FXUS64 KMOB 062147
AFDMOB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOBILE AL
345 PM CST SUN DEC 6 2009
.SHORT TERM (TONIGHT THROUGH WEDNESDAY NIGHT)...HIGH PRESSURE MOVES
OFF TO THE EAST COAST THIS EVENING WHILE A POSITIVELY TILTED UPPER
TROF OVER THE WESTERN STATES SENDS A VIGOROUS SERIES OF SHORTWAVES
ACROSS THE CENTRAL AND SOUTHERN PLAINS. THE FIRST SET OF THESE MOVE
A PLAINS SURFACE LOW TO ACROSS THE GREAT LAKES ON MONDAY WHILE A
SURFACE LOW MOVES ALONG THE GULF COAST AHEAD OF THE TRAILING FRONT
WHICH LATER STALLS ALONG THE WESTERN GULF COAST. THE COASTAL LOW
BRINGS SLIGHT CHANCE POPS TO THE WESTERN THIRD OF THE FORECAST AREA
LATE TONIGHT THEN CHANCE POPS TO MUCH OF THE AREA ON MONDAY WITH
LIKELY POPS OVER THE NORTHWESTERNMOST PORTION BEFORE WEAKENING.
WILL KEEP CHANCE POPS OVER THE WESTERN PORTION OF THE AREA MONDAY
NIGHT WITH SLIGHT CHANCE ELSEWHERE AS BOTH THE ECMWF/GFS ARE IN
GENERAL AGREEMENT ON A WELL DEFINED SHORTWAVE EJECTING FROM THE
SOUTHERN PLAINS AND MOVING ACROSS THE SOUTHEAST STATES WITH A WARM
FRONT ADVANCING NORTHWARD THROUGH THE FORECAST AREA AHEAD OF A DEEP
SYSTEM ADVANCING ACROSS THE WESTERN PLAINS. THE GFS/ECMWF/NAM ARE
IN FAIR AGREEMENT ON ANOTHER VIGOROUS SHORTWAVE MOVING ACROSS THE
SOUTHEAST STATES AND BRINGING STRONG DEEP LAYER LIFT TO THE REGION
ON TUESDAY WITH A STRONG COLD FRONT APPROACHING FROM THE PLAINS.
PERIODS OF SHOWERS WITH ISOLATED EMBEDDED THUNDERSTORMS DEVELOP
MAINLY ACROSS THE NORTHWESTERN HALF OF THE FORECAST AREA TAPERING
EASTWARD AND WILL HAVE CATEGORICAL POPS IN THIS AREA WITH LIKELY
ELSEWHERE. EXPECT TO SEE A SQUALL LINE FORM UPSTREAM AND MOVE
THROUGH THE FORECAST AREA TUESDAY NIGHT WITH HIGH POPS CONTINUING
FOR THE AREA. GULF MOISTURE SURGES INTO THE SOUTHEAST STATES
THROUGH TUESDAY WITH PRECIPITABLE WATER VALUES INCREASING TO AROUND
1.75 INCHES BUT DAYTIME INSTABILITY WILL BE LIMITED BY RELATIVELY
WARM TEMPERATURES FROM 850-500 MB AND RESULTING WEAK LAPSE
RATES...WITH EVEN LESS INSTABILITY TUESDAY NIGHT. ALTHOUGH
FAVORABLE SHEAR WILL BE HIGH THANKS TO A 50-55 KNOT SOUTHWEST FLOW
AT 850 MB OVER A SOUTHEASTERLY SURFACE FLOW...INSTABILITY WILL BE
LIMITED DUE TO THE WARM TEMPERATURES ALOFT PRODUCING SURFACE BASED
CAPES OF 500 J/KG OR LESS. THESE CONDITIONS SUGGEST POTENTIAL
SUPERCELL DEVELOPMENT DURING THE DAY...IF INSTABILITY PROVES
ADEQUATE...WITH A WEAKENING SQUALL LINE MOVING THROUGH THE AREA
