423
FXUS63 KDVN 222001
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
301 PM CDT TUE APR 22 2025
KEY MESSAGES
- SPC'S MARGINAL RISK (LEVEL 1 OF 5) CONTINUES FOR THE FORECAST
AREA THROUGH TONIGHT FOR THE POTENTIAL FOR LARGE HAIL AND
DAMAGING WINDS. A MARGINAL RISK HAS BEEN ADDED TO THE
NORTHWESTERN CWA FOR DAY 2 WED NIGHT.
- ACTIVE AND MILD WEATHER PATTERN STILL ON TRACK WITH PRECIP
CHANCES ALMOST EVERY DAY UNTIL THE WEEKEND, AND HIGH TEMPS IN
THE 60S AND 70S.
- MORE STORM CHANCES EARLY NEXT WEEK.
SHORT TERM /THROUGH TONIGHT/
ISSUED AT 257 PM CDT TUE APR 22 2025
TONIGHT...THE LATEST SFC ANALYSIS WAS INDICATING A RATHER MESSY
PATTERN ACRS THE AREA OF A WARM FRONT TRYING TO RETREAT ACRS THE
NORTHERN CWA, A TRAILING COOL FRONT LAID OUT ALMOST DIAGONALLY ACRS
NORTHEAST INTO SOUTHWEST IA, AND SOME MORE SUBTLE STORM OUTFLOW AND
DIFFERENTIAL HEATING BOUNDARIES ACRS THE SOUTHERN HALF OF THE CWA.
UPPER AIR ANALYSIS WAS SHOWING WESTERLY STEERING FLOW ACRS IA WITH A
FETCH BACK ACRS NE AND THE CENTRAL ROCKIES. WATER VAPOR IMAGERY WAS
SHOWING AN UPSTREAM SHORT WAVE ACRS NE, AND ALTHOUGH NOT ALL THAT
VIGOROUS SHOULD STILL BE A LIFTING AGENT FOR THIS EVENING. BUT MORE
OF A FACTOR WILL BE A SOUTH TO SOUTHWESTERLY CONVERGENT 25 KT LLJ
IMPINGING ACRS IA FROM WEST TO EAST. WHERE THIS ISOLATED TO SCTRD
ACTIVITY LINES UP(HOW FAR NORTH OR SOUTH) IS STILL SOMEWHAT UNCERTAIN
WITH ALL THE BOUNDARIES, BUT SREF PLACEMENT OF THE H85 MB FRONT
SUGGESTS I-80 AND NORTH MAY BE MORE FAVORED ESPECIALLY AFTER
MIDNIGHT. FCST SOUNDINGS, MID LAYER LAPSE RATES OF 7+ C/KG, 400-800
J/KG MID LAYER CAPES AND EFFECTIVE SHEAR PROFILES OF 30-40 KTS
SUPPORT LARGE HAIL UP TO QUARTERS OR HALF DOLLARS IF SOMEWHAT
ELEVATED. FURTHER SOUTH BASED STORMS MAY ALSO BE ABLE TO PRODUCE
DOWNBURST WINDS. PWATS OF 1 TO 1.1 INCHES TONIGHT WILL ALSO SUPPORT
LOCALLY HEAVY RAINFALL WITH A FEW SWATHS OF 1 TO 1.5 INCHES,
ESPECIALLY REPEATING OR BACK-BUILDING STORM CLUSTERS ALONG A
BOUNDARY. THESE SWATHS MAY OCCUR MORE FAVORABLY ALONG AND NORTH OF
I-80 AGAIN FROM MIDNIGHT ON INTO EARLY WED MORNING. LOW TEMPS IN THE
LOW TO MID 50S. THERE MAY BE SOME TRANSITIONARY FOG ALONG ANY
BOUNDARIES TONIGHT, BUT LOW CONFIDENCE ON THAT AS WELL AS PLACEMENT
FOR MUCH OF A GRID PLACEMENT.
WEDNESDAY...A DAY THAT MAY BE SIMILAR TO TODAY, WITH CONVECTION
LINGERING OUT OF TUE NIGHT INTO THE DAY WITH SOME DIURNAL DOWN
TRENDS. CONVECTIVE DEBRIS AND LINGERING BOUNDARIES WILL MESS WITH
HIGH TEMP POTENTIAL, WITH RANGES IN THE 70S. WILL HAVE TO KEEP POPS
FOR ISOLATED TO SCTRD DAYTIME ACTIVITY, BUT BY AFTERNOON INTO EARLY
EVENING BETTER CONVECTIVE INITIATION GROUNDS DEVELOP ACRS THE KS/NE
INTO SOUTHWEST IA REGION. THEN THERE IS THE CHANCE FOR SOME OF THAT
CONVECTION TO FEED EASTWARD INTO THE LOCAL AREA LATER WED NIGHT INTO
THU MORNING. EXPECT A GENERAL WEAKENING AS IT MIGRATES EASTWARD
TOWARD OUR AREA AND AWAY FROM BETTER SUPPORT, BUT THERE IS SOME LOW
CHANCE THAT THEY MAINTAIN SOME STRENGTH INTO THE WESTERN CWA LATER
WED NIGHT. THUS THE MARGINAL SPREAD INTO THE NORTHWESTERN CWA FOR
DAY 2.
