Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 262014
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
314 PM CDT TUE MAY 26 2015

.SYNOPSIS...
ISSUED AT 242 PM CDT TUE MAY 26 2015

LATEST SFC ANALYSIS WAS INDICATING THE MAIN LOW CENTER STILL
DEEPENING MOVING NORTH OUT OF THE CWA INTO SW WI. OCCLUDED FRONT
ASSOCIATED WITH THIS WAVE ARCHING ACRS NORTHEASTERN INTO EAST
CENTRAL IL. SECONDARY LOW PIVOTING ACRS SOUTHWESTERN IA...WITH
SOME LEE SIDE LLVL MOISTURE CONVERGENCE EVIDENT ALONG AND NORTH
OF THE IA/MO BORDER REGION. ALOFT...LOOKING AT CURRENT WATER VAPOR
LOOP VIGOROUS UPPER LEVEL VORT MAX OVERHEAD LOOKING TO MAKE
HEADWAY NORTHEAST INTO WI...WITH A SECONDARY VORT MAX JUST A BIT
WEAKER NOTED ACRS EASTERN NEB LOOKING TO ALMOST FUJI-WARA IT/S WAY
AROUND THE DEPARTING MAX AND PROPAGATE EASTWARD ACRS IA THIS
EVENING AND INTO THE OVERNIGHT. THE STRONG LLVL AS WELL AS DEEP
LAYER SHEAR THAT WAS OVER THE AREA THIS MORNING THAT PRODUCED
SEVERAL ROTATING LOW-TOPPED CELLS...HAS PUSHED EAST OF THE AREA
ACRS LK MI.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 242 PM CDT TUE MAY 26 2015

THIS EVENING/TONIGHT...SOME AFTERNOON BREAKS HAS ALLOWED FOR SFC
TEMPS TO RECOVER INTO THE LOW TO MID 70S FOR MARGINAL SBCAPES
THAT MAY FUEL SOME EVENING SCTRD/ISOLATED SHOWERS AND STORMS AS
THE WAVE OFF TO THE WEST OVER EASTERN NEB PUSHES THIS WAY.
AGAIN...WITH THE HIGHER SHEAR PLUME OFF TO THE EAST AND JUST
MARGINAL INSTABILITY DEVELOPED THIS AFTERNOON IN THE WAKE OF THIS
MORNING/S SHOWER/STORM COMPLEX...A LOW CHC FOR ANY SVR STORMS TO
FORM. MAY BE MORE OF SCATTERED GARDEN VARIETY SHOWERS AND STORMS
THIS EVENING WITH THE STRONGER CELLS PRODUCING SMALL HAIL AND
WIND GUSTS TO 45 MPH...ALONG WITH LOCALIZED HEAVY DOWNPOURS.
ALTHOUGH THE VORT MAX WILL STILL BE PUSHING OVERHEAD...EXPECT THE
SCATTERED SHOWERS AND STORMS TO DECREASE AS WE GET INTO THE
OVERNIGHT/LATE NIGHT HOURS WITH NOCTURNAL PROCESSES SETTLING IN.
POTENTIAL FOR A LOT OF THE AREA TO BECOME OR STAY MOSTLY CLOUDY
AS WRAP AROUND STRATOCU NOW ACRS NW/NORTHERN IA AND SOUTHERN MN
GET DRAGGED ACRS BY THE APPROACHING NEB VORT MAX. LOWS TONIGHT
GENERALLY IN THE UPPER 50S TO LOWER 60S IF CLOUD COVER
MAINTAINS...AREAS THAT CLEAR LONGER COULD GET COOLER AS WELL AS
HAVE SOME SPOTTY FOG IF SFC WINDS GO LIGHT ENOUGH OVER RECENT
HEAVY RAIN AREAS.

WEDNESDAY...L/W UPPER TROF COMPLEX CONTINUED TO SLIDE OVER AND
EAST OF THE AREA WITH EVENTUAL SUBSIDENCE REGIME MAKING FOR A
DRIER AND GENERALLY NICE DAY WITH AT LEAST PARTLY SUNNY SKIES.
ENOUGH LATE MAY INSOLATION AND MIXING TO MAKE FOR HIGHS IN THE
UPPER 70S TO AROUND 80. WILL KEEP THE FCST MAINLY DRY...BUT COOL
CORE ALOFT UNDER MID TROF AXIS AS WELL AS LINGERING VORT MAX MAY
TRY TO KICK UP ISOLATED TO SCTRD SHOWERS IN EASTERN/NORTHEASTERN
PORTIONS OF THE CWA...OR JUST OFF TO THE EAST/NORTHEAST ACRS WI
INTO NE IL.   ..12..