TUESDAY NIGHT. SPC HAS THE AREA OUTLOOKED FOR A SLIGHT RISK DURING
THIS PERIOD AND WILL CONTINUE TO MONITOR DUE TO CONCERNS WITH TIMING
AND INSTABILITY. THE COLD FRONT MOVES THROUGH WEDNESDAY WITH DRY
CONDITIONS FOLLOWING FOR WEDNESDAY NIGHT. /29
&&
.LONG TERM (THURSDAY THROUGH SUNDAY)...DRY CONDITIONS CONTINUE FOR
THE FORECAST AREA THROUGH THURSDAY NIGHT AS A DOME OF HIGH PRESSURE
MOVES ACROSS THE REGION THEN A CHANCE FOR RAIN RETURNS FOR FRIDAY
AND CONTINUES THROUGH SUNDAY AS THE SERIES OF SOUTHERN STREAM
SHORTWAVES RESUME AND MOVE ACROSS THE REGION. COOL TEMPERATURES ON
THURSDAY GRADUALLY MODERATE TO SEASONABLE LEVELS BY SUNDAY. /29
&&
.MARINE...AN APPROACHING UPPER SYSTEM OVER THE SOUTHERN PLAINS WILL
CONTINUE TO PUSH SURFACE HIGH PRESSURE OVER THE EASTERN CONUS
EASTWARD...WHILE MOVING A SURFACE FRONT EAST OVER THE PLAINS...
TOWARDS THE MISS RIVER VALLEY. ONSHORE FLOW IS BROUGHT BACK OVER THE
MARINE AREA BY TUESDAY. A BIT OF STRENGTHENING IS EXPECTED MONDAY
NIGHT INTO TUESDAY AS THE PRESSURE GRADIENT TIGHTENS AND THE STALLED
FRONTAL BOUNDARY SOUTH OF THE GULF COAST STARTS TO WORK ITS WAY BACK
NORTH. A SECOND SYSTEM WILL PUSH A FRONT OVER THE AREA FROM THE WEST
WEDNESDAY. /16
&&
.AVIATION (18Z ISSUANCE)...WILL SEE INCREASING COVERAGE/LOWERING
CLOUD BASES THROUGH THE FORECAST AS AN UPPER DISTURBANCE APPROACHES
FROM THE WEST. A GOOD CHANCE OF ISENTROPIC UPGLIDE VIRGA/SHOWERS
APPROACHING FROM THE WEST TOWARDS THE END OF THE FORECAST...BUT AM
LEAVING OUT ANY MENTION ATTM. /16
&&
.FIRE WEATHER...GULF MOISTURE GRADUALLY RETURNS TO THE REGION
THROUGH MONDAY WITH RAIN CHANCES INCREASING AS A LOW PRESSURE SYSTEM
ADVANCES ALONG THE NORTHWESTERN GULF COAST. A SERIES OF STRONG
UPPER LEVEL DISTURBANCES WILL BRING PERIODS OF RAIN AND ISOLATED
EMBEDDED THUNDERSTORMS TO MUCH OF THE REGION TUESDAY INTO TUESDAY
NIGHT. A COLD FRONT WILL MOVE THROUGH THE REGION ON WEDNESDAY WITH
DRY CONDITIONS FOLLOWING BY WEDNESDAY NIGHT. RELATIVE HUMIDITIES
WILL REMAIN WELL ABOVE CRITICAL LEVELS THROUGH WEDNESDAY. /29
&&
.PRELIMINARY POINT TEMPS/POPS...
MOBILE 45 65 57 69 / 10 40 40 80
PENSACOLA 45 65 57 69 / 10 20 20 70
DESTIN 46 63 57 68 / 10 20 20 70
EVERGREEN 38 60 49 67 / 10 40 20 80
WAYNESBORO 38 58 51 67 / 20 60 50 90
CAMDEN 38 58 48 65 / 10 50 30 80
CRESTVIEW 37 62 49 70 / 10 20 20 70
&&
.MOB WATCHES/WARNINGS/ADVISORIES...
AL...NONE.
FL...NONE.
MS...NONE.
GM...NONE.
&&
$$
