Small Craft Advisory 5, NWS Mobile, AL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOBILE AL
526 AM CST WED JAN 20 2010

.SHORT TERM...FOR TODAY THROUGH TONIGHT...UPPER SHORTWAVE OVER THE SOUTHERN
ROCKIES WILL MOVE EAST ACROSS THE SOUTHERN PLAINS THROUGH TONIGHT.
CYCLOGENESIS OCCURRING OVER SOUTHEAST COLORADO THIS MORNING...WITH THE
LOW INITIALLY TRACKING SOUTHEAST ACROSS THE TEXAS PANHANDLE...AND
THEN EAST REACHING NORTHERN ARKANSAS BY LATE TONIGHT.

A MOIST DEEP SOUTHWEST FLOW DEVELOPING OVER THE REGION TODAY AHEAD
OF THE MAIN SYSTEM WILL PUSH PRECIPITABLE WATER VALUES UP TO 1.5
INCHES. WARM AIR ADVECTION WILL ALSO INCREASE OVER THE GULF COAST
STATES AS SOUTH WINDS RAMP UP...PUTTING THE ENTIRE FORECAST AREA
WELL WITHIN THE WARM SECTOR. ONSET OF LIGHT RAIN SHOWERS EXPECTED
LATE THIS MORNING ACROSS OUR WESTERN ZONES. THIS PRECIPITATION WILL
EXPAND EASTWARD IN COVERAGE AND INCREASE IN INTENSITY THROUGH THIS
AFTERNOON AND EVENING.

INSTABILITY WILL ALSO BE INCREASING ACROSS OUR WESTERN ZONES WITH
500-1000 J/KG MLCAPES POSSIBLE BY LATE AFTERNOON...AND EXPANDING
EASTWARD THIS EVENING. THE STRONG LOW LEVEL WIND SHEAR ASSOCIATED
WITH THIS SYSTEM SUGGESTS A FEW ROTATING SUPERCELLS WITH LARGE HAIL
AND ISOLATED TORNADOES POSSIBLE. BOWING SEGMENTS ARE LIKELY
OVERNIGHT...WITH DAMAGING THUNDERSTORM WINDS AND HEAVY RAIN BEING
THE MAIN THREATS.

CLOUDY TODAY WITH ABOVE NORMAL HIGH TEMPERATURES RANGING FROM 64 TO
68 DEGREES. A MOIST MODERATE SOUTHERLY WIND FLOW AND CONTINUED
CLOUDY SKIES WILL RESULT IN LOW TEMPERATURES BEING ABOUT 20 DEGREES
ABOVE NORMAL. THE LOWS WILL ACTUALLY OCCUR AROUND MID EVENING
(AROUND 60 DEGREES)...WITH TEMPERATURES VERY SLOWLY RISING THROUGH
THE REMAINDER OF THE NIGHT. /22

BY THURSDAY MORNING...THE UPPER LOW HAS MOVED OVER NE OK...WITH THE
SURFACE LOW OVER/NEAR THE AR/MO/TN JUNCTURE(ACCORDING TO THE NAM/GFS.
ECMWF HAS SURFACE LOW FARTHER WEST...JUST EAST OF THE KS/OK/MO/AR
JUNCTURE)...WITH THE SURFACE FRONT STARTING ACROSS THE FA. AM
EXPECTING THE CURRENT EVEN TO BE ONGOING OVER THE FA...THOUGH
STARTING TO EAST OVER THE WESTERN EDGE OF THE FA. GUIDANCE IS
ADVERTISING THE UPPER LOW SLOWLY SPINNING EAST...WITH THE GFS
ADVERTISING A SLIGHT FASTER PACE. BOTH THE NAM AND GFS ARE
ADVERTISING SOME UPPER ENERGY GETTING DRAGGED OVER THE FA...SOUTH OF
THE MAIN SYSTEM DURING THE DAY. WITH GUIDANCE ADVERTISING GOOD
INSTABILITY AND JET DYNAMICS LASTING INTO THURSDAY MORNING...HAVE
ADDED SVR WORDING TO THE FORECAST THROUGH NOONTIME. A GENERAL 1 TO 2
INCHES OF QPF ARE EXPECTED BY THE END OF THIS EVENT. BY
NOONTIME...THE ADDED UPPER DYNAMICS HAVE MOVED EAST OF THE
FA...THOUGH GUIDANCE IS STILL TRYING TO PAINT SOME PRECIP INTO THE
EVENING HOURS...MAINLY OVER THE SOUTHEASTERN SECTION OF THE FA AND
EASTERN GULF OF MEX. HAVE TRIED TO SHARPEN THE BACK EDGE OF THE
PRECIP FROM GUIDANCE IS ADVERTISING. ALSO...SOME DISCREPANCY IN THE
TEMP GUIDANCE DUE TO THE TIMING DIFFERENCE AMONGST THE NAM AND
GFS...WITH THE FASTER GFS ALLOWING FOR MORE POST FRONTAL SUN
THURSDAY...THUS A HIGHER MAXT. HAVE TAKEN A HINT FROM THE 00Z ENSEMBLES AND
TONED DOWN THE GFS HIGH TEMPS...TOWARDS THE COOLER NAM...WITH A
FEELING THAT A SLIGHTLY SLOW TIMING MIGHT BE WARRANTED.

