539
FXUS63 KDVN 180433
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1133 PM CDT SAT MAY 17 2025
..UPDATED FOR 06Z AVIATION
KEY MESSAGES
- NEAR TO MOSTLY BELOW NORMAL TEMPERATURES THROUGH NEXT WEEK.
- ACTIVE PATTERN RAMPS UP MONDAY INTO WEDNESDAY WITH HIGH RAIN
CHANCES AND WIDESPREAD BENEFICIAL SOAKING RAIN WITH THE
POTENTIAL FOR LOCALLY HEAVY RAINFALL. SEVERE WEATHER POTENTIAL
REMAINS UNCERTAIN.
SHORT TERM /THROUGH SUNDAY/
ISSUED AT 145 PM CDT SAT MAY 17 2025
WINDY WEATHER AS OF LATE WILL GIVE WAY TO A VERY PLEASANT
EVENING TOWARDS 7 PM, AS THE GRADIENT SURROUNDING THE
UPPER/SURFACE LOW TO THE NORTHEAST RELAXES. THE PROCESS OF
THINNING/LIFTING THE STRATUS HAS BEEN UNDERWAY SINCE MID
MORNING, WITH MOST AREAS NOW SEEING MOSTLY SUNNY SKIES AS OF 1
PM. THIS CLEARING, AND LIGHTER WIND REGIME WILL ALLOW FOR THE
FIRST OF TWO COLDER NIGHTS FOR OUR AREA WITH DRY AIR IN PLACE.
TONIGHT, LOWS IN THE UPPER 30S NORTHWEST TO MID 40S SOUTH/EAST
ARE FORECAST, WHICH MORE OR LESS MATCHES THE CURRENT DEW POINT
IN THE CWA.
SUNDAY IS THE DAY TO BE OUTSIDE THIS WEEK!!
LIGHT WINDS, DRY AIR, 70S, AND SUNSHINE ARE FORECAST AREA-WIDE,
AS HIGH PRESSURE IS POSITIONED OVER THE CWA. THIS IS CERTAINLY A
RELIEF FROM RECENT WINDS, HEAT, AND SPOTTY STRONG CONVECTION.
LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/
ISSUED AT 145 PM CDT SAT MAY 17 2025
SUNDAY NIGHT, WARM ADVECTION ALOFT WILL BEGIN IN EARNEST, WITH
ANY RAINFALL HOLDING OFF UNTIL AROUND MIDNIGHT SOUTHWEST, TO THE
EARLY MORNING HOURS FARTHER NORTH. PRIOR TO THE ARRIVAL OF
OPAQUE CLOUDS, NORTHERN AREAS WILL SEE A COLD NIGHT WITH LOWS IN
THE LOWER TO MID 40S, AND AS WINDS INCREASE FROM THE
EAST/NORTHEAST. THE WARM FRONTAL POSITION DEVELOPING SUNDAY
NIGHT AND MONDAY WILL BECOME THE MOST IMPORTANT FEATURE OF THE
WEEK AHEAD, AS THIS WILL BECOME THE FOCUS FOR BOTH WIDESPREAD
RAINFALL TO IT'S NORTH, AND SEVERE WEATHER MAINLY ALONG AND TO
ITS SOUTH.
LOOKING AT TEMPERATURES MONDAY AND TUESDAY, THIS FRONT SEEMS
LIKELY TO HOLD UP JUST SOUTH OF OUR CWA IN NORTHERN MISSOURI,
WITH A GUARANTEE OF CLOUDS AND EAST WINDS NORTH OF IT.
TEMPERATURES MAY BE QUITE COOL, ESPECIALLY NORTH OF I-80 WHERE
LAKE ENHANCED LOW LEVEL FLOW IS EXPECTED WITH A TRAJECTORY OF
LAKE MICHIGAN AIR FROM THE NORTHEAST/EAST. COMBINED WITH BOUTS
OF RAINFALL, THE WEATHER APPEARS QUITE UNPLEASANT MONDAY THROUGH
WEDNESDAY, WITH HIGHS POTENTIALLY AS COOL AS THE 50S. THERE IS A WIDE
DISTRIBUTION OF HIGH TEMPERATURE IN THE NBM IN THIS PERIOD, AND
THE TIGHT GRADIENT ALONG AND NORTH OF THE FRONT SEEMS THE
CULPRIT. WE MAY BE ABLE TO REFINE TEMPERATURES MONDAY -
WEDNESDAY WITH MORE DETAIL IN THE COMING DAYS, BUT FOR NOW, THE
NBM REMAINS A BEST FIT WITH MID 50S NORTH TO LOWER 70S FAR
SOUTH.
