931
FXUS64 KJAN 201125 AAA
AFDJAN
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE JACKSON MS
525 AM CST THU FEB 20 2020
UPDATE
UPDATED FOR 12Z AVIATION DISCUSSION
AVIATION
12Z TAF DISCUSSION:
MVFR/IFR FLIGHT CATEGORIES WILL PERSIST THROUGH THE MORNING AND
AFTERNOON HOURS AS A DISTURBANCE PUSHES THROUGH THE REGION,
RESULTING IN WIDESPREAD RAIN AND LOW CLOUDS ACROSS THE REGION. LATE
THIS AFTERNOON AND OVERNIGHT, BOTH CLOUDS AND RAIN WILL SHIFT OUT OF
THE REGION, RESULTING IN A RETURN TO VFR FLIGHT CATEGORIES AREAWIDE
BY DAY BREAK FRIDAY. WINDS TODAY, AND CONTINUING THROUGH THIS
EVENING, WILL BECOME GUSTY FROM THE NORTH. SUSTAINED NORTH WINDS
WILL BE BETWEEN 13-17 KNOTS, GUSTING BETWEEN 21-26 KNOTS, TODAY. IN
THE DELTA, SUSTAINED WINDS WILL BE HIGHER AND SUSTAINED BETWEEN 17-
21 KNOTS, GUSTING BETWEEN 26-30 KNOTS. WINDS WILL BEGIN TO SUBSIDE A
BIT LATER THIS EVENING, BUT WILL REMAIN BREEZY OVERNIGHT AND INTO
EARLY FRIDAY MORNING. /19/
DISCUSSION
TODAY AND TONIGHT: WITH A FRONT SOUTH OF THE FORECAST AREA, A
DISTURBANCE ALOFT TRAVERSING THE REGION WILL CONTINUE TO RESULT IN
RAIN FALLING ACROSS MUCH OF THE CWA THROUGH THE MORNING AND A
GOOD BIT OF THE AFTERNOON. INCREASED MOISTURE ASCENT FROM THE
SOUTHWEST OVER THE FRONT, IS RESULTING IN A MORE MODERATE TO HEAVY
BAND OF RAIN PROPAGATING EAST GENERALLY ALONG THE INTERSTATE 20
CORRIDOR, WHERE A FLASH FLOOD WATCH REMAINS IN EFFECT UNTIL 9 AM
TODAY. IN THE WATCH AREA, 1-3 INCHES OF RAINFALL IN A SHORT AMOUNT
OF TIME WILL BE LIKELY. GIVEN THE EXTREMELY SATURATED SOIL
CONDITIONS ACROSS THE AREA, THIS COULD RESULT IN SOME LOCALIZED
FLASH FLOODING. HOWEVER AND MORE IMPORTANTLY, IT COULD WORSEN
ONGOING RIVER FLOODING.
AS THE MORNING PROGRESS, THIS ASCENT WILL WEAKEN AND SLIDE
FURTHER EAST OF THE REGION, WITH RAINFALL BECOMING MORE LIGHT TO
OCCASIONALLY MODERATE IN NATURE DURING THE LATE MORNING AND
AFTERNOON. MEANWHILE, SURFACE AND LOW LEVEL WINDS WILL BECOME
INCREASING NORTHERLY AS STRONG HIGH PRESSURE BEGINS RAPIDLY BUILDING
INTO THE REGION FROM THE NORTHWEST. RAIN WILL ALSO STEADILY END FROM
NORTHWEST TO SOUTHEAST LATE THIS AFTERNOON INTO EARLY THIS EVENING
AS THE SURFACE HIGH BUILDS IN FROM THE NORTHWEST.
THE RESULTING TIGHT PRESSURE GRADIENT OVER THE FORECAST AREA WILL
CAUSE GUSTY NORTHERLY WINDS ACROSS MUCH OF THE CWA BY LATE MORNING,
AND CONTINUING INTO EARLY THIS EVENING. SUSTAINED WINDS WILL
GENERALLY BE BETWEEN 15-20 MPH, GUSTING BETWEEN 25-30 AT TIMES.
HOWEVER, IN THE DELTA, WINDS ARE EXPECTED TO BE SUSTAINED BETWEEN 20-
25 MPH, WITH GUSTS BETWEEN 30-35 MPH POSSIBLE. AS A RESULT, I'VE
HIGHLIGHTED MUCH OF THE WESTERN PORTION OF THE CWA WITH A "LIMITED
THREAT" FOR STRONG WINDS THROUGH THIS AFTERNOON.
