Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 231744
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1244 PM CDT WED JUL 23 2014

.SYNOPSIS...
ISSUED AT 313 AM CDT WED JUL 23 2014

THE SURFACE COLD FRONT REACHED FROM NEAR SOUTH BEND THROUGH ST LOUIS
INTO SE KS AT 2 AM. AREA RADARS INDICATED A LINE OF THUNDERSTORMS
ALONG THIS FRONT FROM NORTH CENTRAL IL EAST ACROSS NORTHERN INDIANA
AND OHIO. THE POST-FRONTAL TRANSITION TO COOLER AND DRIER AIR HAS
BEEN RATHER SLOW TO TAKE PLACE OVER EASTERN IA AND NORTHERN IL...
WHERE TEMPERATURES RANGED FROM THE MID 60S TO MID 70S WITH
DEWPOINTS NOT FAR BEHIND IN THE 60S TO LOWER 70S. HIGH PRESSURE
ANCHORED OVER SE MANITOBA AND ITS ASSOCIATED COOLER AND DRIER
AIRMASS WILL BUILD SOUTHEAST INTO THE REGION TODAY AND TONIGHT...
PROVIDING A SHARP CHANGE FROM TUESDAY/S HEAT AND HUMIDITY.
ALOFT...00Z ANALYSIS INDICATED A LARGE RIDGE OF HIGH PRESSURE
ANCHORED OVER THE FOUR CORNERS REGION WITH A RIDGE AXIS REACHING
INTO THE CANADIAN PRAIRIES. THE UPPER LEVEL NW FLOW AND THERMAL
GRADIENT ON THE NORTHEAST PERIMETER OF THIS RIDGE WILL KEEP RIDGE
RUNNING THUNDERSTORM COMPLEXES WELL WEST OF THE AREA IN THE SHORT
TERM AND ALLOW THE CANADIAN HIGH TO MIGRATE TOWARD THE GREAT LAKES
BY THURSDAY.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 313 AM CDT WED JUL 23 2014

TEMPERATURES ARE THE MAIN FOCUS AS CANADIAN HIGH PRESSURE BUILDS
INTO THE REGION. TODAY...NORTH TO NORTHEAST WINDS AND THE
APPROACHING HIGH WILL PULL YESTERDAY/S AIRMASS OVER NORTHEAST MN AND
NORTHERN WI SOUTHWARD INTO THE REGION TODAY. THIS WILL SUPPORT
DEWPOINTS LOWERING TO THE MID 50S TO LOWER 60S BY AFTERNOON. BASED
ON THIS TRAJECTORY...MOS GUIDANCE HIGHS FROM THE MID 70S NORTHEAST
TO NEAR 80 CENTRAL AND SOUTH LOOKED REASONABLE AND ONLY MINOR
CHANGES WERE MADE TO THE PREVIOUS FORECAST. SKIES SHOULD BE MOSTLY
SUNNY WITH SCATTERED FAIR WEATHER CUMULUS CLOUDS FROM LATE MORNING
THROUGH AFTERNOON.

TONIGHT...THE CENTER OF THE HIGH IS EXPECTED TO REACH SOUTHERN WI BY
MORNING. RESULTING CLEAR SKIES AND LIGHT WINDS SHOULD LEAD TO A
RATHER COOL NIGHT FOR LATE JULY WITH LOWS FROM THE LOWER 50S
NORTHEAST TO UPPER 50S SOUTHWEST. THIS SETUP WILL BE FAVORABLE FOR
AT LEAST PATCHY FOG AND HAVE ADDED MENTION FOR THE LATE NIGHT HOURS
OVER EASTERN IA AND NW IL...CLOSEST TO THE HIGH CENTER.


.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 313 AM CDT WED JUL 23 2014

CHANGEABLE WEATHER MORE LIKE A TRANSITION SEASON RATHER THAN MID
SUMMER IS SETTING UP FOR OUR AREA IN THE LONG TERM.

THURSDAY...HIGH PRESSURE SETTLING OVER THE MIDWEST WILL BRING
COOLER THAN NORMAL AND DRY CONDITIONS AHEAD OF THE NEXT STORM SYSTEM.

