Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 211724
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1224 PM CDT SUN SEP 21 2014

.UPDATE...
ISSUED AT 1223 PM CDT SUN SEP 21 2014

STRATOCU DECK ASSOCIATED WITH THE SURFACE THROUGH 850 MB TROUGH
THAT EXTENDED WEST FROM THE GREAT LAKES LOW HAS ENCOMPASSED MOST
OF THE FORECAST AREA NORTH OF I-80 AS OF NOON. THIS WAS HOLDING
TEMPERATURES IN THE UPPER 50S ALONG THE HIGHWAY 20 CORRIDOR...
WHILE SUNSHINE HAD WARMED READINGS TO THE UPPER 60S TO NEAR 70
ACROSS THE SOUTH. AREA RADARS SHOWED SHOWERS DEVELOPING DEEPER
INTO THE CYCLONIC FLOW AND UNDER A MID LEVEL SHORTWAVE OVER
SOUTHERN WI...WITH VERY WEAK RETURNS...BUT NO GROUND TRUTH...
UPSTREAM IN NE IA INTO SE MN.

HAVE UPDATED TO LOWER HIGHS A COUPLE DEGREES ACROSS THE NORTH WHERE
AT LEAST BROKEN CLOUD COVER WILL PERSIST THROUGH MID AFTERNOON
WITH COLD ADVECTION CONTINUING ON BRISK NW WINDS. WILL CONTINUE
SLIGHT CHANCE POPS FOR SHOWERS THERE AS WELL. ELSEWHERE...CLOUDS
WILL LIKELY REACH THE HIGHWAY 34 CORRIDOR BEFORE THE DIURNAL
WANING PROCESS. THESE CLOUDS...ALONG WITH NW WINDS FROM 15 TO 25
MPH AND MIXING INTO THE CONTINUED LOW LEVEL COLD AIR ADVECTION
REGIME WILL LIKELY LIMIT MUCH FURTHER WARMING AND HIGHS FROM THE
MID 60S TO LOWER 70S CENTRAL AND SOUTH LOOK ON TRACK.

&&

.SYNOPSIS...
ISSUED AT 305 AM CDT SUN SEP 21 2014

COLD FRONT HAS PUSHED SOUTHEAST OF THE CWA WITH CLEAR SKIES OVER
MUCH OF THE CWA. COLD AIR ADVECTION WAS BRINGING COOLER AND DRIER
AIR INTO THE AREA. 3 AM TEMPERATURES RANGED FROM THE LOWER 50S NW
TO THE LOWER 60S SE.

WATER VAPOR LOOPS SHOWED A STRONG SHORT WAVE IN FAR NORTHERN WI
WHICH WAS MOVING SOUTHEAST. STRATUS/LIGHT RAIN WAS FOUND IN
NORTHEAST MN/WESTERN UPPER MI AND NORTHERN WI WITH THIS FEATURE.
TEMPERATURES WERE IN THE MID 40S TO MID 50S ACROSS THE NORTHERN
PLAINS WHERE THE SURFACE HIGH PRESSURE WAS CENTERED.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 305 AM CDT SUN SEP 21 2014

FORECAST FOCUS ON A COOLER AND BRISK DAY WITH A SLIGHT CHANCE OF SHOWERS.

TODAY...COLD AIR ADVECTION WILL CONTINUE TO USHER COOLER/DRIER AIR INTO
THE CWA ON NORTHWEST WINDS GUSTING TO 25 TO 30 MPH. SURFACE PARCEL
TRAJECTORIES SUGGEST MAXIMUM TEMPERATURES RANGING FROM THE MID 60S
ALONG HIGHWAY 20 TO THE LOWER 70S IN OUR FAR SOUTHERN COUNTIES.
WITH COLDER AIR ALOFT THERE SHOULD BE SCATTERED TO BROKEN INSTABILITY
STRATOCUMULUS FORMING LATER THIS MORNING AND THROUGH THE AFTERNOON.
THESE CLOUDS SHOULD THEN BEGIN TO DISSIPATE BY EVENING WITH LOSS
OF HEATING. WILL KEEP A MENTION OF SLIGHT CHANCE POPS IN FAR NW
IL LATE THIS MORNING INTO A PORTION OF THE AFTERNOON. THIS DUE TO
THE STRONG SHORT WAVE DIVING SOUTHEAST OUT OF NORTHERN WI. HOWEVER...
MODELS SIMILAR IN KEEPING THE BULK OF THE RAIN NORTH AND EAST OF
THE DVN CWA WHERE THE COLD POCKET WILL EXIST.

