940
FXUS63 KDVN 271055
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
555 AM CDT MON OCT 27 2025
KEY MESSAGES
- TEMPERATURES ARE EXPECTED TO BE SLIGHTLY ABOVE NORMAL THROUGH THE
FINAL WEEK OF OCTOBER
- A LARGER STORM SYSTEM IS EXPECTED TO IMPACT THE REGION TUESDAY THROUGH
WEDNESDAY, BRINGING THE NEXT CHANCES OF WIDESPREAD RAINFALL
TO THE REGION, ALONG WITH WINDY CONDITIONS TUESDAY NIGHT
THROUGH WEDNESDAY, WITH GUSTS OVER 30 MPH POSSIBLE
- RAINFALL TOTALS WITH THE TUESDAY/WEDNESDAY SYSTEM ARE LIKELY
TO RANGE FROM AROUND 0.25-0.50 INCHES OVER NORTHWESTERN
ILLINOIS TO AROUND ONE INCH OR MORE ALONG AND SOUTH OF HIGHWAY
34
SHORT TERM /THROUGH TONIGHT/
ISSUED AT 303 AM CDT MON OCT 27 2025
THE SHORT-TERM PERIOD WILL FEATURE A PERIOD OF QUIET WEATHER BEFORE
A LARGER SYSTEM MOVES IN FOR TUESDAY AND WEDNESDAY. FOR TODAY, WE
CONTINUE TO BE UNDER THE INFLUENCE OF A LARGE AREA OF CANADIAN HIGH
PRESSURE, WHICH IS CURRENTLY SITUATED OVER QUEBEC CANADA. DRY
EASTERLY FLOW HAS HELPED STAVE OFF CLOUD COVER, EXCEPT ACROSS OUR
SOUTHERN AREAS ALONG AND SOUTH OF HIGHWAY 92 AS A COMPACT MID-LEVEL
SHORTWAVE NEAR THE BOOTHEEL OF MISSOURI WILL TRANSLATE EASTWARD.
MEANWHILE, A LONGWAVE UPPER-LEVEL TROUGH CONTINUES TO DEVELOP OVER
THE PACIFIC NW REGION, WHICH WILL ONLY INTENSIFY AS A VERY STRONG
130-140+ KT UPPER-LEVEL JET STREAK (OVER THE 99TH CLIMATOLOGICAL
PERCENTILE OF THE ECMWF ENSEMBLE 200-HPA WIND SPEEDS!) HELPS TO
"DIG" THE TROUGH AND BRING IT CLOSER TO OUR REGION LATE TONIGHT. THE
27.00Z HREF ENSEMBLE SOUNDINGS SHOW A TREMENDOUS AMOUNT OF DRY AIR
BELOW THE 500 MB LEVEL, SO PRECIPITATION WILL BE VERY DIFFICULT TO
COME BY. IN FACT, WE HAVE TRIMMED BACK THE POPS FOR LATE TONIGHT
OVER THE PREVIOUS FORECAST DUE TO THE HREF HIGH-RES GUIDANCE
TRENDING DRIER DURING THIS PERIOD OVER ITS TIME-LAGGED ENSEMBLE
MEMBERS. CLOUD COVER SHOULD RAMP UP TONIGHT AS THE PACIFIC NW TROUGH
APPROACHES, BUT ANY RAINFALL THAT DOES OCCUR WILL LIKELY BE OVER OUR
FAR WESTERN AREAS AND REMAIN LIGHT, IF IT RAINS AT ALL.
WITH DEEPER BOUNDARY LAYER MIXING, WIND GUSTS IN EXCESS OF 20 MPH IS
POSSIBLE TODAY, SO BREEZY BUT SHOULDN'T BE TOO STRONG. ALSO,
TEMPERATURES LOOK TO WARM UP, ESPECIALLY FOR LOCATIONS THAT SEE MORE
SUNSHINE, WITH HIGHS IN THE LOWER TO MIDDLE 60S FOR MOST LOCATIONS.
TONIGHT'S LOW SHOULD DIP ONLY TO THE LOWER 40S NORTHEAST TO THE
UPPER 40S SOUTHWEST - WHICH WOULD BE SLIGHTLY WARMER THAN AVERAGE
FOR THIS TIME OF THE YEAR.
