058
FXUS64 KMOB 251834
AFDMOB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOBILE AL
1234 PM CST SAT JAN 25 2020
DISCUSSION
SEE UPDATED INFORMATION FOR LAND AREAS AND AVIATION
DISCUSSION BELOW.
NEAR TERM UPDATE /THIS AFTERNOON THROUGH SUNDAY NIGHT/
FORECAST
FOR THIS AFTERNOON APPEARS TO BE ON TRACK WITH LIGHT WINDS AND
TEMPERATURES WARMING INTO THE MID TO UPPER 50S UNDER MOSTLY SUNNY
SKIES.
A WEAK MID LEVEL SHORTWAVE OVER THE PLAINS STATES EARLY THIS
EVENING WILL BE MOVING INTO THE SOUTHEAST STATES LATE TONIGHT
THROUGH SUNDAY. THIS WILL BE PUSHING THE SURFACE HIGH PRESSURE
THAT HAS BEEN CENTERED OVER THE AREA OFF TO THE EAST TONIGHT AND
SUNDAY WHILE A SURFACE TROUGH DEVELOPS TO OUR WEST WITH A WEAK
LOW ALONG THE TROUGH OVER THE WEST-CENTRAL GULF OF MEXICO BY LATE
SUNDAY AFTERNOON.
TONIGHT, AS THE SHORTWAVE APPROACHES THE REGION, MID/UPPER LEVEL
CLOUD COVER INCREASES, WITH LIGHT RAIN- SHOWERS BEGINNING TO
APPROACH THE WESTERN BORDER OF THE FORECAST AREA BY AROUND SUNRISE
SUNDAY. WITH THE SURFACE HIGH THAT HAS BEEN OVER OUR AREA
DRIFTING EAST, AND WITH INCREASING MID/UPPER LEVEL CLOUD COVER
TONIGHT, OVERNIGHT RADIATIONAL COOLING WILL BE SOMEWHAT HINDERED
COMPARED TO LAST FEW NIGHTS. LOWS TONIGHT WILL BE CLOSER TO
NORMAL FOR THIS TIME OF THE YEAR, LIKELY RANGE FROM THE UPPER 30S
OVER INTERIOR LOCATIONS TO THE MID AND UPPER 40S ALONG THE COAST
(AND A FEW LOWER 50S ALONG BARRIER ISLANDS AND BEACHES).
ON SUNDAY, AS THE MID LEVEL SHORT WAVE CROSSES OVER THE AREA AND
WITH THE WEAK SURFACE LOW OVER THE GULF WELL TO OUR SOUTHWEST, A
CHANCE FOR RAIN RETURNS TO THE LOCAL FORECAST. WITH VERY LIMITED
MOISTURE OUT AHEAD OF THE SYSTEM, AND WITH MODELS SHOWING VERY
LITTLE IF ANY INSTABILITY, MAINLY ONLY LIGHT SHOWERS ARE
EXPECTED, ALTHOUGH A FEW RUMBLES OF THUNDER CAN'T BE RULED OUT
OUT OVER THE GULF WATERS. RAINFALL TOTALS ARE EXPECTED TO BE LOW,
LESS THAN A QUARTER OF AN INCH, BUT GLOBAL MODELS INDICATE
COVERAGE SHOULD BE WIDESPREAD ENOUGH TO WARRANT GOOD CHANCE TO
LIKELY POPS ACROSS PORTIONS OF THE AREA ON SUNDAY (ESPECIALLY
WESTERN AND COASTAL AREAS) AND WILL MAINTAIN THIS FROM PREVIOUS
FORECAST. IT SHOULD BE NOTED HOWEVER THAT MANY OF THE HIRES MODELS
ARE LESS AGGRESSIVE WITH RAINFALL COVERAGE ON SUNDAY, SO SOME
ADJUSTMENTS COULD BE MADE ON LATER FORECAST UPDATES. DAYTIME HIGHS
