Area Forecast Discussion
Issued by NWS Mobile, AL

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329
FXUS64 KMOB 120011
AFDMOB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOBILE AL
611 PM CST THU FEB 11 2016

.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

&&

.AVIATION...
12/06Z ISSUANCE...VFR FLIGHT CATEGORIES SHOULD CONTINUE ACROSS THE REGION
THROUGH THE EARLY EVENING HOURS. STILL A LITTLE BREEZY AT BEGINNING
OF THE PERIOD...WITH GENERAL SOUTH TO SOUTHWEST WINDS OF 10 TO 15
KNOTS. INCREASING LOW- LEVEL MOISTURE AND DIMINISHING WIND SPEEDS
WILL AID IN THE DEVELOPMENT OF FOG AND LOW STRATUS OVERNIGHT...MAINLY
AT OR NEAR THE COAST. MADE NO CHANGES TO EXPECTED OVERNIGHT REDUCED
VSBYS AND LOW CIGS THAT WILL LIKELY RESULT IN FLIGHT CATEGORIES
BECOMING MVFR BETWEEN 12/0600-0900Z. GUIDANCE STILL INDICATING SOME
POTENTIAL FOR LOWER FLIGHT CATEGORIES TOWARD SUNRISE. VSBYS/CIGS
SHOULD IMPROVE BY MID-MORNING FRIDAY AS INCREASED MIXING OCCURS WITH
DAYTIME HEATING. 12/DS

&&

.PREV DISCUSSION... /ISSUED 404 PM CST THU FEB 11 2016/

NEAR TERM /NOW THROUGH FRIDAY/...A NEARLY STATIONARY FRONT
STRETCHES ALONG A ROUGHLY MONROE LOUISIANA...TO JACKSON
MISSISSIPPI...TO MACON GEORGIA LINE AT MID-AFTERNOON. AS
PERTURBATIONS CONTINUE MOVING THROUGH THE REGION IN A NORTHWESTERLY
FLOW ALOFT...WE MAY SEE THE FRONT SAG A SKOSH FARTHER SOUTH TONIGHT
AND WIND UP IN THE FAR NORTHERN PART OF OUR FORECAST AREA. DESPITE
THE PRESENCE OF THE BOUNDARY...CLOUD COVER SHOULD BE RATHER LIMITED
OVER THE REGION OVER THE NEXT 24 HOURS.

THE EXCEPTION MAY BE CLOSER TO THE COAST OVERNIGHT.  PERSISTENT
SOUTHWEST TO WEST WINDS THROUGH THE BOUNDARY LAYER (AND REALLY INTO
THE MID-LEVELS) CONTINUE TO ADVECT MOISTURE INTO THE REGION.  AS
THIS AIRMASS CONTINUES MOVING OVER THE COOLER WATERS IN AREA
BAYS/WATERWAYS...SOME PATCHY FOG AND LOW CLOUDS WILL LIKELY DEVELOP
TONIGHT. EXPECT FOG TO DEVELOP CLOSER TO THE COAST BETWEEN MIDNIGHT
AND 3 AM...THEN EXPAND NORTHWARD DURING THE PRE-DAWN HOURS. THIS IS
IN GENERAL AGREEMENT WITH THE LATEST PROBABILISTIC GUIDANCE. ANY FOG
OR LOW CLOUDS SHOULD DISSIPATE AROUND MID-MORNING FRIDAY AS
MECHANICAL MIXING INCREASES.

ANOTHER SURGE OF ENERGY SHOULD MOVE SOUTHEAST FROM THE NORTHERN
PLAINS FRIDAY...PUSHING THE SURFACE BOUNDARY THROUGH OUR AREA LATE
IN THE AFTERNOON.  UNTIL THAT HAPPENS...EXPECT ANOTHER WARM AND DRY
DAY WITH ABOVE NORMAL TEMPERATURES.  MOST HIGHS SHOULD WARM INTO THE
LOWER (AND MAYBE MIDDLE) 70S. /BUTTS/

SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...THE SHORT TERM
REMAINS RAIN-FREE. AS A COLD FRONT SURGES SOUTHWARD DEEP INTO THE
GULF FRIDAY NIGHT...A STRONG AREA OF SURFACE HIGH PRESSURE (CENTRAL
PRESSURES TO AROUND 1036 MILLIBARS) BUILDS AND EXPANDS OVER THE
MISSISSIPPI RIVER VALLEY ON SATURDAY. TEMPERATURES TREND ABOUT 6 TO
11 DEGREES COLDER FRIDAY NIGHT...RANGING FROM THE MID/UPPER 30S
INTERIOR TO THE MID/UPPER 40S COAST. SATURDAY`S HIGH TEMPERATURES
MUCH COOLER AND FLIPPING TO WELL BELOW SEASONAL...GENERALLY FROM THE
LOWER/MID 50S. WITH CLEAR SKIES...DRY CONDITIONS => WITH MID
TEENS/LOWER 20S DEWPOINTS AND LIGHT WINDS...MAXIMUM RADIATIONAL
COOLING PROCESSES FAVOR COLDEST OVERNIGHT LOW TEMPERATURES DROPPING
OFF INTO THE UPPER HALF OF THE 20S OVER THE INTERIOR SATURDAY NIGHT.

