920
FXUS63 KDVN 161318 CCA
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
619 AM CDT TUE JUN 16 2026
KEY MESSAGES
- A SEASONABLY STRONG SYSTEM WILL BRING THE POTENTIAL FOR SEVERE
THUNDERSTORMS ON WEDNESDAY. AN ENHANCED RISK (LEVEL 3 OF 5) OF
SEVERE THUNDERSTORMS IS IN EFFECT FOR AREAS SOUTH OF HIGHWAY
30, WITH THE REMAINDER OF THE AREA UNDER A SLIGHT (LEVEL 2 OF
5) RISK. A MODERATE RISK ( LEVEL 4 OF 5) IS CLIPPING OUR FAR
SOUTHEAST AND EASTERN COUNTIES.
- HEAVY RAINFALL IS POSSIBLE, ESPECIALLY OVER NORTHERN ILLINOIS
THROUGH WEDNESDAY. FLASH FLOODING WILL BE A RISK FOR AREAS
THAT SEE REPEATED ROUNDS OF INTENSE RAINFALL.
- AFTER SEVERAL QUIET DAYS, THE ACTIVE PATTERN WILL RESUME WITH
HEAVY RAIN POTENTIAL DEVELOPING LATE IN THE WEEKEND IN ZONAL
FLOW ALOFT.
SHORT TERM /THROUGH WEDNESDAY NIGHT/
ISSUED AT 221 AM CDT TUE JUN 16 2026
A SHORTWAVE WITH A WEAK COLD FRONT WILL TRACK THROUGH THE AREA THIS
MORNING, WITH LIFTING AHEAD OF THE FRONT PRODUCING SCATTERED
SHOWERS. THESE SHOWERS ARE EXPECTED TO MOVE EAST OF THE AREA BY MID
MORNING. HOWEVER, GIVEN DRY LOW LEVELS, THESE SHOWERS ARE PRODUCING
LIGHT TO NO RAINFALL. AS A RESULT, EXPECT LITTLE TO NO
ACCUMULATIONS. HOWEVER, SUBSIDENCE WITHIN THE SHOWERS MAY PRODUCE
SOME GUSTY WINDS, WITH OBSERVATIONS IN NORTHWEST IOWA SHOWING GUSTS
OF 25-35 KTS. THESE SHOWERS WILL EXIT THE AREA BY 9 AM THIS MORNING
WITH THE FRONT. FOLLOWING FRONTAL PASSAGE, ANOTHER SEASONABLY COOL
AND DRY DAY. HIGHS IN THE MID TO UPPER 70S ARE EXPECTED, ALONG WITH
WESTERLY WINDS OF 15-20 MPH. DEEP MIXING DURING THE DAY WILL SUPPORT
GUSTS UP TO 25-30 MPH.
TUESDAY NIGHT, THE STORY SHIFTS TO AN APPROACHING STRONG SHORTWAVE
TRACKING ACROSS THE UPPER MIDWEST. GUIDANCE HAS NARROWED IN ON THE
LOW TRACKING ACROSS SOUTHERN MINNESOTA, WITH THE POTENTIAL FOR AN
ADDITIONAL AREA OF LOW PRESSURE TO DEVELOP ACROSS EASTERN IOWA. THIS
SYSTEM HAS IMPRESSIVE DYNAMICS AND KINEMATICS FOR MID-JUNE, WITH MID-
AND LOW-LEVEL WIND SPEEDS IN THE NAEFS 99TH PERCENTILE FOR THIS
TIME OF YEAR. A WESTERLY 500 MB JET WITH A JET MAX OVER 65 KTS WILL
MOVE IN ACROSS EASTERN NEBRASKA AND WESTERN IOWA LATE TUESDAY NIGHT,
REACHING EASTERN IOWA BY EARLY WEDNESDAY MORNING. AT THE SAME TIME,
THE LLJ WILL BE ANGLED FROM THE SOUTHWEST WITH SPEEDS OVER 50 KTS.
WITH THIS STRONG LOW LEVEL SOUTHWESTERLY FLOW AHEAD OF THE
SHORTWAVE, AMPLE MOISTURE ADVECTION IS EXPECTED ALONG THE WARM
CONVEYOR BELT. GUIDANCE CONTINUES TO SHOW PWATS OF 1.5- 2.0 FEEDING
INTO THE AREA OVERNIGHT THROUGH THE MORNING HOURS. THIS WILL LEAD TO
A NOTICEABLE INCREASE IN HUMIDITY AS DEWPOINTS REACH INTO THE MID
60S TO LOW 70S AFTER OUR RECENT BOUT OF DRIER WEATHER. AS A RESULT
OF THIS HIGH MOISTURE CONTENT, ANY SHOWERS AND STORMS THAT OCCUR
WILL BE CAPABLE OF HEAVY RAIN. THERE IS A SCATTERED RISK OF
FLASH FLOODING, NAMELY FOR THOSE AREAS THAT RECEIVE MULTIPLE
ROUNDS OF STORMS. AS A RESULT, A SLIGHT (LEVEL 2 OF 4) RISK OF
FLASH FLOODING IS IN PLACE.
