420  
FXUS64 KJAN 172315 AAA  
AFDJAN  
 
AREA FORECAST DISCUSSION...UPDATED  
NATIONAL WEATHER SERVICE JACKSON MS  
515 PM CST THU JAN 17 2019  
   
UPDATE
 
 
UPDATED FOR 00Z AVIATION DISCUSSION  
 

 
   
AVIATION
 
 
00Z TAF DISCUSSION:  
MVFR CONDITIONS AT THE BEGINNING OF THE PERIOD WILL RAPIDLY  
DETERIORATE TO IFR DURING THE EVENING AND LIFR IN SPOTS AFTER  
MIDNIGHT. THE BROKEN STRATUS DECK IN PLACE WILL QUICKLY FILL IN  
ANY HOLES THAT HAVE FORMED THIS AFTERNOON. AFTER THIS OCCURS AND  
THE BOUNDARY LAYER BEGINS TO COOL, CEILINGS WILL BEGIN TO LOWER AS  
FOG DEVELOPS AT THE SURFACE. A WEAK COLD FRONT WILL MOVE INTO THE  
GLH AND GWO AREAS DURING THE LATE EVENING AND MAY SPARE THESE  
AREAS THE POOR VISIBILITIES EXPECTED ELSEWHERE. WHILE VISIBILITIES  
WILL IMPROVE BY MID TO LATE MORNING FRIDAY, IFR CEILINGS DO NOT  
LOOK TO RISE TO MVFR UNTIL THE AFTERNOON./26/  
 

 
   
DISCUSSION
 
 
THROUGH FRIDAY:  
 
THE WEAK DISTURBANCE MOVING THROUGH THE REGION TODAY HAS HELPED KEEP  
THE REGION CLOUDY WITH PATCHES OF DRIZZLE AND LIGHT SHOWERS  
PROLONGING THE DAMPNESS. DESPITE THE CLOUDS, WARM AIR ADVECTION IN  
THE ATMOSPHERIC LOWER LEVELS HAS BEEN GRADUALLY RAISING TEMPERATURES  
WITH SOME LOCATIONS ACROSS SOUTHERN MS AND WEST OF THE MS RIVER  
LIKELY ACHIEVING THE 60 DEGREE MARK THIS AFTERNOON. BUT THIS SUBTLE  
WARMTH AND MOISTURE ADVECTION WILL ALSO ENSURE LOW CLOUDS CONTINUE  
INTO TONIGHT AHEAD OF A WEAK APPROACHING COLD FRONT THAT IS EXPECTED  
TO DROP INTO THE ARKLAMISS DELTA BEFORE STALLING. ANY FURTHER RAIN  
TONIGHT WILL GENERALLY BE LIMITED TO PATCHY LIGHT DRIZZLE AS THE  
INCOMING AND STALLING FRONT WILL LACK UPPER SUPPORT AND LIFT FOR  
MORE SIGNIFICANT PRECIPITATION. THE MAIN CONCERN FOR LATER TONIGHT  
(AND LASTING INTO AT LEAST TOMORROW MORNING) WILL BE DENSE FOG.  
CONFIDENCE AT THIS JUNCTURE IS HIGH THAT AREAS OF FOG WILL GRADUALLY  
BECOME WIDESPREAD THROUGH THE NIGHT DUE TO A COMBINATION OF SUBTLE  
MOISTURE ADVECTION AT THE SURFACE AND COOL GROUND AIDING IN "BUILD-  
DOWN" OF LOW STRATUS TOWARD THE SURFACE. HOWEVER, AT THIS TIME  
CONFIDENCE IS NOT HIGH THAT FOG WILL BE TRULY DENSE ON A WIDESPREAD  
ENOUGH BASIS TO WARRANT ISSUANCE OF A DENSE FOG ADVISORY. SO, FOR  
NOW, WE WILL MENTION PATCHY DENSE FOG CONCERNS IN THE HWO AND  
GRAPHICS FOR TONIGHT AND THE ONCOMING SHIFT WILL MONITOR THE  
SITUATION CLOSELY.  
 
