104
FXUS64 KJAN 212339 AAA
AFDJAN
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE JACKSON MS
639 PM CDT TUE APR 21 2026
..NEW AVIATION
KEY MESSAGES
- FIRE DANGER IS INCREASING FOR TODAY AS DRY WEATHER CONTINUES THIS
WEEK.
- MULTIPLE ROUNDS OF SHOWERS AND STORMS WILL RESULT IN
SIGNIFICANT RAINFALL FROM LATE THIS WEEK INTO EARLY NEXT WEEK.
DISCUSSION
ISSUED AT 432 PM CDT TUE APR 21 2026
THIS WEEK THROUGH EARLY NEXT WEEK...
AFTER A FAIRLY QUIET RECENT FEW WEEKS, IT APPEARS THAT OUR
FORECAST AREA MAY BE SHIFTING INTO A MORE ACTIVE CONVECTIVE
PATTERN OVER THE NEXT SEVERAL DAYS. WHILE I WOULD CONTINUE WITH
SKEPTICISM ABOUT THE COVERAGE OF ANTICIPATED RAINFALL, GIVEN THE
CURRENT EXPANDING DROUGHT IN THE REGION, A PATTERN SHIFT WILL
BRING US MORE INTO ALIGNMENT WITH INCREASING CHANCES FOR SHOWERS
AND THUNDERSTORMS FOR LATE WEEK. STRONG TO SEVERE THUNDERSTORMS
WILL BE POSSIBLE AT TIMES, AND WITH INCREASING HUMIDITY EXPECT
SOME POTENTIAL FOR LOCALLY HEAVY RAINFALL AS WELL.
THE RIDGE OF HIGH PRESSURE OVER THE SOUTHEAST US HAS BEEN
PERSISTENT, WITH DEEP MIXING IN ITS DRY AIR MASS TODAY PUSHING RH
VALUES TO AROUND 25%. BUT THIS WILL CHANGE AS THE RIDGE GRADUALLY
PUSHES EAST OVER THE ATLANTIC. BROAD TROUGHING AND CYCLOGENESIS
OVER THE NORTHERN ROCKIES PUSH A COLD FRONT TOWARD OUR REGION THIS
WEEKEND, BUT UPPER-LEVEL FORCING WILL REMAIN DISPLACED FARTHER
NORTH. THE BOUNDARY WILL HOWEVER HELP TO CONCENTRATE ATMOSPHERIC
MOISTURE RETURNING TO THE REGION. PWAT VALUES OF 1.5+ INCHES WILL
BECOME COMMON THROUGH THE SOUTHERN MISSISSIPPI RIVER VALLEY FRIDAY
INTO SATURDAY. THE UPTICK BEFORE THAT WILL SUPPORT ISOLATED TO
SCATTERED DIURNAL CONVECTION ESPECIALLY IN NORTHERN LA/SOUTHERN AR
THURSDAY. SBCAPE NEAR 1000 J/KG IN THE MOISTURE PLUME AND DEEP
LAYER SHEAR OF 20-30 KTS ARE NOT TOO CONCERNING FOR ORGANIZED
SEVERE WEATHER, BUT WOULD NOT BE SURPRISED FOR ONE OR TWO STRONGER
STORMS IN THE AREA DURING PEAK HEATING.
THE FRIDAY, THE APPROACHING FRONT TO OUR NORTH AND WEST WILL
INTERACT WITH AN ATMOSPHERE MORE CHARACTERIZED BY SBCAPE VALUES OF
2000-3000 J/KG AND DEEP LAYER SHEAR OF 30-40 KTS BETTER SUPPORTIVE
OF CONVECTIVE INITIATION AND ORGANIZATION. EVEN IN OUR OWN FORECAST
AREA, AFTERNOON HEAT AND HUMIDITY SHOULD SUPPORT SOME CONVECTION
DEVELOPING LOCALLY, THOUGH WITH WEAKER SHEAR. UPSTREAM ACTIVITY WILL
BE FAVORED TO SPREAD SOUTH AND EAST EVEN INTO THE EVENING HOURS WITH
WIND SHEAR AND SUFFICIENT MLCAPE TO SUSTAIN ANY MCS TYPE OF ACTIVITY
INTO OUR AREA. CURRENT PROBABILITIES FOR SEVERE THUNDERSTORMS DO NOT
RISE TO THE 15% THRESHOLD REQUIRED FOR A DAY 4 SLIGHT RISK OUTLOOK,
BUT DO THINK PARTS OF OUR AREA HAVE AT LEAST A MARGINAL RISK LEVEL
OF THREAT FRIDAY INTO FRIDAY NIGHT.
GUIDANCE HINTS AT CONVECTIVE ACTIVITY OUTRUNNING THE FRONT AND
SETTLING CLOSER TO THE GULF COAST SATURDAY, BUT RAIN CHANCES
PERSIST. REBUILDING INSTABILITY COULD CREATE A SIMILAR SETUP FOR MCS
TYPE ACTIVITY TO SPREAD SOUTHEAST INTO OUR AREA SUNDAY INTO SUNDAY
NIGHT. AND THEN FINALLY MONDAY NIGHT INTO TUESDAY MORNING, THE COLD
FRONT ITSELF WILL GET A RENEWED SOUTHEASTWARD PUSH AND LIKELY
TRIGGER THUNDERSTORMS AS THE FRONT AND UPPER-LEVEL SHORTWAVE PASS
THROUGH. INSTABILITY SHOULD BE HIGHER (ASSUMING NO LINGERING
DISRUPTIONS TO THE ATMOSPHERE FROM THE WEEKEND), AND DEEP LAYER
SHEAR SHOULD BE STRONGER (40-50 KTS) TO SUPPORT ORGANIZED SEVERE
STORMS. SPC HAS HIGHLIGHTED MUCH OF THE AREA ON MONDAY WITH A SLIGHT
RISK FOR SEVERE THUNDERSTORMS, BUT GIVEN THE 3 DAYS OF UNADVERTISED
POTENTIAL FOR SEVERE THUNDERSTORMS, DO NOT FEEL CONFIDENT TO
HIGHLIGHT ONLY A DAY 7 RISK AT THIS TIME. STAY TUNED FOR UPDATES TO
THE FORECAST TIMING AND IMPACTS AS THIS WEEKEND NEARS AND DETAILS
COME INTO BETTER FOCUS. /NF/
AVIATION
(00Z TAFS)
ISSUED AT 639 PM CDT TUE APR 21 2026
VFR FLIGHT CONDITIONS WITH SOUTHERLY WINDS BETWEEN 5-8 KTS WILL
PREVAIL THROUGH THE PERIOD. WINDS WILL GRADUALLY SUBSIDE TO 3-5 KTS
AFTER 03Z WEDNESDAY. /SW/
PRELIMINARY POINT TEMPS/POPS
JACKSON 59 80 60 83 / 10 10 0 10
MERIDIAN 57 82 57 83 / 0 10 0 0
VICKSBURG 60 80 61 84 / 10 10 0 10
HATTIESBURG 56 83 57 84 / 0 10 0 0
NATCHEZ 60 81 61 83 / 10 10 0 30
GREENVILLE 61 80 62 84 / 10 10 10 10
GREENWOOD 60 81 61 84 / 10 0 10 10
JAN WATCHES/WARNINGS/ADVISORIES
MS...NONE.
LA...NONE.
AR...NONE.
NF/SW
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