571
FXUS63 KDVN 090609
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
109 AM CDT WED SEP 9 2026
KEY MESSAGES
- A STORM SYSTEM PASSING THROUGH THE UPPER MIDWEST WILL BRING WIDESPREAD
SHOWERS AND STORMS TO THE AREA TONIGHT INTO WEDNESDAY
MORNING. SEVERE STORMS AND HEAVY RAINFALL WITH THE POTENTIAL
FOR SOME LOCALIZED FLASH FLOODING WILL BE POSSIBLE IN EASTERN
IOWA.
- QUIET COOLER WEATHER THURSDAY INTO FRIDAY, AS HIGH PRESSURE PASSES
OVERHEAD.
- ANOTHER STRETCH OF POTENTIALLY ACTIVE WEATHER THIS WEEKEND
INTO THE NEXT WORK WEEK, BRINGING DAILY CHANCES OF
PRECIPITATION FOR SOME.
SHORT TERM /THROUGH THURSDAY/
ISSUED AT 245 PM CDT TUE SEP 8 2026
THIS AFTERNOON'S WATER VAPOR IMAGERY SHOWING TONIGHT'S AND WED
WEATHER MAKER WAVE ACRS SOUTHWEST MT, AND ALSO SHOWING LARGE LONG
FETCH BAROCLINIC LEAF FROM SOUTHWEST OF THE CA BAJA TO WESTERN
QUEBEC. THIS AS WELL AS LLJ FEED OFF THE WESTERN GULF WILL MAKE FOR
A MOIST ATMOSPHERIC COLUMN TONIGHT WITH 2+ INCH PWATS STILL ON TRACK
ACRS THE REGION INTO WED MORNING. THE CURRENT ACTIVITY FROM NE INTO
NORTHERN IA WILL LOOK TO GET REVVED UP BY A INCREASING SW LLJ OF 35-
45 KTS AND INCREASING EFFECTIVE SHEAR PROFILES OF AT LEAST 35 KTS AS
THE EVENING AND NIGHT PROGRESS. THIS AND MLCAPES OF 1000-1500 J/KG
MAY MAKE FOR SOME STRONG TO MARGINALLY SEVERE STORMS AS THEY FLAME
UP IN THE AREA OR MOVE IN FROM THE WEST AS MATURING BOWS, WITH THE
ALREADY ADVERTISED DAMAGING WINDS BEING THE PRIMARY THREAT. BUT
MARGINAL MID LEVEL LAPSE RATES OF ONLY 6 C/KM AND SIGNS IN THE FCST
SOUNDINGS OF DEVELOPING LLVL INVERSIONS OVERNIGHT MAY LIMIT THE WIND
CAUSE ESPECIALLY LATE.
STORM OUTFLOWS MAY GUSH OUT WELL AHEAD OF THE MAIN SFC FRONT TONIGHT
INTO WED MORNING, SETTING THE FOCUS OF REPEATED STORM DEVELOPMENT
AND THEN TRAINING ALONG THESE OUTFLOW BOUNDARIES OR EVEN THE
INCOMING MAIN FRONT ITSELF, IF THE FCST SHEAR PROFILES AND
ORIENTATION ARE CORRECT. THIS POTENTIAL UTILIZING THE HIGH PWAT FEED
SUPPORTS THE ADVERTISED THREAT FOR SOME SWATHS OF HIGH RAINFALL(1-3+
INCHES) AND LOCALIZED FLASH FLOODING ESPECIALLY IN URBAN ENVIRONMENTS
SUCH AS CEDAR RAPIDS. SOME UNCERTAINTY REMAINS ON THE EVENTUAL
PRIMARY AXIS NORTH-SOUTH LAY OUT OF THE MAIN CONVECTIVE ZONE IN THE
LATEST CAMS AND COARSER MODELS, BUT ENSEMBLES ARE POINTING TO MORE
OF THE ALONG AND NORTH OF I-80 TO HWY 30 CORRIDOR FOR LONGER
DURATION STORMS AND RAINS MAKING IT THE MORE LIKELY AXIS FOR HEAVY
RAINFALL. LOW TEMPS TONIGHT IN THE UPPER 60S TO LOW 70S, WITH SOME
PATCHY FOG AT LEAST TEMPORARILY POSSIBLE IN RAIN LULLS ALONG WITH
LIGHT AND VARIABLE SFC WIND TRENDS ALONG BOUNDARIES.
