799
FXUS64 KJAN 061506 AAB
AFDJAN
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE JACKSON MS
1006 AM CDT WED MAY 6 2026
..NEW MESOSCALE UPDATE
KEY MESSAGES
- SEVERE STORMS CAPABLE OF PRODUCING TORNADOES, SOME POSSIBLY
STRONG, DAMAGING WINDS AND LARGE HAIL, ARE LIKELY THIS AFTERNOON
INTO EARLY THURSDAY.
- LOCALLY HEAVY RAINFALL AND AREAS OF FLOODING ARE LIKELY, WITH
FURTHER DROUGHT RELIEF EXPECTED.
MESOSCALE UPDATE
ISSUED AT 1005 AM CDT WED MAY 6 2026
REST OF TODAY...THE THREAT FOR SEVERE STORMS REMAINS ACROSS THE
ENTIRE FORECAST AREA LATER THIS AFTERNOON INTO EARLY THURSDAY. UNTIL
THEN, WARM ADVECTION SHOWERS HAVE ALREADY DEVELOPED BENEATH THE
CAPPING INVERSION, WHICH IS FAIRLY STOUT ACCORDING TO THIS MORNING'S
12Z KJAN RAOB. THIS TREND IS FORECAST TO CONTINUE THROUGH THE
MORNING HOURS INTO EARLY THIS AFTERNOON AS A COLD FRONT, WHICH IS
CURRENTLY ORIENTED ACROSS THE FORECAST AREA ALONG A NORTHEAST TO
SOUTHWEST LINE EXTENDING FROM AROUND GREENWOOD, MS TO AROUND
BASTROP, LA. AS DAYTIME HEATING CONTINUES INTO MID-AFTERNOON,
STORMS ARE FORECAST TO BEGIN DEVELOPING ALONG AND NEAR THIS FRONT AS
IT SLOWLY MOVES MORE INTO EAST CENTRAL LOUISIANA AND CENTRAL AND
NORTHEAST MISSISSIPPI. THIS IS WHEN THE THREAT FOR SEVERE STORMS
WILL BEGIN TO INCREASE, AS THESE STORMS WILL HAVE THE POTENTIAL FOR
PRODUCING WIND GUSTS TO 70 MPH AND UP TO GOLF BALL SIZE HAIL.
AS WE MOVE INTO THE LATE AFTERNOON AND EVENING HOURS, AN AREA OF
ASCENT LIFTS NORTHEAST ACROSS THE REGION. WITH THE EXPECTED
WEAKENING CAPPING INVERSION, INCREASING INSTABILITY, STEEP MID-LEVEL
LAPSE RATES, AND INCREASING OVERALL WIND SHEAR AND LENGTHENING
HODOGRAPHS, THE POTENTIAL FOR SEVERE STORMS INCREASES FURTHER, WITH
THE THREAT OF TORNADOES LIKEWISE INCREASING, SOME OF WHICH COULD BE
STRONG. THIS WILL ESPECIALLY BE THE CASE WITHIN AN AREA CURRENTLY
STRETCHING FROM NEAR COLUMBUS, MS TO NEAR RAYVILLE, LA TO NEAR
NATCHEZ, MS AND TO NEAR LAUREL, MS, WHERE AN "ENHANCED RISK" FOR
SEVERE STORMS EXISTS. OUTSIDE OF THIS AREA AND ACROSS THE REMAINDER
OF THE CWA, A "SLIGHT RISK" FOR SEVERE STORMS RESIDES. DAMAGING
WINDS TO 70 MPH, TORNADOES, AND QUARTER TO GOLF BALL SIZE HAIL WILL
BE POSSIBLE.
