576
FXUS64 KJAN 220151 AAA
AFDJAN
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE JACKSON MS
851 PM CDT THU MAY 21 2026
..NEW MESOSCALE UPDATE, AVIATION
KEY MESSAGES
- THERE WILL BE A MARGINAL RISK FOR A FEW BRIEF WEAK TORNADOES
OVER SOUTHEAST TO EASTERN PORTIONS OF THE AREA EARLY FRIDAY
MORNING.
- THE POTENTIAL FOR HEAVY RAINFALL AND FLOODING WILL CONTINUE
THROUGH THE WEEKEND, PEAKING SUNDAY AND MONDAY.
- WE WILL BE MONITORING THE POTENTIAL FOR ADDITIONAL HEAVY
RAINFALL AND FLASH FLOODING NEXT WEEK.
MESOSCALE UPDATE
ISSUED AT 851 PM CDT THU MAY 21 2026
SHORTWAVE TROUGH IS ANALYZED OVER THE GULF COAST REGION, KEEPING
SOUTHERLY FLOW AND FEED OF MOIST ADVECTION OF NEAR 2 INCH
PRECIPITABLE WATER (PWS) ACROSS THE REGION. ANTICYCLONIC FLOW IS
SITUATED ALONG THE FRONTAL ZONE IN THE DELTA, WITH AREAS OF
MESOSCALE CONVECTIVE VORTICES (MCVS) ENHANCING CONVECTION.
LOCALIZED FLASH FLOODING CANNOT BE RULED OUT, MAINLY THROUGH
THIS EVENING, WITH POTENTIAL FOR ADDITIONAL REDEVELOPMENT
OVERNIGHT. WITH WET GROUND AND MOIST BOUNDARY LAYER, PATCHES OF
FOG CANNOT BE RULED OUT, ESPECIALLY WHERE RAIN COVERAGE DECREASES.
THERE REMAINS POTENTIAL THAT AS TWO STOUT SHORTWAVES SWING
THROUGH THE ARKLATEX INTO THE GULF COAST STATES, ENHANCED MCV
POTENTIAL WILL LEAD TO AN INCREASE IN THE LOW-LEVEL JET (AROUND
25-30KTS). THIS COULD SPARK SOME CELLS THAT COULD EXHIBIT SOME
ROTATION AND LOW PROBS OF TORNADOES OVERNIGHT. ONGOING SEVERE AND
FLASH FLOOD GRAPHICS IN HWO LOOK GOOD. SEASONABLY WARM LOWS ARE
EXPECTED OVERNIGHT, SOME 4F TO 8F ABOVE NORMAL (64F TO 70F).
UPDATES WERE SENT OUT EARLIER. /DC/
DISCUSSION
ISSUED AT 345 PM CDT THU MAY 21 2026
IN THE NEAR TERM, THE NEXT IN A SERIES OF WEAK MCVS HAS COMBINED
WITH A VERY MOIST AIRMASS (PRECIPITABLE WATER NEAR 2 INCHES AND
SURFACE DEWPOINTS IN THE LOWER 70S) AND PEAK HEATING TO INITIATE
ANOTHER ROUND OF SHOWERS/STORMS WITH INTENSE RAINFALL RATES THIS
AFTERNOON. FOLLOWING DAYS OF HEAVY RAINFALL, SOME LOCATIONS ARE
BECOMING MORE FLOOD PRONE AND SENSITIVE TO ADDITIONAL HEAVY
RAINFALL, AND SO HAVE CONTINUED THE LIMITED FLASH FLOOD THREAT
MESSAGING IN OUR HWO GRAPHICS. FLASH FLOOD THREATS WILL TEND TO
PEAK DURING THE DAY INTO THE EVENING, BUT PERSISTENT CONVERGENT
ZONES THAT FOCUS INTENSE RAINFALL RATES FOR LONG DURATIONS COULD
DEVELOP AT JUST ABOUT ANYTIME.