OTHERWISE, EXPECT LOWS REMAINING IN THE RELATIVELY MILD UPPER 40S TO  
LOWER 50S. TOMORROW, LOW LEVEL WARMTH AND MOISTURE ADVECTION WILL  
CONTINUE AND SHOULD FINALLY DELIVER WIDESPREAD HIGHS IN THE 60S BY  
THE AFTERNOON. IT IS NOT OUT OF THE QUESTION LOCATIONS ALONG AND  
SOUTH OF THE I-20 CORRIDOR MAY MAKE A RUN AT 70 DEGREES IF A DECENT  
AMOUNT OF SUNSHINE PREVAILS BY THE AFTERNOON HOURS. HOWEVER, GIVEN  
RECENT HISTORY OF MUCH MORE CLOUDS THAN SUN, IT IS HARD TO NOT BE  
BIASED ON CLOUDS BEING DOGGED ACROSS MUCH OF THE AREA TOMORROW. IT  
IS ALSO EASIER TO HAVE THIS STANCE WHEN MUCH OF THE GUIDANCE IS  
SUGGESTING FOG MAY NOT BREAK UP IN MANY LOCATIONS TOMORROW UNTIL THE  
LATE MORNING TO MIDDAY TIME WINDOW. REGARDLESS, AT LEAST ANY RAIN  
DURING THE DAY TOMORROW SHOULD BE LIMITED TO VERY PATCHY AND LIGHT  
DRIZZLE IN THE MORNING WITH PRECIPITATION ASSOCIATED WITH THE NEXT  
SYSTEM HOLDING OFF UNTIL TOMORROW NIGHT. /BB/  
 
FRIDAY NIGHT THROUGH SATURDAY: A ROBUST AND QUICK MOVING STORM  
SYSTEM WILL TRACK FROM THE RED RIVER VALLEY FRIDAY NIGHT INTO THE  
MIDSOUTH BY SATURDAY MORNING, BRINGING A COLD FRONT ACROSS THE  
AREA EARLY IN THE DAY. SHOWERS WILL BEGIN TO INCREASE FRIDAY  
EVENING, WITH GREATER RAIN CHANCES AND A FEW STORMS POSSIBLE  
OVERNIGHT. WITH A POTENT LOW LEVEL JET AND STRONG DEEP LAYER SHEAR  
TRAVERSING THE REGION AND WEAK INSTABILITY DEVELOPING AHEAD OF  
THE FRONT, A FEW SEVERE STORMS CAN'T BE RULED OUT MAINLY JUST  
AHEAD OF THE FRONT. MODELS HAVE BEEN TRENDING FASTER WITH THIS  
SYSTEM, AND THE LIMITED WINDOW OF SEVERE WEATHER THREAT IS  
EXPECTED TO CLOSE BY THE AFTERNOON IN MOST AREAS. OF COURSE, THE  
MORNING TIMING IS NOT GENERALLY FAVORABLE FOR A SIGNIFICANT UPTICK  
IN INSTABILITY. WE'LL CONTINUE TO ADVERTISE THE MARGINAL RISK FOR  
SEVERE STORMS IN THE HWO/GRAPHICS. ONE OTHER HAZARD WE WILL HAVE  
TO KEEP IN MIND IS THE GRADIENT WIND THREAT GIVEN FORECAST 925 MB  
WINDS IN THE 40-50 KT RANGE WITH THE SURFACE LOW PASSING CLOSE TO  
THE AREA. LATER SHIFTS MAY NEED TO INCLUDE THE WIND THREAT IN THE  
HWO. LIMITED WRAP AROUND SHOWER ACTIVITY WILL LINGER INTO THE  
AFTERNOON AND EVENING MAINLY ACROSS NORTHERN AND EASTERN PORTIONS  
OF THE AREA. IT WILL TURN SHARPLY COLDER BEHIND THE FRONT, AND  
FORECAST THERMAL PROFILES SUGGEST LIGHT RAIN COULD BRIEFLY MIX  
WITH OR CHANGE TO LIGHT SNOW ALONG THE HWY 82 CORRIDOR BEFORE  
ENDING SATURDAY NIGHT. HOWEVER, NO ACCUMULATIONS OR TRAVEL ISSUES  
ARE ANTICIPATED IN OUR AREA. MOST PRECIPITATION IS EXPECTED TO BE  
GONE BEFORE MIDNIGHT.  
 