NOW WITH ALL THAT SAID, THERE ARE SOME "FLIES IN THE OINTMENT" THAT
COULD INDEED HAMPER THE DEVELOPMENT OF STORMS, ALONG WITH THEIR
POTENTIAL INTENSITY TODAY. MUCH OF IT IS WHAT WE'RE CURRENTLY
SEEING ACROSS THE AREA AT THE TIME OF THIS DISCUSSION. THE
COMBINATION OF MASKING CLOUD COVER AND LIGHT WARM ADVECTION SHOWERS
COULD LIMIT HEATING ACROSS THE AREA TODAY. THIS WOULD BRING INTO
QUESTION LATER THIS AFTERNOON AND EVENING WHETHER OR NOT THE CAPPING
INVERSION BECOMES THE DOMINATE FEATURE THAT LIMITS THE DEVELOPMENT
OF ROBUST CONVECTION. THIS WILL CONTINUE TO MONITORED DURING THE
DAY THROUGH OBSERVATIONS, HIGH-RES MODEL DATA, AND A SPECIAL KJAN
RAOB THAT'S EXPECTED TO BE RELEASED EARLY THIS AFTERNOON.
IN ADDITION TO THE SEVERE WEATHER THREAT TODAY, AN "ELEVATED THREAT"
FOR FLASH FLOODING DUE TO HEAVY RAINFALL AND TRAINING OF CONVECTION
IS LIKELY GIVEN THE INCREASE IN ATMOSPHERIC MOISTURE ACROSS THE
REGION, 2-2.25 INCH PRECIPITABLE H2O VALUES ADVERTISED. THIS WILL
PARTICULARLY BE THE CASE ACROSS PORTIONS OF EAST CENTRAL LOUISIANA
AND INTO PORTIONS OF CENTRAL, EAST CENTRAL, AND SOUTH MISSISSIPPI.
HERE, RAINFALL AMOUNTS OF 3-5 INCHES, AND LOCALLY HIGHER, WILL BE
POSSIBLE IN A SHORT AMOUNT OF TIME. ELSEWHERE, A "LIMITED THREAT"
FOR FLASH FLOODING EXISTS WITH RAINFALL AMOUNTS RANGING FROM 2-3
INCHES WILL BE POSSIBLE IN A SHORT AMOUNT OF TIME.
THE ONGOING FORECAST IS CURRENTLY IN GOOD SHAPE. HWO GRAPHICS WILL
BE UPDATED ACCORDINGLY THROUGH THE COURSE OF THE DAY TO REFLECT OUR
LATEST THINKING AND COLLABERATIVE EFFORTS WITH BOTH SPC AND WPC IN
TERMS OF SEVERE RISK AND HEAVY RAINFALL THREAT AREAS. OTHERWISE,
OTHER THAN SOME MINOR TWEAKS TO HOURLY ELEMENTS OF THE FORECAST
BASED ON CURRENT TRENDS, NO MAJOR CHANGES WILL BE MADE ON THIS
MORNING'S FORECAST UPDATE. /19/
DISCUSSION
ISSUED AT 529 AM CDT WED MAY 6 2026
TODAY THROUGH EARLY NEXT WEEK...
TODAY AND THURSDAY: WATER VAPOR AND SYNOPTIC IMAGERY EARLY THIS
MORNING DEPICT LONGWAVE TROUGH AXIS STRETCHED FROM BAJA PENINSULA TO
DESERT SOUTHWEST AND EXTENDING NORTHEAST TO THE COLD CORE OVER
EASTERN CANADA AND THE HUDSON BAY AREA. THIS IS HELPING
SOUTHWESTERLY FLOW BECOME ENTRENCHED IN THE AREA AND MOIST ASCENT TO
CONTINUE TO FEED INTO THE AREA. GOES EAST SATELLITE DERIVED TOTAL
PRECIPITABLE WATER (PWS) INDICATE MOIST ASCENT HAS REALLY MOISTENED
THE DEEP ATMOSPHERIC COLUMN (AROUND ONE AND A HALF INCHES TO ONE AND
THREE QUARTER INCHES). THIS IS DRIVING WIDESPREAD CLOUDINESS ACROSS
THE REGION, WITH FRONTAL ZONE DRAPED ACROSS CENTRAL TX INTO THE
ARKLATEX AND MID SOUTH. THERE CONTINUES TO BE JUXTAPOSITION OF LAPSE
RATES, DESTABILIZATION ALOFT (MUCAPE AROUND 1000 J/KG) AND DEEP
LAYER EFFECTIVE BULK SHEAR (50-55KTS) TO SUPPORT A LOW END SEVERE
THREAT THROUGH DAYBREAK IN THE DELTA. THERE IS SOME CONVECTION
ONGOING ACROSS SOUTHEAST AR THAT MAY SUPPORT SOME ISOLATED SEVERE
STORMS, WITH DAMAGING WIND GUSTS AND HAIL THREAT, THROUGH DAYBREAK.
