496
FXUS63 KDVN 061724
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1224 PM CDT THU AUG 6 2026
KEY MESSAGES
- DRIER CONDITIONS TODAY BEFORE AN ACTIVE PATTERN AND HUMID
CONDITIONS RETURN THIS WEEKEND THROUGH THE MIDDLE OF NEXT
WEEK. SOME ISOLATED STRONG TO SEVERE STORMS ARE POSSIBLE
FRIDAY AFTERNOON AND EVENING AND AGAIN SATURDAY NIGHT FOR
PORTIONS OF THE AREA.
SHORT TERM /THROUGH FRIDAY NIGHT/
ISSUED AT 137 AM CDT THU AUG 6 2026
COMPARED TO WEDNESDAY, TODAY WILL BE DRIER FOR MUCH OF THE AREA
OUTSIDE SOME LINGERING SHOWERS (20-30% CHANCE) ALONG AND SOUTH
OF A LINE BETWEEN MEMPHIS, MO AND PRINCETON, IL THIS MORNING.
THE SHORTWAVE TROUGH THAT BROUGHT US THE ON-AND-OFF SHOWERS AND
STORMS YESTERDAY IS FORECAST TO PROPAGATE EASTWARD AS A HIGH
PRESSURE SLIDES IN TO REPLACE THE SURFACE BOUNDARY STALLED OVER
THE CWA. TEMPERATURES WILL BE SLIGHTLY BELOW AVERAGE FOR AUGUST
WITH HIGHS IN THE UPPER 70S TO LOW 80S AND LOWS TONIGHT IN THE
LOW TO MID 60S WITH LIGHT AND VARIABLE WINDS.
FRIDAY THROWS A WRENCH INTO THE DRY CONDITIONS WITH THE NEXT
SHORTWAVE TROUGH DIVING IN FROM THE NORTHWEST ON THE BACKSIDE
OF A LONGWAVE TROUGH OVER CENTRAL CANADA. THIS IS GOING TO FORCE
ANOTHER WEAK SURFACE TROUGH TO MOVE INTO THE AREA AND ACT AS A
FOCAL POINT FOR SOME SCATTERED SHOWERS AND STORMS (30-50%
COVERAGE). A WIND SHIFT TO OUT OF THE SOUTHWEST WILL ALSO
ENABLE LOW-LEVEL WAA TO INCREASE HIGHS A FEW DEGREES, ADDING TO
THE LIMITED INSTABILITY AHEAD OF THIS BOUNDARY. CURRENT REFS
GUIDANCE HAS 1500-2250 J/KG OF SBCAPE ACROSS EASTERN IOWA WITH
THE GREATEST 0-6 KM BULK SHEAR OF 35-40 KNOTS DISPLACED TO THE
WEST. WITH THIS DISCONNECT BETWEEN INSTABILITY AND SHEAR, THE
SEVERE THREAT WITH ANY DEVELOPING STORMS SHOULD BE LIMITED. THE
SPC HAS A MARGINAL RISK (LEVEL 1 OUT OF 5) FOR SEVERE WEATHER
FOR LOCATIONS TO THE NORTH AND WEST OF A LINE FROM KEOSAUQUA,
IA TO DUBUQUE, IA WHERE THERE SHOULD BE BRIEF OVERLAP IN BULK
SHEAR AND SBCAPE PRIOR TO SUNSET. PRIMARY HAZARD WOULD BE
DAMAGING WINDS WITH THE POTENTIAL FOR AN MCS DEVELOPMENT.
BY FRIDAY NIGHT, BOTH THE SURFACE AND SHORTWAVE TROUGHS WILL SHIFT
TO OUR SOUTHEAST AS ANOTHER WEAK HIGH PRESSURE SETTLES OVER THE AREA
FOR SATURDAY. LOWS AGAIN WILL BE SEASONABLE IN THE LOW TO MID
60S. DRY AND SEASONABLE CONDITIONS PERSIST INTO SATURDAY, BUT
THEY WILL NOT LAST LONG HEADING INTO THE SECOND HALF OF THE
WEEKEND.
