280  
FXUS63 KDVN 201122  
AFDDVN  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE QUAD CITIES IA IL  
522 AM CST MON JAN 20 2025  
   
KEY MESSAGES
 
 
- DANGEROUSLY COLD CONDITIONS CONTINUE TODAY THROUGH TUESDAY MORNING  
BEFORE TEMPERATURES REBOUND FOR WEDNESDAY AND BEYOND  
 
- COLD WEATHER ADVISORIES REMAIN IN EFFECT FOR THIS MORNING,  
WITH ADDITIONAL HEADLINES NOW IN EFFECT FOR THIS EVENING  
THROUGH TUESDAY MORNING, INCLUDING AN EXTREME COLD WARNING  
ALONG AND NORTH OF HIGHWAY 30  
 
- DRY CONDITIONS ARE EXPECTED FOR MOST OF THE EXTENDED, WITH THE  
EXCEPTION FOR CHANCES (20-30%) OF LIGHT SNOW WEDNESDAY  
 

 
   
SHORT TERM /THROUGH TUESDAY/
 
 
ISSUED AT 328 AM CST MON JAN 20 2025  
 
OUR PERIOD OF DANGEROUSLY COLD CONDITIONS MARCHES ON TODAY THROUGH  
TUESDAY MORNING, WITH THE COLDEST CONDITIONS YET TO COME! THE  
CONTIGUOUS US CONTINUES TO BE UNDER A HUMONGOUS UPPER-LEVEL TROUGH,  
WITH AN UPPER-LEVEL LOW LOITERING OVER HUDSON BAY IN CANADA, LEAVING  
US UNDER PERSISTENT NORTHWESTERLY CYCLONIC FLOW/COLD AIR ADVECTION.  
850 MB LEVEL TEMPERATURES EARLY THIS MORNING ARE PROGGED AT 12Z/6 AM  
PER THE GEFS AND EPS ENSEMBLE MEANS AROUND -23 TO -25 DEGREES C, SO  
A BITTERLY COLD AIR MASS IN PLACE. WESTERLY WINDS AROUND 5 MPH HAS  
RESULTED IN WIDESPREAD WIND CHILLS BETWEEN -15 TO -30 DEGREES. AREAS  
AROUND MACOMB, IL HAVE FALLEN TO -15 TO -20 DEGREE WIND CHILLS, AND  
THUS, WE HAVE EXPANDED THE ONGOING COLD WEATHER ADVISORY TO AREAS  
SOUTH AND EAST OF THE CURRENT ONE, WITH CONDITIONS EXPECTED TO  
IMPROVE BY THE MID- TO LATE-MORNING TIME FRAME.  
 
THIS AFTERNOON, WE ARE TRACKING A LOBE OF WEAK PVA THAT IS PROGGED  
TO SWEEP THROUGH THE AREA THIS AFTERNOON AND EVENING. THERE SHOULD  
BE ENOUGH MOISTURE AVAILABLE TO GENERATE SOME VERY FINE ICE CRYSTAL  
SNOW, SO WE HAVE INTRODUCED WIDESPREAD CHANCES (10-30%) OF  
FLURRIES/LIGHT SNOW TO THE AREA THIS PM. THE BIGGER IMPACT OF THIS  
WAVE WILL UNDOUBTEDLY BE IN HELPING TO USHER IN THE COLDEST PART OF  
THIS ARCTIC AIR MASS YET FOR TONIGHT THROUGH TUESDAY MORNING.  
 