THURSDAY NIGHT THROUGH SATURDAY...A COUPLE OF OPPORTUNITIES FOR
RAINFALL ARE FORECAST IN THIS TIME FRAME. WARM AIR ADVECTION
SETTING UP THURSDAY NIGHT AND CONTINUING INTO FRIDAY IS THE FIRST
CHANCE. AT THIS POINT HAVE TAPERED POPS HIGHEST IN THE NORTHWEST
AND LOWER IN THE SOUTHEAST IN LINE WITH LOW-LEVEL FORCING. HAVE
KEPT POPS IN THE SCATTERED CATEGORY DUE TO LACK OF
CAPE...ESPECIALLY THURSDAY NIGHT. THE FOCUS WILL BE ALONG THE 850
MB BOUNDARY.  MOISTURE WILL BE PLENTIFUL WITH THE NAM PROG OF 1.5
INCH PLUS PWS LOOKING REASONABLE.

THE GFS...ECMWF AND GEM MOVE A SURFACE WAVE ALONG THE WARM FRONT
INTO SOUTHEAST IOWA LATE FRIDAY AFTERNOON AND NIGHT. LOW-LEVEL
SUPPORT LOOKS PRETTY GOOD WITH THE PROXIMITY OF THE 850 MB
THERMAL-MOISTURE BOUNDARY AND A DEVELOPING LOW-LEVEL JET IN
ADDITION TO THE SURFACE WAVE. DECENT CAPE...MODERATE-HIGH SHEAR
AND HEFTY PWS ARE PROGGED DURING THAT TIME FRAME. THUS BOTH SEVERE
WEATHER AND HEAVY RAIN ARE A POTENTIAL THREAT...THOUGH IT IS TOO
EARLY TO GET OVERLY EXCITED ABOUT THIS POTENTIAL EVENT.

SUNDAY...GFS AND 12Z ECMWF DIFFER ON THE TIMING OF THE UPPER LEVEL
TROUGH PASSAGE WITH THE GFS THE FASTER OF THE TWO. QUICK LOOK AT
THE 00Z ECMWF SUGGESTS IT HAS COME MORE IN LINE WITH THE GFS. THUS
PRECIP MAY LINGER SUNDAY AND HAVE SOME LOW POPS IN THE FORECAST TO
ACCOUNT FOR THIS.

MONDAY AND TUESDAY...SURFACE HIGH PRESSURE ONCE AGAIN SETTLING
INTO THE AREA WILL DELIVER MORE BELOW NORMAL TEMPERATURES AND DRY
WEATHER. THERE IS A HINT OF RETURN FLOW AND POSSIBLE WAA-DRIVEN
STORMS LATE TUESDAY...BUT IT IS DAY 7.  WOLF

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1233 PM CDT WED JUL 23 2014

DIURNAL CELLULAR VFR CU OF SCTRD TO BKN COVERAGE THIS AFTERNOON TO
DECAY THIS EVENING FOR MAINLY CLEAR SKIES. A LARGE AREA OF HIGH
PRESSURE MOVING ACRS MN INTO WI WILL CONTINUE TO SQUEEZE
NORTHEASTERLY SFC WINDS OF 8-14KTS AND HIGHER GUSTS ACRS THE AREA
THIS AFTERNOON...BUT GO LIGHT EASTERLY OVERNIGHT. THIS MAY ALLOW
FOR SOME MVFR FOG TO FORM IN THE VCNTY OF A FEW TAF SITES AND WILL
KEEP THE CONTINUITY OF ADVERTISING FOG IN A TEMPO GROUP AT MLI AND
CID. BUT IT COULD FORM AT BRL AS WELL. SOME LIGHT SOUTHEASTERLY
RETURN FLOW AT CID OF 5-8 KTS BY LATE THU MORNING...OTHERWISE
LIGHT AND VARIABLE WIND REGIME TO CONTINUE OUT OF TONIGHT AND INTO
THU MORNING.    ..12..

&&

.CLIMATE...
THE CPC WEEK 2 OUTLOOK INDICATES A HIGH PROBABILITY THAT COOLER
THAN NORMAL TEMPERATURES WILL PERSIST THE END OF JULY INTO EARLY
AUGUST. ODDS FAVOR NEAR TO BELOW NORMAL RAINFALL DURING THAT SAME
TIME FRAME.  WOLF

&&

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

$$

SYNOPSIS...SHEETS
SHORT TERM...SHEETS
LONG TERM...WOLF
AVIATION...12
CLIMATE...WOLF






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