WILL CONTINUE THE ONGOING HWO SEVERE GRAPHIC THIS MORNING.
MAIN CONCERNS TURNS TO THE SEVERE STORMS EXPECTED AND HEAVY RAIN AND
FLASH FLOOD POTENTIAL THIS AFTERNOON INTO TONIGHT. AS THE FRONT SAGS
SOUTHWARD THROUGH TODAY, MOIST ASCENT WILL BRING INCREASED COVERAGE
OF RAIN AND STORM COVERAGE WILL BEGIN TO PICK UP INTO THE AFTERNOON.
BROAD ZONE OF INCREASED DEEP LAYER SHEAR (0-1KM AROUND 20-30KTS, 0-
3KM AROUND 35-40KTS AND 0-6KM AROUND 55-70KTS), STEEPENING LAPSE
RATES/VERTICAL TOTALS AND DESTABILIZATION (1500-2500 J/KG MLCAPE AND
2500-3500 J/KG MUCAPE). THIS ENVIRONMENT WILL SUPPORT A STORM MODE
OF PREDOMINATELY SUPERCELL AND BOWING SEGMENTS, WITH SOME SPLITTING
CELL STORM MODE AS WELL. ALL MODES OF SEVERE WEATHER REMAIN LIKELY,
INCLUDING TORNADOES, DAMAGING WIND GUSTS UP TO 70MPH AND LARGE HAIL
UP TO GOLF BALL SIZE. WITH AN INCREASE IN THE LOW-LEVEL JET (LLJ)
INTO THE AFTERNOON TO EVENING, A RAMP UP IN TORNADO POTENTIAL WILL
INCREASE ON THE EDGE OF A SIGNIFICANT TORNADO PARAMETER (STP)
GRADIENT. THIS GRADIENT HAS SHIFTED FROM THE NORTHERN HALF OF THE
NATCHEZ TRACE CORRIDOR TO FURTHER SOUTHWARD INTO THE INTERSTATE 20
CORRIDOR. CONVECTIVE ALLOWING MODELS, INCLUDING THE HRRR, ARW AND
FV3, AND ENSEMBLES (REFS AND HREF), ARE NARROWING THE CORRIDOR
CLOSER TO ALONG AND SOUTH OF THE INTERSTATE 20 CORRIDOR. THERE WILL
BE LARGE ELEVATED MIXED LAYER (EML) CAPPING INVERSION THAT WILL
GRADUALLY ERODE WITH DAYTIME HEATING AND MIXING OF THE PLANETARY
BOUNDARY LAYER (PBL) AND AS ASCENT WEAKENS THE CAP. CONVECTIVE
INITIATION (CI) SHOULD DEVELOP AROUND 1-3PM, WITH THE PRIMARY SEVERE
WEATHER THREAT AFTER AROUND 3-4PM ONWARD. THIS WILL ONLY HEIGHTEN AS
THE LLJ INCREASES INTO THE EVENING, WITH THE STRONG TORNADO
POTENTIAL BECOMING HEIGHTENED IN THIS TIMEFRAME INTO LATE AFTERNOON
AND EVENING HOURS. RECENT MODEL TRENDS IN UPDRAFT HELICITY (UH)
TRACKS HAVE SHIFTED SOUTHWARD TO ALONG AND SOUTH OF THE INTERSTATE
20 TO HIGHWAY 84 CORRIDORS. BASED ON THAT AND WITH RECENT
COORDINATION WITH SPC, ADJUSTED THE HWO GRAPHIC FOR SEVERE STORMS
(ENHANCED RISK AREA) GRAPHIC SLIGHTLY SOUTHWEST TO ACCOUNT FOR SOME
CI AND UH TRACKS NEAR THE MS RIVER CORRIDOR AND AS FAR SOUTHWARD AS
NEAR HIGHWAY 84 TO INTERSTATE 59 CORRIDORS. ALSO PULLED ALL OF THE
PINE BELT INTO THE SLIGHT RISK AREA. THIS SHOULD PERSIST THROUGH
AROUND MIDNIGHT TO 1AM, BUT CANNOT RULE OUT SOME POTENTIAL
PERSISTING INTO THE OVERNIGHT HOURS. SOME WESTERLY SHEAR AND
DESTABILIZATION MAY REINVIGORATE INTO THURSDAY AFTERNOON, BUT RECENT
TRENDS HAVE PUSHED THE BOUNDARY SOUTHWARD TOWARDS THE GULF COAST. NO
HWO GRAPHICS ARE NEEDED FOR THURSDAY.