GUIDANCE HAS TRENDED EVEN COLDER FOR TONIGHT/TUESDAY MORNING, WITH  
OVERNIGHT LOWS IN THE -5 TO -15 DEGREE F RANGE. BOTH THE GEFS AND  
EPS ENSEMBLE MEAN 850 MB TEMPERATURES CONTINUE TO BE THEIR COLDEST  
RIGHT AROUND 12Z/6 AM TUESDAY MORNING, WITH VALUES HOVERING AROUND  
30 DEGREES BELOW ZERO ACROSS THE AREA! TO PUT THIS INTO  
CLIMATOLOGICAL PERSPECTIVE, IF THESE 850 MB TEMPERATURES ACTUALLY  
OCCUR AT THAT TIME, THESE VALUES WOULD BE NEAR THE COLDEST 850 MB  
TEMPERATURE IN THE ENTIRE SPC SOUNDING CLIMATOLOGY FOR DVN, WHICH  
DATES BACK TO 1995 (THE COLDEST VALUE IN THE WHOLE CLIMATOLOGY IS -  
29.5 DEGREES C FROM THE 00Z 12/24/2022 RAOB)! LATEST SOUNDINGS  
INDICATE PERSISTENTLY STEEP LOW-LEVEL LAPSE RATES IN THE COLD AIR  
ADVECTION, LEADING TO WINDS HOVERING AROUND 10 MPH THROUGHOUT THE  
NIGHT, WHICH SHOULD SUPPORT WIND CHILLS IN THE -20 TO -35 DEGREE  
RANGE ACROSS THE AREA - COLDEST ACROSS OUR NORTH. THESE VALUES ARE  
FIRMLY WITHIN CRITERIA FOR ANOTHER NIGHT OF COLD WEATHER ADVISORIES,  
AND EVEN AN EXTREME COLD WARNING HAS BEEN ISSUED FOR AREAS ALONG AND  
NORTH OF HIGHWAY 30 WHERE WIND CHILLS OF -30 TO -35 DEGREES F WILL  
BE POSSIBLE. AT THIS POINT, THE WARNING GOES FROM MIDNIGHT TONIGHT  
THROUGH 9 AM TUESDAY, BUT FURTHER REFINEMENTS TO THE END TIME ARE  
POSSIBLE. A RIDGE OF SURFACE HIGH PRESSURE DOES APPEAR TO SWEEP  
THROUGH THE AREA BY MID-DAY TUESDAY, WITH SOUTHERLY RETURN FLOW  
DEVELOPING IN ITS WAKE IN THE AFTERNOON HOURS. THIS SHOULD HELP  
TEMPERATURES WARM UP A BIT, BUT THEY SHOULD REMAIN IN THE SINGLE  
DIGITS ABOVE ZERO - STILL QUITE FRIGID!  
 

 
   
LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/
 
 
ISSUED AT 328 AM CST MON JAN 20 2025  
 
ALTHOUGH THERE WILL BE CONTINUED WARM AIR ADVECTION INTO TUESDAY  
NIGHT, IT SHOULD STILL BE QUITE COLD, WITH OVERNIGHT LOWS AROUND  
ZERO DEGREES (STILL WARMER THAN LOWS THIS MORNING AND EXPECTED LOWS  
TUESDAY MORNING). FURTHER RELIEF FROM THE DANGEROUS WIND CHILLS WILL  
MOVE IN DURING THE DAYLIGHT HOURS WEDNESDAY AS THE LARGE-SCALE  
PATTERN CHANGES, WITH FURTHER WARM AIR ADVECTION HELPING  
TEMPERATURES WARM UP CLOSER TO SEASONAL VALUES. HIGHS BY WEDNESDAY  
ARE PROGGED TO WARM BACK UP TO THE MIDDLE 20S NORTHEAST TO THE LOWER  
30S SOUTHWEST. THESE TEMPERATURES LOOK TO CONTINUE THROUGH FRIDAY,  
PERHAPS EVEN WARMER BY SATURDAY (HIGHS BACK ABOVE FREEZING?).  
 
