123  
FXUS63 KLSX 082359  
AFDLSX  
 
AREA FORECAST DISCUSSION...UPDATED AVIATION  
NATIONAL WEATHER SERVICE SAINT LOUIS MO  
559 PM CST THU DEC 8 2022  
   
SHORT TERM
 
(THROUGH LATE FRIDAY NIGHT)  
ISSUED AT 211 PM CST THU DEC 8 2022  
 
CURRENT WATER VAPOR IMAGERY SHOWS SOUTHWESTERLY FLOW ACROSS THE  
MIDDLE MISSISSIPPI VALLEY WITH A SHORTWAVE OVER THE CENTRAL PLAINS.  
THE UPPER-LEVEL JET STREAK AND LOW-LEVEL JET MAINLY RESPONSIBLE FOR  
THE EARLY DAY RAIN ACROSS SOUTHERN PORTIONS OF THE CWA HAVE MOVED  
EASTWARD, SHIFTING THE AREA OF RAIN AWAY FROM THE AREA. IN ITS WAKE,  
WEAK WARM AIR ADVECTION AHEAD OF THE SHORTWAVE AND CORRESPONDING  
SURFACE LOW IS PRODUCING WIDELY SCATTERED AREAS OF LIGHT RAINFALL  
ACROSS THE CWA. THIS IS EXPECTED TO CONTINUE THROUGH THE AFTERNOON  
INTO THIS EVENING.  
 
THE AFOREMENTIONED SURFACE LOW THAT CAN BE FAINTLY MADE OUT IN  
SURFACE OBSERVATIONS OVER KANSAS WILL MOVE NORTHEASTWARD THIS  
EVENING INTO NORTHERN MISSOURI AND IOWA. LIFT FROM THIS FEATURE AND  
THE ASSOCIATED SHORTWAVE WILL INCREASE RAIN COVERAGE MAINLY OVER  
NORTHEASTERN MISSOURI AND WEST-CENTRAL ILLINOIS TONIGHT AHEAD OF A  
COLD FRONT. THIS COLD FRONT WILL SWEEP THROUGH THE AREA LATE TONIGHT  
INTO TOMORROW MORNING, BRINGING AN END TO THE RAIN AT THE  
LATEST SHORTLY AFTER SUNRISE TOMORROW MORNING.  
 
THE POST-FRONTAL AIRMASS IS NOT PARTICULARLY POTENT IN TERMS OF  
TEMPERATURES, BUT WILL USHER DRIER AIR INTO THE REGION. THIS WILL  
RESULT IN TEMPERATURES PEAKING TOMORROW AFTERNOON AT TO JUST ABOVE  
CLIMATOLOGICAL VALUES UNDER CLEARING SKIES FOR MUCH OF THE CWA. THE  
EXCEPTION TO THIS WILL BE NORTHEASTERN MISSOURI AND WEST-CENTRAL  
ILLINOIS WHERE DENSER CLOUD COVER IS EXPECTED TO LINGER.  
 
ELMORE  
   
LONG TERM
 
(SATURDAY THROUGH NEXT THURSDAY)  
ISSUED AT 211 PM CST THU DEC 8 2022  
 
OUR FOCUS FOR THIS PORTION OF THE FORECAST PERIOD REMAINS ON  
MULTIPLE ROUNDS OF RAINFALL AND THE POTENTIAL FOR EARLY WEEK  
THUNDERSTORMS.  
 
ON SATURDAY, ENSEMBLE CONSENSUS IS THAT A SHORTWAVE WILL QUICKLY  
PROGRESS THROUGH THE CENTRAL PLAINS AND MIDWEST. IN RESPONSE, A WEAK  
SURFACE LOW WILL FORM ALONG A STALLED BOUNDARY TO OUR SOUTH AND  
TRACK EASTWARD TOWARD THE CWA. AHEAD OF THIS LOW, AN UPPER-LEVEL JET  
STREAK WILL PAIR WITH ISENTROPIC LIFT VIA A LOW-LEVEL JET  
INTERACTING WITH THE BOUNDARY TO BRING ANOTHER ROUND OF RAINFALL TO  
PORTIONS OF THE AREA. THE PROBABILITY FOR RAINFALL IS HIGHEST OVER  
SOUTHEASTERN MISSOURI AND SOUTHWESTERN ILLINOIS WHERE NEARLY EVERY  
ENSEMBLE MEMBER HAS RAINFALL OCCURRING SATURDAY MORNING INTO THE  
DAY. HOWEVER, CONFIDENCE IN RAINFALL DECREASES FURTHER NORTHWARD  
ALONG THE I-70 CORRIDOR, WITH A VERY SHARP GRADIENT EXPECTED IN  
RAINFALL VS. LITTLE TO NO RAINFALL. RAIN CHANCES WILL DECREASE  
THROUGH THE AFTERNOON AND EVENING AS THE BETTER FORCING ALOFT AND  
SURFACE LOW MOVE EASTWARD.  
 
