AIRMASS AND
GIVE THE MOST LEAD TIME POSSIBLE...HAVE GONE AHEAD AND ISSUED A HARD
FREEZE WATCH FOR SUNDAY NIGHT FOR THE NORTHWEST PORTION OF THE
FORECAST AREA. /29

.LONG TERM (TUESDAY THROUGH FRIDAY)...THE DEEP UPPER LOW OVER THE
EASTERN GREAT LAKES...EXTREME SOUTHEAST ONTARIO...MOVE EASTWARD
ACROSS THE NEW ENGLAND AREA TO NEAR THE NORTHEAST COAST THROUGH
WEDNESDAY.  THE COLD RIDGE OF HIGH PRESSURE OVER THE AREA SHIFTS
EASTWARD ALLOWING FOR A RETURN FLOW TO ENSUE...AND A SURFACE LOW
DEVELOPS OVER THE SOUTHERN PLAINS AS THE UPPER PATTERN OVER THE
SOUTHERN STATES BECOMES FAIRLY ZONAL.  AFTER A COLD START TUESDAY
MORNING...TEMPERATURES MODERATE SOMEWHAT BUT HIGHS TUESDAY WILL
STILL BE AROUND TEN DEGREES BELOW SEASONABLE LEVELS.  TEMPERATURES
CONTINUE TO MODERATE TO NEAR SEASONABLE LEVELS WEDNESDAY...THEN
GUIDANCE CONTINUES TO SHOW A RATHER MILD DAY THURSDAY WITH HIGHS IN
THE LOWER SEVENTIES ACROSS MUCH OF THE AREA.  CONTINUE TO PREFER THE
SLOWER ECMWF SOLUTION...AS DOES HPC...WHICH MOVES THE SURFACE LOW
ACROSS THE LOWER/MID MISSISSIPPI RIVER VALLEY THURSDAY NIGHT THEN TO
THE CENTRAL EAST COAST STATES ON FRIDAY...BRINGING A COLD FRONT
THROUGH THE FORECAST AREA.  MODEST ISENTROPIC LIFT SEEN IN THE
295-305 LAYER ON WEDNESDAY SPREADS EASTWARD THROUGH THURSDAY INTO
FRIDAY AHEAD OF THE SURFACE LOW AND AN ASSOCIATED TRAILING FRONT.
WILL HAVE SMALL POPS OVER THE WESTERN PORTION OF THE AREA WEDNESDAY
THEN THE ENTIRE AREA THURSDAY THROUGH FRIDAY. /29

&&

.AVIATION (12Z ISSUANCE)...INCREASING HIGH CLOUDINESS THIS MORNING
FOLLOWED BKN TO OVC CEILINGS AT 3K TO 5K FT THIS AFTERNOON...
FOLLOWED BY LOWERING CEILINGS TO AROUND 1K FT THIS EVENING WITH
NUMEROUS SHOWERS AND EMBEDDED THUNDERSTORMS...SOME STRONG MAY BE
STRONG TO SEVERE...FOLLOWED BY A STRONG NORTHWEST FLOW AT AROUND 20
KNOTS IN THE WAKE OF A STRONG COLD FRONT EARLY SUNDAY MORNING. LOW
CEILINGS IN THE WAKE OF THE FRONT WILL GRADUALLY IMPROVE ON SUNDAY.
32/EE

&&

.MARINE...SOUTHERLY WINDS AND SEAS WILL BUILD TO 20 TO 25 KNOTS
LATER TODAY AND TONIGHT AHEAD OF A STRONG COLD FRONT WHICH IS
FORECAST TO MOVE ACROSS THE MARINE AREA LATE TONIGHT. SEAS WILL
BUILD TO AROUND 5 FEET OUT TO 60 NM WITH THE ONSHORE FLOW THIS
AFTERNOON. SHOWERS AND THUNDERSTORMS ARE EXPECTED AHEAD OF THE FRONT
WITH THE BEST COVERAGE OCCURRING THIS EVENING...CONTINUING THROUGH
EARLY SUNDAY MORNING. A STRONG OFFSHORE WIND AT 25 TO 30 KNOTS WITH
HIGHER GUSTS IS EXPECTED IN THE WAKE OF THE FRONT OVERNIGHT AND ON
SUNDAY...CONTINUING THROUGH MONDAY AFTERNOON. SEAS WILL RANGE FROM 4
TO 6 FEET OUT TO 20 NM AND 7 TO 10 FEET FROM 20 TO 60 NM OUT.
NORTHERLY WINDS AND SEAS WILL GRADUALLY DECREASE MONDAY NIGHT
THROUGH TUESDAY...BECOMING SOUTHEAST AND REBUILDING ON WEDNESDAY AS
ANOTHER COLD FRONT APPROACHES FROM THE WEST.32/EE