IN ADDITION, AN MCV FORECAST TO CROSS THE AREA LATE TONIGHT INTO
FRIDAY APPEARS IT WILL ENHANCE THE LOW LEVEL SHEAR/VORTICITY IN A
VERY MOIST BOUNDARY LAYER MAKING ANY CONVECTIVE UPDRAFTS MORE
PRONE TO SPINNING UP WEAK AND BRIEF TORNADOES. AFTER ASSESSMENT OF
THE NEAR TERM GUIDANCE LOW LEVEL SHEAR PARAMETERS AND CONVECTIVE
EVOLUTION, IT APPEARS THAT LOCATIONS ALONG THE I-59 CORRIDOR WILL
HAVE PEAK TORNADO THREAT DURING THE 4 AM TO 10 AM TIME FRAME. AN
ADDITIONAL LIMITED FLASH FLOOD THREAT WILL ACCOMPANY THIS MCV AS
WELL.
LOOKING AHEAD, AN UNUSUALLY LONG DURATION OF WET WEATHER WILL
CONTINUE FOR THE FORESEEABLE FUTURE AS A LARGE AND PERSISTENT
TROUGH TO RIDGE LONGWAVE PATTERN REMAINS ANCHORED OVER THE CONUS.
THIS WILL CONTINUE TO BRING OUR REGION A STEADY STREAM OF
SUBTROPICAL MOISTURE WITH SEASONABLY HIGH PRECIPITABLE WATER
VALUES, AND MULTIPLE UPPER LEVEL PERTURBATIONS THAT WILL PROVIDE
LIFT AND HELP INITIATE ADDITIONAL ROUNDS OF CONVECTIVE RAINFALL.
ONCE WE GET TO ABOUT SUNDAY, A GREATER THREAT FOR FLASH FLOODING
SHOULD EVOLVE AS A MORE FAVORABLE SET-UP AND COUPLE UPPER LEVEL
JET INTERACTION MAY TEAM UP WITH THE VERY MOIST AIR TO BRING A
MORE WIDESPREAD HEAVY RAINFALL THREAT. AS OF NOW THIS APPEARS IT
WILL BE OVER MAINLY WESTERN/SOUTHERN PORTIONS OF THE AREA AND HAVE
INCLUDED AN "ELEVATED" FLOOD THREAT IN THIS AREA.
OTHERWISE, IT APPEARS THE THERMODYNAMIC/SHEAR PROFILES WILL NOT
BE PARTICULARLY FAVORABLE FOR SEVERE WEATHER CONCERNS GIVEN THE
DEEP MOISTURE AND INFLUENCE FROM THE SOUTHEAST CONUS RIDGE, BUT AS
IS THE CASE IN THE NEAR TERM, WE'LL NEED TO MONITOR FOR MARGINAL
TORNADO RISKS GIVEN THE POTENTIAL FOR ENHANCED LOW LEVEL SHEAR IN
THE VERY MOIST AIR. AS PREVIOUSLY MENTIONED, IT'S DIFFICULT TO
FIND AN END TO THIS WET PATTERN IN THE GUIDANCE THROUGH MOST OF
THE REMAINDER OF THE MONTH. /EC/
AVIATION
(00Z TAFS)
ISSUED AT 851 PM CDT THU MAY 21 2026
A MIX OF MVFR TO IFR STRATUS (DOWN TO LIFR AT MEI, PIB AND HBG)
IS EXPECTED TONIGHT, AS RAIN AND LOW CEILINGS IMPACT THE AREA.
FLIGHT CATEGORIES WILL REMAIN RESTRICTIVE BEFORE IMPROVING TO
MVFR/VFR THROUGH MID-MORNING (I.E. AFTER 22/14-16Z FRIDAY). BRIEF
PERIODS OF LOWERED FLIGHT CATEGORIES WILL BE POSSIBLE DURING
HEAVIER RAINFALL. /KP/DC/
PRELIMINARY POINT TEMPS/POPS
JACKSON 68 80 68 85 / 90 80 60 70
MERIDIAN 68 81 68 85 / 70 90 80 80
VICKSBURG 67 81 68 85 / 80 60 40 70
HATTIESBURG 70 82 69 85 / 70 90 70 90
NATCHEZ 68 81 69 85 / 90 70 40 80
GREENVILLE 67 81 67 84 / 80 70 40 60
GREENWOOD 67 80 67 85 / 90 80 70 60
JAN WATCHES/WARNINGS/ADVISORIES
MS...NONE.
LA...NONE.
AR...NONE.
DC/EC/KP
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