LONG TERM /SATURDAY THROUGH WEDNESDAY/
ISSUED AT 137 AM CDT THU AUG 6 2026
SATURDAY NIGHT-MONDAY...AS THE LONGWAVE TROUGH THAT HAS BEEN
STATIONARY OVER CENTRAL CANADA FINALLY PROPAGATES EASTWARD, ZONAL
UPPER-LEVEL FLOW OVER THE NORTHERN ROCKIES AND PLAINS RETURNS,
SHIFTING THE DIRECTION OF THE STORM TRACK ALONG WITH IT. A SUBTLE
SHORTWAVE IS EXPECTED TO DEEPEN A LOW PRESSURE ALONG THE LEEWARD
SIDE OF THE NORTHERN ROCKIES AND FRONT RANGE SATURDAY INTO SATURDAY
NIGHT. THIS LOW PRESSURE SYSTEM WILL HELP GENERATE A WARM FRONT
ALONG THE PRESSURE GRADIENT FROM THE HIGH PRESSURE OVER THE REGION
THAT WILL BE PULLED NORTHWARD INTO IOWA AND WESTERN ILLINOIS.
THE FRONTAL PASSAGE AND CONVERGENCE ALONG A DEVELOPING LLJ IS
LIKELY TO GENERATE SCATTERED SHOWERS WITH EMBEDDED THUNDERSTORMS
(50-70% COVERAGE) SATURDAY NIGHT INTO SUNDAY AND SET THE STAGE
FOR A WARMING AND MOISTENING TREND EARLY NEXT WEEK. BY MONDAY,
THE LOW PRESSURE MOVES ACROSS NORTHERN IOWA AND SOUTHERN
MINNESOTA INTO WISCONSIN, KEEPING STORM CHANCES ON THE TABLE
AND PUSHING A COLD FRONT SOUTHWARD. THESE STORMS DO HAVE A
POTENTIAL TO TURN SEVERE, ESPECIALLY IN NORTHERN IOWA, WHERE WAA
AND LOW-LEVEL WIND SHEAR CLOSE TO THE LOW PRESSURE CENTER COULD
ENABLE SOME CONVECTIVE ORGANIZATION, BUT IT IS TOO EARLY TO
DETERMINE THE SEVERITY. WHAT IS MORE CERTAIN IS THE FRONT
STALLING OUT ACROSS THE CWA MONDAY NIGHT INTO TUESDAY AS
DYNAMICAL SUPPORT IS LOST.
TUESDAY-WEDNESDAY...ANOTHER WEAK SHORTWAVE MOVES ACROSS THE CENTRAL
ROCKIES, SPAWNING A FRONT RANGE LOW ON THE TAIL-END OF THE
STATIONARY FRONT DRAPED ACROSS THE CENTRAL PLAINS AND MIDWEST.
THIS COULD LEAD TO A DEFORMATION ZONE TO FORM NEAR THE SURFACE
ACROSS THE CWA AND ALLOW FOR ROUNDS OF STORMS TO DEVELOP BUT
ALSO POOL MOISTURE (AND THEREFORE, DEW POINTS). WHILE IT IS
DIFFICULT TO ADDRESS THE EXCESSIVE HEAT AND/OR SEVERE POTENTIAL
THIS FAR OUT, THERE IS GROWING CONFIDENCE (50-70% CHANCE PER
05.12Z LREF GUIDANCE) THAT DEW POINTS WILL ONCE AGAIN BE BACK IN
THE LOW-TO-MID 70S MAKING CONDITIONS OUTDOORS FEEL MUGGY FOR
MIDDLE OF NEXT WEEK.
AVIATION /18Z TAFS THROUGH 18Z FRIDAY/
ISSUED AT 1218 PM CDT THU AUG 6 2026
WEAK CONVERGENT WINDS AND AMPLE MOISTURE WILL CONTINUE TO KEEP
LOW CLOUDS AS PART OF OUR FORECAST THROUGH FRIDAY. THE LOW
CLOUDS ARE GENERALLY MVFR TO VFR AS OF 17Z, AS THE SCATTER OUT
SOMEWHAT, BUT THIS PROCESS WILL REVERSE AGAIN LATER TONIGHT, AS
LOW CLOUDS AND SOME FOG RETURN TO THE AREA. THERE COULD ALSO BE
A FEW VERY SMALL SHOWERS TODAY, BUT WE ARE NOT EXPECTING
ANYTHING OTHER THAN BRIEFLY WETTING RAINS FROM THESE. TONIGHT'S
FOG AND LOW CLOUDS ARE FORECAST TO BE IFR, BUT COULD AGAIN
PRODUCE SOME PERIODS OF LIFR FOG AND VVS AROUND 100 FT, AS WE
SAW AT DBQ THIS MORNING. FRIDAY MORNING, WE'RE LOOKING AT
IMPROVEMENT TO VFR SLOWLY BY LATE MORNING, SIMILAR TO TODAY.
DVN WATCHES/WARNINGS/ADVISORIES
IA...NONE.
IL...NONE.
MO...NONE.
SHORT TERM...DELAUNE
LONG TERM...DELAUNE
AVIATION...ERVIN
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page