RAINFALL REMAINS FORECAST WITH HIGH POPS FROM EARLY MONDAY
THROUGH WEDNESDAY AS BOTH HIGH PWAT MOISTURE FEED IS IN PLAY,
AND PERSISTENT SYNOPTIC FORCING IN A FAVORED LOCATION FOR RAIN
(NORTH OF SURFACE WARM FRONT). THIS STATICAL VIEW REMAINS
CONSISTENT FROM LAST NIGHT'S AFD: A PERSISTENT SOUTHERLY LOW
LEVEL FLOW WILL LEAD TO AN ENTRAINMENT OF GULF MOISTURE (PWATS
RAMPING TO NEAR 1.5 INCHES, WHICH WOULD BE ABOVE 90TH PERCENTILE
FOR ALL DVN RAOBS FOR MON MAY 19TH AND TUE MAY 20TH PER SPC
SOUNDING CLIMATOLOGY) AND FAIRLY PERSISTENT BOUTS OF LOW TO MID
LEVEL MOISTURE CONVERGENCE RESULTING IN PERIODIC ROUNDS OF
SHOWERS AND STORMS. STRENGTH OF FORCING SUGGESTS AT LEAST
RAINFALL ACCUMULATING TO NEAR THE PWAT, OR ROUGHLY 1 TO 2 INCHES
WIDESPREAD BETWEEN 06Z MONDAY AND 12Z WEDNESDAY, BUT WITH
CONVECTION AND PERSISTENT MOIST CONVEYOR AND SLOW MOVING SYSTEM
FOR REPETITIVE ROUNDS IT'S POSSIBLE TO SEE LOCALLY HIGHER
AMOUNTS OF 3-4+ INCHES. LATEST NBM SHOWS PROBABILITIES OF 40-60%
FOR >2 INCHES OF RAIN OVER 72 HOUR PERIOD ENDING 12Z WEDNESDAY
FOR AREAS ROUGHLY ALONG AND SOUTH OF CEDAR RAPIDS TO QUAD CITIES
LINE WITH THE HIGHEST PROBABILITIES FOCUSED ACROSS FAR SE IOWA,
NE MISSOURI AND WC ILLINOIS. MUCH OF THE AREA IS IN ABNORMAL
DRYNESS TO MODERATE DROUGHT PER THE LATEST U.S. DROUGHT MONITOR
AND COULD REALLY USE 2-3+" OF RAIN. ONE THING TO WATCH FOR IS
THE LIKELIHOOD OF MCS ACTIVITY TO OUR SOUTH MAINLY THE NEXT FEW
NIGHTS ALONG THE RETREATING WARM FRONT, AND WHETHER OR NOT THIS
CONVECTION WILL HAMPER THE POLEWARD PROGRESS OF THE RETREATING
WARM FRONT AND SUBSEQUENTLY ALTER WHERE THE HEAVIER RAINS OCCUR.
SEVERE WEATHER APPEARS QUITE CONDITIONAL, TO THE LOCATION OF
THIS FRONT. THERE ARE SOME INDICATIONS THAT A WAVE OF LOW
PRESSURE COULD FORCE THE FRONT NORTHWARD MONDAY NIGHT/TUESDAY,
WHICH COULD ALLOW FOR A SHALLOWER STABLE AIR MASS AT THAT TIME.
DIRECTIONAL SHEAR IS A GIVEN NORTH OF THE FRONT, BUT
INSTABILITY REMAINS UNLIKELY. HOWEVER, A SHALLOWER STABLE LAYER
COULD ALLOW FOR SOME WINDS TO REACH THE SURFACE, AS WELL AS
ALLOW STRONGER STORMS TO MOVE INTO THE SOUTHERN 1/2 OF THE CWA.
FOR THE MAJORITY OF HOURS, RAIN WITH EMBEDDED THUNDER IS MUCH
MORE LIKELY IN OUR CWA, AS THE SURFACE SEVERE WEATHER REMAINS IN
CENTRAL AND SOUTHERN MO TO IL. WE WILL CONTINUE TO MESSAGE
SPC'S POTENTIAL IN THESE PERIODS OF COURSE. NO MATTER HOW IT ALL
ENDS UP, THIS IS A CHALLENGING WEEK OF FORECASTS, BUT A
BENEFICIAL PERIOD OF RAINFALL FOR OUR AREA.
THURSDAY INTO NEXT WEEKEND, PLEASANT TEMPERATURES ARE FORECAST
AS THE UPPER LOW SHIFTS TOWARDS THE EASTERN CONUS. THOUGH A FEW
SHOWERS COULD OCCUR IN NORTHWEST FLOW, THE DRY AIR IN PLACE
WOULD KEEP THE THREAT FOR RAINFALL LOW. HIGHS IN THE 60S TO 70S
ARE FORECAST.
AVIATION /06Z TAFS THROUGH 06Z MONDAY/
ISSUED AT 1130 PM CDT SAT MAY 17 2025
PREDOMINANTLY VFR EXPECTED THROUGH THE PERIOD, ALTHOUGH AT THE START
OF THE PERIOD THROUGH MID-MORNING SUNDAY WE'LL SEE SOME LOWER CLOUDS
AND MVFR CEILINGS DIP SOUTHWARD INTO THE CID AND DBQ TERMINALS. THESE
SHOULD LIFT/ERODE AND RETURN TO VFR AT CID AND DBQ BY 15Z-18Z. CONFIDENCE
ON THESE MVFR CEILINGS REACHING MLI IS TOO LOW AT THIS TIME FOR ANY
MENTION, AND THEY ARE NOT EXPECTED AT BRL. WINDS WILL BE MUCH LIGHTER
AROUND 10 KTS FROM A NORTHERLY DIRECTION. LATE IN THE TAF PERIOD AND
JUST BEYOND THERE'S INDICATIONS OF A BACKDOOR LAKE ENHANCED FRONT PUSHING
THROUGH THE TERMINALS FOLLOWED BY GUSTY EASTERLY WINDS OF 15-25 KT.
DVN WATCHES/WARNINGS/ADVISORIES
IA...NONE.
IL...NONE.
MO...NONE.
SHORT TERM...ERVIN
LONG TERM...ERVIN/MCCLURE
AVIATION...MCCLURE
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