Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 251755
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1255 PM CDT MON MAY 25 2015

.SYNOPSIS...
ISSUED AT 333 AM CDT MON MAY 25 2015

RAIN MODERATE IN INTENSITY AT TIMES CONTINUES LIFTING NWD ACROSS
CWA WITH BEST COVERAGE OVER EASTERN IA ALONG/N OF I-80 EARLY THIS
AM. ADDITIONAL RAIN/SHOWERS MOVING ACROSS SOUTHWEST IA INTO
NORTHWEST MO ATTENDANT TO AN UPPER LEVEL DISTURBANCE WILL BE
LIFTING BACK ACROSS PORTIONS OF THE AREA ESPECIALLY WEST OF THE
MISSISSIPPI RIVER THROUGH MID-MORNING. ALL OF THIS ACTIVITY IS
OCCURRING IN ACTIVE SOUTHWEST FLOW ALOFT AHEAD OF AN UPPER LOW
OVER THE ROCKIES.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 333 AM CDT MON MAY 25 2015

WILL CONTINUE TO SEE OCCASIONAL RAIN/SHOWERS THROUGH MID MORNING
BEFORE TAPERING OFF FROM SOUTHWEST TO NORTHEAST THROUGH MIDDAY
WITH KS/NW MO DISTURBANCE LIFTING NWD INTO WI BY EARLY AFTERNOON.
THEN...ANTICIPATE DRYING THIS AFTERNOON WITH VEERING GUSTY
SOUTHWEST WINDS AND BRIEF BOUT OF MID/UPPER LEVEL RIDGING IN WAKE
OF DISTURBANCE. SOME INCREASE IN PRESSURE GRADIENT AND MIXING OF
WINDS ALOFT SUPPORT BREEZY TO WINDY CONDITIONS WITH SOUTHWEST
WINDS 15-30+ MPH. BANKING ON THE DRYING TO AT LEAST BRING ABOUT
PARTIAL SUNSHINE AND WITH GUSTY SOUTHWEST WINDS BOOST HIGHS IN THE
UPPER 70S TO LOWER 80S.

LATE THIS AFTERNOON INTO EARLY EVENING... ANTICIPATE STORM
DEVELOPMENT TO INCREASE FROM KS THROUGH CENTRAL IA INTO SOUTHWEST
WI AHEAD OF FRONT AND APPROACHING UPPER LEVEL DISTURBANCE FROM CO.
THIS ACTIVITY IS LIKELY TO DEVELOP OR SPREAD EASTWARD INTO CWA BY
MID TO LATE EVENING AND CONTINUE OVERNIGHT. SUFFICIENT SHEAR WITH
0-6KM 30-35 KTS AND INSTABILITY WITH MLCAPE OF 1000-2000 J/KG
SUPPORTS POTENTIAL FOR A FEW STRONG TO ISOLD MARGINAL SEVERE
STORMS POSSIBLE THIS EVENING WEST OF THE MISSISSIPPI RIVER. SOME
MIXED SIGNALS IN MODELS REGARDING POTENTIAL FOR THIS ACTIVITY TO
GROW UPSCALE INTO MCS...OR ONE OR MORE STORM CLUSTERS CARRYING
ATTENDANT HEAVY RAIN POTENTIAL. AS SUCH... HAVE GENERALLY CAPPED
POPS AT HIGH CHC UNTIL LATE TONIGHT ACROSS THE WESTERN CWA WHEN
FORCING INCREASES AHEAD OF APPROACHING SHORTWAVE. OTHERWISE...
MUGGY LOWS TONIGHT IN THE LOWER TO MID 60S.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 333 AM CDT MON MAY 25 2015

MAIN FORECAST CONCERN IN THE LONG TERM FORECAST ARE
THE CHANCES FOR RAIN AND THUNDERSTORMS ARE THE BEGINNING AND THE END
OF THE PERIOD.  BETWEEN THESE TWO EVENTS WE SHOULD HAVE A FEW DAYS
TO DRY OUT.

