451
FXUS64 KJAN 181919
AFDJAN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON MS
219 PM CDT MON MAY 18 2026
..NEW DISCUSSION
KEY MESSAGES
- ISOLATED SEVERE STORMS ARE POSSIBLE IN THE NORTHWEST TUESDAY
EVENING.
- HEAT AND HUMIDITY MORE TYPICAL OF EARLY SUMMER CAN BE EXPECTED
ALONG WITH INCREASING THUNDERSTORM CHANCES THIS WEEK INTO THE
WEEKEND.
MESOSCALE UPDATE
ISSUED AT 1218 PM CDT MON MAY 18 2026
REST OF TODAY AND TONIGHT...
THE REGION REMAINS ON THE WESTERN PERIPHERY OF SUBTROPICAL RIDGE
PARKED JUST EAST OF THE ATLANTIC SEABOARD AND AMPLIFIED MEAN
TROUGHING, WITH THE CENTER OVER THE ROCKIES. THE COLD CORE AND
ATTENDANT SURFACE LOW/FRONTAL SYSTEM WILL EJECT INTO THE NORTHERN
PLAINS TO GREAT LAKES REGION TONIGHT. WITH WARM/MOIST ADVECTION
(THERMAL PROFILES AT 850MB IN THE MID TO UPPER TEENS AND PWS OF 1.5
TO 1.75 INCHES ALONG AND WEST OF INTERSTATE 55), INCREASED CLOUD
COVERAGE AND ISOLATED TO SCATTERED RAIN AND STORM CHANCES WILL BE
POSSIBLE ACROSS SOUTHERN TO SOUTHWEST MS AND NORTHEAST LA THIS
AFTERNOON INTO EARLY EVENING. GOES EAST AND OBSERVED SOUNDINGS TO
THE EAST INDICATE DRIER THERMAL PROFILES (1.0 TO 1.2 INCH PWS), SO
RAIN CHANCES SHOULD REMAIN LOW TO NON-EXISTENT. SEASONABLE WARMTH IS
EXPECTED TODAY, SOME 4F TO 8F ABOVE (HIGHS: 86F TO 91F).
THERMODYNAMIC PARAMETERS REMAIN SUFFICIENT (7.0 DEG C MID LEVEL
LAPSE RATES;25C TO 28C VERTICAL TOTALS; MLCAPE (800-1200J/KG) AND
SBCAPE (1200-2000J/KG). DEEP SHEAR (20 TO 25KTS) THAT COULD SUPPORT
SOME STRONG STORMS IN THE WEST THIS AFTERNOON TO EVENING BUT
CONFIDENCE IN SEVERE STORMS REMAINS LOW. THIS HAS A FEEL OF A
TYPICAL DIURNAL SUMMERTIME STORM AFTERNOON, BUT A ROGUE MULTICELL
STORM OR MICROBURST CANNOT BE RULED OUT.
RETURN FLOW OF LOW LEVEL MOISTURE WILL BRING SOME LOW CLOUDS AND
VISIBILITY REDUCTIONS. PROBABILITIES REMAIN LOW FOR DENSE FOG AND
SOME LIGHT WIND WILL BE PRESENT. THUS, NO MENTION IS NEEDED IN HWO
JUST PATCHY VISIBILITY REDUCTIONS IN THE PINE BELT BY DAYBREAK.
FORECAST WAS SHIPPED OUT EARLIER. LOWS WILL BE SEASONABLY WARM, SOME
10F TO 15F ABOVE (70F TO 72F EAST OF I-55 TO 73F TO 75F ALONG AND
DISCUSSION
ISSUED AT 219 PM CDT MON MAY 18 2026
REST OF THE WEEK INTO WEEKEND (TUESDAY THROUGH SUNDAY)...
