Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 202031
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
331 PM CDT WED MAY 20 2015

.SYNOPSIS...
ISSUED AT 330 PM CDT WED MAY 20 2015

THE LATEST SFC ANALYSIS WAS INDICATING A MAIN LOW CENTER ACRS FAR
SOUTH CENTRAL MO...WITH AN INVERTED TROF EXTENDING BACK UP INTO
CENTRAL IA. RIDGE LOBES FLANKED THIS FEATURE TO THE NORTH AND WEST.
LEE TROF SIDE LLVL NORTHEAST FLOW WITH LOW DPT INFLUX MAKING FOR
EVAPO-COOLING MACHINE WITH THE PASSING RAIN SHEILD OFF THE VORT MAX
PUSHING ACRS NW INTO CENTRAL IA ATTM. SFC TEMPS HAVE BEEN STRUGGLING
ALL AFTERNOON LONG OR EVEN HAVE LOST GROUND-COOLED INTO THE LOW/MID
40S...BUT THERE STILL MAY BE A LATE AFTERNOON RECOVERY BACK INTO THE
UPPER 40S OR EVEN NEAR 50 WHERE THE RAIN ENDS IN TIME. SOME SLEET OR
EVEN MELTING SNOW FLAKES MIXED IN WITH THE RAIN HERE AND THERE
PRODUCED FROM EVAPO-COOLED DRY LAYER/LAYERS ALOFT. H85 MB LAYER
COOLED TO AT LEAST 0C.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 330 PM CDT WED MAY 20 2015

TONIGHT...WHILE THE ORGANIZED PRECIP SHEILD WILL HAVE MOVED OFF TO
THE EAST OF THE CWA BY 23Z-00Z...LINGERING LIFT FROM VORT MAX
ROLLING IN OVERHEAD MAY SQUEEZE OUT AREAS OF DRIZZLE...SPRINKLES OR
EVEN MORE OF A SPOTTY LIGHT CONVECTIVE SHOWER PHENOMENA THROUGH AT
LEAST MID EVENING DEPENDING ON CIG HEIGHTS OF THE CLOUD DECKS.
EVENTUALLY EXPECT SOME CLOUD CLEARING...ESPECIALLY THE LOWER DECKS
FROM NW-TO-SE LATER TONIGHT AFTER MIDNIGHT INTO EARLY THU MORNING.
ALONG WITH THIS PROCESS...SFC WINDS TO BACK AROUND FROM THE
NORTHEAST TO THE NORTH AND WEST AROUND THE PASSING SFC TROF AND THEN
DECREASE OVERNIGHT. SOME CONCERN IN THIS WIND SWITCH/DECREASE
PROCESS FOR AREAS OF FOG TO FORM IN ANY CONVERGENT RIBBON ESPECIALLY
IN AREAS THAT GOT AT LEAST A FEW TENTHS OF AN INCH OF RAINFALL
TODAY...BUT HOPE LINGERING CLOUD COVER PREVENTS WIDESPREAD DENSE
DEVELOPMENT AND WILL NOT MENTION IT AT THIS TIME. WEST TO NORTHWEST
WINDS OF AT LEAST 5-7 MPH TO START TO ADVECT LOWER DPTS LATE
TONIGHT...THIS DRYING FLOW TO ALSO HOPEFULLY LIMIT MUCH OF ANY DENSE
FOG DEVELOPMENT. THIS DRY LATE FETCH TO BRING ABOUT A COOL AMBIENT
TEMP POTENTIAL AS WELL...BUT AGAIN WILL BANK ON LINGERING MID OR
HIGH CLOUDS TO PREVENT SFC VALUES FROM DIPPING BELOW THE UPPER 30S
TO LOWER 40S.

THURSDAY...DEEP MIXING NORTHWEST FLOW TO MAKE THE MOST OF A COOLED
COLUMN...AND ACTUALLY START TO WARM ADVECT AS THE DAY PROGRESSES AS
WELL. THUS SEE WIDESPREAD UPPER 60S TO AROUND 70 FOR HIGHS UNDER
MOSTLY SUNNY SKIES. DEEP MIXING MAY MAKE FOR RATHER BREEZY
CONDITIONS AS WELL OF 10-20 MPH BY MIDDAY AND INTO THE AFTERNOON. CU
RULE SAY SCTRD CLOUD COVERAGE IN THE SOUTHEASTERN THIRD OF THE DVN
CWA FROM LATE MORNING THROUGH EARLY AFTERNOON BEFORE BEING MIXED OUT
TO MAINLY CLEAR.    ..12..


