314
FXUS63 KDVN 081907
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
207 PM CDT FRI MAY 8 2026
KEY MESSAGES
- WARMING INTO SATURDAY WITH OCCASIONAL CHANCES FOR NUISANCE
LIGHT SHOWERS IN OR NEAR THE LOCAL FORECAST AREA, BUT MANY
MORE DRY HOURS THAN THOSE WHO EXPERIENCE A WETTING RAIN.
- A CLIPPER-LIKE SYSTEM LATE MONDAY NIGHT INTO TUESDAY MORNING
IS FORECASTED TO BRING SCATTERED (30-70%) SHOWERS AND
THUNDERSTORMS TO THE REGION.
SHORT TERM /THROUGH SATURDAY NIGHT/
ISSUED AT 206 PM CDT FRI MAY 8 2026
WATER VAPOR IMAGERY(WV) AND UPPER AIR ANALYSIS SHOWING BROAD
NORTHWESTERLY STEERING FLOW WRAPPING AROUND A LARGE CUT-OFF UPPER
LOW ACRS THE HUDSON/JAMES BAY REGION AND DOWN ACRS MUCH OF THE MID
CONUS. SEVERAL EMBEDDED VORT MAX'S IN THIS FLOW, WITH TWO OF NOTE
FOR THE LOCAL AREA...ONE BEING THE WAVE CURRENTLY ROLLING ACRS
SOUTHERN IA AND NORTHERN MO PRODUCING THE SHOWERS ACRS THOSE AREAS,
AND ANOTHER ONE FURTHER UPSTREAM STILL ACRS SOUTHERN SASKATCHEWAN.
AS THE WAVE IN THE SOUTH EXITS TAKING THE SHOWER ACTIVITY WITH IT
THROUGH THE EVENING, THE UPSTREAM VORT MAX OR EVEN MULTIPLE FEATURES
WILL LOOK TO RIPPLE IN CLIPPER-STYLE DOWN ACRS THE UPPER AND MID MS
RVR VALLEY THROUGH SAT. THUS THE LOCAL AREA WILL BE OPEN TO PASSING
PATCHES OR SMALL CLUSTERS OF MAINLY LIGHT SHOWERS INTO THE WEEKEND.
BUT THESE FEATURES WILL HAVE TO BATTLE AN ONGOING DRY LOW TO MID
LEVEL AIRMASS ACRS THE REGION FOR MUCH PRECIP TO REACH THE SFC. ONE
SUCH LEAD VORT MAX CURRENTLY ACRS CENTRAL MN MAY TRY TO INDUCE SOME
LIGHT SPOTTY HIGH BASED SHOWERS OR SPRINKLES ACRS THE NORTHEAST HALF
OF THE CWA TONIGHT, WITH THE ABOVE MENTIONED LARGER SASKATCHEWAN
WAVE PRODUCING SHOWERS ACRS MAINLY MN INTO WI LATE TONIGHT INTO
EARLY SAT AFTERNOON. SOME OF THIS ACTIVITY MAY TRY TO BLEED DOWN TO
THE HWY 20 CORRIDOR ON SATURDAY.
OVERALL THOUGH, THE MESSAGE SHOULD BE THAT MOST OF THE AREA TO HAVE
MANY MORE DRY HOURS THAN IMPACTED WITH SHOWERS THROUGH SATURDAY LATE
AFTERNOON. LOW TEMPS TONIGHT IN THE MID 40S TO LOW 50S BEING HELD UP
BY SOUTH WINDS AND SOME CLOUDS, WHILE HIGH TEMPS ON SATURDAY HELPED
OUT BE PRE-FRONTAL WAA AND DEEPER MIXING/BREEZY WIND REGIME HELPING
BOOST TEMPS WELL UP IN THE 70S ACRS MOST OF THE AREA. WE MAY HAVE A
10 DEGREE RANGE FROM THE NORTHERN CWA TO THE SOUTH, DEPENDING ON
WHERE LAYERED CLOUD BANDS LAY OUT.
SATURDAY NIGHT...ANOTHER VORT MAX SIMILAR TO THE ONE OCCURRING IN OUR
SOUTH RIGHT NOW, WILL LOOK TO PROPAGATE OUT OF THE CENTRAL PLAINS
AND PRODUCE SCTRD SHOWERS AND POSSIBLY A THUNDERSTORM ALONG AND
SOUTH OF THE HWY 34 CORRIDOR SAT NIGHT. BUT THE LATEST GUIDANCE
STILL VARIES ON HOW MUCH PRECIP WILL MOVE ACRS THE LOCAL CWA AND IT
MAY NOT BE MUCH IF THE LATEST ECMWF AND CAM RUNS HAVE THEIR WAY.
LONG TERM /SUNDAY THROUGH THURSDAY/
ISSUED AT 206 PM CDT FRI MAY 8 2026
SUNDAY...AFTER WHATEVER WAVE CAN RIPPLE ALONG AND SOUTH OF THE AREA
SATURDAY NIGHT, SUNDAY SHOULD BE CHARACTERIZED BY INCOMING RIDGING
AND COOLING NORTHERLY BOUNDRY LAYER FLOW FOR A MAINLY SUNNY, DRY BUT
SOMEWHAT BELOW NORMAL TEMP DAY. HIGHS BACK IN THE 60S, AND A COOL
SUNDAY NIGHT IN THE LOW 40S TO UPPER 30S.