ON SUNDAY WILL BE SIMILAR TO THOSE OF SATURDAY (BUT PERHAPS
SLIGHTLY COOLER IN A FEW LOCATIONS), RANGING FROM THE MID 50S OVER
INTERIOR NORTHWEST ZONES TO THE UPPER 50S SOUTHERN ZONES. /12
AVIATION
25/18Z ISSUANCE...VFR CONDITIONS EXPECTED THIS AFTERNOON INTO THE
EVENING HOURS, BUT WILL BE SEEING INCREASING MID AND UPPER LEVEL
CLOUDS LATE THIS AFTERNOON AND THIS EVENING (WHILE WILL NOT IMPACT
OPERATIONS). TOWARD DAYBREAK ON SUNDAY WE WILL START SEE SOME
CLOUD BASES LOWER TO MVFR CRITERIA, WITH MVFR CEILINGS (LOOKING TO
BE AROUND 2500-3000 FEET) DEVELOPING BY LATE MORNING AHEAD OF AN
APPROACHING WEATHER SYSTEM. WITH THIS INCREASING CLOUD COVER TREND
ALSO EXPECT AN INCREASING TREND IN PRECIPITATION, WITH A GOOD
CHANCE OF SHOWERS, ESPECIALLY OVER OUR WESTERN HALF AND COASTAL
SECTIONS OF OUR FORECAST AREA. LIGHT MAINLY NORTHWESTERLY WINDS
THIS THIS EVENING, BECOMING MORE VARIABLE LATE TONIGHT AND SUNDAY.
/12
PREV DISCUSSION
/ISSUED 506 AM CST SAT JAN 25 2020/
DISCUSSION...SEE UPDATED INFORMATION FOR LAND AREAS AND AVIATION
DISCUSSION BELOW.
NEAR TERM UPDATE...NO CHANGED FROM PREVIOUS ISSUANCE. MOSTLY
SUNNY TO SUNNY SKIES AND TEMPERATURES TOPPING OUT IN THE LOW TO
MID 60S EXPECTED TODAY. TONIGHT WILL SEE INCREASING CLOUDS, ALONG
WITH LIGHT RAIN-SHOWERS APPROACHING THE WESTERN BORDER OF THE
FORECAST AREA AT SUNRISE. LOW TEMPERATURES BOTTOMING OUT AROUND 40
INLAND TO LOW TO MID 40S CLOSE TO THE COAST ARE EXPECTED TONIGHT.
/16
AVIATION...
12Z ISSUANCE...VFR CONDITIONS EXPECTED THROUGH THE FORECAST. THE
AREA WILL SEE INCREASING MID LEVEL CLOUDS LATER TODAY THROUGH
TONIGHT, BUT THESE ARE NOT EXPECTED TO IMPACT OPERATIONS. NORTH
WINDS 5 TO 10 KNOTS WILL BECOME LIGHT AND VARIABLE TONIGHT AS LOW
LEVEL HIGH PRESSURE MOVES OVER THE FORECAST AREA.
/16
PREV DISCUSSION... /ISSUED 406 AM CST SAT JAN 25 2020/
NEAR TERM /NOW THROUGH SATURDAY NIGHT/...A MID-LEVEL SHORTWAVE
APPROACHES THE SOUTHEAST FROM OVER THE PLAINS. LOW LEVEL HIGH
PRESSURE CENTERED OVER THE LOWER MISSISSIPPI RIVER SHIFTS EAST OVER
THE FORECAST AREA TODAY THROUGH TONIGHT INTO RESPONSE. FOR TODAY,
EVEN WITH NORTHERLY FLOW OVER THE FORECAST AREA WEAKENING, THE
AIRMASS REMAINS COOL ENOUGH FOR HIGH TEMPERATURES TODAY TO RISE TO,
BUT REMAIN A BIT BELOW SEASONAL NORMS. HIGH TEMPERATURES IN THE
MID TO UPPER 50S EXPECTED ACROSS THE FORECAST AREA TODAY.
