821
FXUS63 KDVN 231909
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
209 PM CDT TUE JUN 23 2026
KEY MESSAGES
- A PASSING SYSTEM WILL BRING THE RISK OF THUNDERSTORMS TO THE
AREA ON WEDNESDAY. THE SPC HAS PARTS OF THE AREA UNDER A
MARGINAL (LEVEL 1 OUT OF 5) RISK OF SEVERE STORMS DURING THE
AFTERNOON. IF SEVERE STORMS OCCUR, THE PRIMARY RISKS WOULD BE
HAIL AND DAMAGING WINDS.
- A PATTERN CHANGE THIS WEEKEND AND INTO NEXT WEEK WILL BRING
HIGH HUMIDITY AND ABOVE NORMAL TEMPERATURES TO THE AREA. HEAT
HEADLINES MAY BE NEEDED AT TIMES NEXT WEEK.
SHORT TERM /THROUGH WEDNESDAY/
ISSUED AT 208 PM CDT TUE JUN 23 2026
SATELLITE SHOWS BUILDING CUMULUS EITHER SIDE OF A LINE FROM
MANCHESTER, IA TO WOODHULL, IL. IT IS ONLY A MATTER OF TIME BEFORE
SHOWERS AND A FEW THUNDERSTORMS DEVELOP WITHIN THIS BAND. ONCE
CONVECTION DEVELOPS, IT WILL CONTINUE THROUGH SUNSET AND THEN
DISSIPATE. OVERALL COVERAGE LOOKS TO BE 15-30 PERCENT.
LATE TONIGHT AND INTO WEDNESDAY MORNING A BAND OF WAA PRECIPITATION
WILL MOVE INTO THE AREA IN THE FORM OF NOCTURNAL CONVECTION. OVERALL
COVERAGE WILL RANGE FROM 20-40 PERCENT WITH THE NOCTURNAL CONVECTION
SLOWLY DISSIPATING WEDNESDAY MORNING AS THE LLJ WEAKENS.
WEDNESDAY AFTERNOON THE COLD FRONT MOVES INTO THE AREA. THE
COMBINATION OF THE FRONT, LEFTOVER BOUNDARIES FROM THE EARLIER
CONVECTION AND DIFFERENTIAL HEATING WILL ALLOW DIURNAL CONVECTION TO
DEVELOP DURING THE AFTERNOON.
COLDER AIR ALOFT ARRIVING WITH THE ASSOCIATED UPPER LEVEL
DISTURBANCE WILL STEEPEN MID-LEVEL LAPSE RATES AND INCREASE THE
POTENTIAL FOR THE STRONGER STORMS TO PRODUCE HAIL.
THE STRONGER MID-LEVEL WINDS ALOFT REMAIN ACROSS WISCONSIN, BUT, THE
PROGGED STEEP LAPSE RATES ACROSS THE AREA DOES RAISE THE POSSIBILITY
OF LOCALLY DAMAGING WINDS IN THE FORM OF DOWNBURSTS.
LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/
ISSUED AT 208 PM CDT TUE JUN 23 2026
WEDNESDAY NIGHT THROUGH SATURDAY NIGHT
ASSESSMENT...HIGH (>80%) CONFIDENCE OF HUMIDITY LEVELS REMAINING
FAIRLY COMFORTABLE. MEDIUM (35-50%) CONFIDENCE ON RAIN CHANCES
CONVECTION THAT DEVELOPS WEDNESDAY AFTERNOON WILL CONTINUE INTO
WEDNESDAY EVENING AND DISSIPATE WITH SUNSET.
A STORM SYSTEM IS FORECAST TO PASS THROUGH MISSOURI AND INTO THE
OHIO VALLEY THURSDAY AFTERNOON INTO FRIDAY EVENING. AREAS GENERALLY
NORTH OF HIGHWAY 30 LOOK TO REMAIN DRY THROUGH THE END OF THE WEEK.
AREAS SOUTH OF I-80 RUN THE RISK OF SEEING SOME RAIN (CURRENT
CHANCES ARE 20-30%). HOWEVER, THE BETTER RAIN CHANCES GENERALLY LOOK
TO BE SOUTH OF AN OTTUMWA, IA TO GALESBURG, IL LINE.
