Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 222043
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
343 PM CDT FRI MAY 22 2015

.SYNOPSIS...
ISSUED AT 330 PM CDT FRI MAY 22 2015

A WEAK SURFACE TROUGH/COLD FRONT WAS STRETCHED ACROSS THE AREA THIS
AFTERNOON ROUGHLY FROM WATERLOO/ALO TO PEORIA/PIA.  SUNNY SKIES WERE
PREVALENT NORTHEAST OF THE BOUNDARY...WITH A HIGH LEVEL CIRRUS DECK
COVERING AREAS TO THE SOUTHWEST.  TEMPERATURES ACROSS THE CWFA AT 2
PM WERE IN THE 70 TO 76 DEGREE RANGE WITH DEW POINT TEMPS IN THE
LOW 30S TO MID 40S.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 330 PM CDT FRI MAY 22 2015

QUIET WEATHER WILL CONTINUE TONIGHT AND DURING THE DAY SATURDAY...
AS HIGH PRESSURE MOVES OFF TO THE EAST AND A LOW PRESSURE SYSTEM
DEVELOPS IN THE CENTRAL PLAINS. ONLY MINOR CHANGES MADE IN THE SHORT
TERM... WITH THE GOING FORECAST STILL ON TRACK.  HIGH LEVEL
CLOUDINESS WILL THICKEN AND LOWER OVERNIGHT AND SATURDAY...WITH RAIN
CHANCES INCREASING JUST BEYOND THIS PERIOD.  WITH MID AND HIGH
CLOUDS OVERHEAD...OVERNIGHT LOWS WILL BE ABOUT 10 DEGREES WARMER
THAN THOSE THIS MORNING...WITH VALUES IN THE UPPER 40S AND 50S.
HIGHS SATURDAY WILL BE IN THE LOW 70S WEST...TO UPPER 70S EAST.


.LONG TERM...(SATURDAY NIGHT THROUGH NEXT FRIDAY)
ISSUED AT 330 PM CDT FRI MAY 22 2015

SATURDAY NIGHT THROUGH MONDAY...WHILE A SLIGHTLY TILTED LOW COMPLEX
WITH CYCLONIC FLOW SPILLS NORTH ACRS THE PLAINS...12Z RUN MODEL
GUIDANCE IN GOOD AGREEMENT OF SUGGESTING UPPER RIDGE HOLDING ON
ALONG AND EAST OF THE CWA SAT NIGHT. THUS MAY JUST SEE AN INITIAL
ELEVATED WAA WING OF SHOWERS AND A FEW STORMS LATE SAT NIGHT MAINLY
WEST OF THE MS RVR. WOULDN/T BE SURPRISED IF MUCH OF THE AREA STAYS
DRY AT LEAST UNTIL 12Z SUNDAY WHILE BRUNT OF MOISTURE CONVERGENCE
AND FORCING FOCUS ORGANIZED CONVECTION OVER THE PLAINS INTO WESTERN
IA. WARM FRONTAL RETREAT ALONG WITH UPPER RIDGE SLIDING OFF ENOUGH
MAY ALLOW FOR MORE SCTRD SHOWERS/STORMS ON SUNDAY. WITH ENOUGH DRY
HOURS...SUNDAY HIGH TEMPS IN THE LOW TO MID 70S WITH A FEW AREAS
PUSHING THE UPPER 70S.

BULK OF MODELS PROBABLY OVERDOING LLVL MOISTURE/SFC DPTS FOR TOO
HIGH OF CAPES AND PWATS LOCALLY WHILE THE MORE OPTIMUM DEEP SHEAR
PROFILES AND DIFFLUENT MID LEVEL JET MAX SUPPORT STRONG/SVR STORMS
MORE TOWARD THE SOUTHEASTERN PLAINS. THUS SVR CHANCES STILL APPEAR
SLIM FOR SUNDAY INTO SUNDAY NIGHT...BUT SOME SIGN OF AN EJECTING
WAVE AND ADEQUATE THTA-E ADVECTION/ CONVERGENT PLUME FOR A HEAVY
RAIN PRODUCING NOCTURNAL STORM CLUSTER OR MCS TYPE FEATURE SUNDAY
NIGHT ACRS PORTIONS OF THE CWA. UP TO AN INCH OF RAINFALL POSSIBLE
BY MON MORNING IN AREAS OF REPEAT CONVECTIVE OCCURRENCE. WHAT
HAPPENS AND LINGERS OUT OF SUNDAY NIGHT SUCH AS CONVECTIVE DEBRIS
TO IMPACT MEMORIAL MONDAY...BUT SEVERAL OF THE LATEST 12Z MEDIUM
RANGE RUNS INCLUDING THE GFS/ECMWF AND CANADIAN GEM...ALL SUGGEST
AFTER THE MORNING DEBRIS OR LINGERING PRECIP CLEARS/DECAYS...MUCH
OF THE REST OF MON MAY BE MAINLY BREEZY...WARM AND DRY UNTIL
EVENING.

