AFDMOB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOBILE AL
340 PM CDT MON APR 18 2011

.SHORT TERM (TONIGHT THROUGH THURSDAY NIGHT)...A VIGOROUS SHORTWAVE
SYSTEM SWEEPS ACROSS THE NORTHERN STATES TONIGHT THROUGH WEDNESDAY
WITH MODEST DEEP LAYER RIDGING OVER THE SOUTHEASTERN STATES SHIFTING
INTO THE ATLANTIC.  A SURFACE LOW CURRENTLY EVOLVING TO THE LEE OF
THE ROCKIES MOVES ACROSS THE CENTRAL PLAINS TUESDAY AND ACROSS THE
EASTERN GREAT LAKES ON WEDNESDAY MORNING...BRINGING A TRAILING COLD
FRONT INTO THE SOUTHEAST STATES ON WEDNESDAY.  THE FRONT STALLS
NORTH OF THE FORECAST AREA OVER NORTHERN MISSISSIPPI/ALABAMA ON
WEDNESDAY AFTERNOON.  A SURFACE-700 MB RIDGE ORIENTED OVER THE
NORTHERN GULF SHIFTS GRADUALLY NORTHWARD MEANWHILE AND MAINTAINS A
MODEST SOUTHERLY FLOW OVER THE AREA.  PRECIPITABLE WATER VALUES
CURRENTLY NEAR 1.3 INCHES OVER THE WESTERN PORTION OF THE
AREA...WHERE SUBSIDENCE IS WEAKER...WORK EASTWARD THROUGH WEDNESDAY
AS THE RIDGING RELAXES AND THE FRONT APPROACHES.  WILL STAY WITH A
DRY FORECAST THROUGH TUESDAY NIGHT THEN WILL HAVE POPS INCREASING TO
LOW END CHANCE POPS OVER THE NORTHERN PORTION OF THE AREA AND SLIGHT
CHANCE MOST OF THE REMAINING AREA FOR WEDNESDAY INTO WEDNESDAY NIGHT
DUE TO WEAK ISENTROPIC LIFT IN 300-305K LAYER AND PERIPHERAL
CONVECTION ASSOCIATED WITH THE FRONT AS IT MOVES INTO AND THEN
STALLS OVER THE NORTHERN PORTION OF MISSISSIPPI/ALABAMA.  SLIGHT
CHANCE POPS FOLLOW FOR THURSDAY AS THE STALLED BOUNDARY RETURNS
NORTHWARD IN RESPONSE TO ANOTHER SYSTEM DEVELOPING OVER THE PLAINS.
WILL HAVE MENTION OF PATCHY FOG OVER THE WESTERN PORTION OF THE AREA
LATE TONIGHT WHERE BETTER SURFACE DEWPOINTS ARE PRESENT...THEN WILL
HAVE PATCHY FOG ACROSS THE FORECAST AREA TUESDAY NIGHT AS THE
SOUTHERLY FLOW BRINGS GULF MOISTURE INTO THE EASTERN PORTION OF THE
AREA.  SOUTHERLY WINDS WILL BECOME BREEZY TUESDAY AFTERNOON BUT
SHOULD REMAIN GENERALLY BELOW WIND ADVISORY GUIDELINES.  DAYTIME
TEMPERATURES WILL BE A FEW DEGREES ABOVE SEASONABLE LEVELS WITH MILD
NIGHTTIME TEMPERATURES. /29

.LONG TERM (FRIDAY THROUGH MONDAY)...THE SECOND SYSTEM TO FORM OVER
THE CENTRAL PLAINS FOLLOWS A VERY SIMILAR PATH TO THE FIRST AND
MOVES ACROSS THE EASTERN GREAT LAKES FRIDAY NIGHT INTO SATURDAY
MORNING.  A TRAILING FRONT ASSOCIATED WITH THIS SYSTEM STALLS
FURTHER TO THE NORTH THOUGH WHICH RESULTS IN THE FORECAST AREA
REMAINING MOSTLY DRY THROUGH THE PERIOD.  HAVE KEPT SMALL POPS IN
THE FORECAST FOR SUNDAY AFTERNOON AND MONDAY AFTERNOON FOR ISOLATED
CONVECTION DEVELOPING DUE TO WEAK DEEP LAYER LIFT FROM A PASSING
SERIES OF SHORTWAVES AND POTENTIAL SEA BREEZE DEVELOPMENT AS DAYTIME
TEMPERATURES CONTINUE 3-6 DEGREES ABOVE SEASONABLE LEVELS. /29

&&

.AVIATION (18Z ISSUANCE)...GENERALLY VFR CONDITIONS THROUGH THE
REMAINDER OF THE DAY WITH MVFR CIGS POSSIBLE ESPECIALLY AT MOB AND
BFM. CIGS WILL DROP TONIGHT AS LOW STRATUS DEVELOPS WITH IFR/MVFR
CIGS EXPECTED OVERNIGHT THROUGH EARLY TUESDAY MORNING. ENOUGH MIXING
IS EXPECTED TO KEEP WIDESPREAD DENSE FOG FROM DEVELOPING. /13

&&

.MARINE...A RIDGE OF HIGH PRESSURE WILL REMAIN ACROSS THE MARINE
THROUGH THE FORECAST PERIOD. SOUTHERLY FLOW WILL INCREASE BRIEFLY
TUESDAY AS AN AREA OF LOW PRESSURE MOVES ACROSS THE OHIO VALLEY. THE
ONSHORE FLOW WILL DECREASE LATER TUESDAY NIGHT INTO WEDNESDAY WITH A
GENERALLY LIGHT ONSHORE FLOW THROUGH THE REMAINDER OF THE WEEK. /13

&&

.FIRE WEATHER...A RIDGE OF HIGH PRESSURE OVER THE NORTHERN GULF WILL
MAINTAIN A SOUTHERLY WIND FLOW OVER THE AREA THROUGH MID WEEK WHILE
A COLD FRONT APPROACHES FROM THE NORTH.  MOISTURE LEVELS WILL
GRADUALLY INCREASE AND KEEP AFTERNOON RELATIVE HUMIDITIES ABOVE
CRITICAL LEVELS.  PATCHY FOG WILL DEVELOP LATE TONIGHT OVER
SOUTHEAST MISSISSIPPI AND EXTREME SOUTHWEST ALABAMA...THEN PATCHY
FOG DEVELOPMENT IS ANTICIPATED ACROSS THE AREA TUESDAY NIGHT. /29

&&

.PRELIMINARY POINT TEMPS/POPS...
MOBILE      65  82  69  83 /  05  05  10  20
PENSACOLA   66  81  70  83 /  05  05  10  10
DESTIN      64  78  70  78 /  05  05  10  10
EVERGREEN   58  87  66  86 /  05  05  10  20
WAYNESBORO  64  86  69  85 /  05  10  10  30
CAMDEN      60  87  67  85 /  05  10  10  30
CRESTVIEW   55  87  64  88 /  05  05  10  10

&&

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

$$