SOUTH TO SOUTHWEST H5 FLOW WILL CONTINUE INTO TUESDAY AND EVEN
WEDNESDAY.  THIS WILL ENSURE AMPLE MOISTURE STAYS IN THE AREA.
CURRENT GUIDANCE SUGGESTS THAT PWAT VALUES NEAR 1 INCH ARE VERY
POSSIBLE. WHILE THIS WILL BE LESS THAN WHAT OCCURRED ON SUNDAY...THE
POTENTIAL FOR HEAVY RAIN IS STILL POSSIBLE.  GUIDANCE SUGGESTS
CONVECTION WILL POSSIBLY DEVELOP ACROSS THE AREA ON TUESDAY
AFTERNOON AND THEN PUSH TO THE EAST THROUGH THE AFTERNOON HOURS.
SOME REMNANT  SHOWERS AND THUNDERSTORMS ARE POSSIBLE INTO THE LATE
EVENING HOURS BASED ON GUIDANCE.

CURRENT THINKING FOR TUESDAY INTO WEDNESDAY IS THAT CONVECTION WILL
BE ONGOING AT THE BEGINNING OF THE PERIOD. THIS CONVECTIVE DEBRIS
COULD LIMIT OVERALL THUNDERSTORM CHANCES LATE ON TUESDAY.   MODELS
DO SUGGEST THAT WE COULD SEE SOME RECHARGING OF THE ATMOSPHERE BY
LATE AFTERNOON. GFS MODEL SOUNDINGS HAVE AROUND 1500 J/KG OF SBCAPE
BY LATE AFTERNOON TUESDAY.  THE 4KM WRF MODELS SUGGEST THUNDERSTORM
REDEVELOPMENT TO OUR WEST BEFORE 00Z. I THINK THESE MODELS DO NOT
HAVE A GOOD HANDLE ON CONVECTION FOR MONDAY NIGHT INTO TUESDAY.  IF
NOTHING OCCURS TONIGHT...THEN THE 4KM WRF MODELS PROBABLY HAVE AN
ACCURATE REPRESENTATION OF WHATS GOING TO HAPPEN TUESDAY PM. DO NOT
THINK STRONG THUNDERSTORMS CAN BE RULED OUT IN THE AFTERNOON.

AFTER TUESDAY NIGHT...WEAK RIDGING BUILDS IN UNTIL THE NEXT TROF TO
OUR WEST DIGS IN.  GUIDANCE SUGGESTS NUMEROUS RIPPLES IN THE FLOW
WEDNESDAY INTO FRIDAY.  AS SUCH POPS HAVE INCREASED FOR WEDNESDAY
NIGHT INTO THURSDAY.

THE BEGINNING OF THE WEEKEND LOOKS LIKE THE BEST CHANCES FOR POPS
WITH THUNDERSTORMS BEING POSSIBLE AS WELL.  AT THIS TIME IT WILL BE
HARD TO NAIL DOWN TIMING OF SHOWERS AND THUNDERSTORMS AS MESOSCALE
PROCESSES WILL DICTATE WHAT HAPPENS. THE TROF LOOKS TO BE SLOW
MOVING OUT OF THE WESTERN UNITED STATES...THIS MEANS WE COULD SEE A
COUPLE OF DAYS OF RAIN AND THUNDERSTORMS MUCH LIKE THIS LAST EVENT.
ON THE BRIGHT SIDE...IT APPEARS THAT THE NEXT SYSTEM LOOKS TO BE
SLIGHTLY MORE PROGRESSIVE THAN THE CURRENT ONE.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1239 PM CDT MON MAY 25 2015

MVFR LEVEL BKN CU WILL CONTINUE TO SCATTER OUT AND LIFT TO VFR
OVER THE NEXT FEW HOURS ACRS THE TAF SITES...WITH SOUTHWEST SFC
WINDS GUSTING TO 25 KTS. WINDS TO DECREASE AND BACK TO THE SOUTH
THIS EVENING TO 7-12KTS. AS FOR SCTRD SHOWERS AND THUNDERSTORMS...
WILL HAVE TO WATCH FOR DEVELOPMENT DURING THE LATE AFTERNOON AND
EARLY EVENING ACRS CENTRAL INTO NORTHEASTERN IA...WHICH MAY
EVENTUALLY MOVE EAST AND GET INTO THE VCNTY OF CID AND POSSIBLY
DBQ FROM 8 PM THROUGH MIDNIGHT/1 AM CDT. OTHERWISE VFR CONDITIONS
UNTIL TUE MORNING. THEN A CLUSTER OF SHOWERS AND THUNDERSTORMS MAY
THEN MOVE OUT OF MISSOURI NORTHWARD TOWARD THE BRL AND MLI VCNTY
BY EARLY TO MID TUE MORNING.    ..12..

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&

$$

SYNOPSIS...05
SHORT TERM...05
LONG TERM...GIBBS
AVIATION...12


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