LATEST INDICATIONS SUGGEST SEVERAL MCS INDUCING PARAMETERS COME
TOGETHER TO PRODUCE SUCH A CONVECTIVE SYSTEM ACRS WESTERN INTO
CENTRAL IA MON EVENING...WHICH MAY THEN PROPAGATE EASTWARD INTO
THE CWA LATER MON NIGHT INTO TUE MORNING WITH ANOTHER ROUND OF
HEAVY RAIN POSSIBLE. IF ANY STORM MANAGES TO OCCUR MON AFTERNOON...
IT MAY BE MORE OF AN ISOLATED TO WDLY SCTRD PULSE TYPE LOOKING AT
LONG RANGE THERMODYNAMICS AND SHEAR PROFILES. WITH ENOUGH DRY
HOURS...THERE MAY BE SOME TEMPS NEAR 80 MON AFTERNOON.

TUESDAY AND WEDNESDAY...DEPENDING ON PHASING WITH CENTRAL INTO
SOUTHERN PLAINS TROF EVOLUTION EASTWARD INTERACTING WITH WARM MOIST
RETURN FLOW CONVEYOR...SEVERAL OF THE MEDIUM RANGE SOLUTIONS BREAK
OUT HEAVIER CONVECTIVE SYSTEMS WITH LARGE COVERAGE MAINLY SOUTH AND
EAST OF THE DVN CWA TUE INTO EARLY WED. BUT THAT FAR OUT AND MODEL
PHASING/HANDLING UNCERTAINTIES...WILL HAVE TO KEEP AT LEAST MODERATE
CHC POPS GOING THRU MID WEEK. BUT LATER WED INTO PART OF THU MAY BE
A DRY WINDOW TO TARGET WITH LATER FCSTS IN THE WAKE OF THIS PHASING
IF IT INDEED SEEMS TO BE POSSIBLE.

NEXT THURSDAY AND FRIDAY...LONGER RANGE INDICATIONS SUGGEST THE
ACTIVE PATTERN TO TEMPORARILY RELOAD WITH SOUTHEAST ATLANTIC RIDGE
COMPLEX SETTING UP GULF MOISTURE PUMP TO THE LEE OF ANOTHER WESTERN
PLAINS TROF COMPLEX. THUS POPS WARRANTED FOR LATE THU INTO NEXT FRI.
WHENEVER THAT L/W TROF CAN PUSH THROUGH THE REGION WILL MAKE WAY FOR
A COOLER AND DRIER REGIME ACRS THE UPPER MIDWEST INTO GRT LKS
WHETHER IT BE FOR PART/SECOND HALF OF NEXT WEEKEND LIKE THE CURRENT
MREF SUGGESTS...OR FOR THE FIRST FEW DAYS OF JUNE.     ..12..

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1241 PM CDT FRI MAY 22 2015

VFR CONDITIONS WILL CONTINUE THROUGH THIS TAF PREIOD. HIGH LEVEL
CLOUDS WILL GRADUALLY OVERSPREAD THE AREA FROM THE SOUTHWEST AND
LOWER...AS MOISTURE LEVELS INCREASE ON THE WEST SIDE OF A
DEPARTING HIGH PRESSURE. LIGHT AND VARIABLE WINDS WILL BECOME MORE
SOUTHERLY LATE IN THE PERIOD AT ABOUT 5-10KTS.

&&

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

$$

SYNOPSIS...14
SHORT TERM...14
LONG TERM...12
AVIATION...14



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