FOR THURSDAY NIGHT INTO FRIDAY...AS THE COMING EVENT'S UPPER LOW
PULLS AWAY...THE FA WILL DRY OUT FOR A BIT...THOUGH A SIGN OF THINGS
TO COME IS A SECOND ROUND OF UPPER ENERGY MOVING ACROSS THE WESTERN
CONUS LATE THURSDAY NIGHT THROUGH FRIDAY.

.LONG TERM...(FRIDAY NIGHT ON)FRIDAY NIGHT INTO SATURDAY...THE UPPER
DYNAMICS OVER THE WESTERN CONUS MOVE EAST...WITH THE MAIN UPPER LOW
MOVING FROM OVER THE NORTHWESTERN CONUS TO OVER THE NORTHERN
PLAINS....AND A "WHIP" OF ENERGY STRETCHING SOUTH OVER THE PLAINS FROM
THE UPPER LOW...THEN WEST ALONG THE US/MEX BORDER. BY THE END OF THE
DAY SATURDAY...THE MEDIUM RANGE GUIDANCE IS PAINTING A RETURN TO
SOUTHERLY FLOW OVER THE FA...AND MOISTURE LEVELS ON THE INCREASE. AS
THE "WHIP OF UPPER ENERGY SWINGS AROUND THE UPPER LOW LATER SATURDAY
INTO SUNDAY...IS PUSHED A SQUALL LINE ACROSS THE FA EITHER LATE
SATURDAY NIGHT INTO SUNDAY(GFS) OR ENTIRELY SUNDAY(ECMWF). BOTH ARE
ADVERTISING THE FRONT CROSSING THE FA SUNDAY INTO EARLY SUNDAY
NIGHT...THOUGH THE ECMWF KEEPS THE SQUALL LINE CLOSER TO THE SURFACE
FRONT. AM EXPECTING ANOTHER ROUND OF SEVERE WEATHER POSSIBLE WITH
THIS SYSTEM...THOUGH THE UPPER DYNAMICS ARE A BIT OUT OF PHASE IN THE
GFS. ECMWF IS MORE FAVORABLE. SPC HAS A SLIGHT RISK OUT FOR THIS SYSTEM
FOR SATURDAY INTO SUNDAY MORNING IN YESTERDAY'S OUTLOOK FOR THE
EXTENDED...THOUGH WITH THE CURRENT FORECAST...HAVE FEELING THEY WILL
PUSH IT LATER...WITH SATURDAY NIGHT THROUGH SUNDAY THE CURRENT
TIMING.