COLD ADVECTION WILL BE ONGOING THIS EVENING AND OVERNIGHT, AS A
STRONG TROUGH DROPS EAST SOUTHEAST INTO THE SOUTHEAST UNITED STATES
EARLY FRIDAY MORNING. THIS WILL RESULT IN A NOTICEABLY COLDER DRIER
AIRMASS OVER THE REGION AS DAY BREAKS ON FRIDAY. AS SKIES CLEAR
THROUGH THE OVERNIGHT HOURS, LOWS EARLY FRIDAY MORNING WILL RANGE
FROM THE MIDDLE 20S TO LOWER 30S. /19/
FRIDAY THROUGH THURSDAY: THE PERIOD WILL START OUT COLDER THAN
NORMAL AND DRY AS NORTHWEST FLOW ALOFT CONTINUES FRIDAY AND A 1040MB
HIGH DROPS OVER OUR REGION. DESPITE NEAR FULL INSOLATION FRIDAY CAA
WILL HOLD TEMPERATURES IN THE 40S AT MOST LOCATIONS BUT OUR
SOUTHEAST MOST ZONES WILL SEE LOWER 50S. NORTHWEST FLOW ALOFT WILL
CONTINUE FRIDAY NIGHT AS THE SURFACE HIGH BECOMES CENTERED OVER OUR
CWA. THIS WILL LEAD TO PRIME RADIATIONAL COOLING OF OUR COLD DRY
AIRMASS AND RESULT IN THE COLDEST MORNING OF THE FORECAST PERIOD
SATURDAY. GUIDANCE HAS TRENDED COLDER AND MORNING LOWS LOOK TO BE IN
THE MID TO UPPER 20S AREAWIDE. SHORTWAVE RIDGING ALOFT WILL MOVE
OVER OUR REGION SATURDAY WHILE THE SURFACE HIGH SHIFTS EAST OF
MISSISSIPPI. A LIGHT RETURN FLOW WILL RESULT BY AFTERNOON HELPING
TEMPERATURES CLIMB IN THE 50S AS A GRADUAL WARMING TREND STARTS
SATURDAY. AFTERNOON HIGHS WILL STILL BE COOLER THAN NORMAL SATURDAY.
DRY WEATHER WILL CONTINUE SATURDAY NIGHT INTO SUNDAY MORNING
ALTHOUGH CLOUDS WILL BEGIN TO INCREASE AHEAD OF THE NEXT APPROACHING
LOW PRESSURE SYSTEM. MODELS ARE IN DECENT AGREEMENT INITIALLY THAT A
CLOSED LOW OVER THE FOUR CORNERS REGION SUNDAY MORNING WILL TRACK
EAST THROUGH THE DAY BUT DIFFER ON HOW FAST THE LOW OPENS UP OVER
THE CENTRAL PLAINS SUNDAY NIGHT INTO MONDAY. MOISTURE WILL INCREASE
OVER OUR CWA SUNDAY AHEAD OF THE THIS SYSTEM AND CONSENSUS SUGGESTS
RAIN CHANCES WILL RETURN TO OUR WESTERN ZONES SUNDAY AFTERNOON. RAIN
CHANCES WILL INCREASE THROUGH MONDAY INCLUDING A FEW STORMS DURING
THE DAY. THE ASSOCIATED COLD FRONT IS EXPECTED TO MOVE ACROSS OUR
CWA MONDAY NIGHT. THE COLD FRONT IS EXPECTED TO CLEAR OUR CWA BY
TUESDAY MORNING BUT OUR WINDS ALOFT WILL QUICKLY BECOME
SOUTHWESTERLY AGAIN TUESDAY AHEAD OF A SHORTWAVE TROUGH DROPPING
OVER THE CENTRAL CONUS. MODELS DIFFER SIGNIFICANTLY WITH DEEPNESS
AND EVOLUTION OF THE TROUGH BUT COOLER THAN NORMAL TEMPERATURES WITH
LOW CHANCES OF LIGHT RAIN ARE EXPECTED TUESDAY NIGHT THROUGH
WEDNESDAY. COOLER THAN NORMAL TEMPERATURES AND DRY WEATHER IS
EXPECTED WEDNESDAY NIGHT THROUGH THURSDAY. /22/
PRELIMINARY POINT TEMPS/POPS
JACKSON 49 30 48 28 / 100 8 0 0
MERIDIAN 49 29 49 25 / 100 13 0 0
VICKSBURG 48 30 46 27 / 100 4 0 0
HATTIESBURG 55 33 51 28 / 100 22 0 0
NATCHEZ 49 30 47 28 / 100 10 0 0
GREENVILLE 46 28 43 27 / 100 3 0 0
GREENWOOD 47 27 45 25 / 100 4 0 0
JAN WATCHES/WARNINGS/ADVISORIES
MS...FLASH FLOOD WATCH UNTIL 9 AM CST THIS MORNING FOR MSZ035>059-
062>066.
LA...FLASH FLOOD WATCH UNTIL 9 AM CST THIS MORNING FOR LAZ008-009-015-
016-023-025.
AR...NONE.
19
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