LONGWAVE TROUGH WILL BE EJECTING INTO CANADA AND HUDSON BAY
REGION. PERSISTENT SUMMERTIME PATTERN OF SEASONABLE WARMTH (4F TO
8F ABOVE AND HIGHS IN 88F TO 92F) AND MOISTURE (FORECASTS OF 1.5
TO 1.9 INCHES) WILL BE THE NORM. DIURNAL SHOWER AND THUNDERSTORM
ACTIVITY WILL BE A CONCERN AHEAD OF A FEW PERTURBATIONS IN THE
SOUTHWESTERLY FLOW (20 TO 55 PERCENT) AND INCREASED HEAT AND
HUMIDITY. WITH SOME STEEP LAPSE RATES (VERTICAL TOTALS NEAR 27C TO
29C), SOME STRONG TO ISOLATED SEVERE STORMS REMAIN POSSIBLE
TUESDAY AND INTO MID WEEK. THERE IS ANTICIPATED OF AFTERNOON
DEVELOPMENT IN THE PLAINS SHOULD SINK SOUTHEAST INTO THE OZARKS IN
THE EVENING AND MAKE IT INTO THE AREA BY LATE AFTERNOON INTO EARLY
EVENING. STORM MODE IS A QUESTION BUT EVEN A SOUTHEAST TRAVERSING
COLD POOL COULD INITIATE SOME STRONG TO ISOLATED SEVERE
THUNDERSTORM ACTIVITY INTO TUESDAY EVENING. WHILE THERE COULD BE
SOME DIURNAL ACTIVITY BETWEEN 3-5PM, THE CONCERN FOR SEVERE STORMS
WILL BE MAINLY AFTER 6PM AND LAST UNTIL JUST AFTER MIDNIGHT. THE
ONGOING HWO GRAPHIC REMAINS VALID, BUT THE TIMING HAS BEEN SLOWED
DOWN INTO THE EVENING TO JUST AFTER MIDNIGHT (6PM TUESDAY THROUGH
2AM WEDNESDAY). DEEP FLOW/BULK SHEAR WILL BE LIGHT (15-25KTS) AND
VARIABLE AND STORM ORGANIZATION WILL NEED TO BE IN TANDEM TO THE
SOUTHWESTERLY LOW LEVEL FLOW. THIS COULD HINDER ANY SOUTHEASTWARD
PROPAGATING MCS, WHICH IS ALLUDED TO IN SOME CONVECTIVE ALLOWING
MODEL (CAMS) OUTPUT. WITH GENERALLY SOUTHERLY TO SOUTHWESTERLY
FLOW IN THE LOW LEVELS, COLD POOLS MAY EVENTUALLY GET OUT OF
BALANCED AND MORE COLD POOL DOMINANT, DECREASING THE SEVERE
POTENTIAL CLOSER TO INTERSTATE 55 AND CENTRAL PORTIONS OF THE AREA
CLOSER TO OR JUST AFTER MIDNIGHT. DAMAGING WIND GUSTS AND HAIL
REMAIN THE MAIN CONCERNS.
AS A STRONGER WAVE SWINGS INTO THE GREAT LAKES AND SURFACE LOW
EJECTS INTO EASTERN CANADA (995MB TO 1000MB), FRONT WILL SHIFT
SOUTH SOUTHEAST TOWARDS THE GULF STATES. SEVERAL PERTURBATIONS
WILL ENHANCE UPPER DIFFLUENCE, INCREASING ASCENT AND MOISTURE
ADVECTION. THIS WILL DRIVE HIGHER COVERAGE OF RAIN AND STORMS (45
TO 90 PERCENT WEDNESDAY AND THURSDAY). HIGH TEMPERATURES WILL BE
SEASONABLE (MID TO UPPER 80S WEDNESDAY TO LOW TO MID 80S REST OF
THE WEEK) WITH LOWS LESS SEASONABLE, FROM 8F TO 12F ABOVE (UPPER
60S TO LOW 70S). WITH LESS SEASONABLE TEMPERATURES, HUMIDITY AND
LAPSE RATES, SOME STRONGER STORMS ARE LIKELY AND MARGINALLY SEVERE
STORMS REMAIN POSSIBLE. MID TO DEEP LAYER BULK SHEAR WILL REMAIN
SUFFICIENT (AROUND 30KTS), WITH LOW LEVEL SHEAR AROUND 15-25KTS.
