869
FXUS64 KJAN 041800 AAB
AFDJAN
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE JACKSON MS
100 PM CDT SAT JUL 4 2026
..NEW AVIATION
KEY MESSAGES
- DANGEROUS LEVELS OF HEAT STRESS WILL CONTINUE TODAY WITH LESS
OPPRESSIVE CONDITIONS EXPECTED SUNDAY.
DISCUSSION
ISSUED AT 351 AM CDT SAT JUL 4 2026
THROUGH TONIGHT: THE LARGE MID LEVEL HIGH THAT HAS BEEN OVER THE
REGION THE PAST SEVERAL DAYS HAS SHIFTED EAST OF OUR REGION LEAVING
A FLATTER RIDGE EARLY THIS MORNING. THIS FLAT RIDGE WILL GRADUALLY
DEEPEN INTO A WEAK UPPER LEVEL TROUGH ALOFT THROUGH TONIGHT IN
RESPONSE TO A LARGE HIGH ANCHORING OVER THE SOUTHERN PLAINS. THE 00Z
SAT JAN SOUNDING SHOWED A PWAT BACK UP TO TWO INCHES. THIS MOIST
AIRMASS AND THE LOWER HEIGHTS TODAY WILL LEAD TO A GREATER COVERAGE
OF ISOLATED TO SCATTERED AFTERNOON INTO EARLY EVENING SHOWERS AND
THUNDERSTORMS. ALTHOUGH THE GREATER COVERAGE OF CONVECTION TODAY AND
POTENTIALLY EARLIER DEVELOPMENT WILL RESULT IN LOWER PEAK HEAT INDEX
VALUES. HOWEVER, THE COMBINATION OF TEMPERATURES IN THE 90S AND HIGH
HUMIDITY WILL RESULT IN PEAK HEAT INDEX VALUES IN EXCESS OF 105F
OVER MOST OF THE CWA AGAIN. A HEAT ADVISORY WILL REMAIN IN EFFECT
FOR THE WHOLE CWA TODAY. THE CONVECTION TODAY WILL SEE A DISTINCT
DIURNAL TREND BUT THE PRESENCE OF THE DEEPENING UPPER LEVEL TROUGH
MAY HELP PROLONG CONVECTION TONIGHT. /22/
SUNDAY THROUGH NEXT SATURDAY...
THE SUBTROPICAL RIDGE WILL START TO WEAKEN SLIGHTLY ACROSS THE
SOUTHEAST CONUS HEADING INTO SUNDAY. THIS COMBINED WITH SOUTHERLY
MOISTURE RETURN FLOW FROM THE GULF WILL HELP SUPPORT GREATER
COVERAGE OF SCATTERED SHOWERS AND STORMS MUCH OF THE AREA WITH RAIN
CHANCES AROUND 25-50% ESPECIALLY DURING LATE AFTERNOON/EARLY EVENING
TIMEFRAME. AREAS ALONG AND SOUTH OF I-20 WILL HAVE BETTER CHANCES
(50-76%) OF SCATTERED CONVECTIVE RAINFALL COVERAGE. A FEW STRONG
STORMS WITH WIND GUSTS BETWEEN 40-50 MPH CANNOT BE RULED OUT.
BECAUSE OF THE SHOWERS AND STORMS FORECASTED FOR SUNDAY, MOST OF OUR
FORECAST AREA COULD SEE HEAT INDEX VALUES DROP BELOW THE 105 DEGREES
THRESHOLD, SO WILL HOLD OFF ON EXTENDED THE HEAT ADVISORY FURTHER.
SHOWERS WILL PERSIST HEADING INTO THE NEW WORK WEEK AS THE HOT AND
HUMID AIRMASS REMAINS UNCHANGED. LONG TERM GUIDANCE IS STARTING TO
SHOW THE SFC HIGH RESTRENGTHENING ACROSS THE AREA BY THE MID WEEK.
THIS WILL ALLOW FOR HEAT PEAK HEAT INDEX VALUES TO CLIMB BACK INTO
POTENTIAL HEAT ADVISORY CRITERIA. HEAT GRAPHICS AND ADVISORIES MAY
EVENTUALLY BE NEEDED AS WE GET CLOSER TO THE LATE WEEK. HEAT TRENDS
WILL CONTINUE TO BE MONITORED ON A DAILY BASIS. MUCH OF OUR AREA
WILL SEE DECENT RAIN CHANCES (15-40%) BY NEXT WEEK FRIDAY. SCATTERED
SHOWERS AND STORMS CANNOT BE RULED OUT ACROSS MUCH OF OUR AREA
HEADING INTO THE WEEKEND. /CR/
AVIATION
(18Z TAFS)
ISSUED AT 100 PM CDT SAT JUL 4 2026
VFR WILL BE THE PREVAILING CATEGORY FOR THE TAF PERIOD ACROSS THE
AREA. THAT BEING SAID THERE REMAINS A NOT INSIGNIFICANT CHANCE FOR
SHOWERS AND ISOLATED THUNDER AMONG SOME OF OUR WESTERN SITES, WITH A
TROUGH BEGINNING TO TAKE HOLD IN WESTERN FORECAST ZONES. FOR THE
TIME BEING CHANCES ARE LOW ENOUGH THAT TS HAS NOT BEEN HIGHLIGHTED
FOR MAJORITY OF SITES. INSTABILITY DOES LOOK HIGH ENOUGH OVER
CENTRAL MS SO EXPECT CONVECTIVE ACTIVITY IN THE AREA ALONG WITH RAIN
SHOWERS FROM 18Z-22Z. OVER NIGHT GUIDANCE HAS PICKED UP ON CHANCES
FOR MIST/FOG DEVELOPMENT ACROSS THE CWA, FOR NOW VISIBILITIES ARE
FORECAST TO REMAIN VFR, BUT AS WE MOVE CLOSER TO TOMORROW MORNING
AND UPDATED DATA BECOMES AVAILABLE; DEVELOPMENT COULD BE MORE
AGGRESSIVE THAN IS CURRENTLY FORECAST./OAJ/
PRELIMINARY POINT TEMPS/POPS
JACKSON 75 91 74 90 / 20 50 10 70
MERIDIAN 75 93 74 91 / 20 60 20 70
VICKSBURG 75 91 75 91 / 10 60 10 60
HATTIESBURG 75 93 74 91 / 10 70 20 80
NATCHEZ 75 91 74 91 / 30 70 10 70
GREENVILLE 75 92 75 92 / 20 40 30 40
GREENWOOD 75 93 74 92 / 30 50 20 60
JAN WATCHES/WARNINGS/ADVISORIES
MS...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR MSZ018-019-025>066-
072>074.
LA...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR LAZ007>009-015-016-
023>026.
AR...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR ARZ074-075.
EC/EC/OAJ
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