SUNDAY AND MONDAY: THE NEW WEEK WILL GET OFF TO A BLUSTERY START.  
THOUGH PRECIP WILL BE CLEAR OF THE AREA, LOW CLOUDS MAY LINGER  
INTO AT LEAST A PORTION OF THE DAYTIME SUNDAY. AFTER A BREEZY AND  
COLD MORNING WITH WIND CHILLS POSSIBLY IN THE 20S (TEENS POSSIBLE  
IN THE DELTA), TEMPS AREN'T EXPECTED TO GET OUT OF THE 30S IN  
NORTH MS. WITH WINDS DROPPING OFF DURING THE EVENING, IF THERE IS  
SUFFICIENT CLEARING WE COULD SEE STRONG RADIATIONAL COOLING  
SUNDAY NIGHT/MONDAY MORNING WITH TEMPS GETTING WELL INTO THE 20S  
ACROSS MOST OF THE AREA. AS SURFACE FLOW QUICKLY TURNS BACK  
AROUND, CONDITIONS WILL BEGIN TO MODERATE AGAIN MONDAY. THE BREAK  
IN THE RAIN CHANCES WILL BE FLEETING, HOWEVER, AS THE PATTERN  
REMAINS QUITE PROGRESSIVE.  
 
TUESDAY THROUGH NEXT THURSDAY: ANOTHER SHARP MID/UPPER TROUGH  
WILL BRING A RESURGENCE OF SHOWER ACTIVITY AS EARLY AS THE  
DAYTIME HOURS TUESDAY, WITH GREATER RAIN CHANCES AS ANOTHER COLD  
FRONT MOVES INTO THE AREA TUESDAY NIGHT. WITH A MORE LIMITED  
WINDOW FOR MOISTURE/INSTABILITY RECOVERY AHEAD OF THIS SYSTEM,  
WE'RE NOT ANTICIPATING THUNDER AT THIS TIME. THERE REMAINS SOME  
MODEL DISAGREEMENT ON EXACTLY HOW THIS SYSTEM WILL EVOLVE, WITH  
THE GFS SUGGESTING A LESS PROGRESSIVE SURFACE FRONT/WAVE AND THE  
POTENTIAL FOR COLDER AIR TO "CATCH UP" WITH THE SYSTEM AND A  
POSSIBLE TRANSITION IN PRECIP TYPE ON THE BACK END.  
CLIMATALOGICALLY, THIS IS NOT A TYPICAL SETUP FOR NOTABLE WINTRY  
PRECIP IN OUR AREA, AND GIVEN THE DISAGREEMENT WITH THE EURO  
SOLUTION, WE'LL CONTINUE TO LEAVE OUT ANY MENTION OF WINTRY  
WEATHER FOR THIS PORTION OF THE FORECAST.  
 
DRIER AND COOLER WEATHER IS ANTICIPATED NEXT THURSDAY. CLOUDS MAY  
LINGER THROUGH THE DAY AS WE REMAIN UNDER THE AXIS OF A LONGWAVE  
UPPER TROUGH. /DL/  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
JACKSON 50 65 57 65 / 34 8 79 87  
MERIDIAN 49 64 56 68 / 36 10 52 90  
VICKSBURG 49 66 58 64 / 19 9 91 77  
HATTIESBURG 51 67 58 68 / 28 11 50 86  
NATCHEZ 50 67 59 64 / 17 9 88 77  
GREENVILLE 46 61 56 60 / 21 8 96 75  
GREENWOOD 48 62 56 63 / 26 8 91 88  
 

 
   
JAN WATCHES/WARNINGS/ADVISORIES
 
 
MS...NONE.  
LA...NONE.  
AR...NONE.  
 

 
 

 
 
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