205
FXUS64 KJAN 130512
AFDJAN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON MS
1212 AM CDT THU AUG 13 2026
..NEW AVIATION
KEY MESSAGES
- AN ELEVATED THREAT FOR DANGEROUS HEAT STRESS CONDITIONS IS
EXPECTED THROUGH THIS WEEKEND AND INTO NEXT WEEK. SIGNIFICANT
HEAT IS POSSIBLE IN SOME AREAS.
- RAIN CHANCES ARE MINIMAL THROUGH MOST OF THE FORECAST PERIOD.
DISCUSSION
ISSUED AT 149 PM CDT WED AUG 12 2026
THE THREAT FOR DANGEROUS HEAT STRESS CONDITIONS CONTINUES TO BE
OUR GREATEST MESSAGE BY FAR. THE SUBTROPICAL RIDGE BUILDING,
EXPANDING, AND INTENSIFYING OVERHEAD AS WE MOVE INTO THE WEEKEND
WILL BE QUITE STRONG. 500 MB HEIGHTS OF 597 TO 598 DAM ARE JUST
BELOW RECORDS FOR MID AUGUST. SUBSIDENCE BENEATH THE RIDGE AND
INCREASED SUNSHINE WILL CONTINUE TO DRY AND BAKE THE SOUTH INTO
NEXT WEEK. AS THE RIDGE STRENGTHENS, SOME OF THE HUMIDITY WILL BE
EASED, BUT ACTUAL AIR TEMPERATURES WILL BEGIN TO PUSH OR EXCEED
100 DEGREES. THE COMBINATION OF HEAT AND HUMIDITY WILL ENSURE MOST
DAYS SEE PEAK HEAT INDEX VALUES IN THE 105-110 DEGREE RANGE
THROUGH THE WEEKEND.
LOCAL TEMPERATURE CLIMATOLOGY STUDIES SUGGEST THAT A RANGE OF
850MB TEMPERATURES OF 21-24C WOULD SUPPORT HIGH TEMPERATURES
PRETTY REASONABLY IN THE 97 TO 103 DEGREE RANGE. OFFICIAL FORECAST
VALUES ARE ON THE UPPER END OF THIS RANGE, SO WOULD CONSERVATIVELY
SAY THAT AT LEAST PARTS OF OUR FORECAST AREA WILL HIT THE 100
DEGREE MARK DURING THE NEXT 7 DAYS, AND A FEW LOCATIONS MAY REACH
103, OR HOT ENOUGH TO SET RECORD HIGHS. DEEPER MIXING WOULD PUSH
THE DEW POINTS SLIGHTLY LOWER, BUT WOULD ALSO FEEL PRETTY
CONFIDENT IN THE 105+ HEAT INDEX VALUES, ESPECIALLY AS RECENT
GUIDANCE HAS COME IN WITH SLIGHTLY HIGHER RH FORECASTS. WILL
CONTINUE TO MONITOR FOR POTENTIAL EXPANSION AND INCREASE OF
MESSAGING TO "SIGNIFICANT" RISK OF DANGEROUS HEAT (110+ HEAT INDEX
OR 105+ AIR TEMPERATURE) AS WE MOVE INTO LATE WEEK AND THE
WEEKEND. AN AREAWIDE HEAT ADVISORY IS IN EFFECT, AND EXPECT
ADDITIONAL ADVISORIES OR EXCESSIVE HEAT WARNINGS TO BE ISSUED OVER
THE COMING DAYS.
IN TERMS OF RAIN CHANCES, THEY ARE MOSTLY NON-EXISTENT UNTIL EARLY
NEXT WEEK. AT THAT TIME, THERE IS A SIGNAL FOR DEEPER MOISTURE IN
THE WESTERLIES NORTH OF THE HIGH CENTER TO CIRCULATE AROUND THE
HIGH AND POTENTIALLY INCREASE CONVECTIVE RAINFALL CHANCES OVER
EASTERN PORTIONS OF THE FORECAST AREA. RAIN CHANCES COULD BE
FURTHER INCREASED BY AN APPROACHING FRONTAL BOUNDARY, BUT ANY
RELIEF FROM THE HEAT THAT COULD RESULT IS UNCERTAIN AT THIS TIME.
/NF/EC/
AVIATION
(06Z TAFS)
ISSUED AT 1212 AM CDT THU AUG 13 2026
VERY ISOLATED SHRA CANNOT BE RULED OUT LATER THIS AFTERNOON.
OTHERWISE, VFR CONDITIONS ARE ANTICIPATED THROUGH THE TAF PERIOD.
/DL/
PRELIMINARY POINT TEMPS/POPS
JACKSON 98 76 99 75 / 0 0 0 0
MERIDIAN 98 77 99 76 / 0 0 0 0
VICKSBURG 97 75 97 74 / 0 0 0 0
HATTIESBURG 98 76 100 76 / 0 0 0 0
NATCHEZ 98 73 99 74 / 0 0 0 0
GREENVILLE 100 78 100 77 / 0 0 0 0
GREENWOOD 97 78 99 75 / 0 0 0 0
JAN WATCHES/WARNINGS/ADVISORIES
MS...HEAT ADVISORY UNTIL 7 PM CDT FRIDAY FOR MSZ018-019-025>066-
072>074.
LA...HEAT ADVISORY UNTIL 7 PM CDT FRIDAY FOR LAZ007>009-015-016-
023>026.
AR...HEAT ADVISORY UNTIL 7 PM CDT FRIDAY FOR ARZ074-075.
EC/DL
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