.LONG TERM...(THURSDAY NIGHT THROUGH NEXT WEDNESDAY)
ISSUED AT 330 PM CDT WED MAY 20 2015

ANOTHER PERIOD OF ACTIVE WEATHER BEGINNING THIS WEEKEND IS THE MAIN
FOCUS OF THE LONG TERM PERIOD.

INITIALLY...EXPECT DRY CONDITIONS AND SEASONAL TEMPERATURES THROUGH
FRIDAY NIGHT AS UPPER RIDGING GRADUALLY BUILDS INTO THE REGION. A
NOTABLE TREND FOR SATURDAY...IN PARTICULAR THE ECMWF/GEM...IS A
DEEPER WESTERN CONUS UPPER TROUGH AND SLOWER TIMING FOR INITIAL RAIN
CHANCES ACROSS THE FORECAST AREA. HAVE TRIMMED BACK SATURDAY
AFTERNOON POPS TO SLIGHT CHANCE IN THE FAR WEST...AND LOWERED POPS
ACROSS THE NORTHEAST HALF ON SATURDAY NIGHT.

FOR SUNDAY INTO MONDAY...THE ECMWF CONTINUES TO DISPLAY SOLID
CONTINUITY FOR WIDESPREAD SHOWERS AND THUNDERSTORMS. THE LATEST WPC
QPF THROUGH MONDAY AFTERNOON HAS A SIGNIFICANT AREA OF 1 TO 2 INCHES
OF RAIN...QUITE REASONABLE GIVEN THE PERSISTENT SOUTHWEST FLOW AND
AMPLE MOISTURE. SO THE MAIN HIGHLIGHT OF THIS PERIOD CONTINUES TO BE
WIDESPREAD MODERATE TO LOCALLY HEAVY RAINFALL. MUCH UNCERTAINTY
REMAINS REGARDING SEVERE WEATHER POTENTIAL. AS WAS THE CASE WITH
YESTERDAY`S FORECAST...NO ONE PARTICULAR PERIOD STANDS OUT SEVERAL
DAYS AWAY FROM THE EVENT. POPS ARE GENERALLY LOWER FOR TUESDAY INTO
WEDNESDAY AS MODEL CONSENSUS BREAKS DOWN...BUT THERE IS STILL
POTENTIAL FOR CONTINUED ACTIVE WEATHER. TEMPERATURES SHOULD REMAIN
NEAR SEASONAL NORMALS THROUGH THE WEEKEND BEFORE A MODEST WARMING
TREND EARLY NEXT WEEK.    RP KINNEY

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1245 PM CDT WED MAY 20 2015

PASSING RAIN SYSTEM WITH SOME EMBEDDED SLEET...MAINLY LOW VFR
LEVELS BUT THERE IS SOME TRENDING IN BOTH CIGS AND RAIN VSBYS TO
MVFR IN SPOTS. NORTHEAST SFC WINDS WILL TRY TO BATTLE THAT
LOWERING THRU THE REST OF THE AFTERNOON. WILL ADVERTISE VFR CIGS
TONIGHT AFTER THE RAIN CLEARS BY THIS EVENING...NORTHEAST WINDS
BACKING TO THE WEST AND DECREASING OVERNIGHT AFTER THE SFC TROF
PASSES TO THE EAST. WILL BANK ON WEST TO NORTHWEST WINDS
MAINTAINING AROUND 5 KTS AS WELL AS AT SOME LINGERING CLOUD COVER
TO LIMIT ANY VSBY REDUCTION BECAUSE OF FOG OVERNIGHT. WEST WINDS
PICK UP TO 8-10KTS LATE THU MORNING.    ..12..

&&

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

$$

SYNOPSIS...12
SHORT TERM...12
LONG TERM...RP KINNEY
AVIATION...12


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