SUNDAY NIGHT INTO MONDAY...THOUGH GUIDANCE IS ADVERTISING MORE UPPER
DYNAMICS BEHIND THIS FIRST "WHIP"...THE SYSTEM OCCLUDES AND DRIES OUT
OVER THE LOWER MISS RIVER VALLEY AND SOUTHEASTERN CONUS...CUTTING OFF
THE CHANCE FOR RAIN. THIS SECOND SHOT OF UPPER ENERGY BRINGS A COOLER
AIRMASS WITH...DROPPING TEMPS TO A BIT BELOW SEASONAL FOR TUESDAY
INTO MID WEEK. MOS IS TRYING TO ADVERTISING SOME COLD SURGE STRATUS
WITH THIS TRAILING ENERGY. HAVE A HARD TIME SEEING THIS...WITH THE
DRY AIR MOVING IN WITH THE OCCLUSION OF THE SURFACE FRONT.

&&

.AVIATION...(12Z ISSUANCE)VARYING MVFR VISIBILITIES OCCURRING OVER
THE GULF COAST TERMINALS EARLY THIS MORNING WILL IMPROVE BY MID
MORNING. CEILINGS AROUND 7000 FEET THIS MORNING ARE FORECAST TO
LOWER OVER THE NEXT 24 HRS. EXPECT DEVELOPING SHOWERS AFTER
16Z...AND THEN WIDESPREAD SHOWERS AND THUNDERSTORMS DURING THE
AFTERNOON AND OVERNIGHT. THERE IS POTENTIAL OF +RA AND A REDUCTION
IN VSBY AOB 1/2SM IN STRONG STORMS. A FEW STORMS COULD BECOME SEVERE
AS WELL BETWEEN 20/21Z AND 21/06Z. /22

&&

.MARINE...HIGH PRESSURE CENTERED OVER FLORIDA WILL MOVE EAST INTO
THE WESTERN ATLANTIC TODAY. SOUTHERLY WINDS AND SEAS WILL INCREASE
THROUGH TONIGHT AS A STORM SYSTEM DEVELOPING OVER THE SOUTHERN PLAINS
AND MOVES EAST. SHOWERS AND THUNDERSTORMS WILL BECOME NUMEROUS OVER
THE MARINE AREA THIS AFTERNOON THROUGH THURSDAY MORNING. WINDS AND
SEAS WILL DECREASE ON FRIDAY AS HIGH PRESSURE BUILDS ONCE AGAIN OVER
THE NORTH CENTRAL GULF. SOUTHERLY WINDS AND SEAS WILL INCREASE OVER
THE WEEKEND AS THE NEXT STORM SYSTEM MOVES EAST OUT OF THE CENTRAL
PLAINS. /22

&&

.FIRE WEATHER...INCREASING LOW LEVEL FLOW TODAY AHEAD OF A SYSTEM
EXPECTED TO BRING RAIN TO THE AREA LATER TODAY INTO THURSDAY. AFTER
THIS FIRST SYSTEM MOVES TROUGH...SOME DRIER AIR WILL MOVE IN FOR
FRIDAY INTO FRIDAY NIGHT...BUT BY SATURDAY MORNING...SOUTHERLY FLOW
BECOMES RE-ESTABLISHED AHEAD OF ANOTHER ROUND OF RAIN LATE SATURDAY
NIGHT THROUGH SUNDAY. AM NOT EXPECTING RH VALUES TO DIP MUCH BELOW 40
PERCENT FRIDAY.

&&

.PRELIMINARY POINT TEMPS/POPS...
MOBILE      67  60  74  48  71 /  80 100  40  05  00
PENSACOLA   66  61  70  51  69 /  70  90  60  05  00
DESTIN      65  61  69  52  67 /  40  90  70  10  00
EVERGREEN   67  60  73  47  71 /  70 100  60  05  00
WAYNESBORO  66  58  75  45  70 /  90 100  30  05  00
CAMDEN      67  58  75  46  71 /  80 100  60  05  05
CRESTVIEW   68  60  74  48  72 /  50 100  70  05  00

&&

.MOB WATCHES/WARNINGS/ADVISORIES...
AL...NONE.
FL...NONE.
MS...NONE.
GM...NONE.
&&

HAZARDOUS WEATHER OUTLOOK...CORRECTED...
NATIONAL WEATHER SERVICE MOBILE AL
933 AM CST WED JAN 20 2010

ALZ051>064-FLZ001>006-GMZ630-650-655-670-675-MSZ067-075-076-078-
079-211330-
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-
717 AM CST WED JAN 20 2010

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHEAST
MISSISSIPPI...SOUTHWEST AND SOUTH CENTRAL ALABAMA...THE WESTERN
FLORIDA PANHANDLE...AND THE ADJACENT GULF COASTAL WATERS OF ALABAMA
AND NORTHWEST FLORIDA.

