860  
FXUS64 KJAN 211613  
AFDJAN  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE JACKSON MS  
1013 AM CST SAT DEC 21 2024  
   
..NEW MESOSCALE UPDATE  
 
   
MESOSCALE UPDATE  
 
ISSUED AT 1011 AM CST SAT DEC 21 2024  
 
ALL IS GENERALLY ON TRACK FOR THIS NEAR TERM UPDATE WITH A CHILLY  
DAY UNDERWAY. HAVE JUST MADE SOME MINOR T/TD ADJUSTMENTS TO  
ACCOUNT FOR RECENT OBS TRENDS. /EC/  
 
 
   
DISCUSSION  
 
ISSUED AT 359 AM CST SAT DEC 21 2024  
 
TODAY AND TONIGHT: COLDER THAN NORMAL AND DRY THROUGH THE PERIOD.  
EARLY MORNING SATELLITE IMAGERY/RAP ANALYSIS SHOWED ANOTHER  
SHORTWAVE TROUGH OVER THE CENTRAL PLAINS THAT WILL ROTATE AROUND  
THE BASE OF THE MEAN UPPER LEVEL TROUGH CENTERED OVER THE EASTERN  
CONUS. THIS WILL HELP MAINTAIN NORTHWEST FLOW ALOFT ACROSS OUR CWA  
THROUGH TONIGHT AND HELP A >1038MB HIGH CENTERED OVER THE NORTHERN  
PLAINS EARLY THIS MORNING, TRACK EAST ACROSS THE GREAT LAKES REGION.  
TOGETHER THESE FEATURES WILL HELP KEEP MUCH OF OUR CWA IN THE 40S  
TODAY. OUR NORMAL HIGHS RUN IN THE MID 50S NORTH TO THE LOWER 60S  
SOUTH. ALTHOUGH THE CENTER OF THE LARGE SURFACE HIGH WILL REMAIN  
NORTH OF OUR CWA TONIGHT, DECENT RADIATIONAL COOLING OF OUR COLD DRY  
AIRMASS WILL LEAD TO THE COLDEST NIGHT OF THE NEXT SEVEN DAYS.  
TEMPERATURES WILL DROP OFF RAPIDLY AFTER SUNSET AND BOTTOM OUT  
SUNDAY MORNING IN THE MID TO UPPER 20S. NORMAL LOWS RUN IN THE MID  
TO UPPER 30S. /22/  
 
THROUGH THE WEEKEND  
 
SUNDAY MORNING SHOULD BE OUR LAST DAY OF FRIGID OVERNIGHT  
TEMPERATURES THAT DIP INTO THE 20S. EXPECT WIDESPREAD FROST  
DEVELOPMENT AS A RESULT OF THESE COLD TEMPERATURES CROSSING OVER OUR  
MID 20 DEGREE DEW POINTS. TOMORROW NIGHT MOST SECTORS TO THE WEST OF  
I-55 WILL BOTTOM OUT ABOVE FREEZING, WITH EASTERN ZONES DIPPING  
BELOW BEFORE SUNRISE.  
 
MONDAY THROUGH FRIDAY  
 
MOVING ONTO CHRISTMAS WEEK EXPECT TO REBOUND INTO TEMPERATURES THAT  
ARE FAR ABOVE SEASONAL NORMS WITH HIGHS IN THE MID 60S FOR AREAS  
NORTH OF I-20, AND LOW 70S TO THE SOUTH. OUR LOWS WILL TAKE A BIT  
LONGER TO RECOVER AS OUR GULF FLOW IS NOT PARTICULARLY ROBUST AND  
REMAINS MORE EAST-SOUTHEASTERLY UNTIL LATE NEXT WEEK. GOOD NEWS IS  
THAT ALL COUNTIES/PARISHES WILL SEE LOWS ABOVE FREEZING, AND REACH  
LOW 50S BY CHRISTMAS NIGHT/THURSDAY MORNING. RAIN AND THUNDERSTORMS  
WILL BEGIN TO MAKE THEIR WAY INTO THE AREA THE AFTERNOON OF  
CHRISTMAS EVE FROM THE NORTHWEST AND AFFECT THE ENTIRE CWA BY  
CHRISTMAS MORNING. THIS IS IN RESPONSE TO SOUTHERLY MOISTURE ON TAP  
COMBINED WITH 500MB HEIGHT FALLS OUT AHEAD OF A MINOR TROUGH SET TO  
EJECT SLOWLY FROM EAST TEXAS CHRISTMAS MORNING. THIS MINOR TROUGH  
WILL BE ABSORBED INTO A MUCH MORE SUBSTANTIAL TROUGH FROM CENTRAL  
TEXAS THROUGHOUT THE REMAINDER OF THE WEEK, WHICH WILL ELICIT  
WIDESPREAD ASCENT OUT AHEAD OF IT, AS SIGNIFICANT HEIGHT FALLS TAKE  
HOLD. CONTINUED SURFACE MOISTURE THAT BECOMES MORE STURDY AS THE  
WEEK PROGRESSES, IN CONJUNCTION WITH THIS AFOREMENTIONED MAJOR  
TROUGH WILL CULMINATE IN EFFECTIVELY CONTINUOUS RAINFALL FOR THE  
REMAINDER OF THE WEEK, WITH EMBEDDED THUNDERSTORM ACTIVITY.  
 
MODEL RESOLUTIONS WITH THIS SYSTEM HAVE CONTINUED TO COME INTO FOCUS  
PROVIDING MORE CONFIDENCE IN THE OVERALL FORECAST FOR CHRISTMAS  
ONWARDS. RAIN TOTALS (BOTH 24HR AND 7 DAY AVERAGES) FOR THIS  
RAINFALL EVENT REMAIN WITHIN SEASONAL NORMS, SO THERE IS NO  
EXPECTATION OF SIGNALING ANY SORT OF HEAVY RAIN THREAT. AS ALWAYS  
WITH SYSTEMS THAT HAVE HAD DIVERGENT RESOLUTIONS WE CAN NOT TOTALLY  
RULE OUT THE POSSIBILITY FOR HEAVY RAIN NOR A SMALL CHANCE FOR MORE  
DYNAMICALLY SUPPORTED EMBEDDED CONVECTIVE ACTIVITY THAT COULD  
PRODUCE LOCAL, ISOLATED, STRONG WINDS.  
 
IN SUMMARY, THE HOLIDAY WEEK LOOKS TO BE A WET AND DREARY ONE. IF  
THERE ARE ANY OUTDOOR PLANS THAT DON'T INVOLVE FROLICKING IN THE  
RAIN, IT WOULD BE ADVISABLE TO HAVE A BACKUP PLAN. /OAJ/  
 
 
   
AVIATION  
 
(12Z TAFS)  
ISSUED AT 619 AM CST SAT DEC 21 2024  
 
VFR CONDITIONS WL PREVAIL THROUGH THE TAF PERIOD. /22/  
 
 
   
PRELIMINARY POINT TEMPS/POPS  
 
JACKSON 49 28 55 33 / 0 0 0 0  
MERIDIAN 49 26 53 29 / 0 0 0 0  
VICKSBURG 49 27 56 33 / 0 0 0 0  
HATTIESBURG 52 29 56 32 / 0 0 0 0  
NATCHEZ 50 29 57 35 / 0 0 0 0  
GREENVILLE 44 28 51 32 / 0 0 0 0  
GREENWOOD 47 27 53 34 / 0 0 0 0  
 
 
   
JAN WATCHES/WARNINGS/ADVISORIES  
 
MS...NONE.  
LA...NONE.  
AR...NONE.  
 
 
 
 
 
EC/22/OAJ  
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