LONG TERM /WEDNESDAY THROUGH MONDAY/
ISSUED AT 257 PM CDT TUE APR 22 2025
THURSDAY AND FRIDAY...WITH THE ONGOING PATTERN, WILL HAVE TO KEEP
CHANCE POPS GOING DURING THE DAY THURSDAY ESPECIALLY IN THE MORNING
FOR LINGERING CONVECTION OUT OF WED NIGHT. PRECIP AND CLOUD DEBRIS
DECAY AND SOUTHERLY RETURN FLOW MAY HELP THE DAY PUSH THE 80 DEGREE
MARK. CURRENT ENSEMBLE WAVE TIMING AGAIN HAS A RIDGE-RIDING VORT MAX
PROPAGATING ACRS THE AREA LATE THU NIGHT INTO FRIDAY MORNING WITH A
POTENTIAL MORE ORGANIZED STORM CLUSTER DEVELOPMENT(MCS?) ACRS THE
AREA AT THAT TIME. HOPEFULLY THE TIME OF DAY MAY LIMIT A SEVERE
CHANCE DURING THAT PERIOD, BUT HEAVY RAINFALL MAY BE A FACTOR INTO
FRIDAY MORNING. AFTER THAT SYSTEM EXITS OFF TO THE EAST, A BACKDOOR
SFC HIGH SLIDING DOWN THE WESTERN GRT LKS AND UPPER RIDGE LOBE
PRESSING IN FROM THE WEST WILL MAKE FOR CLEARING AND COOLER
CONDITIONS INTO EARLY SATURDAY.
SATURDAY THROUGH MONDAY...THE BOUT OF BOTH SFC AND UPPER RIDGING
WILL MAKE FOR A FAIR AND SEASONABLE SATURDAY WITH SOME SUNSHINE. SAT
NIGHT WILL LOOK TO BE ON THE COOL SIDE IN THE LOW 50S AND 40S. 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. LONGER RANGE SIGNALS SUGGEST A LARGE
PIECE OF THE UPSTREAM LONG WAVE ACRS THE WESTERN ROCKIES WILL EJECT
OUT ACRS THE PLAINS AND UPPER MIDWEST SOMETIME EARLY NEXT WEEK.
PLENTY OF CONCEPTUAL SYNOPTIC SCALE FEATURES SUGGEST THIS SYSTEM
COULD BE A SEVERE WEATHER MAKER, BUT IT'S STILL FAR OUT AND PLENTY
TIME TO CHANGE WITH RESPECT TO TIMING, PHASING AND EJECTION PATH AS
IT RELATES TO THE LOCAL CWA. BUT A WINDOW TO WATCH FOR SURE OVER THE
NEXT SEVERAL DAYS.
AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/
ISSUED AT 1250 PM CDT TUE APR 22 2025
MAINLY VFR CONDITIONS THIS AFTERNOON, BUT WITH ISOLATED SHOWERS
AND THUNDERSTORMS ALONG AND SOUTH OF I-80 WITH THEM POSSIBLY
GETTING INTO THE VCNTY OF MLI AND ESPECIALLY BRL WITH PASSING
BOUTS OF MVFR VSBYS AND VARIABLE WIND UPTICKS. MORE SCATTERED
THUNDERSTORMS WILL LIKELY BE ON TAP FOR TONIGHT ESPECIALLY AFTER
10 PM AS A LLJ INCREASES AND PRODUCES THEM ON IT'S CONVERGENT
NOSE. WHERE THE MAIN WEST-TO-EAST LINE OF STORMS LAYS OUT IS
STILL SOMEWHAT UNCERTAIN, BUT ALL SITES MAY BE AT RISK. MANY OF
THE LATEST CAMS HINT AT THE ACTIVE ZONE ALONG AND NORTH OF I-80
AFTER MIDNIGHT. SOME OF THESE STORMS MAY BE SEVERE WITH LARGE
HAIL AND BOUTS OF LOW MVFR TO IFR HEAVY RAIN REDUCED VSBYS. MAY
HAVE TO WATCH FOR SOME TRANSIENT FOG ALONG A WEAK SFC BOUNDARY
WHEN IT'S NOT RAINING. THE BETTER CHANCE FOR AT LEAST SOME
PATCHY FOG LOOKS TO BE NORTH OF HWY 30 LATE TONIGHT BUT LOW
CONFIDENCE ON THAT.
DVN WATCHES/WARNINGS/ADVISORIES
IA...NONE.
IL...NONE.
MO...NONE.
SHORT TERM...12
LONG TERM...12
AVIATION...12
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