895
FXUS63 KDVN 201734
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1134 AM CST MON JAN 20 2025
KEY MESSAGES
- DANGEROUSLY COLD CONDITIONS CONTINUE THROUGH TUESDAY MORNING
BEFORE TEMPERATURES REBOUND FOR WEDNESDAY AND BEYOND
- COLD WEATHER ADVISORIES ARE 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 /18Z TAFS THROUGH 18Z TUESDAY/
ISSUED AT 1130 AM CST MON JAN 20 2025
WEAK UPPER LEVEL DISTURBANCE ASSOCIATED WITH THE THERMAL TROF
WILL ROTATE THROUGH THE AREA THROUGH 06Z/21 BRINGING SPOTTY
FLURRIES TO EASTERN IOWA AND NORTHERN ILLINOIS. HOWEVER,
CONDITIONS SHOULD REMAIN VFR. GUSTY WINDS ARE EXPECTED THROUGH
06Z/21 BEFORE DIMINISHING AS ARCTIC HIGH PRESSURE MOVES INTO
THE MIDWEST. WINDS WILL AGAIN BECOME GUSTY AFTER 18Z/21 ACROSS
EASTERN IOWA AND NORTHERN ILLINOIS AS THE ARCTIC HIGH MOVES
INTO THE EASTERN GREAT LAKES.
DVN WATCHES/WARNINGS/ADVISORIES
IA...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.
IL...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.
MO...COLD WEATHER ADVISORY FROM 9 PM THIS EVENING TO 9 AM CST
TUESDAY FOR MOZ009-010.
SHORT TERM...SCHULTZ
LONG TERM...SCHULTZ
AVIATION...08
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page