139
FXUS63 KDVN 242337
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
637 PM CDT THU APR 24 2025
KEY MESSAGES
- ISOLATED SHOWERS/STORMS POSSIBLE THIS EVENING, BUT THE MAIN
ROUND OF SHOWERS AND STORMS IS EXPECTED LATER TONIGHT INTO
FRIDAY MORNING. SEVERE STORMS ARE NOT ANTICIPATED.
- SEASONABLE WEEKEND WITH COOL NIGHTS ON TAP
- SEVERE STORMS ARE POSSIBLE EARLY NEXT WEEK.
SHORT TERM /THROUGH FRIDAY NIGHT/
ISSUED AT 254 PM CDT THU APR 24 2025
TONIGHT...THE LATEST SFC ANALYSIS WAS INDICATING A WEAK BOUNDARY
UNDULATING ACRS THE NORTHERN AND WESTERN CWA, WITH WARM AMBIENT
TEMPERATURES IN THE MID TO UPPER 70S/80. SOME INSTABILITY OUT THERE
INDICATED BY THE CELLULAR CU FIELD, AND THERE MAY BE A CHANCE FOR
AN ISOLATED SHOWER OR STORM DEVELOPING IN THIS FIELD THROUGH EARLY
EVENING. BUT THE MCV NOTED IN CURRENT WATER VAPOR IMAGERY ACRS
CENTRAL/EASTERN NE WILL INTERACT WITH A BETTER POOL OF INSTABILITY
ACRS THE MO RVR VALLEY TO SPAWN STORM CLUSTERS OR EVEN AN MCS TYPE
FEATURE OUT THAT WAY THIS EVENING. AS THE MCV AND 20-30 KT
SOUTHWESTERLY LLJ GETS INDUCED AHEAD OF IT AND MIGRATES EASTWARD
ACRS IA, SO SHOULD THE STORM CLUSTERS. BUT WEAKER SHEAR AND MID
LAYER MUCAPES OVER THIS WAY SHOULD MAKE FOR A GENERAL WEAKENING
TREND AS THEY ARRIVE FROM WEST-TO-EAST THUS HOPEFULLY LIMITING MUCH
OF ANY SEVERE THREAT LOCALLY LATE TONIGHT. HOWEVER, STILL FEEL THERE
COULD BE SOME MARGINALLY STRONG CELLS IN THE SOUTHERN CWA AFTER
MIDNIGHT WITH HAIL AND GUSTY WINDS. PWAT FEED OF AN INCH OR MORE
WILL FUEL MORE LOCALLY HEAVY DOWNPOURS, BUT THE TRUE HEAVY RAIN
THREAT LIES OFF TO THE WEST OF THE LOCAL AREA OF CONCERN ACRS
WESTERN INTO CENTRAL IA IN HIGHER CONVERGENT/MOISTURE FEED ZONES.
BUT STILL SEE MANY AREAS RECEIVING 0.25 TO 0.75 OF AN INCH BY FRIDAY
MORNING. ISOLATED 1 INCH AMOUNTS ON THE IA SIDE. FRONTAL PLACEMENT
WILL HELP LOW TEMPS RANGE FROM THE UPPER 40S NORTH, TO THE UPPER 50S
SOUTH.
FRIDAY...WILL WALK OUT THE LINGERING SHOWERS OFF TO THE EAST BY LATE
MORNING, WITH THEN INCREASING POST-FRONTAL NORTH WINDS INCREASING TO
10-20 MPH BY THE AFTERNOON. TEMPS CONTINUE TO RANGE FROM NORTH TO
SOUTH AS THE SIMILAR ORIENTED LLVL BAROCLINICITY SLIPS SOUTHWARD.
FRIDAY NIGHT LOOKS COOL WITH CLOUD CLEAR OFF AND ONGOING CAA. LOWS
IN THE 40S AND EVEN SOME UPPER 30S POSSIBLE IN THE NORTH.
LONG TERM /SATURDAY THROUGH THURSDAY/
ISSUED AT 254 PM CDT THU APR 24 2025
SATURDAY AND SUNDAY...BACKDOOR SFC HIGH, ALONG WITH INCOMING UPPER
RIDGING WILL CONTINUE TO A FAIR AND RATHER SEASONABLE SATURDAY WITH
HIGHS IN THE 60S. SAT NIGHT WILL LOOK TO BE ON THE COOL SIDE IN THE
LOW 40S AND UPPER 30S. MAY HAVE TO WATCH AREAS THAT ARE UNDER THE
INFLUENCE OF THE RIDGE LONGER SUCH AS NORTHWEST IL WHERE WE MAY DIP
INTO THE MID 30S AND HAVE POSSIBLE PATCHY FROST. ON SUNDAY AS WE GET
ON THE OTHER SIDE OF THE PROGRESSING RIDGE AXIS, ELEVATED RETURN
FLOW MAY SPAWN MORE SHOWERS AND STORMS TRYING TO SPREAD IN FROM THE
WEST. BUT THE LINGERING RIDGE EFFECTS AND DRY AIR MAY ERODE INCOMING
ACTIVITY FROM THE WEST UNTIL THERE'S BETTER SUPPORT LATER SUNDAY
NIGHT. IT MAY ALSO SHUNT THE BETTER PRECIP CHANCES TO THE NORTH AND
NORTHWEST, BUT WE MAY STILL HAVE TO DEAL WITH DECAY DEBRIS/CLOUDS IN
SOME PORTIONS OF THE LOCAL AREA. STILL A WARMER DAY SUNDAY WITH
HIGHS IN THE UPPER 60S TO LOW 70S.
