619
FXUS63 KDVN 300755
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
255 AM CDT THU JUL 30 2026
KEY MESSAGES
- SEASONABLE TEMPERATURES, DRY CONDITIONS, AND SOME HAZY SKIES
TODAY.
- WIDESPREAD SHOWERS AND THUNDERSTORMS LIKELY FRIDAY. THERE IS
AN 80-90% CHANCE OF RAINFALL AMOUNTS OVER 1" AND A 40-70%
CHANCE OF RAINFALL AMOUNTS OVER 2".
- ISOLATED STRONG TO SEVERE THUNDERSTORMS MAY BE POSSIBLE IN
SOUTHEAST IOWA, NORTHEAST MISSOURI, AND WEST-CENTRAL ILLINOIS
FRIDAY AFTERNOON. SPC HAS ISSUED A MARGINAL (LEVEL 1 OF 5)
RISK OF SEVERE THUNDERSTORMS.
SHORT TERM /THROUGH TONIGHT/
ISSUED AT 235 AM CDT THU JUL 30 2026
WATER VAPOR IMAGERY THIS MORNING DENOTES A MID-LEVEL RIDGE ACROSS
THE WESTERN CONUS AND A TROUGH TO THE EAST. BENEATH THE TROUGH, HIGH
PRESSURE SITS OVER NORTHERN ILLINOIS, WHICH WILL SHAPE MUCH OF THE
FORECAST TODAY AND TONIGHT. MEANWHILE, A SHORTWAVE CURRENTLY OVER
SOUTHWEST WYOMING WILL ARRIVE LATE TONIGHT INTO EARLY FRIDAY
MORNING, BRINGING OUR NEXT CHANCE FOR RAIN.
TODAY, AS WE REMAIN UNDER THE INFLUENCE OF HIGH PRESSURE, YET
ANOTHER DRY AND SEASONABLE LATE JULY DAY IS IN STORE. WITH HIGH
PRESSURE JUST TO OUR EAST, SKIES WILL BE CLEAR SAVE FOR SOME HIGH
CIRRUS AND LOW CONCENTRATIONS OF DISPERSING WILDFIRE SMOKE ALOFT.
THIS SHOULD HAVE A NEGLIGIBLE IMPACT ON DIURNAL HEATING, ALLOWING
TEMPERATURES TO RISE INTO THE MID TO UPPER 80S.
BY TONIGHT, HIGH PRESSURE WILL SHIFT SOUTHEASTWARD AS THE SHORTWAVE
PROGRESSES ALONG THE NORTHERN PERIPHERY OF THE RIDGE. THIS WILL
SUPPORT THE DEVELOPMENT OF A SURFACE LOW OVER EASTERN NEBRASKA INTO
WESTERN IOWA. AHEAD OF THIS LOW, MOISTURE ADVECTION WILL INCREASE
WITH PWATS OF 1.8-2.2 INCHES STREAMING IN FROM THE SOUTHWEST. THIS
IS WELL ABOVE THE 90TH PERCENTILE OF PWATS FOR LATE JULY (1.7 IN),
BUT FALLS WITHIN THE COMMON TIME OF YEAR FOR PWATS TO BE MAXIMIZED.
THIS AMPLE MOISTURE WILL SET THE STAGE FOR A WIDESPREAD RAIN EVENT
ON FRIDAY.
LONG TERM /FRIDAY THROUGH WEDNESDAY/
ISSUED AT 235 AM CDT THU JUL 30 2026
FRIDAY THROUGH SATURDAY... AS THE SHORTWAVE MOVES EAST-
SOUTHEAST ACROSS IOWA, SHOWERS AND THUNDERSTORMS WILL DEVELOP
ALONG THE NOSE OF THE LLJ IN WESTERN AND CENTRAL IOWA, REACHING
THE WESTERN EDGE OF THE CWA BY 10-12Z. MARGINAL INSTABILITY OF
UP TO 500 J/KG OF MUCAPE WILL SUPPORT EMBEDDED STORMS WITHIN THE
SHOWERS, ESPECIALLY SOUTH OF INTERSTATE 80, THROUGH THE
MORNING. THE POTENTIAL FOR ANY SEVERE STORMS WILL BE LIMITED
THROUGH THE MORNING DUE TO TO WEAK INSTABILITY. COME AFTERNOON,
SOME CLEARING ACROSS SOUTHEAST IOWA, NORTHEAST MISSOURI, AND
WEST- CENTRAL ILLINOIS WILL HELP INCREASE MUCAPE TO 1000-1500
J/KG. THIS, COMBINED WITH 0-6KM SHEAR OF 30-35 KTS, COULD
SUPPORT ISOLATED STRONG TO SEVERE THUNDERSTORMS FRIDAY
AFTERNOON WITH THE PRIMARY THREATS BEING LOCALIZED DAMAGING
WINDS AND ISOLATED TORNADOES.
SHOWERS AND STORMS WILL CONTINUE OVERNIGHT FRIDAY INTO SATURDAY.
THIS SYSTEM WILL BE SLOW TO EXIT THE AREA, RESULTING IN LINGERING
SHOWERS THROUGH SATURDAY MORNING TO AFTERNOON. GIVEN THE AMPLE
MOISTURE AVAILABLE, RAINFALL ACCUMULATIONS CONTINUE TO TREND
UPWARDS. AT LEAST 1 INCH OF RAIN IS HIGHLY LIKELY (NBM 80-90%), AND
THE CHANCES OF 2 INCHES OR MORE FROM THE NBM ARE NOW AT 40-70% FROM
SOUTHWEST TO NORTHEAST. THIS WILL BE QUITE WELCOME DUE TO THE RECENT
DRY CONDITIONS, THOUGH HEAVY RAIN RATES OVER A SHORT PERIOD COULD
RESULT IN LOCALIZED FLOODING CONCERNS, ESPECIALLY IN URBAN AREAS.
LASTLY, AS THE SHORTWAVE DEPARTS SATURDAY, A TIGHT PRESSURE GRADIENT
WILL CAUSE GUSTY WINDS UP TO 30 MPH THROUGH THE EVENING.
SUNDAY THROUGH THURSDAY... FOLLOWING THE PASSAGE OF THE
SHORTWAVE, A RIDGE WILL BRIEFLY TAKE HOLD OVER THE REGION BEFORE
THE FLOW ALOFT BECOMES MORE ZONAL. OF NOTE IS A DEEP TROUGH
OVER SOUTHERN CANADA THROUGH MUCH OF NEXT WEEK, WHICH WILL SEND
IMPULSES THROUGH THE FLOW AND PROVIDE MULTIPLE CHANCES FOR
RAINFALL.
AVIATION /06Z TAFS THROUGH 06Z FRIDAY/
ISSUED AT 1208 AM CDT THU JUL 30 2026
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD. HIGH PRESSURE OVER
NORTHERN ILLINOIS WILL KEEP WINDS LIGHT AND SOUTH-SOUTHEASTERLY THROUGH
30/16Z, AFTER WHICH WINDS WILL STRENGTHEN TO 10-12 KTS AS THE HIGH
SHIFTS SOUTHEASTWARD. HIGH CIRRUS WILL MOVE IN AFTER 30/12Z AND
INCREASE IN COVERAGE AFTER 30/21Z AHEAD OF AN INCOMING
DISTURBANCE.
DVN WATCHES/WARNINGS/ADVISORIES
IA...NONE.
IL...NONE.
MO...NONE.
SHORT TERM...ELLINGWORTH
LONG TERM...ELLINGWORTH
AVIATION...ELLINGWORTH
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