&&

.FIRE WEATHER...RELATIVE HUMIDITIES DROP INTO THE LOWER THIRTIES
OVER THE NORTHWEST FLORIDA PANHANDLE SUNDAY AFTERNOON.  THE DURATION
WILL NOT BE SUFFICIENT BUT NORTHWEST WINDS WILL BE 15-20 MPH SO HAVE
ISSUED A FIRE WEATHER WATCH FOR THIS AREA.  SURFACE DEWPOINTS DROP
TO THE SINGLE DIGITS...EVEN SLIGHTLY BELOW ZERO IN SPOTS ON MONDAY.
DESPITE THE VERY COOL DAYTIME TEMPERATURES...THIS RESULTS IN
AFTERNOON RELATIVE HUMIDITIES NEAR TWENTY PERCENT.  AS SUCH...HAVE
ISSUED A FIRE WEATHER WATCH FOR SOUTHWEST AND SOUTH CENTRAL ALABAMA
AND THE NORTHWEST FLORIDA PANHANDLE FOR MONDAY. /29

&&

.PRELIMINARY POINT TEMPS/POPS...
MOBILE      65  41  48  21 /  20  80  05  00
PENSACOLA   63  45  51  26 /  05  80  10  00
DESTIN      60  48  54  29 /  05  80  10  00
EVERGREEN   65  40  45  21 /  10  80  10  00
WAYNESBORO  66  35  46  20 /  30  90  05  00
CAMDEN      65  38  44  20 /  20 100  10  05
CRESTVIEW   65  47  51  25 /  05  80  10  00

&&

.MOB WATCHES/WARNINGS/ADVISORIES...
AL...HARD FREEZE WATCH FROM MIDNIGHT MONDAY TO 8 AM MONDAY FOR THE
     FOLLOWING ZONES: CHOCTAW...CLARKE...MONROE...WASHINGTON...
     AND WILCOX.

     FIRE WEATHER WATCH FROM 10 AM MONDAY TO 6 PM MONDAY FOR THE
     FOLLOWING ZONES: BUTLER...CHOCTAW...CLARKE...CONECUH...
     COVINGTON...CRENSHAW...ESCAMBIA...LOWER BALDWIN...LOWER
     MOBILE...MONROE...UPPER BALDWIN...UPPER MOBILE...
     WASHINGTON...AND WILCOX.

FL...FIRE WEATHER WATCH FROM 1 PM SUNDAY TO 5 PM SUNDAY FOR THE
     FOLLOWING ZONES: COASTAL ESCAMBIA...COASTAL OKALOOSA...
     COASTAL SANTA ROSA...INLAND ESCAMBIA...INLAND OKALOOSA...
     AND INLAND SANTA ROSA.

     FIRE WEATHER WATCH FROM 10 AM MONDAY TO 6 PM MONDAY FOR THE
     FOLLOWING ZONES: COASTAL ESCAMBIA...COASTAL OKALOOSA...
     COASTAL SANTA ROSA...INLAND ESCAMBIA...INLAND OKALOOSA...
     AND INLAND SANTA ROSA.

MS...HARD FREEZE WATCH FROM MIDNIGHT MONDAY TO 8 AM MONDAY FOR THE
     FOLLOWING ZONES: GREENE...PERRY...AND WAYNE.

GM...SMALL CRAFT ADVISORY FROM 6 PM SATURDAY TO 6 PM SUNDAY FOR THE
     FOLLOWING ZONES: COASTAL WATERS FROM DESTIN TO PENSACOLA FL
     OUT 20 NM...COASTAL WATERS FROM PENSACOLA FL TO PASCAGOULA
     MS OUT 20 NM...MOBILE BAY...WATERS FROM DESTIN TO PENSACOLA
     FL FROM 20 TO 60 NM...AND WATERS FROM PENSACOLA FL TO
     PASCAGOULA MS FROM 20 TO 60 NM.