THE AXIS OF THE STRONG HIGH TO OUR NORTH MOVES EAST ACROSS THE
APPALACHIANS ON SUNDAY...THEN OFF THE MID ATLANTIC COAST BY LATE
SUNDAY NIGHT. THIS WILL CAUSE WINDS TO COME BACK AROUND FROM THE
SOUTHEAST AND TEMPERATURES TO BEGIN A SLOW MODERATION TOWARD THE END
OF THE SHORT TERM PERIOD. /10

LONG TERM /MONDAY THROUGH THURSDAY/...NEXT UPPER LEVEL STORM SYSTEM
IS FORECAST TO DROP SOUTHEAST OUT OF THE PLAINS AND PIVOTS ACROSS
THE LOWER MISSISSIPPI RIVER VALLEY ON MONDAY. THE 11.12Z OPERATIONAL
GLOBAL SPECTRAL MODELS DIFFER SUBSTANTIALLY ON TIMING OF
PRECIPITATION MOVING ACROSS THE AREA MONDAY AND MONDAY NIGHT. THE
FASTER SOLUTION IS THE ECMWF AND THE SLOWER SOLUTION...THE GFS.
THOUGH...THERE IS A BIT MORE CONTINUITY BETWEEN THE TWO
MODELS WITH RESPECT TO THE TRACK OF A WAVE OF SURFACE FRONTAL LOW
PRESSURE TO MOVE EAST ACROSS NORTHERN MISSISSIPPI AND NORTHERN
ALABAMA THROUGH THE COURSE OF THE DAY MONDAY. ATTENDANT COLD FRONT
MAKES PASSAGE AND BRINGS A WIND SHIFT TO THE LOCAL AREA MONDAY NIGHT.

GIVEN THE CONTINUED SPREAD IN THE PRECIPITATION TIMING...FORECASTERS
HAVE MADE VERY LITTLE ADJUSTMENTS TO THE CURRENT PACKAGE...KEEPING
THE HIGHEST PROBABILITIES OF PRECIPITATION FOR MONDAY AND SHIFTING
EASTWARD MONDAY EVENING.

THE WIND PROFILES IN BOTH THE GFS AND ECMWF NOW BRING A STRONG 850
MILLIBAR JET STREAK...EASTWARD ACROSS THE LOCAL AREA MONDAY/MONDAY
NIGHT. THE ECMWF IS THE STRONGEST WITH A SPEED MAXIMA OF 45 TO 55
KNOTS. CONSIDERING THIS...ALONG WITH THE INCREASE IN MOISTURE DEPTH
AND LAYER LIFT...THERE IS SOME CONCERN FOR THE POTENTIAL OF STRONG TO
ISOLATED SEVERE STORMS. THE LIMITING FACTOR FOR STORM COVERAGE IS A
LOW DEGREE OF AVAILABLE INSTABILITY. WITH THIS BEING SAID...IT
APPEARS THE POTENTIAL FOR SEVERE STORMS ON MONDAY/MONDAY NIGHT IS
LIMITED. WILL CONTINUE TO MONITOR.

DRIER CONDITIONS TUESDAY THROUGH THURSDAY WITH COOL NIGHTS AND MILD
DAYS. /10

MARINE...NOW THROUGH FRIDAY...MODERATE SOUTHWEST TO WEST WINDS WILL
CONTINUE OVER THE MARINE AREA INTO FRIDAY. WIND SPEEDS WILL BE
SLIGHTLY HIGHER OVER THE GULF OF MEXICO WATERS...AND SMALL CRAFT WILL
LIKELY NEED TO CONTINUE EXERCISING CAUTION THROUGH FRIDAY. A MOIST
AIRMASS ADVECTING OVER THE COOLER WATERS OF THE BAYS AND INLAND
WATERWAYS MAY RESULT IN SOME PATCHY FOG DURING THE PRE-DAWN HOURS.

FRIDAY NIGHT THROUGH TUESDAY NIGHT...A COLD FRONT SHOULD MOVE ACROSS
THE MARINE AREA FRIDAY EVENING...HERALDING A RETURN TO AN OFFSHORE
FLOW. THE COMBINATION OF LOCAL DRAINAGE EFFECTS DURING THESE
SITUATIONS AND A TIGHT PRESSURE GRADIENT BEHIND THE FRONT MAY RESULT
IN SMALL CRAFT ADVISORY CONDITIONS BEING MET OVER THE GULF OF MEXICO
SATURDAY.  WIND SPEEDS SHOULD ABATE BY SATURDAY EVENING...AS WINDS
START VEERING TO A MORE SOUTHERLY DIRECTION.  ANOTHER COLD FRONT IS
FORECAST TO MOVE THROUGH THE MARINE AREA MONDAY NIGHT...WITH
OFFSHORE FLOW RETURNING FOR THE MIDDLE OF THE UPCOMING WEEK. /BUTTS/

&&

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

$$

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