633
FXUS64 KMOB 162320
AFDMOB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOBILE AL
520 PM CST WED JAN 16 2019
DISCUSSION
UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
AVIATION
00Z ISSUANCE...MOSTLY CLEAR SKIES AND LIGHT WINDS PREVAIL
OVERNIGHT TONIGHT. SOUTH WINDS AROUND 10 KNOTS EXPECTED SATURDAY
AS CLOUD COVER INCREASES AND SCATTERED SHOWERS MOVE IN FROM THE
WEST. CIGS ARE GENERALLY EXPECTED TO REMAIN AT VFR LEVELS. /49
PREV DISCUSSION
/ISSUED 358 PM CST WED JAN 16 2019/
NEAR TERM /NOW THROUGH THURSDAY/...SURFACE HIGH PRESSURE WILL
SHIFT EAST OF THE FORECAST AREA OVERNIGHT INTO THURSDAY, BRINGING
RETURN FLOW OFF THE GULF OF MEXICO BACK TO THE AREA TONIGHT INTO
THURSDAY. THURSDAY, A WEAK SURFACE COLD FRONT MOVES TOWARDS THE
FORECAST AREA FROM THE NORTHWEST AS A WEAK UPPER SHORTWAVE BEGINS TO
PASS THE AREA, BRINGING INCREASING MID LEVEL CLOUD COVER TO THE
AREA. THURSDAY, THE BEST COMBINATION OF MOISTURE RETURN, UPPER
DYNAMICS AND THE POSITION OF THE SURFACE FRONT REMAIN NORTHWEST OF
THE FORECAST AREA FOR RAIN DEVELOPMENT, BUT CLOSE ENOUGH TO BRING
ISOLATED TO SCATTERED RAINSHOWERS TO PORTIONS OF THE FORECAST AREA
GENERALLY NORTHWEST OF THE ALABAMA RIVER. OVERNIGHT TONIGHT,
TEMPERATURES BEGIN TO REBOUND WITH THE RETURN OF SOUTHERLY FLOW,
WITH AROUND SEASONAL LOW TEMPERATURES EXPECTED TONIGHT (UPPER 30S
INLAND TO LOW 40S NEAR THE COAST). THURSDAY, THE INCREASING CLOUD
COVER WILL HELP TO LIMIT DAYTIME HEATING, BUT AM STILL EXPECTING
DAYTIME HIGHS (GENERALLY 60 - 65) A BIT ABOVE SEASONAL NORMS.
16/SAM
SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...A COLD FRONT WILL
MOVE INTO THE SOUTHEAST AND STALL THURSDAY NIGHT AS A STRONGER SYSTEM
BEGINS TO DEVELOP TO THE WEST. THE FRONT WILL REMAIN NEARLY STATIONARY
OVER THE SOUTHEASTERN STATES THROUGH MOST OF FRIDAY, THEN BEGIN TO
MOVE NORTH AS A WARM FRONT LATE FRIDAY AND SATURDAY AS LOW PRESSURE
DEVELOPS ACROSS THE SOUTHERN PLAINS AND MOVES EAST. ONLY ISOLATED
TO SCATTERED POPS EXPECTED THURSDAY NIGHT INTO FRIDAY WITH LIMITED
LOW LEVEL MOISTURE AND WEAK DYNAMICS. SOUTHERLY FLOW WILL INCREASE
FRIDAY NIGHT THROUGH THE DAY ON SATURDAY AS THE LOW AND ASSOCIATED
COLD FRONT APPROACH FROM THE WEST. THIS SOUTHERLY FLOW WILL TRANSPORT
DEEP LAYER MOISTURE NORTHWARD ACROSS THE REGION, ALLOWING FOR THE
DEVELOPMENT OF WIDESPREAD SHOWERS AND SCATTERED THUNDERSTORMS
DURING THE DAY ON SATURDAY AS THE COLD FRONT MOVES EAST ACROSS OUR
AREA. THIS WILL BE A FAST MOVING FRONT, THEREFORE RAIN AMOUNTS ARE
NOT EXPECTED TO BE EXCESSIVE.
MODELS STILL INDICATE THAT INSTABILITY WILL BE RATHER WEAK OVER
MOST OF OUR FORECAST AREA DUE TO WIDESPREAD CLOUDS AND PRECIP OUT
AHEAD OF THE FRONT, BUT MAY HAVE A SMALL POCKET OF SURFACE BASED
CAPE OF 330-500 J/KG OVER OUR COASTAL COUNTIES AROUND MIDDAY
SATURDAY. HOWEVER, MODELS ALSO STILL INDICATE RATHER STRONG
VERTICAL WIND SHEAR OVER MOST OF OUR AREA, WHICH MAY ALLOW FOR A
FEW HIGHER WIND GUSTS WITH ANY STRONGER STORMS THAT DEVELOP. THE
CURRENT GFS IS INDICATING AN SOUTHWESTERLY 850 MB JET OF 55 KNOTS
TO NEAR 65 KNOTS OVER OUR NORTHWESTERN ZONES AROUND MIDDAY. IT
APPEARS AT THIS TIME THAT THE BETTER DYNAMICS ARE SLIGHTLY OUT OF
PHASE WITH THE BETTER INSTABILITIES, SO WHILE AN ISOLATED STRONG
OR SEVERE STORM IS POSSIBLE, WIDESPREAD SEVERE STORMS ARE NOT
EXPECTED. SHOWERS AND STORMS END WEST TO EAST SATURDAY NIGHT.