TONIGHT, AS THE SHORTWAVE APPROACHES AND BEGINS TO MOVE ACROSS THE
REGION, MID/UPPER LEVEL CLOUD COVER INCREASES, WITH LIGHT RAIN-
SHOWERS BEGINNING TO APPROACH THE WESTERN BORDER OF THE FORECAST
AREA AFTER MIDNIGHT. INCREASING MID/UPPER LEVEL CLOUD COVER WILL
INCREASINGLY INHIBIT OVERNIGHT RADIATIONAL COOLING OF THE COOL
AIRMASS THAT HAS MOVED OVER THE AREA, BUT OVERNIGHT TEMPERATURES
DROPPING CLOSE TO SEASONAL NORMS ARE EXPECTED. LOW TEMPERATURES IN
AROUND 40 INLAND TO LOW TO MID 40S CLOSE TO THE COAST EXPECTED.
/16
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...SUNDAY INTO MONDAY, THE
MID LEVEL SHORTWAVE PASSES OVER THE AREA, BRINGING RAIN-SHOWERS TO
THE FORECAST AREA. WITH LIMITED MOISTURE RETURN AHEAD, AND MODEL
SOUNDINGS SHOWING LITTLE TO NO INSTABILITY PRESENT OVER LAND AREAS,
RAINFALL AMOUNTS ARE EXPECTED TO BE LOW, BUT WIDESPREAD ENOUGH TO
WARRANT SCATTERED TO NUMEROUS WORDING IN THE FORECAST. SOUNDINGS
OVER OPEN GULF WATERS SHOW ENOUGH INSTABILITY TO WARRANT ADDING A
MENTION OF THUNDER TO THE SUNDAY/SUNDAY EVENING TIME FRAME. THE RAIN
AND CLOUD COVER WILL BE SUFFICIENT TO TIGHTEN THE DIURNAL
TEMPERATURE RANGE SUNDAY/SUNDAY NIGHT, WITH HIGH TEMPERATURES SUNDAY
IN THE MID 50S, LOW TEMPERATURES SUNDAY NIGHT IN THE MID TO UPPER
40S.
FOR THE REST OF MONDAY THROUGH MONDAY NIGHT, ZONAL UPPER FLOW
RETURNS TO THE SOUTHEAST. WEAK NORTHERLY LOW LEVEL FLOW MOVES OVER
THE REGION AS THE SHORTWAVE MOVES OFF, BRINGING A BIT DRIER AIR BACK
TO THE FORECAST AREA AND ALLOWING FOR GOOD DAYTIME HEATING/NIGHT
TIME COOLING. HIGH TEMPERATURES MONDAY ARE EXPECTED TO REBOUND TO
THE LOW TO MID 60S, A BIT ABOVE SEASONAL NORMS. LOW TEMPERATURES
MONDAY NIGHT ARE EXPECTED TO DROP INTO THE LOW TO MID 40S, AGAIN.
/16
LONG TERM /TUESDAY THROUGH FRIDAY/...A PROGRESSIVE PATTERN WILL
OCCUR AS TWO MAIN SYSTEMS IMPACT THE REGION. THE FIRST UPPER
CLOSED LOW PRESSURE AREA OVER THE SOUTHERN PLAINS TUESDAY MORNING
WILL ADVANCE EASTWARD, BUT QUICKLY EVOLVE INTO AN OPEN WAVE BEFORE
REACHING THE ARKLATEX REGION. THIS SHORTWAVE WILL THEN PASS OVER
THE LOWER MISSISSIPPI RIVER WEDNESDAY MORNING, AND THEN OVER THE
FORECAST AREA WEDNESDAY AFTERNOON. A WEAK LOW PRESSURE CENTER
REFLECTED AT THE SURFACE ACROSS TEXAS TUESDAY MORNING WILL ALSO
MOVE EAST, TRACKING JUST SOUTH OF THE NORTHERN GULF COAST TUESDAY
NIGHT THROUGH WEDNESDAY AFTERNOON. THIS TRACK WILL KEEP THE
FORECAST AREA IN THE COOL SECTOR, ALONG WITH A NORTHEASTERLY WIND
FLOW, SO CONVECTION WILL BE SHALLOW WITH NO THUNDERSTORMS
EXPECTED. MODELS ARE IN GOOD AGREEMENT WITH THE TIMING OF THIS
SYSTEM, SO EXPECTING DRY CONDITIONS TUESDAY, FOLLOWED BY ISOLATED
TO SCATTERED RAIN SHOWERS SPREADING FROM WEST TO EAST ACROSS THE
AREA TUESDAY EVENING. THESE LIGHT TO MODERATE ISOLATED TO
SCATTERED RAIN SHOWERS WILL PERSIST LATE TUESDAY NIGHT AND
WEDNESDAY MORNING BEFORE TAPERING OFF WEDNESDAY AFTERNOON. A BRIEF
DRY PATTERN WILL THEN OCCUR WEDNESDAY NIGHT THROUGH THURSDAY
AFTERNOON AS SURFACE HIGH PRESSURE BUILDS IN FROM THE NORTH.
