631
FXUS63 KDVN 231902
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
202 PM CDT THU APR 23 2026
KEY MESSAGES
- THERE IS A SLIGHT (LEVEL 2 OUT OF 5) RISK FOR SEVERE WEATHER
LATE THIS AFTERNOON/EVENING WEST OF A LINE FROM DUBUQUE TO
KEOKUK. DAMAGING WIND WILL BE THE PRIMARY THREAT, WITH A FEW
STRIPES OF HEAVY RAINFALL.
- DRY WEEKEND, WITH A RETURN OF ACTIVE WEATHER EARLY NEXT WEEK.
SHORT TERM /THROUGH FRIDAY/
ISSUED AT 157 PM CDT THU APR 23 2026
A BREEZY MILD DAY CONTINUES OVER EASTERN IOWA, MISSOURI AND
ILLINOIS THIS AFTERNOON, WITH DRY WEATHER LASTING INTO EARLY
AFTERNOON SO FAR. THERE IS A MID LEVEL THETE-E ADVECTION AXIS
JUST WEST OF OUR CWA, WHICH HAS BEEN ASSOCIATED WITH A FEW
FLARE-UPS OF SHOWERS AND WEAK THUNDERSTORMS SINCE THIS MORNING
OVER CENTRAL IOWA. THIS IS THE FEATURE WE WILL FOLLOW FOR
AFTERNOON DEVELOPMENT AS IT SLOWLY WORKS INTO OUR WESTERN CWA.
WHILE OUR ATMOSPHERE REMAINS WEAKLY CAPPED OVER THE EAST 1/2 PER
OUR 18Z SOUNDING, FARTHER WEST, THIS WEAK CAPPING IS EXPECTED
TO GIVE WAY TO SCATTERED STORMS THIS AFTERNOON, WITH COVERAGE
REMAINING LOW, BUT IN GENERAL THE HIGHEST PROBABILITY IN OUR
WESTERN 1/3 OF THE CWA. CAPE VALUES OF 1200 TO 2000 ARE FOUND
OVER EASTERN IOWA, WITH 0-3KM SHEAR VALUES UNDER 20KTS, MID
LEVEL LAPSE RATES AROUND 7C/KM, AND PWATS OF 1 TO 1.25" THIS
AFTERNOON IN IOWA. THIS COMBINATION WILL ALLOW FOR SOME
SCATTERED STRONG, TO LOWER END SEVERE STORMS AT TIMES THROUGH
EARLY EVENING.
TO OUR WEST, THE FRONT IS LOCATED NEAR THE MISSOURI RIVER, WITH THE
MAIN LOW PRESSURE FOUND NEAR SOUTHERN MANITOBA, AND SECONDARY LOW
PRESSURE ALONG THE FRONT FOUND NEAR SOUTHWEST KANSAS. THUNDERSTORMS,
SOME SEVERE, HAVE FORMED FROM NEAR OMAHA NE NORTHWARD TO SOUTHWEST
MINNESOTA AS OF 130 PM. THIS FRONTAL ZONE TO OUR WEST IS EXPECTED
TO BECOME THE PRIMARY CONVECTION FOCUS THROUGH 8 PM TO OUR WEST, BUT
AFTER THAT TIME, BOTH THE FRONT'S PROGRESSION EAST AND COLD POOL
MERGERS TO OUR WEST (BECOMING A LINE OF STORMS), WILL HELP SPREAD
STORMS EAST INTO EASTERN IOWA AND NORTHEAST MISSOURI BETWEEN 8 PM
AND 10 PM. FROM 10 PM TO 6 AM, THIS LINE IS EXPECTED TO MOVE THROUGH
OUR ENTIRE AREA, WITH A WEAKENING IN INTENSITY BOTH DUE TO A LOSS OF
CAPE, AND INCREASING SPEED OF THE LINE, RESULTING IN TILTING OF
UPDRAFTS TO THE COOL SIDE OF THE BOUNDARY, THAT NEARLY ALWAYS CAUSES
THE LINE TO BEGIN TO BUBBLE/FESTER EAST RATHER THAN REMAIN SOLID.
AS THIS LINE ARRIVES LATER TONIGHT, WIND GUSTS ARE THE PRIMARY
THREAT, WITH A LOWER END SEVERE WEATHER THREAT SUPPORTED BY THE
MATURE LINE, BUT WEAKENING INSTABILITY, COMBINED WITH A STABILIZING
BOUNDARY LAYER. SPC'S OUTLOOK GENERALLY SUPPORTS THIS TRANSITION AS
WELL.
RAINFALL THIS AFTERNOON THROUGH TONIGHT, WILL BE HEAVY, BUT
RATHER SPOTTY IN NATURE, WITH SOME STRIPES OF 1"+ IN OUR WEST,
AND MAINLY AMOUNTS UNDER 0.5" IN THE EAST 1/2.
LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/
ISSUED AT 157 PM CDT THU APR 23 2026
AN UPPER LEVEL LOW OVER SOUTH-CENTRAL CANADA WILL BRING SEASONABLE
CONDITIONS AND ADDITIONAL PRECIPITATION CHANCES THROUGH NEXT
WEEK BEFORE MOVING TO THE EAST.
SOME SHOWERS AND THUNDERSTORMS WILL LINGER THROUGH FRIDAY
MORNING AS THE COLD FRONT CONTINUES TO MOVE THROUGH THE REGION.