MONDAY...HIGHS LOOK TO CONTINUE TO BE NEAR SEASONABLE IN THE MID-60S
TO LOW 70S, BUT MONDAY NIGHT LOWS NOT AS COOL AHEAD OF AN INCOMING
CLIPPER SYSTEM. REGARDING THAT SYSTEM, THE PATTERN LOOKS TO SHIFT
MONDAY NIGHT AS THE WINDS TREND SOUTHERLY AS THE NEXT LOW PRESSURE
CLIPPER-LIKE SYSTEM CLOSES IN. ASSOCIATED LEESIDE WAA PROCESSES MAY
PRODUCE A FEW LATE NIGHT SHOWERS OR EVEN A THUNDERSTORM INTO AT
LEAST THE NORTHWESTERN PORTION OF THE DVN CWA BEFORE 12Z TUE.
TUESDAY-WEDNESDAY...THE CLIPPER SYSTEM IS FORECAST TO DIVE INTO THE
NORTHERN PLAINS TUESDAY MORNING. SHORTWAVE TROUGHING AND RIDGING
WILL ENHANCE DIVERGENCE ALOFT OVER EASTERN IOWA, WISCONSIN, AND
NORTHERN ILLINOIS AS A VORTICITY MAXIMUM PUSHES INTO MINNESOTA. THE
LOW-TO-MID-LEVEL RESPONSE WILL ALSO BE STRONG WITH A 850-700 MB F-
GEN BAND DEVELOPING OVER THE CWA, WAA AT 850 MB AHEAD OF THE FRONT,
AND A DEEPENING LOW PRESSURE OVER NORTHERN IOWA. THE ONLY LIMITING
FACTOR IS THE LACK OF MID-LEVEL MOISTURE WITH MODEL DISAGREEMENT ON
THE EXACT PLACEMENT OF A NARROW BAND OF HIGH 700 MB RH. LREF
CURRENTLY HAS A 70% SPREAD ON 700 MB RH VALUES TUESDAY MORNING, BUT
THERE IS AGREEMENT ON A BAND OF HEAVIER PRECIPITATION (0.2 TO 0.4
INCHES) MOVING ACROSS NORTHWEST ILLINOIS, BUT THE SOUTHWESTWARD
EXTENT REMAINS QUESTIONABLE.
AS THE LOW PRESSURE CONTINUES TO SLIDE TO THE SOUTHEAST INTO THE
OHIO RIVER VALLEY TUESDAY NIGHT, A WEAK SURFACE TROUGH UNDERNEATH
THE PASSING 500 MB TROUGH AXIS COULD SUPPORT SOME RAIN SHOWERS
THROUGH WEDNESDAY MORNING BEFORE ANOTHER HIGH PRESSURE ANCHORS OVER
THE NORTHERN PLAINS AS LONGWAVE RIDGING BUILDS OVER THE ROCKIES.
THURSDAY...A LITTLE DEJU VU FROM MONDAY NIGHT AS THE SURFACE HIGH
PRESSURE OVER THE UPPER MISSISSIPPI RIVER VALLEY SHIFTS TO THE EAST,
SETTING UP SOUTHEASTERLY FLOW OVER IOWA AHEAD OF THE NEXT
APPROACHING COLD FRONT. THERE IS THE POTENTIAL FOR SOME PRE-FRONTAL
SHOWERS, BUT THERE IS MODEL UNCERTAINTY ON THE POSITION OF THE
DEVELOPING WARM FRONT WITH A 10-DEGREE SPREAD IN HIGH TEMPERATURES
ACCORDING TO THE LREF.
AVIATION /18Z TAFS THROUGH 18Z SATURDAY/
ISSUED AT 1240 PM CDT FRI MAY 8 2026
GENERALLY ANOTHER VFR TAF FCST THROUGH MIDDAY SATURDAY. BOUTS OF
MID AND HIGH CLOUDS STREAMING ACRS THE AREA WITH DRY LLVL'S, AND
WILL BANK ON THE ONGOING SHOWERS STAYING SOUTH OF THE BRL SITE
THIS AFTERNOON. ANOTHER UPPER WAVE DROPPING DOWN ACRS MN AND WI
MAY ALLOW FOR A FEW LIGHT SHOWERS AND SPRINKLES TO SKIRT ACRS
THE NORTHEAST HALF OF THE LOCAL FCST AREA TONIGHT, BUT AGAIN
ONGOING DRY LOW TO MID LEVEL AIRMASS MAY KEEP MOST OF THAT
PRECIP IN VIRGA FORM AND WILL NOT MENTION ANY PRECIP IN THE
TAFS. LIGHT SOUTHERLY SFC WINDS WILL VEER TO THE WEST AND
INCREASE TO 8-12 KTS THROUGH THIS EVENING WITH A SFC TROF
PASSAGE, BUT THEN BACK AGAIN TO THE SOUTH OVERNIGHT. ANOTHER
STRONGER FRONT WILL VEER THE WINDS AGAIN TO THE WEST-NORTHWEST
BY MIDDAY SATURDAY AND THEY MAY GUST OVER 20 KTS INTO SAT
AFTERNOON.
DVN WATCHES/WARNINGS/ADVISORIES
IA...NONE.
IL...NONE.
MO...NONE.
SHORT TERM...12
LONG TERM...DELAUNE/12
AVIATION...12
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