IN TERMS OF PRECIPITATION, THE ONLY TIME THAT WE SEE WHEN WE COULD  
GET SOME LIGHT SNOW IS ON WEDNESDAY AND WEDNESDAY NIGHT AS AN  
EMBEDDED MID-LEVEL IMPULSE SWEEPS THROUGH THE AREA. THE 20.00Z LREF  
EXCEEDANCE PROBABILITIES OF MEASURABLE SNOW (0.1" OR MORE) HAS  
TRENDED MUCH HIGHER THAN 24 HOURS AGO, AROUND 70 TO 90 PERCENT.  
SOUNDINGS DO INDICATE A SATURATED DENDRITIC GROWTH ZONE, WITH FAIRLY  
WEAK LARGE-SCALE FORCING ASSOCIATED WITH THE WAVE. WE LEANED A  
LITTLE HIGHER ON THE POPS THAN THE NBM TOWARDS THE DETERMINISTIC GFS  
SOLUTION WHICH GIVES AROUND 20 TO 30% CHANCES OF LIGHT SNOW. IN  
TERMS OF AMOUNTS, THE WSE PLUME VIEWER INDICATES THE POTENTIAL FOR  
TOTAL SNOW AMOUNTS OF AROUND AN INCH OR LESS FOR MOST LOCATIONS,  
ALTHOUGH THERE ARE SOME ENSEMBLE MEMBERS THAT SUGGEST AMOUNTS  
BETWEEN 1-2", SO WE WILL HAVE TO KEEP AN EYE ON GUIDANCE TO MAKE  
REFINEMENTS TO THE FORECAST.  
 

 
   
AVIATION /12Z TAFS THROUGH 12Z TUESDAY/
 
 
ISSUED AT 522 AM CST MON JAN 20 2025  
 
LARGELY VFR CONDITIONS ARE EXPECTED THROUGHOUT THE TAF PERIOD.  
A MID-LEVEL TROUGH SHOULD SWEEP THROUGH THE AREA THIS AFTERNOON  
AND EVENING, WHICH SHOULD GENERATE SOME LIGHT FLURRIES. UPSTREAM  
OVER THE DAKOTAS WHERE THE TROUGH IS CURRENTLY LOCATED, THERE IS  
SOME MVFR CEILINGS BEING REPORTED, BUT CONFIDENCE IN THESE  
CONDITIONS PERSISTING IS A BIT LOWER HERE. WE ALSO CAN'T RULE  
OUT SOME MVFR VISIBILITY RESTRICTIONS, ALTHOUGH THIS TOO IS  
LOWER CONFIDENCE. WEST TO WEST-NORTHWEST WINDS WILL REMAIN WITH  
US, STRENGTHENING BY LATE THIS MORNING INTO THE AFTERNOON,  
GUSTING BETWEEN 20 TO 25 KNOTS.  
 

 
   
DVN WATCHES/WARNINGS/ADVISORIES
 
 
IA...COLD WEATHER ADVISORY UNTIL 11 AM CST THIS MORNING FOR  
IAZ040>042-051>054-065-066.  
COLD WEATHER ADVISORY FROM 6 PM THIS EVENING TO MIDNIGHT CST  
TONIGHT FOR IAZ040>042-051>054-066.  
EXTREME COLD WARNING FROM MIDNIGHT TONIGHT TO 9 AM CST TUESDAY  
FOR IAZ040>042-051>054-066.  
COLD WEATHER ADVISORY FROM 9 PM THIS EVENING TO 9 AM CST  
TUESDAY FOR IAZ063>065-067-068-076>078-087>089-098-099.  
COLD WEATHER ADVISORY UNTIL 9 AM CST THIS MORNING FOR IAZ067-  
068-078-089-099.  
IL...COLD WEATHER ADVISORY UNTIL 11 AM CST THIS MORNING FOR ILZ001-  
002-007.  
COLD WEATHER ADVISORY FROM 6 PM THIS EVENING TO MIDNIGHT CST  
TONIGHT FOR ILZ001-002-007.  
EXTREME COLD WARNING FROM MIDNIGHT TONIGHT TO 9 AM CST TUESDAY  
FOR ILZ001-002-007.  
COLD WEATHER ADVISORY FROM 9 PM THIS EVENING TO 9 AM CST  
TUESDAY FOR ILZ009-015>018-024>026-034-035.  
COLD WEATHER ADVISORY UNTIL 9 AM CST THIS MORNING FOR ILZ009-  
015>018-024>026-034-035.  
MO...COLD WEATHER ADVISORY FROM 9 PM THIS EVENING TO 9 AM CST  
TUESDAY FOR MOZ009-010.  
 

 
 

 
 
SHORT TERM...SCHULTZ  
LONG TERM...SCHULTZ  
AVIATION...SCHULTZ  
 
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