488
FXUS63 KDVN 091936
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
236 PM CDT TUE SEP 9 2025
KEY MESSAGES
- OUR WARM UP CONTINUES THIS WEEK WITH HOT TEMPERATURES IN THE
90S BECOMING MORE WIDESPREAD THIS WEEKEND.
- LARGELY DRY WEATHER CONTINUES THIS WEEK, THOUGH RAIN CHANCES
INCREASE AS WE HEAD TOWARD NEXT WEEK.
SHORT TERM /THROUGH WEDNESDAY/
ISSUED AT 236 PM CDT TUE SEP 9 2025
A SHORTWAVE TROUGH IS CURRENTLY MOVING VERY SLOWLY OUT OF THE
PLAINS INTO THE MISSISSIPPI VALLEY TODAY. THE BETTER COMBINATION
OF LIFT AND LIMITED MOISTURE HAS BEEN TO THE NORTH ACROSS
MINNESOTA, THOUGH ANOTHER MORE CONCENTRATED AREA OF SHOWERS AND
STORMS HAS DRIFTED EAST THROUGH MISSOURI. IN BETWEEN WE HAVE
BEEN LEFT WITH HIGH CLOUDS AND DRY. SURFACE DEWPOINTS IN THE 40S
HAVEN'T HELPED OUR RAIN CHANCES TODAY, AND THE SOUTHERLY LOW
LEVEL FLOW IS JUST DRAGGING IN MORE RECYCLED DRY AIR FROM AROUND
THE SURFACE HIGH NOW IN NEW ENGLAND. THE CLOUDS HAVE KEPT
TEMPERATURES A BIT COOLER TODAY THAN THEY'D OTHERWISE BE, AND
THEIR PRESENCE TONIGHT WILL ALSO HELP KEEP THINGS A BIT WARMER
AS WELL. RAIN CHANCES REMAIN LOW, BUT HIGHEST IN OUR NORTHERN
FORECAST AREA. AT THIS POINT ONLY UP TO 30 PERCENT OF HREF
ENSEMBLE MEMBERS PRODUCE MEASURABLE RAIN NEAR THE WISCONSIN
BORDER TONIGHT, BUT IF WE INCREASE THAT TO 0.05 INCH WE SEE
THAT DROPS TO 10 PERCENT OR LESS. SO EVEN IF WE DO SEE A SHOWER,
IT WON'T BE VERY IMPACTFUL. AS THE TROUGH SLOWLY MOVES EAST ON
WEDNESDAY WE'LL OPEN UP TO A BIT WARMER TEMPERATURES AS RIDGING
TAKES HOLD.
LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/
ISSUED AT 236 PM CDT TUE SEP 9 2025
THE LONG WAVE PATTERN THIS WEEK AND THROUGH THE WEEKEND FEATURES
A LARGE WESTERN US TROUGH AND A DOWNSTREAM RIDGE OVER THE
CENTRAL US. THIS SPELLS WARMER TEMPERATURES FOR OUR AREA, AND IN
FACT WE'LL FEEL MORE LIKE SUMMER FOR A WHILE. SOUTHWEST FLOW
FROM THE TROUGH INTO THE RIDGE WILL TRANSFER SEVERAL SHORTWAVE
TROUGHS UP AND AROUND THE RIDGE WHICH WILL PLAY SOME ROLE IN THE
TEMPERATURE AND PRECIPITATION FORECAST, ESPECIALLY AFTER THIS
WEEKEND.