&&

HAZARDOUS WEATHER OUTLOOK...CORRECTED
NATIONAL WEATHER SERVICE MOBILE AL
638 AM CST SAT DEC 11 2010

ALZ051>064-FLZ001>006-GMZ630-650-655-670-675-MSZ067-075-076-078-
079-121200-
CHOCTAW-WASHINGTON-CLARKE-WILCOX-MONROE-CONECUH-BUTLER-CRENSHAW-
ESCAMBIA-COVINGTON-UPPER MOBILE-UPPER BALDWIN-LOWER MOBILE-
LOWER BALDWIN-INLAND ESCAMBIA-COASTAL ESCAMBIA-INLAND SANTA ROSA-
COASTAL SANTA ROSA-INLAND OKALOOSA-COASTAL OKALOOSA-MOBILE BAY-
COASTAL WATERS FROM PENSACOLA FL TO PASCAGOULA MS OUT 20 NM-
COASTAL WATERS FROM DESTIN TO PENSACOLA FL OUT 20 NM-
WATERS FROM PENSACOLA FL TO PASCAGOULA MS FROM 20 TO 60 NM-
WATERS FROM DESTIN TO PENSACOLA FL FROM 20 TO 60 NM-WAYNE-PERRY-
GREENE-STONE-GEORGE-
638 AM CST SAT DEC 11 2010

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTH CENTRAL
ALABAMA...SOUTHWEST ALABAMA...NORTHWEST FLORIDA AND SOUTHEAST
MISSISSIPPI...AS WELL AS FOR THE COASTAL WATERS OF ALABAMA AND
NORTHWEST FLORIDA.

.DAY ONE...TODAY AND TONIGHT

A STRONG COLD FRONT IS FORECAST TO MOVE ACROSS THE REGION LATE
TONIGHT THROUGH EARLY SUNDAY. SHOWERS AND THUNDERSTORMS ARE EXPECTED
AHEAD OF THE FRONT WITH THE BEST COVERAGE OCCURRING THIS EVENING AND
EARLY SUNDAY MORNING. DUE TO GOOD VERTICAL SHEAR AND MARGINAL
INSTABILITY AHEAD OF THE FRONT A FEW STORMS MAY BECOME STRONG TO
SEVERE...MOSTLY WEST OF THE I-65 CORRIDOR INLAND AND ALONG THE COAST
OF ALABAMA AND NORTHWEST FLORIDA SOUTH OF THE I-10 CORRIDOR.
DAMAGING STRAIGHT LINE WINDS AND ISOLATED TORNADOES WILL BE THE MAIN
THREAT WITH THE STRONGER STORMS.

SOUTHERLY WINDS AND SEAS WILL INCREASE OVER THE MARINE AREA THIS
AFTERNOON AND THIS EVENING AHEAD OF STRONG COLD FRONT APPROACHING
FROM THE WEST. SHOWERS AND THUNDERSTORMS ARE EXPECTED AHEAD OF THE
FRONT WITH SOME STORMS BECOMING STRONG TO SEVERE. IN THE WAKE OF THE
FRONT A STRONG OFFSHORE FLOW CAN BE EXPECTED DEVELOPING ACROSS THE
MARINE AREA BEFORE SUNRISE SUNDAY MORNING. A SMALL CRAFT ADVISORY IS
IN EFFECT FOR THE COASTAL WATERS OF ALABAMA AND NORTHWEST FLORIDA
OUT TO 60 NM BEGINNING EARLY THIS EVENING CONTINUING THROUGH MONDAY
AFTERNOON.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

A STRONG NORTHERLY WIND FLOW WILL CONTINUE TO GIVE WAY TO HAZARDOUS
CONDITIONS FOR SMALL CRAFT SUNDAY THROUGH MONDAY.

THERE WILL BE AN INCREASED RISK OF WILDFIRES ACROSS THE CENTRAL GULF
COAST REGION SUNDAY THROUGH MIDWEEK DUE TO LOW AFTERNOON RELATIVE
HUMIDITY VALUES...COMBINED WITH A MODERATE TO STRONG NORTHERLY WIND
OCCURRING MOSTLY ON SUNDAY.

VERY COLD AIR WILL FLOW INTO THE REGION IN THE WAKE OF THE COLD
FRONT.  A HARD FREEZE WATCH IS IN EFFECT SUNDAY NIGHT INTO EARLY
MONDAY MORNING FOR THE INTERIOR PORTION OF SOUTHEAST MISSISSIPPI AND
SOUTHWEST ALABAMA.  A HARD FREEZE IS ALSO POSSIBLE MONDAY NIGHT OVER
SOUTH CENTRAL ALABAMA AND INTERIOR SOUTHWEST ALABAMA...AND THE
INTERIOR PORTION OF THE NORTHWEST FLORIDA PANHANDLE.

.SPOTTER INFORMATION STATEMENT...

ACTIVATION OF STORM SPOTTERS AND EMERGENCY MANAGEMENT IS NOT
EXPECTED AT THIS TIME.