LONG TERM /TUESDAY THROUGH SUNDAY/
ISSUED AT 303 AM CDT MON OCT 27 2025
THE PACIFIC NW LONGWAVE TROUGH IS PROGGED TO ARRIVE ON TUESDAY, WITH
CHANCES OF RAIN INCREASING AFTER 12Z/7 AM TUESDAY MORNING. CAMS
SUGGEST THAT IT WILL TAKE A LITTLE BIT OF TIME FOR THE COLUMN TO
SATURATE, SO ONLY OUR WESTERN CWA COULD SEE LIGHT RAIN BEFORE
EXPANDING EASTWARD. EVENTUALLY, AS LARGE-SCALE LIFT INCREASES AND AN
ATTENDANT SURFACE COLD FRONT BEGINS TO MOVE IN, MOISTURE AHEAD OF
THE BOUNDARY LOOKS TO INCREASE AS PWATS BETWEEN 0.8" TO 1.0" PER THE
HREF ENSEMBLE MEAN. MUCH OF THE GLOBAL DETERMINISTIC AND LREF
CLUSTER ANALYSIS ENSEMBLE MEMBERS AGREE ON A CUT-OFF UPPER LOW
DEVELOPING JUST SOUTH OF OUR REGION, MEANING A SLOWER, STRONGER
SYSTEM IS LIKELY TO DEVELOP. MOISTURE APPEARS TO BE FAVORABLE TO
LINGER ACROSS OUR SOUTHERN CWA DUE TO THIS EVOLUTION. NBM EXCEEDANCE
PROBABILITIES OF TOTAL RAINFALL OF A HALF INCH TUESDAY/WEDNESDAY
RANGES FROM 30-50% ACROSS OUR NORTHEAST TO 60-80% ACROSS OUR
SOUTHWEST. GIVEN THE DRY CONDITIONS WE'VE HAD LATELY AND EXPANDING
DROUGHT, THIS WILL BE BENEFICIAL RAINFALL.
THE OTHER ASPECT OF THIS UPCOMING SYSTEM WILL BE A TIGHTENING
PRESSURE GRADIENT AND DEEPER BOUNDARY LAYER MIXING ON WEDNESDAY,
WHICH SHOULD SUPPORT GUSTY CONDITIONS. THE 50TH PERCENTILE OF THE
NBM FOR PEAK WIND GUSTS IS RANGING BETWEEN 30 TO 40 MPH, SO
SOMETHING WE WILL NEED TO KEEP AN EYE ON AS WE GET CLOSER TO
WEDNESDAY. WILL THESE WINDS REACH WIND ADVISORY CRITERIA? AT THIS
TIME, IT DOESN'T APPEAR LIKELY, GIVEN THE LREF PROBABILITIES OF
GUSTS 40 MPH OR STRONGER ARE ONLY AROUND 10 PERCENT.
EVENTUALLY, THE TROUGH WILL EXIT THE REGION BY THURSDAY, MAKING WAY
FOR A PERIOD OF CALMER WEATHER THROUGH THE UPCOMING WEEKEND. A
COOLER AIR MASS WILL RESULT IN SOME CHILLY NIGHTS FOR WEDNESDAY
NIGHT THROUGH THE END OF THE WEEK, WITH LOWS IN THE 30S EACH NIGHT.
DAYTIME HIGHS WILL CONTINUE TO BE IN THE 50S.
AVIATION /12Z TAFS THROUGH 12Z TUESDAY/
ISSUED AT 555 AM CDT MON OCT 27 2025
VFR CONDITIONS WILL CONTINUE THROUGHOUT THE TAF PERIOD. THE
MAIN FOCUS FOR TODAY WILL BE ON GUSTY EASTERLY WINDS DURING THE
DAYLIGHT HOURS, WITH GUSTS AROUND 20 KNOTS AREA-WIDE. SOME MID-
TO HIGH-CLOUDS WILL SLOWLY FILTER IN THIS AFTERNOON AND
EVENING AS A SYSTEM APPROACHES FROM THE WEST, WHICH WILL BRING
INCREASING CHANCES OF SHOWERS ON TUESDAY.
DVN WATCHES/WARNINGS/ADVISORIES
IA...NONE.
IL...NONE.
MO...NONE.
SHORT TERM...SCHULTZ
LONG TERM...SCHULTZ
AVIATION...SCHULTZ
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