052  
FXUS63 KLSX 191130  
AFDLSX  
 
AREA FORECAST DISCUSSION...UPDATED AVIATION  
NATIONAL WEATHER SERVICE SAINT LOUIS MO  
530 AM CST SUN JAN 19 2020  
   
SHORT TERM
 
(THROUGH LATE MONDAY AFTERNOON)  
ISSUED AT 208 AM CST SUN JAN 19 2020  
 
FOCUS THRU THE PERIOD CONTINUES TO BE TEMPS THRU TONIGHT, THEN  
TURNING TO PRECIP CHANCES ON MON. ONGOING HEADLINES CONTINUE.  
 
SURFACE RIDGE CONTINUES TO BUILD INTO THE REGION THRU THE PERIOD.  
AREA IS EXPECTED TO REMAIN UNDER DEEP CYCLONIC FLOW TODAY, WHICH  
SHUD LEAD TO CONTINUED CLOUD COVER. NW WINDS WITH GUSTS IN THE 20  
TO 25 KTS RANGE ARE EXPECTED TO CONTINUE THRU THIS AFTERNOON.  
WINDS SHUD GRADUALLY DIMINISH THIS EVENING AS THE PRESSURE  
GRADIENT RELAXES. GOING FORECAST FOR TEMPS APPEARS TO BE ON TRACK  
AND HAVE ONLY MADE MINOR CHANGES TO THE GOING FORECAST. LIKEWISE,  
ONLY MINOR CHANGES TO TEMPS TONIGHT AS CAA CONTINUES AS THE RIDGE  
CONTINUES TO BUILD INTO THE AREA. WITH LIGHTER WINDS EXPECTED  
TONIGHT, WIND CHILL VALUES REMAIN JUST UNDER ADVISORY CRITERIA.  
 
FOCUS THEN TURNS TO PRECIP CHANCES FOR MON. MODELS CONTINUE TO  
DEPICT A POTENT S/W DROPPING ACROSS WESTERN PORTIONS OF THE AREA  
ON MON AFTERNOON INTO THE EVENING. MODEL SOLNS DIFFER SOMEWHAT ON  
PRECIP LOCATION WITH SOME HIGH LEVEL FRONTOGENESIS ALONG THE SW  
FLANK, PUSHING PRECIP FURTHER FROM THE S/W TRACK. HAVE GENERALLY  
ALIGNED POPS ALONG AND AHEAD OF THE S/W INTO MON EVENING. THIS  
SHUD BE A LOW QPF SYSTEM, BUT WITH VERY COLD AIR IN PLACE, SLRS  
WILL BE HIGH. STILL, MODELS SUGGEST SYSTEM WEAKENING AS IT  
ARRIVES. GOING FORECAST FOR POPS AND SNOW MAY BE TOO LOW, BUT  
CONFIDENCE IS LOWER ON WHERE HIGHER BAND OF SNOW WILL SETUP.  
 
TILLY  
   
LONG TERM
 
(MONDAY THROUGH NEXT SATURDAY)  
ISSUED AT 311 PM CST SAT JAN 18 2020  
 
THE MODELS ARE CONSISTENT THAT A STRONG NORTHWEST FLOW SHORTWAVE  
WILL DROP SOUTHWARD THROUGH OUR AREA MONDAY AFTERNOON AND  
EVENING. ALTHOUGH THE SURFACE/BOUNDARY LAYER WILL CONTINUE TO BE  
DRY WITH SURFACE RIDGING OVER OUR AREA, IT APPEARS THAT THERE  
WILL LIKELY BE AT LEAST FLURRIES AHEAD OF THIS SHORTWAVE ON  
MONDAY AND MONDAY EVENING. COULD NOT RULE OUT A BRIEF PERIOD OF  
LIGHT SNOW MONDAY AFTERNOON AND EVENING, MAINLY ACROSS CENTRAL  
AND SOUTHEAST MO LEADING TO A DUSTING OF SNOW ACCUMULATION. WILL  
SEE THE START OF A WARMING TREND BY TUESDAY AFTERNOON DUE TO  
RISING UPPER LEVEL HEIGHTS, AND AS THE SURFACE WIND BECOMES  
SOUTHERLY AS THE SURFACE RIDGE FINALLY SHIFTS EAST OF THE REGION.  
THE CHANCE OF PRECIPITATION WILL RETURN TO MUCH OF THE FORECAST  
AREA BY WEDNESDAY NIGHT AS SOUTH-SOUTHWESTERLY WINDS BRING  
INCREASING LOW LEVEL MOISTURE INTO OUR AREA AHEAD OF AN  
APPROACHING UPPER LEVEL TROUGH. THE CHANCE OF PRECIPITATION WILL  
CONTINUE FOR THE REMAINDER OF THE WORK WEEK AS AN UPPER LEVEL LOW  
AND ASSOCIATED SURFACE LOW SHIFT EASTWARD THROUGH OUR AREA. THE  
OPERATIONAL GFS MODEL IS FURTHER NORTH WITH THE TRACK OF THE  
SURFACE LOW WHICH WOULD FAVOR A PRECIPITATION TYPE OF MAINLY  
LIQUID RAIN, WHILE THE ECMWF MODEL IS FURTHER SOUTH WITH THE PATH  
OF THE SURFACE LOW WHICH WOULD FAVOR A WINTRY MIX. FOR NOW WILL  
LEAN TOWARD THE WARMER MODEL SOLUTION, BUT THERE STILL MAY BE A  
WINTRY MIX DURING THE LATE NIGHT AND EARLY MORNING HOURS, MAINLY  
ACROSS NORTHEAST MO AND WEST CENTRAL IL.  
 
GKS  

 
   
AVIATION
 
(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)  
ISSUED AT 530 AM CST SUN JAN 19 2020  
 
VFR FLIGHT CONDITIONS THROUGH THE MORNING HOURS TODAY WILL GIVE  
WAY TO MVFR SC DECK DEVELOPING ACROSS THE REGION WITH HIGHEST  
COVERAGE ALONG AND EAST OF MISSISSIPPI RIVER BY THIS AFTERNOON. SO  
KEPT MVFR CEILINGS OVER KUIN WITH SCATTERED COVERAGE AT REST OF  
TAF SITES. OTHERWISE, GUSTY NORTHWEST WINDS WILL PERSIST THEN  
SHOULD GRADUALLY DIMINISH BY SUNSET. SC WILL LIFT AND SCATTER OUT  
BY EARLY THIS EVENING.  
 
BYRD  

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
SAINT LOUIS 20 9 21 13 / 0 0 10 10  
QUINCY 10 1 15 6 / 0 0 10 5  
COLUMBIA 20 7 18 9 / 0 0 40 10  
JEFFERSON CITY 22 8 20 9 / 0 0 40 10  
SALEM 20 11 25 14 / 0 0 5 5  
FARMINGTON 27 10 23 12 / 0 0 20 20  
 

 
   
LSX WATCHES/WARNINGS/ADVISORIES
 
 
MO...WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR KNOX MO-LEWIS MO.  
 
IL...WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR ADAMS IL-BROWN IL.  
 

 
 

 
 
WFO LSX  
 
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