649
FXUS64 KJAN 180635
AFDJAN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON MS
135 AM CDT SAT JUL 18 2026
..NEW DISCUSSION, AVIATION
KEY MESSAGES
- A WARMING TREND WILL CONTINUE, WITH INCREASING HEAT STRESS A
CONCERN THIS WEEKEND INTO EARLY NEXT WEEK.
DISCUSSION
ISSUED AT 120 AM CDT SAT JUL 18 2026
THERE IS NOT MUCH CHANGE IN THE OVERALL EXPECTATIONS IN THE FORECAST
AND HEAT CONTINUES TO BE THE PRIMARY CONCERN HEADING INTO THE
WEEKEND AND INTO NEXT WEEK.
OUR AREA WILL CONTINUE TO BE UNDER THE INFLUENCE OF A LARGE UPPER
RIDGE, WHICH WILL TEND TO SUPPRESS COVERAGE OF CONVECTION INTO NEXT
WEEK AND REDIRECT LARGER SCALE SYSTEMS TO THE EAST. THAT SAID,
MOISTURE DOES REMAIN SUFFICIENT FOR SOME ISOLATED CONVECTION, SO A
POPUP SHOWER OR STORM CANNOT BE ENTIRELY RULED OUT BUT MOST OF THE
AREA SHOULD REMAIN DRY. THE HEAT WILL CONTINUE TO INCREASE LARGELY
DUE TO THE WEST NORTHWEST FLOW WHICH WILL REINFORCE AN 850 THERMAL
RIDGE OVER THE AREA. FURTHER, THE LOW OVER THE NORTHEAST GULF MAY
ACT TO FURTHER REINFORCE RIDGING OVER THE AREA THIS WEEKEND.
CONFIDENCE IS NOW HIGH ENOUGH TO INTRODUCE A HEAT ADVISORY FOR A
GOOD PORTION OF THE AREA. WILL MAINTAIN THIS THROUGH MONDAY AFTER
WHICH AN UPGRADE TO HEAT WARNING IS LIKELY FOR PORTIONS OF THE AREA
FOR TUESDAY AND WEDNESDAY. WILL MAINTAIN HEAT MESSAGING WITH AN
AREAWIDE "ELEVATED" FOR NOW AND WILL LIKELY ADD CORRESPONDING
"SIGNIFICANT" HEAT STRESS TUESDAY AND WEDNESDAY IN FUTURE UPDATES.
THE TREND HAS BEEN INCREASINGLY TOWARDS PEAK HEAT FOR WEDNESDAY DUE
TO COMPRESSION AND MOISTURE POOLING AHEAD OF A FRONTAL BOUNDARY
POISED TO DRAG ACROSS THE AREA. GUIDANCE HAS GOTTEN MORE CONSISTENT
RUN TO RUN, AS WELL AS ACROSS DIFFERENT MODELS WITH THIS FEATURE.
HEAT INDICES LOOK TO EXCEED 110 FOR A GOOD PORTION OF THE AREA,
ESPECIALLY SOUTH OF I-20 AS TEMPERATURES TOP OUT IN THE LOW 100S.
THE AFOREMENTIONED FEATURE ALSO NECESSITATES MONITORING OF POTENTIAL
ORGANIZED CONVECTION AS THE FLATTENING OF THE RIDGE DUE TO THE
DIGGING UPPER TROUGH INTRODUCES A WEAKNESS THAT COULD LEAVE US
VULNERABLE TO CONVECTIVE SYSTEMS. EVEN IF MOST OF THE AREA REMAINS
DRY AND MOST CONVECTION IS FOCUSED EAST IN ALABAMA, CANNOT RULE OUT
STORMS CLIPPING THE GOLDEN TRIANGLE. WHILE CONFIDENCE IS TOO LOW
FOR ANY MESSAGING AT THIS TIME, THIS IS SOMETHING TO WATCH AS THE
THERMAL ENVIRONMENT AHEAD OF THE BOUNDARY IS MORE THAN SUFFICIENT
TO MAINTAIN CONVECTION SHOULD FLOW BE SUFFICIENT AND SHOULD
CONVECTION GET INITIATED NORTH. HAVE OPTED TO ADJUST POP UPWARDS
TO 15% IN AREAS EAST OF I-55 TO AT LEAST MENTION AN ISOLATED
THUNDERSTORM IN WX.
THE HEAT DOES NOT LOOK TO CEASE POST FRONTAL BOUNDARY EITHER,
MEANINGFUL AIRMASS CHANGE LOOKS SHORT LIVED OR NON EXISTENT. IT
IS SUMMER AFTER ALL. RIDGE SHOULD MAINTAIN AND NW FLOW LOOKS TO
PERSIST INTO LATE NEXT WEEK. THIS WILL CONTINUE TO NECESSITATE
MONITORING FOR BOTH DANGEROUS HEAT ACROSS THE AREA AND POTENTIAL
CONVECTION IN THE NORTHEAST. /SAS/
AVIATION
(06Z TAFS)
ISSUED AT 120 AM CDT SAT JUL 18 2026
VFR CONDITIONS WILL PREVAIL AT THE TAF SITES THROUGH THE PERIOD.
/NF/
PRELIMINARY POINT TEMPS/POPS
JACKSON 94 75 95 75 / 10 0 0 0
MERIDIAN 93 75 95 75 / 10 10 20 10
VICKSBURG 93 75 95 75 / 0 0 0 0
HATTIESBURG 95 76 97 76 / 10 20 10 10
NATCHEZ 92 75 96 74 / 0 0 0 0
GREENVILLE 93 76 96 76 / 0 0 0 0
GREENWOOD 94 75 96 75 / 0 0 10 0
JAN WATCHES/WARNINGS/ADVISORIES
MS...HEAT ADVISORY FROM 10 AM THIS MORNING TO 7 PM CDT MONDAY FOR
MSZ018-019-025-034>036-040>043-047>050-053>066-072>074.
LA...HEAT ADVISORY FROM 10 AM THIS MORNING TO 7 PM CDT MONDAY FOR
LAZ008-009-016-024>026.
AR...HEAT ADVISORY FROM 10 AM THIS MORNING TO 7 PM CDT MONDAY FOR
ARZ075.
SAS20/SAS20/NF
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