TONIGHT...SUBSIDENCE IN THE WAKE OF THE SHORT WAVE TRACKING INTO
THE GREAT LAKES REGION...AND SURFACE HIGH PRESSURE BUILDING IN
FROM THE NORTHERN PLAINS...WILL ALLOW FOR CLEAR SKIES AND COOLER
TEMPERATURES. READINGS WILL BOTTOM OUT IN THE LOWER TO MID 40S NORTH
TO THE UPPER 40S SOUTH.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 305 AM CDT SUN SEP 21 2014

IDEAL EARLY FALL WEATHER AND DRY CONDITIONS WITH SLIGHTLY BELOW
NORMAL TEMPERATURES...WARMING TO SLIGHTLY ABOVE NORMAL THURSDAY INTO
SATURDAY.

LONG TERM FORECAST CONFIDENCE ASSESSMENT...ABOVE AVERAGE OR GOOD
WITH NO SENSIBLE WEATHER ISSUES SINCE GENERALLY DRY CONDITIONS
PREVAIL. AREA HIGH/LOW TEMPERATURES DAYS 2-7 SHOULD BE WITHIN 2-3
DEGREES OF FORECAST.

OVERVIEW...INITIALIZATION AND VERIFICATION GOOD WITH MINOR BL RH
ISSUES WITH A DRY FORECAST. MINOR VARIANCES IN SOLUTIONS WITH A 50/50
MIX OF GFS/HI-RES ECMWF SUGGESTED.  TRENDS CONTINUE TO SUGGEST
HIGHS...TUESDAY ONWARD A DEGREE OR TWO HIGHER AND AREA LOWS A DEGREE
OR TWO LOWER MONDAY NIGHT THROUGH FRIDAY MORNING MANY LOCATIONS.

MONDAY THROUGH SATURDAY...QUIET EARLY FALL WEATHER WITH FAIR SKIES
UNDER LARGE HIGH PRESSURE SYSTEM AND LIGHT WINDS FAVORING THE
SOUTHEAST TO SOUTH TUESDAY ONWARD. VERY MINOR CHANGES MADE.  HIGHS
SHOULD BE MOSTLY 70-75 THROUGH WEDNESDAY...THEN 75-80 THURSDAY
THROUGH SATURDAY WITH SOUTH TO SOUTHEAST WINDS OF 5 TO 10 MPH.
TRIMMED MINS TUESDAY AM A DEGREE OR TWO WITH UPPER 40S RISING
INTO THE MIDDLE 50S THURSDAY THROUGH SATURDAY MORNING. HAVE
REDUCED VERY LOW POPS IN FAR WEST OF DECAYING LIGHT SHOWERS
TO WEDNESDAY AND MAY BE ABLE TO BE PULLED AS LOW MOISTURE AND UPPER
HIGH FOR SUBSIDENCE SHOULD MAKE THESE PRECIPITATION CHANCES
UNFAVORABLE AND TRENDS HAVE CONFIRMED THIS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1223 PM CDT SUN SEP 21 2014

AN EXTENSIVE CLOUD DECK WITH BASES AROUND 2500 TO 3500 FEET OVER
EASTERN IA AND NW IL WILL DISSIPATE OVER THE REGION BY LATE
AFTERNOON AS AN UPPER LEVEL AND SURFACE STORM SYSTEM OVER THE
GREAT LAKES EXITS TO THE EAST. MVFR CIGS AT DBQ...CID AND MLI ARE
EXPECTED TO LIFT TO VFR LEVELS BY MID AFTERNOON. BRISK NW WINDS
WILL DIMINISH AND BECOME VERY LIGHT NORTH OVERNIGHT INTO MONDAY AS
HIGH PRESSURE ADVANCES FROM THE PLAINS. THIS HIGH WILL KEEP
WEATHER IN PLACE THROUGH MONDAY. THERE IS A LOW POTENTIAL FOR
GROUND FOG AROUND SUNRISE...WHICH LOOKS TOO REMOTE TO INCLUDE IN
THE FORECASTS AT THIS TIME.

&&

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

$$

UPDATE...SHEETS
SYNOPSIS...HAASE
SHORT TERM...HAASE
LONG TERM...NICHOLS
AVIATION...SHEETS






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