THIS WILL KEEP POTENTIAL MARGINALLY SEVERE CONCERNS THROUGH THE
REMAINDER OF THE WORK WEEK (WEDNESDAY THROUGH FRIDAY). RAIN TOTALS
FOR THE WEEK WILL BE AROUND A COUPLE OF INCHES (1 TO 3 INCHES),
WHICH WILL HELP LESSEN SOME LONG TERM DROUGHT CONCERNS. LARGE
SCALE SYNOPTIC PATTERN (I.E. SOUTHWESTERLY RETURN FLOW, WARM
ADVECTION, HIGH PWS NEAR 2 INCHES) WILL PERSIST, KEEPING RAIN
CHANCES HIGH LATE WEEK INTO THE WEEKEND (70 TO 90 PERCENT FRIDAY
THROUGH SUNDAY). SOME LOW END SEVERE POTENTIAL CANNOT BE RULED
OUT, BUT LOWER SEVERE PROBS AND LESS HEAT AND SHEAR JUXTAPOSED
WILL KEEP MENTION OF ANYTHING IN HWO ON A DAY-TO-DAY BASIS, EACH
DAY DEPENDENT ON PREVIOUS DAY'S STORM EVOLUTION. RAIN TOTALS WILL
ADD UP (ADDITIONAL ONE TO THREE INCHES, WITH STORM TOTAL RAIN
THROUGH THE WEEKEND OF 4 TO 6 INCHES), CONTINUING IMPROVEMENTS TO
LONG TERM DROUGHT CONCERNS. /DC/
AVIATION
(18Z TAFS)
ISSUED AT 1218 PM CDT MON MAY 18 2026
VFR FLIGHT CATEGORIES WILL PREVAIL AT AREA TAF SITES THIS AFTERNOON
AND INTO THIS EVENING. AN ISOLATED THUNDERSTORM OR TWO CAN'T BE
RULED OUT DURING THE LATE AFTERNOON HOURS, BUT THESE WILL QUICKLY
DISSIPATE AROUND SUNSET. IF OBSERVED ON-SITE, A REDUCTION IN
FLIGHT CATEGORIES TO MVFR/IFR STATUS WILL BE POSSIBLE. ANOTHER
BOUT OF MVFR/IFR CEILINGS WILL BE POSSIBLE AT SITES MAINLY ALONG
SOUTH OF THE INTERSTATE 20 CORRIDOR EARLY TUESDAY MORNING, WITH A
REDUCTION OF VISIBILITIES TO MVFR/IFR STATUS AROUND DAY BREAK DUE
TO PATCHY FOG AT NAMELY KPIB AND KHBG. THROUGH TUESDAY MORNING,
CATEGORIES WILL STEADILY IMPROVE TO VFR STATUS AS BOTH PATCHY FOG
AND LOW STRATUS ERODE. BREEZY SOUTHERLY WINDS WILL SUBSIDE A BIT
THIS EVENING TO BETWEEN 3-8 KNOTS. /19/
PRELIMINARY POINT TEMPS/POPS
JACKSON 73 89 71 86 / 10 30 40 60
MERIDIAN 71 90 70 88 / 10 20 20 30
VICKSBURG 74 90 70 85 / 10 40 50 80
HATTIESBURG 72 89 69 88 / 0 20 10 50
NATCHEZ 75 90 71 86 / 20 50 60 80
GREENVILLE 74 91 71 83 / 10 40 60 90
GREENWOOD 75 91 71 85 / 20 30 60 90
JAN WATCHES/WARNINGS/ADVISORIES
MS...NONE.
LA...NONE.
AR...NONE.
DC/19
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