THE SECOND UPPER CLOSED LOW PRESSURE AREA WILL BE FURTHER SOUTH OVER
THE RED RIVER VALLEY FRIDAY MORNING BEFORE ADVANCING EASTWARD. THIS
SYSTEM WILL ALSO EVOLVE INTO AN OPEN WAVE BEFORE REACHING LOUISIANA.
THE MODELS DIFFER IN THE TIMING AND MAGNITUDE OF THE SHORTWAVE
BEYOND THIS, WITH THE ECMWF BEING FASTER AND WEAKER COMPARED THE
STRONGER AND SLOWER GFS, SO THE NBM OFFERS A NICE SOLUTION BETWEEN
THE TWO. WHILE WE ARE CURRENTLY FORECASTING PRECIPITATION FROM
THURSDAY NIGHT THROUGH FRIDAY NIGHT, THIS WINDOW WILL LIKELY SHORTEN
AS THE MODELS BECOME MORE ALIGNED AS THE EVENT APPROACHES.
NATURALLY, THE LOW PRESSURE CENTERS ARE ALSO OFFSET AT THIS TIME.
THE ECMWF HAS OUR AREA IN THE COOL SECTOR WITH THE LOW TRACKING OVER
THE GULF OF MEXICO, BEFORE IT LIFTS NORTHEAST FRIDAY NIGHT AND
WEAKENS, WHILE THE GFS HAS OUR AREA IN A WARM SECTOR WITH THE LOW
TRACKING FROM SOUTHERN LOUISIANA, BEFORE IT LIFTS NORTHEAST FRIDAY
NIGHT AND DEEPENING. FOR NOW, HAVE KEPT ANY MENTION OF THUNDERSTORMS
OUT OF THE FORECAST PENDING BETTER MODEL CONSISTENCY AND FORECASTER
CONFIDENCE.
HIGH TEMPERATURES WILL BE IN THE LOW TO MID 60S TUESDAY, WITH UPPER
50S TO LOWER 60S WEDNESDAY AND THURSDAY. HIGH TEMPERATURES FRIDAY
WILL DEPEND ON THE TRACK OF THE SURFACE LOW. LOW TEMPERATURES WILL
MAINLY BE IN THE 40S TUESDAY NIGHT THROUGH THURSDAY NIGHT. /22
MARINE...LIGHT TO AT TIMES MODERATE OFFSHORE FLOW SATURDAY WILL
TRANSITION TO A MODERATE EAST TO SOUTHEAST SUNDAY INTO SUNDAY NIGHT
AS A WEAKLY ORGANIZED SURFACE LOW MOVES EAST OVER THE CENTRAL GULF
OF MEXICO. LIGHT TO AT TIME MODERATE OFFSHORE FLOW FOLLOWS BEGINNING
LATER SUNDAY NIGHT AND LASTING INTO MID WEEK, WHEN A SECOND SURFACE
LOW PASSES SOUTH OF AREA COASTAL WATERS. THIS LOW WILL BRING
MODERATE TO AT TIMES STRONG EASTERLY FLOW TO MAINLY OPEN WATERS LATE
TUESDAY NIGHT THROUGH WEDNESDAY. /16
MOB WATCHES/WARNINGS/ADVISORIES
AL...NONE.
FL...NONE.
MS...NONE.
GM...NONE.
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