IF THE SYSTEM WOULD SHIFT FURTHER SOUTH (PROBABLY OF THIS OCCURRING
IS 30-40% DUE TO THE DRY EASTERLY FLOW), THEN MUCH OF THE AREA WOULD
REMAIN DRY THE REMAINDER OF THE WEEK.
SUNDAY THROUGH TUESDAY
ASSESSMENT...VERY HIGH (>90%) CONFIDENCE OF INCREASINGLY HOT AND
HUMID CONDITIONS
BY SUNDAY THE PATTERN CHANGE TO AN UPPER LEVEL HIGH OVER THE OHIO
VALLEY WILL BE IN PLACE AND STRENGTHENING. SAID LARGE SCALE PATTERN
WILL GENERATE MODERATELY STRONG SOUTHERLY FLOW THAT WILL BRING
INCREASINGLY HUMID CONDITIONS TO THE AREA ALONG WITH ABOVE NORMAL
TEMPERATURES.
SUNDAY THROUGH MONDAY WILL BE DRY AS THE MAIN STORM TRACK IS WELL
NORTH OF THE AREA. HOW HIGH THE DEW POINTS GET ARE STILL SOMEWHAT IN
QUESTION BUT READINGS OF 70 TO 75 ARE VERY LIKELY TO OCCUR
ESPECIALLY GIVEN THE RECENT RAINFALL ACROSS THE AREA.
GOING ON THE BASIS OF 70 TO 75 DEW POINTS, HEAT INDICES SUNDAY WOULD
BE IN THE MID TO UPPER 90S ACROSS THE AREA WITH READINGS OVER 100 ON
MONDAY.
THUS THE POTENTIAL IS THERE FOR HEAT HEADLINES ON MONDAY. THE
CURRENT PROBABILITY LOOKS TO BE 33-40% RIGHT NOW.
MONDAY NIGHT INTO TUESDAY THE HEAT AND HUMIDITY WILL CONTINUE.
HOWEVER, A SYSTEM IN THE PLAINS RAISES QUESTIONS REGARDING THE
POSITION OF THE MAIN STORM TRACK. DOES IT REMAIN WELL NORTH OF THE
AREA OR DOES IT SHIFT SOUTHWARD DUE TO THE PLAINS SYSTEM?
FROM THE LARGE SCALE PICTURE, THERE ARE DUAL UPPER HIGHS; ONE IN THE
OHIO VALLEY AND THE OTHER NEAR THE GULF COAST. SOME SOLUTIONS
RETROGRADE THE OHIO VALLEY UPPER HIGH WESTWARD. IF THIS IS CORRECT,
THEN THE STORM TRACK FOR ORGANIZED STORM COMPLEXES WOULD REMAIN WELL
TO THE NORTH OF THE AREA. SOME OTHER SOLUTIONS ALLOW THE OHIO VALLEY
HIGH TO MOVE TOWARD THE EAST COAST, WHICH WOULD ALLOW THE MAIN STORM
TRACK TO MOVE SOUTH.
IF THE MAIN STORM TRACK WOULD MOVE SOUTH, HEAT AND HUMIDITY WOULD
CONTINUE PAST TUESDAY BUT WOULD BE INTERSPERSED WITH THUNDERSTORMS.
RIGHT NOW THE MODEL CONSENSUS IS SUGGESTING THE STORM TRACK TO MOVE
SOUTH AND GRAB PARTS OF THE AREA. WITH PWATS FORECAST TO BE 1.5
INCHES OR HIGHER, THIS SCENARIO WOULD ALSO BRING THE RISK OF HEAVY
RAINFALL WITH REACH ROUND OF STORMS.
AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/
ISSUED AT 1213 PM CDT TUE JUN 23 2026
ISOLATED DIURNAL CONVECTION WILL DEVELOP ACROSS EASTERN IOWA
THROUGH 01Z/24. THE PROBABILITY OF A TAF SITE BEING IMPACTED IS
AROUND 20 PERCENT. AFTER SUNSET WINDS WILL BE UNDER 10 KNOTS.
AFTER 12Z/24 DECAYING NOCTURNAL CONVECTION MAY MOVE INTO THE
HIGHWAY 20 CORRIDOR.
DVN WATCHES/WARNINGS/ADVISORIES
IA...NONE.
IL...NONE.
MO...NONE.
SHORT TERM...08
LONG TERM...08
AVIATION...08
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