ON SATURDAY, DURING THE PERIOD OF STRONGEST ONSHORE FLOW, WILL BE
LOOKING AT A PROBABLY HIGH RISK OF RIP CURRENTS ALONG AREA GULF
BEACHES.
HIGHS WILL CLIMB INTO THE UPPER 60S AND LOWER 70S FRIDAY AND
SATURDAY. MORE OF A ROLLER COASTER RIDE FOR LOWS, WITH THURSDAY
NIGHT MIN TEMPS IN THE LOW 50S INLAND TO UPPER 50S COASTAL, FRIDAY
NIGHT MID 50S TO LOWER 60S. QUITE A BIT COOLER AGAIN SATURDAY
NIGHT AS THE FRONT EXITS, WITH LOWS RANGING FROM THE MID/UPPER 30S
NORTHWEST COUNTIES TO THE MID 40S COASTAL AREAS AND SOUTHEAST
COUNTIES. 12/DS
LONG TERM /SUNDAY THROUGH WEDNESDAY/...COLD BUT DRY HIGH PRESSURE
WILL BUILD EAST ACROSS THE AREA EARLY SUNDAY THROUGH LATE MONDAY.
RAINFREE AND COLD CONDITIONS ARE EXPECTED DURING THIS TIME. BY
WEDNESDAY RETURN FLOW OFF OF THE GULF SETS UP AND A WARMING AND
MOISTENING TREND BEGINS. DAYTIME HIGHS NOT WARMING MUCH MORE THAN
MID/UPPER 40S TO LOWER 50S SUNDAY AND MONDAY, THEN IN THE MID/UPPER
50S TO LOWER 60S ON TUESDAY AND WEDNESDAY. COLDEST NIGHT IN LONG
TERM PERIOD WILL BE SUNDAY NIGHT, WITH LOWS RANGING FROM THE UPPER
20S OVER MOST OF THE INTERIOR NORTH OF THE I-10 CORRIDOR, TO THE
LOWER 30S SOUTH OF I-10 WITH SOME MID TO UPPER 30S ALONG THE
IMMEDIATE COAST. NIGHTTIME LOWS GRADUALLY WARMING BACK INTO THE
40S MONDAY AND TUESDAY NIGHTS, WITH A FEW LOWER 50S ALONG THE
COAST TUESDAY NIGHT. EARLY IN THE LONG TERM PERIOD, A BREEZY NORTHWEST
WIND WILL MAY IT FEEL EVEN COLDER THAN THE ACTUAL TEMPERATURES
ARE. AS TEMPS MODERATE SLIGHTLY TOWARD THE END OF THE PERIOD, WILL
ALSO BE LOOKING AT A GRADUAL INCREASE IN LOW/MID LEVEL MOISTURE AS
RETURN FLOW DEVELOPS, ALONG WITH A CHANCE OF RAIN RETURNING TO THE
AREA. 12/DS
MARINE...SURFACE HIGH PRESSURE OVER THE AREA WILL SHIFT EAST
OVERNIGHT, BRINGING SOUTHERLY FLOW BACK TO AREA WATERS LATER TONIGHT
INTO THURSDAY. WINDS WILL REMAIN GENERALLY LIGHT INTO FRIDAY, THEN
STRENGTHEN LATER FRIDAY AND ESPECIALLY INTO SATURDAY AS A COLD
FRONT APPROACHES THE AREA, BECOMING MODERATE TO STRONG FRIDAY
NIGHT AND STRONG ON SATURDAY. SEAS BUILD IN RESPONSE TO THE
INCREASING FLOW, AND WE ARE EXPECTING A SMALL CRAFT ADVISORY TO
BE ISSUED BEGINNING LATE FRIDAY NIGHT AT THE EARLIEST. A STRONG
COLD FRONT MOVES OVER THE AREA LATER SATURDAY INTO SATURDAY NIGHT,
BRINGING STRONG OFFSHORE WINDS TO AREA WATERS BY SUNDAY. GUIDANCE
IS ADVERTISING WINDS BEHIND THE FRONT BEING STRONG ENOUGH FOR
OCCASIONAL WIND GUSTS TO GALE FORCE SATURDAY NIGHT THROUGH SUNDAY,
AND WITH STRONG COLD ADVECTION BEHIND THE FRONT, AM AGREEING.
WINDS AND SEAS BEGIN TO EASE SUNDAY NIGHT AS SURFACE HIGH PRESSURE
MOVES TOWARDS THE AREA, AND RETURN TO ONSHORE BY MONDAY NIGHT AS
THE SURFACE HIGH MOVES EAST OF THE AREA. 16/SAM
MOB WATCHES/WARNINGS/ADVISORIES
AL...NONE.
FL...NONE.
MS...NONE.
GM...NONE.
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