THERE IS HIGH CONFIDENCE THAT SUNDAY THROUGH MUCH OF MONDAY WILL BE  
RELATIVELY CALM AND DRY AS ENSEMBLE CONSENSUS IS THAT AN UPPER-LEVEL  
RIDGE WILL BUILD INTO THE PLAINS AND MIDWEST. AT THE SURFACE, HIGH  
PRESSURE WILL KEEP CONDITIONS CALM AND SURFACE FLOW TO SOME DEGREE  
EASTERLY. THIS SURFACE FLOW WILL KEEP TEMPERATURES AROUND  
CLIMATOLOGICAL NORMALS THROUGH THIS TWO-DAY STRETCH, WITH ENSEMBLE  
GUIDANCE CONVERGING ON HIGHS IN THE UPPER 40S FOR MUCH OF THE AREA.  
 
THROUGH MONDAY INTO TUESDAY, A TROUGH WILL DEEPEN ACROSS THE  
INTERMOUNTAIN WEST, WITH A LEADING SHORTWAVE WITHIN THE TROUGH  
EJECTING OUT INTO THE CENTRAL PLAINS ON TUESDAY. IN RESPONSE, A  
SURFACE LOW WILL DEVELOP AND DEEPEN ACROSS THE CENTRAL PLAINS,  
SWINGING A COLD FRONT INTO THE MIDWEST. AS THIS OCCURS, THE GENERAL  
CONSENSUS IS THAT THE LOW WILL OCCLUDE AS THE UPPER-LEVEL TROUGH  
BECOMES CUT OFF FROM THE MAIN FLOW, HOWEVER, THERE IS STILL  
DISAGREEMENT ON THE TIMING AND PROGRESSION OF THE OCCLUSION. THIS  
UNCERTAINTY HAS IMPLICATIONS IN HOW UNSTABLE THE AIRMASS IS ABLE TO  
GET AHEAD OF THE COLD FRONT ON TUESDAY. THE NUMBER OF GLOBAL  
ENSEMBLES THAT HAVE AT LEAST 100 J/KG OF SBCAPE CONTINUES TO  
INCREASE, BUILDING CONFIDENCE IN AT LEAST THUNDERSTORMS OCCURRING  
AMONG THE WIDESPREAD RAINFALL ASSOCIATED WITH THE FROPA. HOWEVER,  
THE THREAT OF STRONG TO SEVERE STORMS REMAINS MORE UNCERTAIN, AS  
ENSEMBLES STILL DISAGREE WITH HOW UNSTABLE WE BECOME OR IF THE  
OCCLUDING LOW CUTS OFF THE WARM SECTOR SOUTH OF THE CWA. THEREFORE,  
THE THREAT OF STRONG TO SEVERE STORMS REMAINS LOW AT THIS LEAD TIME,  
BUT CONTINUES TO NEED MONITORING.  
 
RAIN CHANCES MAY LINGER ACROSS PORTIONS OF THE CWA THROUGH THE  
REMAINDER OF THE PERIOD AS MOISTURE WRAPS AROUND THE LOW AS IT  
PROGRESSES SLOWLY EASTWARD. NORTHWESTERLY FLOW ALOFT ON THE  
BACKSIDE OF THE UPPER-LEVEL CUTOFF WILL SUPPORT MORE SEASONABLE  
AIR FILTERING INTO THE CWA BEHIND THE FRONT, WITH ENSEMBLE MEANS  
HOVERING RIGHT AROUND CLIMATOLOGICAL NORMALS THROUGH THE END OF  
THE WORKWEEK.  
 
ELMORE  
 

 
   
AVIATION
 
(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)  
ISSUED AT 558 PM CST THU DEC 8 2022  
 
STRATUS AND OCCASIONAL DRIZZLE AND FOG ARE EXPECTED TO RESULT IN IFR  
FLIGHT CONDITIONS AT ALL TERMINALS THROUGHOUT THE NIGHT AND INTO  
FRIDAY MORNING. PASSING SHOWERS ARE ALSO EXPECTED AT TIMES,  
PRIMARILY AT KUIN, BUT WILL HAVE LITTLE IMPACT GIVEN THE PREVAILING  
IFR FLIGHT CONDITIONS. BRIEF VISIBILITIES BELOW 1SM CANNOT BE RULED  
OUT WITH HEAVIER DRIZZLE AND DENSER FOG, BUT LOW CONFIDENCE IN  
OCCURRENCE AND TIMING PRECLUDED ITS INCLUSION. A COLD FRONT IS  
FORECAST TO TRAVERSE THE AREA FROM WEST TO EAST OVERNIGHT WITH  
GRADUALLY VEERING WINDS, INITIALLY EASTERLY, VEERING MORE QUICKLY  
FROM SOUTHERLY TO WESTERLY AT AND FOLLOWING ITS PASSAGE. IFR FOG AND  
STRATUS, PERHAPS CONTINUED DRIZZLE, WILL LINGER BEHIND THE FRONT  
BEFORE LIFTING AND CLEARING LATE MORNING/MIDDAY FRIDAY. CLEARING MAY  
NOT OCCUR UNTIL MUCH LATER AT KUIN, BUT STRATUS SHOULD AT LEAST LIFT  
TO MVFR DURING EARLY AFTERNOON.  
 
PFAHLER  
 

 
   
LSX WATCHES/WARNINGS/ADVISORIES
 
 
MO...NONE.  
IL...NONE.  

 
 

 
 
WFO LSX  
 
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