160
FXUS63 KDVN 201131
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
631 AM CDT SAT JUN 20 2026
KEY MESSAGES
- WIDESPREAD RAIN IS EXPECTED EARLY SUNDAY MORNING THROUGH
SUNDAY EVENING. ACCUMULATIONS OF 1-3 INCHES ARE LIKELY
(50-70%) ALONG AND SOUTH OF HIGHWAY 34. THERE IS A MODERATE
(LEVEL 3 OUT OF 4) RISK FOR EXCESSIVE RAINFALL ACROSS PORTIONS
OF NORTHEAST MISSOURI AND WEST-CENTRAL ILLINOIS.
- THERE IS A MARGINAL (LEVEL 1 OUT OF 5) RISK FOR SEVERE WEATHER
ON SUNDAY, MAINLY SOUTH OF HIGHWAY 34. PRIMARY THREAT IS
DAMAGING WINDS.
- WEAK DISTURBANCES AND NORTHWESTERLY FLOW ALOFT TO KEEP
TEMPERATURES COMFORTABLE AND SLIGHTLY BELOW AVERAGE THROUGH
THE END OF NEXT WEEK.
SHORT TERM /THROUGH SUNDAY NIGHT/
ISSUED AT 125 AM CDT SAT JUN 20 2026
TODAY...AS A MID-LEVEL TROUGH TO OUR NORTHWEST CLEARS THE AREA, DRY
AND COLD AIR ADVECTION SETS IN AS AN ELONGATED HIGH PRESSURE ANCHORS
OVER IOWA. NORTHWESTERLY SURFACE FLOW AROUND 5-10 KNOTS WILL KEEP
HIGH TEMPERATURES TAMED TO THE MID-70S TO LOW 80S ACROSS OUR CWA
DESPITE THE MOSTLY CLEAR SKIES.
SATURDAY NIGHT...SPLIT FLOW IN THE JET STREAM OVER THE GREAT
PLAINS ALLOWS A SHORTWAVE TROUGH TO PASS UNDERNEATH A BUILDING
RIDGE OVER SOUTH-CENTRAL CANADA. A LOW PRESSURE SYSTEM WILL
DEEPEN ALONG THE FRONT RANGE OF COLORADO, DEVELOPING A WARM
FRONT ACROSS THE CENTRAL PLAINS AND MISSOURI. CLOUD COVER BEGINS
TO INCREASE OVERNIGHT SATURDAY AS CIRRUS OUTFLOW AND MID- LEVEL
CLOUDS MOVE IN AHEAD OF THE SYSTEM. ADDING THIS AND EASTERLY
FLOW NEAR THE SURFACE, LOWS ARE EXPECTED TO BE A COUPLE DEGREES
HIGHER THAN FRIDAY NIGHT IN THE UPPER 50S AND LOW 60S.
SUNDAY...THE LOW PRESSURE EJECTS EASTWARD INTO KANSAS, AND THE
WARM FRONT INCHES NORTHWARD AS DIFFLUENT FLOW ALOFT MAXIMIZES
ALONG THE MISSOURI-IOWA BORDER. THE HREF IS IN GOOD AGREEMENT
(70- 90%) AT A RAIN SHIELD DEVELOPING OVER SOUTHWEST IOWA ALONG
A MID- LEVEL F-GEN BAND BEFORE PROPAGATING EASTWARD INTO OUR CWA
AS EARLY AS 5AM. AS THE LOW PRESSURE MOVES INTO NORTHERN
MISSOURI ON SATURDAY AFTERNOON, THE WARM FRONT WILL REMAIN ALONG
THE IOWA-MISSOURI BORDER WHERE THERE IS A LOW-TO- MEDIUM CHANCE
(30-50%) OF RAINFALL ACCUMULATION EXCEEDING 2 INCH, ESPECIALLY
ALONG AND SOUTH OF HIGHWAY 34. NORTH OF HIGHWAY 34, THERE WILL
BE A SHARP GRADIENT IN RAINFALL ACCUMULATIONS WHERE AREAS NORTH
OF HIGHWAY 30 MAY NOT EVEN EXCEED A QUARTER OF AN INCH (30-60%
CHANCE). THIS IS A SLIGHT SHIFT SOUTHWARD COMPARED TO THE LAST
FEW LREF RUNS, SO THE EXACT PLACEMENT OF THE WARM FRONT (AND
ULTIMATELY THE HIGHEST RAINFALL ACCUMULATION) STILL REMAINS
UNCERTAIN. REGARDLESS, OUR SOUTHERN MOST TIER OF COUNTIES WILL
RECEIVE THE HEAVIEST RAINFALL WHICH IS REFLECTED BY A MODERATE
(LEVEL 3 OUT OF 4) RISK FOR EXCESSIVE RAINFALL AND A FLOOD WATCH
ISSUANCE.