FOLLOWING THE FRONTAL PASSAGE, FRIDAY AFTERNOON AND SATURDAY
WILL BE CLEAR AND DRY DUE TO SUBSIDENCE ASSOCIATED WITH THE
500MB JET AROUND THE UPPER LEVEL TROUGH. HIGHS ARE EXPECTED TO
REMAIN A FEW DEGREES ABOVE NORMAL AT AROUND 70 DEGREES.
THE NEXT CHANCES FOR PRECIPITATION WILL COME SUNDAY INTO MONDAY AS
AN EMBEDDED SHORTWAVE TRANSLATES THROUGH THE UPPER LEVEL FLOW.
AT THIS POINT, THE GREATEST UNCERTAINTY LIES IN THE TRACK OF THE
ASSOCIATED SURFACE LOW. CURRENT ENSEMBLE MEAN FORECASTS PLACE
THE SURFACE LOW OVER EASTERN IOWA, THOUGH SOME MEMBERS HAVE IT
AS FAR WEST AS THE IA-NE BORDER. WHERE THIS LOW TRACKS WILL
DETERMINE THE PRECIPITATION FOOTPRINT AND INSTABILITY. THE
EASTERN LOW SCENARIO, SUCH AS SEEN IN THE DETERMINISTIC GFS, HAS
A PLUME OF IVT UP TO 500 KG M-1 S-1 ADVECTING INTO NORTHEAST
MO/WEST-CENTRAL IL WHILE THE AXIS OF GREATEST IVT REMAINS
SOUTHWEST ALONG THE IL-KY BORDER. THIS RESULTS IN LOWER QPF
TOTALS ACROSS THE REGION. IN A WESTERN LOW SCENARIO, SUCH AS
SEEN IN THE DETERMINISTIC ECMWF, QPF INCREASES ACROSS THE AREA.
WHILE THE SPREAD IN QPF IS STILL QUITE LARGE WITH THESE
SCENARIOS, ENSEMBLE MEANS SUGGEST THAT AT LEAST 0.5 INCHES OF
RAIN WILL BE LIKELY (70% CHANCE) AREA-WIDE. SIMILAR TO QPF,
INSTABILITY WILL DEPEND ON THE TRACK OF THE LOW. WITH AN EASTERN
LOW, THE AXIS OF GREATEST MUCAPE IS PUSHED EAST OF THE AREA,
WHILE A WESTERN LOW ALLOWS FOR MUCAPE TO PEAK ALONG THE MO-IA
BORDER INTO EASTERN IOWA. TOGETHER, THESE GIVE TWO POTENTIAL
SCENARIOS: AN EASTERN LOW THAT HAS REDUCED QPF AND THUNDERSTORM
CHANCES AND A WESTERN LOW WITH ENHANCED QPF AND THUNDERSTORM
CHANCES.
AFTER THIS EMBEDDED SHORTWAVE PASSES THROUGH MONDAY NIGHT, ZONAL
FLOW WILL RETURN ALONG THE SOUTHERN EDGE OF THE UPPER LOW. THE 500MB
JET WILL REMAIN TO THE NORTH, LEADING TO BROAD SYNOPTIC
SUBSIDENCE TUESDAY AND WEDNESDAY. THIS WILL ALLOW FOR ANOTHER
DRY AND CLEAR PERIOD, WITH TEMPERATURES REMAINING SEASONABLE FOR
LATE APRIL.
AVIATION /18Z TAFS THROUGH 18Z FRIDAY/
ISSUED AT 1214 PM CDT THU APR 23 2026
BREEZY CONDITIONS WILL CONTINUE THROUGH EARLY EVENING, AS SOUTH
WINDS ARE FOUND AHEAD OF AN APPROACHING COLD FRONT, WHICH WILL
PASS THROUGH OUR ENTIRE AREA OVERNIGHT. A FEW SCATTERED
THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON IN EASTERN IOWA, AND
THESE ARE INCLUDED AS A PROB30 FOR CID AND DBQ TODAY. ANY STORM
WOULD BRING BRIEF IFR IN HEAVY RAIN, LIGHTNING, SMALL HAIL, AND
GUSTY WINDS. STORMS WILL MOVE NORTHEAST AROUND 35 MPH THIS
AFTERNOON. LATER THIS EVENING, AS THE FRONT MOVES EAST, A MORE
WIDESPREAD LINE OF STORMS IS EXPECTED TO MOVE THROUGH THE AREA
BETWEEN 03Z WEST TO 08Z EAST. THIS LINE OF STORMS REMAINS A
HIGH, 75%+ PROBABILITY AS IT MOVES THROUGH THE REGION, WITH
BRIEF HEAVY RAIN, STRONG WIND GUSTS OVER 40 KTS, AND LOW CLOUDS
EXPECTED WITH THEM. BEHIND THE FIRST 20 MINUTES OF STORMS, RAIN
WITH SOME THUNDER CAN BE EXPECTED TO CONTINUE FOR 2 TO 5 HOURS.
WHILE TIMING IS NOT TOO CONFIDENT, VFR WEATHER IS EXPECTED TO
ARRIVE WITH DRY AIR / NORTHWEST WINDS, FRIDAY MORNING AROUND
12Z.
CLIMATE
ISSUED AT 251 AM CDT THU APR 23 2026
RECORD HIGH TEMPERATURES:
APRIL 23:
KBRL: 84/1960
DVN WATCHES/WARNINGS/ADVISORIES
IA...NONE.
IL...NONE.
MO...NONE.
SHORT TERM...ERVIN
LONG TERM...ELLINGWORTH
AVIATION...ERVIN
CLIMATE...GROSS
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