OF GREATEST CONCERN WITH THIS SYSTEM, HOWEVER, IS THE THREAT OF
SEVERE WEATHER. SHEAR AND INSTABILITY WILL NOT BE DIFFICULT TO COME
BY IN THIS DYNAMICALLY CHARGED ENVIRONMENT, LEADING TO AN ENHANCED
(LEVEL 3 OF 5) RISK ACROSS THE SOUTHERN HALF OF THE CWA AND A SLIGHT
(LEVEL 2 OF 5) RISK TO THE NORTH. A MODERATE (LEVEL 4 OF 5) RISK IS
TO OUR SOUTHEAST ACROSS CENTRAL ILLINOIS. TWO ROUNDS OF STORMS
APPEAR LIKELY: FIRST, A MORNING ROUND ALONG THE WAA WING, FOLLOWED
BY AN AFTERNOON ROUND SUPPORTED BY FRONTAL FORCING. SOME
UNCERTAINTY, NAMELY IN THE EXTENT OF MORNING CONVECTION AND TIMING
OF FRONTAL PASSAGE, GIVE US A FEW SCENARIOS:
SCENARIO 1: MORNING SHOWERS AND STORMS DEVELOP ALONG THE NOSE OF THE
LLJ ACROSS NORTHEAST IOWA AND MOVE SOUTHEAST. LIMITED INSTABILITY
OVERNIGHT WOULD HELP LIMIT THE SEVERE THREAT DURING THE MORNING
HOURS. ONCE THESE SHOWERS AND STORMS MOVE OUT OF THE AREA, DIURNAL
HEATING IS ABLE TO OCCUR PRIOR TO THE FRONT MOVING INTO THE AREA.
STORMS INITIATE ALONG THE BOUNDARY MID-AFTERNOON, WITH ALL SEVERE
HAZARDS POSSIBLE AND MOVE OUT OF THE AREA BY EARLY EVENING.
SCENARIO 2: THE AIRMASS IS NOT ABLE TO RECOVER FOLLOWING MORNING
CONVECTION. THIS CAN HAPPEN IN 2 WAYS: FIRST, SHOWERS AND STORMS IN
THE MORNING PERSIST INTO MID-AFTERNOON, OR SECONDLY, THE COLD FRONT
ADVANCES FASTER THAN FORECAST. BOTH OF THESE WOULD RESULT IN THE
SEVERE THREAT BEING DISPLACED TO OUR EAST.
SCENARIO 3: MOISTURE RETURN OVERNIGHT IS NOT AS STRONG AS GUIDANCE
SUGGESTS, LIMITING SHOWERS AND STORMS DURING THE MORNING HOURS. WITH
MOISTURE ARRIVING LATER IN THE DAY, DIURNAL HEATING WOULD OCCUR AS
MOISTURE FEEDS INTO THE REGION. THIS WOULD ALLOW FOR THE AFTERNOON
STORMS TO NOT BE IMPEDED BY MORNING CONVECTION. ONCE AGAIN, STRONG
FORCING ALONG THE FRONT WOULD SUPPORT ALL SEVERE HAZARDS.
FOR ALL OF THESE SCENARIOS, AN ADDITIONAL CONCERN IS A CAPPED
ENVIRONMENT. 700 MB TEMPERATURES SOUTH OF I-80 ARE FORECAST TO BE
HIGH, WHICH COULD LIMIT ANY CONVECTION ACROSS SOUTHEAST IOWA AND
NORTHEAST MISSOURI. HOWEVER, ANY STORMS THAT ARE ABLE TO DEVELOP
WOULD BE ABLE TO TAKE ADVANTAGE OF A PRIMED ENVIRONMENT.
LONG TERM /THURSDAY THROUGH MONDAY/
ISSUED AT 221 AM CDT TUE JUN 16 2026
PAST WEDNESDAY, THE FORECAST LOOKS TO BE CALMER AS WE RETURN TO THE
BACKGROUND NORTHWESTERLY FLOW BEHIND THE DEPARTING SYSTEM. HIGH
PRESSURE WILL SLIDE IN THURSDAY FROM THE NORTHWEST. PLEASANT
TEMPERATURES WILL REMAIN IN PLACE, BUT THE ACTIVE PATTERN LOOKS TO
RETURN AS ZONAL FLOW DEVELOPS OVER THE MIDWEST BY LATE IN THE
WEEKEND. THIS PATTERN IS A TYPICAL MCS PATTERN WHERE HEAVY RAINFALL
WOULD BE FAVORED BY SHORT WAVES PASSING THROUGH THE ZONAL FLOW. HIGH
AMOUNTS OF MOISTURE ARE EXPECTED IN THIS PATTERN, AS WELL AS A
SEASONAL/TYPICAL WIND THREAT WITH ANY ZONAL MCS PATTERN. WPC IS
ALREADY HIGHLIGHTING OUR REGION WITH SEVERAL INCHES OF RAINFALL IN
THE THE LATER WEEKEND TO EARLY WEEK NEXT WEEK.
AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/
ISSUED AT 615 AM CDT TUE JUN 16 2026
A FEW BRIEF SHOWERS AND THUNDERSTORMS WILL IMPACT NEAR BRL JUST
PRIOR TO 12Z, FOLLOWED BY VFR WEATHER AT ALL SITES, WITH MAINLY
CLEAR SKIES TODAY. WINDS WILL BE GUSTY FROM THE NORTHWEST, AT
10-15 KTS GUSTING TO 25KTS. BY THIS EVENING, AN APPROACHING LOW
PRESSURE WILL DECREASE WINDS, THEN SWITCH THEM TO THE SOUTH LATE
TONIGHT. SOME STRONG THUNDERSTORMS ARE EXPECTED TO FORM BETWEEN
09Z AND 12Z OVER EASTERN IOWA, THEN MOVE SOUTHEAST THROUGH THE
REST OF THE AREA AFTER 12Z. HEAVY RAIN, FREQUENT LIGHTNING, AND
SOME HAIL ARE ALL EXPECTED TOWARDS 12Z TOMORROW.
DVN WATCHES/WARNINGS/ADVISORIES
IA...NONE.
IL...NONE.
MO...NONE.
SHORT TERM...ELLINGWORTH
LONG TERM...ERVIN
AVIATION...ERVIN
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