.DAY ONE...TODAY AND TONIGHT

A LARGE STORM SYSTEM DEVELOPING ACROSS THE SOUTHERN PLAINS TODAY WILL
MOVE OVER NORTHEAST ARKANSAS BY LATE TONIGHT. LIGHT TO MODERATE
SHOWERS DEVELOPING EARLY THIS MORNING ACROSS SOUTHERN LOUISIANA WILL
MOVE OVER SOUTHEAST MISSISSIPPI BY LATE MORNING. THIS PRECIPITATION
WILL EXPAND RAPIDLY TO THE EAST ACROSS THE ENTIRE OUTLOOK AREA DURING
THE AFTERNOON. SCATTERED EMBEDDED THUNDERSTORMS WILL ALSO OCCUR
WITHIN THIS AREA OF PRECIPITATION. THE LATEST INDICATIONS ARE THAT
ENOUGH INSTABILITY AND WIND SHEAR WILL BE IN PLACE TO RESULT IN THE
POTENTIAL FOR STRONG TO SEVERE THUNDERSTORMS BEGINNING MID AFTERNOON.
AT THIS TIME...THE MAIN THREATS FROM THE INITIAL STORMS WILL BE LARGE
HAIL AND ISOLATED TORNADOES.

A SECOND WAVE OF SEVERE WEATHER POTENTIAL WILL BEGIN IN THE EVENING
AND LAST THROUGHOUT THE NIGHT. THE MAIN THREATS FROM THE STORMS WILL
DAMAGING THUNDERSTORM WINDS AND MARGINAL SEVERE HAIL ASSOCIATED WITH
A SQUALL LINE MOVING EAST ACROSS THE AREA...MAINLY AFTER MIDNIGHT.
THE SEVERE THREAT SHOULD CLEAR THE WESTERN FLORIDA PANHANDLE AND
SOUTH CENTRAL ALABAMA BY MID THURSDAY MORNING.

RAINFALL TOTALS FOR THIS EVENT WILL LIKELY RANGE FROM 1 TO 2
INCHES...ALTHOUGH ISOLATED TOTALS OF 3 INCHES ARE POSSIBLE. THIS
COULD RESULT IN SOME MINOR FLOODING ISSUES OF LOW LYING AND POOR
DRAINAGE AREAS.

SOUTHERLY WINDS AND SEAS WILL INCREASE TODAY AS THE STORM SYSTEM
DEVELOPS OVER THE SOUTHERN PLAINS AND MOVES EAST. SOUTHERLY WINDS OF
20 TO 25 KNOTS ARE EXPECTED TONIGHT AND THURSDAY...AND WILL ALLOW
SEAS TO BUILD TO 6 TO 9 FEET. THESE CONDITIONS WILL LEAD TO
SIGNIFICANT IMPACTS FOR SMALL CRAFT OPERATING ON THE GULF AND AREA
BAYS. IN ADDITION...BAYS AND COASTAL WATERWAYS WILL BE ROUGH.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

THE SOUTHERLY WINDS OF 20 TO 25 KNOTS AND SEAS OF 6 TO 9 FEET WILL
CONTINUE OVER THE COASTAL WATERS ON THURSDAY. THE SIGNIFICANT
IMPACTS FOR SMALL CRAFT WILL CONTINUE.

A STRONGER COLD FRONT IS FORECAST TO MOVE ACROSS THE NORTHERN GULF
COAST LATE SATURDAY NIGHT INTO SUNDAY. THERE WILL BE THE POTENTIAL
FOR A FEW STRONG TO SEVERE STORMS IF ENOUGH INSTABILITY
MATERIALIZES.

.SPOTTER INFORMATION STATEMENT...

ACTIVATION OF EMERGENCY MANAGEMENT OFFICIALS AND STORM SPOTTERS FOR
SEVERE WEATHER MAY BE NEEDED LATE WEDNESDAY AND EARLY THURSDAY.