WEDNESDAY AND WEDNESDAY NIGHT...THE POST FRONTAL RAINS WILL CONTINUE
THROUGH AT LEAST MIDDAY, WITH A SLOW SOUTHWARD FRONTAL MIGRATION AS
THE DAY PROGRESSES. THUS COULD SEE HIGH TEMPS HELD DOWN IN THE UPPER
70S TO LOW 80S ACRS MUCH OF THE AREA. FLATTENING STEERING FLOW ALOFT
AND ADDITIONAL SHORT WAVE SHUFFLE MAY KEEP ADDITIONAL OVER-RUNNING
SHOWERS GOING IN THE SOUTHERN CWA THU NIGHT. WITH A LIGHT POST-
FRONTAL SFC WIND REGIME LOOKING TO BE ON TAP, IF THERE WILL BE ANY
CLOUD THINNING OR CLEARING IN THE NORTH LATE WED NIGHT INTO THU
MORNING, MAY HAVE TO KEEP SOME FOG IN MIND ESPECIALLY ACRS HEAVY
RAINFALL AREAS IF THEY OCCUR IN THE NORTHERN CWA.
LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/
ISSUED AT 245 PM CDT TUE SEP 8 2026
THURSDAY AND FRIDAY...A COUPLE OF DECENT LOOKING DAYS LOOK IN STORE
WITH BOUTS OF BOTH SFC AND UPPER RIDGING ALLOWING FOR DRY AND NEAR
SEASONABLE CONDITIONS.
SATURDAY THROUGH MONDAY...THE LATEST SUITE OF MEDIUM RANGE MODELS
CONTINUE TO SUGGEST FLATTENING FLOW AGAIN EMBEDDED WITH PASSING
SHORT WAVE AND ASSOCIATED SFC FRONTS MAKING FOR A POTENTIALLY ACTIVE
PERIOD. FIRST IN LINE MAY BE SATURDAY WITH A SFC FRONT GETTING
SWEPT THROUGH THE AREA OFF A PASSING LLVL CYCLONE ALONG THE
US/CANADIAN BORDER. THEN MAYBE A SHORT LULL FOR SUNDAY BEFORE SIGNS
OF A DIGGING LONGER WAVE TROF ACRS THE WESTERN HIGH PLAINS ARCHING
STEERING FLOW IN A SOUTHWESTERLY FASHION TOWARD THE UPPER MIDWEST.
THIS COULD MAKE FOR ANOTHER UNSETTLES PERIOD FOR SUNDAY NIGHT INTO
EARLY NEXT WEEK IF THIS PATTERN VERIFIES.
AVIATION /06Z TAFS THROUGH 06Z THURSDAY/
ISSUED AT 109 AM CDT WED SEP 9 2026
WIDESPREAD MVFR OR LOWER CONDITIONS ARE EXPECTED THROUGH THE TAF
PERIOD. CURRENTLY, A WIDESPREAD AREA OF SHOWERS WITH EMBEDDED STORM
CLUSTERS IS MAKING ITS WAY THROUGH THE AREA. THESE SHOWERS SHOULD
SUPPORT MVFR VSBYS TO DBQ/CID THROUGH 09/09Z BEFORE SLOWLY DRIFTING
SOUTHWARD, FOLLOWED BY A PERIOD OF MVFR CIGS AS THE SHOWERS BEGIN TO
CLEAR. FARTHER SOUTH, STORMS ARE STILL POSSIBLE (30-60%) AT MLI/BRL,
WITH STORMS ONGOING AT MLI AND EXPECTED TO DESCEND SOUTHWARD TOWARDS
BRL BY 09/07Z. ANY STORMS AT MLI/BRL HAVE THE POTENTIAL FOR MVFR TO
LIFR VSBYS, THOUGH LIFR/IFR CONDITIONS WILL LAST FOR ONLY A SHORT
PERIOD IN THE HEAVIEST AREAS OF RAIN. THESE SHOWERS WILL CLEAR MLI
BY 09/16Z AND BRL BY 09/18Z.
WINDS THROUGH THE BEGINNING OF THE PERIOD WILL BE VARIABLE TO
SOUTHERLY WITH THE POTENTIAL FOR GUSTS TO 30 KTS IN ANY STORMS. PAST
09/18Z, WINDS WILL SHIFT TO NORTHERLY AS A COLD FRONT SLOWLY CLEARS
THE AREA FROM NORTHWEST TO SOUTHEAST, REACHING BRL NEAR THE END OF
THE TAF PERIOD.
DVN WATCHES/WARNINGS/ADVISORIES
IA...NONE.
IL...NONE.
MO...NONE.
SHORT TERM...12
LONG TERM...12
AVIATION...ELLINGWORTH
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