.LONG TERM...(WEDNESDAY NIGHT THROUGH NEXT TUESDAY)
ISSUED AT 242 PM CDT TUE MAY 26 2015

THE EXTENDED FORECAST WILL BE TRENDING DRIER...WITH THE EXCEPTION OF
A WET PERIOD STILL ON TAP FOR THURSDAY NIGHT THROUGH EARLY SATURDAY.
THE DEPARTING UPPER LOW TONIGHT...SHOULD PROVIDE PLENTY OF DRY AIR
THROUGH A DEEP LAYER FOR WEDNESDAY THROUGH THURSDAY MORNING.
THUS...A REMARKABLY PLEASANT WEDNESDAY AND THURSDAY APPEAR
LIKELY...WITH MOST RAIN HOLDING OFF UNTIL LATER THURSDAY NIGHT IN
EASTERN IOWA.  THURSDAY SHOULD SEE A BIT WARMER TEMPERATURES THAN
WEDNESDAY...BUT WITH MOISTURE RETURN DELAYED UNTIL LATER IN THE
DAY...DEWPOINTS WILL LIKELY REMAIN BELOW 60 FOR MOST OF THE
DAY...AND IT SHOULD FEEL PLEASANT FOR EARLY SUMMER.

THURSDAY NIGHT...MOISTURE TRANSPORT BEGINS SPREADING INTO THE UPPER
MIDWEST IN EARNEST. BOTH THE GFS AND ECMWF SHOW THE LLJ DRAWING UP
LOTS OF MOISTURE INTO IOWA...WITH THE MAIN FOCUS OVER NORTHERN IOWA.
THAT SHOULD BE THE LOCATION FOR INITIATION OF STORMS...AND ANY
STORMS ENTERING OUR CWA WILL BE OCCURRING ON AN ESTABLISHED COLD POOL
THURSDAY NIGHT...THUS IT SHOULD BE AS LATE ARRIVAL.

FRIDAY AND FRIDAY NIGHT WILL LIKELY BE THE MAIN PERIODS OF
SIGNIFICANT RAINFALL THIS WEEK...AS THE SLOW MOVING FRONTAL BOUNDARY
SAGS THROUGH IOWA AND ILLINOIS...WITH ABUNDANT MOISTURE...INDICATED
BY MODEL PWAT VALUES OVER 1.5 INCHES...AND BOUNDARY CONVERGENCE.
DYNAMICS FOR SEVERE STORMS SEEM IN DOUBT...BUT CANNOT BE RULED OUT
ON MESOSCALE INTERACTIONS. IN ANY CASE...THIS LOOKS TO BE A RAIN
EVENT...AND LIKE THIS PAST EVENT...LOCALLY HEAVY.

SATURDAY AND SUNDAY NOW APPEAR DRY...AND I HAVE GREATLY REDUCED THE
POPS FOR THESE PERIODS.  WITH HIGH PRESSURE BUILDING INTO THE UPPER
MIDWEST...IT APPEARS WE WILL BE SLIGHTLY BELOW NORMAL...AND
PLEASANT THROUGH TUESDAY. THIS DRY PATTERN FOR A STRETCH OF AT LEAST
4 DAYS APPEARS WELCOME GIVEN OUR INCREASINGLY SATURATED CONDITIONS.
ERVIN

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1231 PM CDT TUE MAY 26 2015

WOUND UP SFC LOW WAS ROLLING NORTHEASTWARD JUST WEST OF DBQ
ATTM...WITH JUST A FEW SCTRD TO ISOLATED SHOWERS ROLLING ACRS THE
AREA. WILL WALK THOSE OUT THROUGH 2 PM...BUT WITH ANOTHER VORT MAX
OVER SOUTHEASTERN NEB PUSHING EASTWARD...THERE COULD BE ANOTHER
UPTICK IN ISOLATED TO SCTRD SHOWERS AND THUNDERSTORMS PUSHING
THROUGH THE AREA LATER THIS AFTERNOON AND EVENING. BUT WITH SOME
UNCERTAINTY IN EXTENT AND COVERAGE HAVE LEFT OUT MENTION IN TAFS
FOR NOW. OTHERWISE LINGERING MVFR DECKS SHOULD SCATTER OUT TO VFR
BY MID AFTERNOON AT MOST SITES. SOUTH OR VARIABLE WINDS NEAR THE
LOW CENTER WILL VEER SOUTHWEST AND INCREASE TO 12 TO 22 KTS WITH
HIGHER GUSTS INTO THE EARLY EVENING BEFORE DECREASING OVERNIGHT.
SOME CHC OF WRAP AROUND MVFR STRATUS LATER TONIGHT AFTER 10 PM AT
ALL TERMINAL SITES. IF WINDS GO LIGHT ENOUGH LATE TONIGHT...SOME
3-6SM FOG POSSIBLE IN RECENT RAINFALL AREAS. CLEARING CONDITIONS
WITH INCREASING WEST WINDS BY MID WED MORNING.   ..12..

&&

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

$$

SYNOPSIS...12
SHORT TERM...12
LONG TERM...ERVIN
AVIATION...12


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