DEEP MOISTURE WILL PEAK TODAY INTO THURSDAY (AROUND 2 TO 2.25 INCH
PRECIPITABLE WATER AND 340-345K 850MB THETA E) COMBINED WITH STRONG
CLOUD BEARING LAYER FLOW AROUND 45-50KTS AND SOMEWHAT OF A SLIGHT
RIDGE OF BACKBUILDING VECTORS, ALBEIT AROUND 20KTS, WILL LIKELY
RESULT IN SOME FLASH FLOODING CONCERNS BEING LIKELY. RECENT CAMS AND
HREF/REFS RUNS INDICATE SOME HIGHER RAINFALL ACCUMULATIONS, OF 3-5
INCHES, WITH AS HIGH AS EXCEEDING 6-8 INCHES IN EAST TO SOUTHEAST
MISSISSIPPI AROUND THE INTERSTATE 59 CORRIDOR. PROBABILITIES OF
RAINFALL TOTALS EXCEEDING 3 TO 5 INCHES ARE REASONABLE (40 TO 70
PERCENT GREATER THAN 3-4 INCHES AND AROUND 30 PERCENT GREATER THAN 5
INCHES). HREF NEIGHBORHOOD PROBS TO EXCEED 3 INCHES (AROUND 30
PERCENT) OVER THE NATCHEZ TRACE CORRIDOR SOUTHEAST INTO THE HIGHWAY
84 TO INTERSTATE 59 CORRIDORS INDICATE POTENTIAL FOR FLASH FLOODING
BEING HEIGHTENED, ESPECIALLY AS THE TOTALS COULD APPROACHED SOME
LOCALIZED PROBABILISTIC MATCH MEAN (LPMM) VALUES AROUND 5 INCHES AND
MAXIMUM VALUES IN EXCESS OF 6-8 INCHES. BASED ON THAT, ADDED AN
ELEVATED IN THE NATCHEZ TRACE TO NORTH OF HIGHWAY 84 TO INTERSTATE
59 CORRIDORS. AREAS OF FLOODING WILL BE LIKELY, ESPECIALLY IN URBAN
LOCATIONS, WHERE RAINFALL TOTALS ACCUMULATE RAPIDLY IN A SHORT
DURATION, WHICH COULD FLOOD ROADS OR STRUCTURES. BASED ON THE HIGH
RAINFALL DURATION IN THESE AREAS, SOME QUICK RISES ON AREA RIVERS
COULD APPROACH ACTION OR MINOR STAGES IF THE HIGHER END TOTALS ARE
REALIZED. OTHERWISE THIS RAIN WILL BE A MUCH NEEDED REPRIEVE IN THE
LONG DURATION RAINFALL DEFICITS THAT HAVE BEEN OBSERVED. RAIN WILL
SHIFT SOUTHWARD INTO THURSDAY NIGHT BUT STALL ACROSS THE GULF COAST
AREAS INTO LATE WEEK.
SEASONABLE WARMTH THIS MORNING WILL TURN TO SEASONABLY COOL DURING
THE MID TO LATE WEEK PERIOD ON THURSDAY.
