Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 070006
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
706 PM CDT WED MAY 6 2015

.SYNOPSIS...
ISSUED AT 328 PM CDT WED MAY 6 2015

CLEARING SKIES FROM THIS MORNING HAS GIVEN WAY TO CUMULUS CLOUDS
AND WARM TEMPERATURES. THE WARM FRONT THAT HAD BEEN OVER THE AREA
FOR A FEW DAYS APPEARS TO HAVE MOVED NORTH TODAY. A SHORTWAVE TROF
WAS MOVING OUT OF THE CENTRAL UNITED STATES TODAY. THIS LEAD TO
THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS ACROSS CENTRAL IOWA.
THESE STORMS WERE PUSHING INTO EASTERN IOWA AND NE MISSOURI AT THE
TIME OF THIS SYNOPSIS.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 328 PM CDT WED MAY 6 2015

MAIN FORECAST CONCERN FOR THE SHORT TERM ARE THE THUNDERSTORM
CHANCES THROUGH THE PERIOD AND THE STRENGTH OF THOSE
THUNDERSTORMS. A DEEP TROF REMAINS IN PLACE ACROSS THE WESTERN
UNITED STATES. A SHORTWAVE FROM THIS TROF WILL EJECT INTO THE
CENTRAL UNITED STATES TODAY AND TONIGHT. THIS TROF WILL PRODUCE
RAIN AND THUNDERSTORMS MOSTLY ACROSS NEBRASKA AND WESTERN IA.

THURSDAY...
A CONSISTENT H85 WIND MAXIMA WILL BE ACROSS IA. DURING THE DAY
THIS IS FORECAST TO MOVE NORTH INTO MN. OVERALL SYNOPTIC FORCING
WILL BE FOCUSED ACROSS THE WESTERN PART OF THE STATE UNTIL LATER
IN THE DAY. THE SYNOPTIC FORCING IS WEAK OVERALL. HOWEVER...WITH
THE H85 FLOW AND SYNOPTIC FORCING...BELIEVE THAT THERE IS A BETTER
CHANCE FOR THUNDER TOMORROW THAN THE REST OF TODAY...ESPECIALLY
ACROSS WESTERN ZONES. CAPE SHOULD BE AOA 2000 J/KG ACROSS THE
AREA. DEEP LAYER SHEAR IS AOA 30 KTS...WHICH COULD LEAD TO SEMI
ORGANIZED THUNDERSTORMS. THIS COULD LEAD TO SOME STRONG
THUNDERSTORMS WITH SMALL HAIL AND SOME GUSTY WINDS. SPC HAS US IN
A MARGINAL RISK FOR SEVERE WEATHER TOMORROW. IF WE SEE SOME
CLEARING...THEN THE STORMS COULD REACH SEVERE LEVELS WITH LARGE
HAIL AND DAMAGING WINDS BEING THE MAIN THREATS.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 328 PM CDT WED MAY 6 2015

OVERALL CONFIDENCE HIGH ON ACTIVE PATTERN THROUGH THE WEEKEND WITH
SEVERAL ROUNDS OF SHOWERS AND STORMS... THEN TURNING COOLER AND
DRIER EARLY TO MID NEXT WEEK.

APPROACHING SURFACE COLD FRONT COUPLED WITH ENERGY RIPPLING UP IN
SOUTHWEST FLOW ALOFT WILL RESULT IN LIKELIHOOD OF SHOWERS AND
STORMS THURSDAY NIGHT THROUGH FRIDAY NIGHT. FRONT WILL THEN
SLIDE THROUGH CWA SATURDAY AND FOCUS RAIN CHANCES IN AND NEAR THE
SOUTHERN PORTIONS OF THE CWA BY AFTERNOON. BREAK IN RAIN WILL
BE SHORT-LIVED AS EXPECT RENEWED ROUNDS OF SHOWERS AND STORMS
SATURDAY NIGHT THROUGH SUNDAY NIGHT AS DYNAMIC NEGATIVE TILT
SHORTWAVE TROUGH LIFTS FROM THE ROCKIES TO THE UPPER MIDWEST.
SEVERE WEATHER POTENTIAL IS BEST ON SUNDAY AFTERNOON INTO
SUNDAY EVENING WHERE COULD SEE LINE OF STRONG TO SEVERE STORMS
WITH HAIL AND WIND SWEEP ACROSS THE CWA. RAIN TOTALS WIDESPREAD
OF 0.5 TO 2 INCHES ANTICIPATED BY MONDAY MORNING... WITH
LOCALLY HIGHER AMOUNTS 3-4+ INCHES WHERE TRAINING OR REPEATED
ACTIVITY OCCURS. THIS COULD POSE RISK OF FLOODING WHERE THESE
HEAVIER AMOUNTS OCCUR. TEMPS EXPECTED TO BE GENERALLY ABOVE NORMAL
THROUGH THE WEEKEND. MAIN CHALLENGE IS THAT HIGHS MAY NEED TO BE
TRIMMED MORE NORTH ON SATURDAY BEING LIKELY IN NORTHEAST POST-FRONTAL
LOW LEVEL FLOW WITH CLOUDS.

EARLY TO MID NEXT WEEK... COLD FRONT ATTENDANT TO PASSING SHORTWAVE
LOOKS TO BRING COOLER AND DRIER CONDITIONS MONDAY INTO WEDNESDAY.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 654 PM CDT WED MAY 6 2015

MAINLY A VFR DECK WITH EMBEDDED SHOWERS STARTING TO PUSH OF THE
GENERAL TAF AREAS...JUST SOME ISOLATED SHOWERS IN THE WAKE OF THE
MAIN BAND THROUGH 02Z OR SO THIS EVENING. WIND TEMPORARY VEERING
TO THE WEST OR SOUTHWEST AND GUSTING UP TO 30KTS HEADING ALONG AND
EAST OF THE MS RVR CURRENTLY...WITH SFC FLOW TO THE WEST BACKING
TO THE SOUTHEAST AT 5-15KTS. WILL BANK ON ENOUGH OF A SOUTH TO
SOUTHEAST SFC BREEZE OF 5-10KTS OVERNIGHT TO LIMIT ANY AMBIENT FOG
PRODUCTION. WINDS ALOFT AT 2K FT AGL LATE TONIGHT SOUTH-SOUTHWEST
AT 35 KTS...MARGINAL LLVL WIND SHEAR IF SFC WINDS GO SOUTHEAST AND DROP
BELOW 5-7KTS. SOUTH WINDS 12-20KTS ON THU AND VFR UNTIL A BAND OF
POSSIBLE SHOWERS AND THUNDERSTORMS MOVE IN FROM THE WEST AS THE
AFTERNOON PROGRESSES.   ..12..

&&

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

$$

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



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