IN TERMS OF SEVERE WEATHER, SOUTH OF HIGHWAY 34 ALSO HAVE THE
HIGHEST CHANCES OF SEEING THUNDERSTORMS AS MUCAPE WILL LIKELY
(60-80%) TO EXCEED 100 J/KG. COMBINING THIS AND 40-50 KNOTS OF
0-6 KM SHEAR, THERE IS A MARGINAL (LEVEL 1 OUT OF 5) RISK FOR
SEVERE WEATHER SUNDAY FOR AREAS SOUTH OF HIGHWAY 34 WITH THE
PRIMARY HAZARD BEING DAMAGING WINDS.
SUNDAY NIGHT...THE LOW PRESSURE MOVES INTO ILLINOIS AS THE
SHORTWAVE TROUGH SHIFTS OVER IOWA. FLOW OUT OF THE NORTHEAST
NEAR THE SURFACE SHOULD ADVECT IN COLD AIR AS THE SKIES CLEAR
OUT DUE TO UPPER-LEVEL CONVERGENCE.
LONG TERM /MONDAY THROUGH FRIDAY/
ISSUED AT 125 AM CDT SAT JUN 20 2026
MONDAY-TUESDAY...BEHIND THE SUNDAY SHORTWAVE, ZONAL FLOW RETURNS
ALOFT, KEEPING CONDITIONS DRY ON MONDAY. NORTHERLY WINDS AT THE
SURFACE WILL KEEP HIGHS IN THE 70S AND LOWS IN THE 50S MONDAY INTO
TUESDAY MORNING UNDERNEATH PARTLY CLOUDY SKIES. ON TUESDAY, THE NEXT
SHORTWAVE TROUGH DIGS SOUTHWARD INTO THE NORTHERN PLAINS. ANOTHER
LOW PRESSURE DEVELOPS AHEAD OF THIS TROUGH ACROSS THE DAKOTAS, BUT
THE POSITIVE TILT OF THE TROUGH DOES NOT PROVIDE A LOT OF UPPER
LEVEL SUPPORT FOR DEEPENING. THIS LOW PRESSURE WILL SWING
SOUTHEASTWARD WITH THE TROUGH, BRINGING POPS BACK UP TUESDAY NIGHT
ALONG THE COLD FRONT. THE ORIENTATION OF THIS SYSTEM SHOULD LIMIT
THE SEVERE AND EVEN THUNDER POTENTIAL.
WEDNESDAY-FRIDAY...AS THE LOW PRESSURE FROM TUESDAY NIGHT CLEARS THE
AREA, A WEAK SURFACE TROUGH DEVELOPS ON THE BACKSIDE, KEEPING SOME
LIGHT SHOWERS AROUND AS THE POSITIVELY TILTED UPPER-LEVEL TROUGH
MOVES OVER IOWA. POPS SHOULD DROP OFF HEADING INTO WEDNESDAY NIGHT
AS CONVERGENCE ALOFT ON THE BACKSIDE OF THE TROUGH ALLOWS FOR
SUBSIDENCE TO SET IN. WEAK PERTURBATIONS IN THE NORTHWESTERLY FLOW
ALOFT WILL KEEP DIURNAL-DRIVEN SCATTERED POPS ON THE TABLE THURSDAY
AND FRIDAY. IN ADDITION, WEAK NORTHERLY FLOW AT THE SURFACE DURING
THIS TIME PERIOD SHOULD KEEP HIGHS IN THE 70S (70-90% CHANCE), BELOW
AVERAGE FOR THIS TIME OF YEAR.
AVIATION /12Z TAFS THROUGH 12Z SUNDAY/
ISSUED AT 625 AM CDT SAT JUN 20 2026
VFR EXPECTED TODAY INTO TONIGHT WITH INCREASING MID/HIGH CLOUDS LATE
IN THE DAY. WNW WINDS GENERALLY UNDER 15 KTS ARE EXPECTED
TODAY, BECOMING LIGHT AND VARIABLE LATE IN THE EVENING. THERE IS
A CHANCE (20-50%) FOR SHOWERS AND THUNDERSTORMS NEAR BRL TOWARD
THE END OF THIS FORECAST CYCLE, BUT DID NOT MENTION IN TAFS YET
DUE TO LOW CONFIDENCE THIS FAR OUT.
DVN WATCHES/WARNINGS/ADVISORIES
IA...FLOOD WATCH FROM SUNDAY MORNING THROUGH SUNDAY EVENING FOR
IAZ099.
IL...FLOOD WATCH FROM SUNDAY MORNING THROUGH SUNDAY EVENING FOR
ILZ034-035.
MO...FLOOD WATCH FROM SUNDAY MORNING THROUGH SUNDAY EVENING FOR
MOZ009-010.
SHORT TERM...DELAUNE
LONG TERM...DELAUNE
AVIATION...UTTECH
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