LATE WEEK THROUGH EARLY NEXT WEEK (FRIDAY THROUGH NEXT TUESDAY): RAIN
CHANCES BEGIN TO SHIFT SOUTHEAST INTO LATE WEEK. SYNOPTIC AND SURFACE
FEATURES WILL CONSIST OF CUTOFF LOW ALOFT NEAR THE INTERNATIONAL
BORDER WITH FRONTAL ZONE SHIFTING SOUTHEAST INTO THE NORTHERN
GULF. THIS WILL KEEP SOME RAIN CHANCES ALONG THE NATCHEZ TRACE
THROUGH BEFORE DAYBREAK FRIDAY, WITH HIGHEST COVERAGE INTO THE
PINE BELT TO HIGHWAY 84 TO INTERSTATE 59 CORRIDORS BUT SHIFTING
NORTHWARD INTO THE INTERSTATE 20 CORRIDOR THROUGH THE DAY. AS
SHORTWAVE TROUGH SWINGS INTO THE ARLATEX INTO THE WEEKEND, EXPECT
RAIN COVERAGE TO PICK UP SATURDAY AND INTO SUNDAY (25 TO 55
PERCENT) AHEAD OF ANOTHER FRONT.
TEMPERATURE FORECAST BECOME MORE SEASONABLE AS RETURN FLOW GRADUALLY
SHIFTS AROUND INTO THE WEEKEND (HIGHS IN UPPER 70S FRIDAY TO LOW TO
MID 80S SATURDAY AND SUNDAY TO MID TO UPPER 80S SUNDAY AND LOWS IN
UPPER 50S TO LOW 60S FRIDAY NIGHT TO LOW TO MID 60S SATURDAY AND
SUNDAY NIGHT). AS SHORTWAVE BECOMES ABSORBED IN THE DEVELOPING
TROUGH AND DEEPENING AXIS OVER THE REGION, THIS WILL HELP DRIVE
CLEARING FRONT THROUGH THE AREA AND RAIN CHANCES OUT LIKELY BY EARLY
TO MIDDAY MONDAY OF NEXT WEEK. HIGH PRESSURE AND SEASONABLY COOL
CONDITIONS WILL BUILD IN THE WAKE. /DC/
AVIATION
(12Z TAFS)
ISSUED AT 652 AM CDT WED MAY 6 2026
SOME MVFR CEILINGS HAVE MOVED IN THROUGHOUT THE AREA AND WILL
PERSIST THROUGH THE MORNING. LATER ON SHOWERS AND THUNDERSTORMS
ARE EXPECTED TO BUILD INTO THE AREA WITH A DECENT POTENTIAL FOR
SEVERE CHARACTERISTICS THROUGHOUT THE AREA AROUND 06/18-20Z FOR
MOST SITES, SHOWERS COULD PRECEDE THUNDER, BUT FOR THE MOST PART
ONCE PRECIPITATION STARTS, THUNDER IS EXPECTED TO FOLLOW SHORTLY
AFTER. CEILINGS COULD DIP DOWN INTO LIFR/IFR RANGE INTERMITTENTLY
AS EARLY AS MIDDAY IN NORTH CENTRAL SITES. A FIRM EYE WILL BE
KEPT ON TRENDS TO ENSURE FORECAST REPRESENTS CURRENT AND EXPECTED
CONDITIONS./OAJ/DC/
PRELIMINARY POINT TEMPS/POPS
JACKSON 83 63 74 58 / 80 100 10 10
MERIDIAN 83 65 77 56 / 80 100 20 10
VICKSBURG 84 60 73 57 / 90 90 0 10
HATTIESBURG 84 69 80 61 / 80 90 60 30
NATCHEZ 85 64 75 60 / 90 100 20 30
GREENVILLE 72 56 71 54 / 100 90 0 0
GREENWOOD 77 58 73 54 / 100 90 0 0
JAN WATCHES/WARNINGS/ADVISORIES
MS...NONE.
LA...NONE.
AR...NONE.
19/
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