INITIALLY THE RIDGE BUILDS OVER THE CENTRAL US THURSDAY AND
FRIDAY WITH OUR TEMPERATURES RISING THROUGH THE 80S AND
POTENTIALLY INTO THE 90S. THE RIDGE AXIS SHIFTS OVERHEAD ON
SATURDAY INTO SUNDAY, LIKELY CORRESPONDING WITH OUR HOTTEST
TEMPERATURES OF THIS AIR MASS. NBM CONTINUES TO RUN A LITTLE
HOTTER THAN EXPECTED, AND SIMILAR TO PRIOR SHIFTS WE HAVE
COLLABORATED TO TAMP DOWN THE NBM HIGH TEMPERATURES A BIT THIS
WEEKEND. IT SEEMS THE GFS IN PARTICULAR IS STRUGGLING WITH TOO
MUCH MIXING, RAISING TEMPERATURES UP TO 10 DEGREES HOTTER THAN
OTHER MODELS, AND THIS IS THEN POLLUTING THE NBM. AS FAR AS
HUMIDITY GOES, WE WILL SEE A GRADUAL INCREASE IN DEWPOINTS AS
THE WEEK GOES ON, BUT THERE CONTINUES TO BE AN EASTERLY FLOW
ACROSS THE GULF WHICH IS KEEPING HUMIDITY SUPPRESSED ACROSS MUCH
OF THE US. THE LIMITED MOISTURE HAS TO GO THE LONG WAY AROUND
THROUGH TEXAS AND UP THE PLAINS BEFORE EVENTUALLY PULLING INTO
OUR AREA. WITH THE DRY PAST FEW WEEKS LOCALLY, WE WON'T HAVE
MUCH IN THE WAY OF LOCAL EVAPOTRANSPIRATION TO ADD TO THE
HUMIDITY EITHER. SO AT THIS POINT WE'RE MAINLY LOOKING AT
DEWPOINTS RISING INTO THE LOW TO MID 60S. THAT MAY BE JUST
ENOUGH TO RAISE THE HEAT INDEX A DEGREE OR TWO OVER THE ACTUAL
TEMPERATURE, BUT REMAINING BELOW THRESHOLDS FOR A SIGNIFICANT
HEAT RISK.
AS FAR AS RAIN CHANCES GO, WE HAVE A COUPLE OPPORTUNITIES,
LIMITED AS THEY MAY BE. THE FIRST COMES LATE SATURDAY WHEN THE
FIRST SHORTWAVE ROTATES AROUND THE TOP OF THE RIDGE AND BACK
DOWN THROUGH THE NORTHWEST FLOW. THE GREATER IMPACT FROM THIS
WILL BE TO OUR NORTHEAST TOWARD THE GREAT LAKES, BUT THERE IS AT
LEAST SOME LOW CHANCE THAT IT BRINGS SOME RAIN TO OUR EASTERN
FORECAST AREA. AMONG THE 00Z ENSEMBLE GUIDANCE, UP TO 50
PERCENT OF MEMBERS BRING RAIN INTO OUR FORECAST AREA IN THE 24
HOURS ENDING SATURDAY NIGHT. NBM POP REMAINS CONSIDERABLY LOWER
THAN THAT DUE TO THE TIMING UNCERTAINTY, BUT THE BEST CHANCES
WILL BE TO THE EAST.
ONCE THE RIDGE AXIS CROSSES OUR AREA, WE'LL GET INTO THE
SOUTHWEST FLOW AND IN THE LINE OF FIRE FOR FOR DISTURBANCES
EJECTING FROM THE WESTERN US TROUGH TO BRING ROUNDS OF SHOWERS
AND STORMS TO OUR AREA. THIS BECOMES MORE LIKELY SUNDAY INTO
NEXT WEEK. GUIDANCE VARIES CONSIDERABLY ON THE TIMING AND
POTENCY OF THESE WAVES, AND THE RESULTING IMPACT ON THE RIDGE
ITSELF. STRONGER WAVES HAVE THE TENDENCY TO KNOCK BACK THE
RIDGE MORE, LEADING TO A BIT COOLER TEMPERATURES. WEAKER ONES
LEAVE THE RIDGE MORE SOLIDLY IN PLACE. THIS UNCERTAINTY SHOWS
UP IN THE PROBABILISTIC NBM WHICH SHOWS A HIGHER IQR SPREAD
SUNDAY ONWARD WITH HOTTER TEMPERATURES CONTINUING ON THE ONE
HAND OR MORE MODERATE TEMPERATURES RETURNING ON THE OTHER.
AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/
ISSUED AT 1224 PM CDT TUE SEP 9 2025
LIGHT SOUTHERLY WINDS ARE EXPECTED WITH MAINLY MID LEVEL CLOUD
COVER FOR THE NEXT 24 HOURS OR SO. WE CAN'T RULE OUT A STRAY
SHOWER, BUT IT IS NOT LIKELY TO IMPACT CONDITIONS MUCH IF IT
OCCURS.
DVN WATCHES/WARNINGS/ADVISORIES
IA...NONE.
IL...NONE.
MO...NONE.
SHORT TERM...KIMBLE
LONG TERM...KIMBLE
AVIATION...KIMBLE
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page