MONDAY THROUGH WEDNESDAY...MEDIUM RANGE ENSEMBLES CONTINUE TO SHOW A
LARGE PIECE OF THE UPSTREAM LONG WAVE ACRS THE WESTERN ROCKIES
EJECTING OUT ACRS THE PLAINS AND UPPER MIDWEST MONDAY INTO TUESDAY.
PLENTY OF CONCEPTUAL SYNOPTIC SCALE FEATURES SUGGEST THIS SYSTEM MAY
BE A SEVERE WEATHER MAKER, BUT SOME OF THE TRENDS SUCH AS POSITIVE
TILT TO THE MAIN UPPER WAVE AND PRE-SYSTEM DEEP SOUTHWESTERLY
UNIFORM FLOW MAYBE NOT SO TORNADIC LOOKING AT THIS TIME. ALSO LIKE
THE PREVIOUS SHIFT STATED, AT THIS FAR OUT STILL PLENTY OF PHASING
AND TIMING ISSUES TO BETTER DEFINE IN THE COMING DAYS, WITH THE
ENERGY CENTER STILL WELL OFF THE WEST COAST. MONDAY LOOKS TO BE FULL
BLOWN WARM SECTOR WITH GUSTY SOUTH WINDS AND STRONG WAA, PUMPING
TEMPS INTO THE 80S AND SFC DPTS IN THE 60S. SO CAPES WILL BE THERE
FOR THE KINEMATICS, AGAIN IT'S TIMING AND PLACEMENT. THIS SCENARIO
WILL BLEED INTO TUESDAY WITH THE FRONTAL TIMING. CURRENT ENSEMBLES
THAT STRIKE OUR AREA WITH MONDAY EVENING AND OVERNIGHT STORMS, THEN
PROGRESS THE FRONT THROUGH EASTWARD ENOUGH FOR TUESDAY CONVECTIVE
REDEVELOPMENT EAST AND SOUTHEAST OF THE DVN CWA. SYSTEM WAKE RIDGING
FOLLOWING THE CYCLONE WOULD BRING ABOUT DRY COOLER WEATHER INTO THE
MID WEEK PERIOD.
AVIATION /00Z TAFS THROUGH 00Z SATURDAY/
ISSUED AT 633 PM CDT THU APR 24 2025
ISOLATED SHRA/TSRA WILL DISSIPATE WITH SUNSET. A SLIGHTLY
STRONGER DISTURBANCE WILL INITIATE NEW SHRA/TSRA ACROSS EASTERN
IOWA AND INTO NORTHERN ILLINOIS AFTER 05Z/25. SCATTERED NATURE
OF THE CONVECTION HAS THE POTENTIAL TO BRING PERIODIC ROUNDS OF
MVFR CONDITIONS TO TAF SITES THROUGH 12Z/25. AFTER 12Z/25 ANY
LINGERING CONVECTION WILL MOVE OUT WITH MVFR/IFR CONDITIONS
OVERSPREADING EASTERN IOWA AND NORTHERN ILLINOIS.
HYDROLOGY
ISSUED AT 1022 AM CDT THU APR 24 2025
WITH RECENT BOUTS OF HEAVY RAINFALL, AND POSSIBLY MORE TONIGHT WITH
INCREASED RUN-OFF ESPECIALLY IN THE UPPER BASINS OF THE IOWA, WAPSI,
AND CEDAR RIVERS, THESE RIVERS WILL LIKLEY EXPERIENCE SIGNIFICANT IN-
BANK RISES. SOME POINTS AND STRETCHES OF THESE RIVERS MAY ALSO
SURPASS ACTION STAGE AND EVEN THE FLOOD STAGE INTO THE WEEKEND. BUT
THERE IS STILL SOME UNCERTAINTY WITH RESPECT TO TONIGHT'S
PLACEMENT OF ADDITIONAL HEAVY RAINFALL AMOUNTS, AS WELL AS
ASSOCIATED EXTENT OF RUN-OFF. SINCE THERE IS STILL SOME TIME TO
ASSESS THESE FACTORS BEFORE THE POTENTIAL CRESTS OCCUR, HAVE
ISSUED RIVER FLOOD WATCHES FOR THE WAPSI AT DE WITT, AND THE
IOWA RIVER AT MARENGO.
DVN WATCHES/WARNINGS/ADVISORIES
IA...NONE.
IL...NONE.
MO...NONE.
SHORT TERM...12
LONG TERM...12
AVIATION...08
HYDROLOGY...12
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