Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 271724
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1224 PM CDT THU AUG 27 2015

...UPDATED AVIATION DISCUSSION...

.SYNOPSIS...
ISSUED AT 314 AM CDT THU AUG 27 2015

COOL HIGH PRESSURE REMAINS OVER THE MISSISSIPPI AND
GREAT LAKES REGIONS EARLY TODAY...WHILE WARM ADVECTION AND UPSLOPE
PRODUCED THUNDERSTORMS HAVE FIRED OVER SOUTH DAKOTA...WITH AN ARC OF
SHOWERS EXTENDING TO NORTHEAST NEBRASKA. THIS ACTIVITY IS SLIDING
EAST SOUTHEAST ALONG THE WARM FRONTAL SLOPE. MEANWHILE...CLEAR SKIES
OVER THE CWA OVERNIGHT HAVE BROUGHT A GOOD RADIATIONAL COOLING
NIGHT...WITH LOWER TO MID 50S WIDESPREAD AS OF 2 AM.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 314 AM CDT THU AUG 27 2015

THE QUESTIONS ON WHERE THE UPPER LOW DEVELOPS AND WHERE IT
MOVES...AS WELL AS HOW STRONG THAT FEATURE WILL BE ARE STILL IN
GREAT DOUBT...DESPITE THAT LOWS EXPECTED IMPACT ON THE REGION
BEGINNING TONIGHT. THIS IS LARGELY DUE TO THE TYPE OF LOW IT IS.
INSTEAD OF TRACKING SOME LARGE JET OR WATCHING THE SLOW EVOLUTION
OF AN UPPER LOW EXITING A DEEP TROF...WE ARE DEALING WITH A
PROCESS MORE IN LINE WITH AN MCV. MONSOONAL CONVECTION AND UPSLOPE
HAVE INDEED FIRED AN CLUSTER OF STORMS...BUT CYCLOGENESIS FROM
THAT PROCESS IS RATHER UNPREDICTABLE. THUS...THE MODELS CONTINUE
TO VARY GREATLY ON DEALING WITH THIS STORM SYSTEM.

THANKFULLY...IN THE SHORT TERM... THE AFFECTS OF THIS TROUBLESOME
STORM SYSTEM WILL NOT GREATLY IMPACT OUR CWA. TODAY WILL BE SUNNY TO
PARTLY SUNNY...WITH SOME INCREASE OF HIGH CLOUD COVER DURING THE
DAY. THE LIGHT SOUTHEAST TO EAST WINDS WILL BECOME SOUTH AROUND 10
MPH BY AFTERNOON...AND WITH SUN...HIGHS IN THE UPPER 70S TO AROUND
80 SEEM ON TARGET.

TONIGHT...WARM ADVECTION WILL BE KICKING IN ALOFT OVERNIGHT...BUT
THE FOCUS WILL HOLD TO THE WEST OF OUR CWA UNTIL AFTER MIDNIGHT. THE
SLOW MOVING UPPER AIR TRANSITION OF THE POTENTIAL LOW...WILL KEEP
WINDS BACKED FOR QUITE A WHILE...BEFORE AN EVENTUAL VEERING INTO
EASTERN IOWA AROUND 3 AM. THIS SHOULD SPREAD SOME SHOWERS AND
EMBEDDED THUNDERSTORMS ...RUMBLES...OVER WESTERN COUNTIES AND
NORTHWESTERN COUNTIES PRIOR TO DAWN. CONFIDENCE ON MEASURABLE RAIN
BEING WIDESPREAD IS NOT HIGH ENOUGH TO WARRANT MORE THAN LIKELY POPS
YET. LOWS UNDER THE INCREASED CLOUDS SHOULD BE WARMER THAN PAST
NIGHTS...GENERALLY IN THE LOWER 60S WEST TO UPPER 50S EAST.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 314 AM CDT THU AUG 27 2015

CONTINUED LOW LEVEL SOUTHEAST FLOW RAISES QUESTIONS AS TO HOW MUCH
EASTWARD PROGRESS THE PRECIPITATION WILL MAKE DURING THE DAY FRIDAY.
BASED ON THE OVERALL FORCING/MOISTURE...ROUGHLY THE EASTERN HALF OF
THE AREA SHOULD REMAIN DRY FRIDAY MORNING. MOST OF THE AREA SHOULD
SEE SOME PRECIPITATION FRIDAY AFTERNOON BUT THE NORTHWEST HALF OF
THE AREA WILL HAVE THE BEST CHANCES.

INSTABILITY ALOFT IS LIMITED BUT WHEN COMBINED WITH WHAT DAY TIME
HEATING THAT OCCURS...SOME ELEVATED THUNDERSTORMS SHOULD DEVELOP IN
THE RAIN SHIELD. TEMPERATURES FRIDAY SHOULD CLIMB UNTIL THE RAIN
BEGINS AND THEN COLLAPSE BACK INTO THE 60S WHERE THE RAIN PERSISTS.

THE UPPER LEVEL DISTURBANCE MOVES ACROSS THE AREA FRIDAY NIGHT WHICH
SHOULD RESULT IN A FAIRLY WIDESPREAD GENERAL RAIN WITH SOME ELEVATED
STORMS. RAINFALL AMOUNTS CURRENTLY LOOK TO BE LIGHT TO POSSIBLY
MODERATE.

RAIN WILL END FROM WEST TO EAST ON SATURDAY AS THE UPPER LEVEL
DISTURBANCE MOVES INTO THE GREAT LAKES. THE BEST CHANCES OF RAIN
SHOULD BE EAST OF THE MISSISSIPPI.

SOME LINGERING SPRINKLES OR LIGHT SHOWERS MAY BE POSSIBLE ACROSS THE
FAR EASTERN AREAS SATURDAY NIGHT BUT THE REST OF THE AREA SHOULD
REMAIN DRY.

SUNDAY ON...

THE MODEL CONSENSUS HAS DRY CONDITIONS FROM SUNDAY THROUGH WEDNESDAY
AS AN UPPER LEVEL HIGH BUILDS INTO THE MIDWEST. THERE ARE WEAK
INFERRED DISTURBANCES MOVING THROUGH IN THE FLOW ALOFT. ALTHOUGH
PRECIPITATION CANNOT BE RULED OUT...THE PROBABILITY OF DRY
CONDITIONS IS MUCH HIGHER THAN ANY RAIN CHANCES.

TEMPERATURES WILL START OUT AROUND NORMAL ON SUNDAY AND SLOWLY RISE
ABOVE NORMAL DURING THE WORK WEEK.&&

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1217 PM CDT THU AUG 27 2015

MAJORITY OF THE TAF PERIOD WILL BE AT VFR. LOW PRESSURE MOVING
THROUGH NEBRASKA INTO W IOWA BY FRI MORNING WILL ADVECT MOISTURE
INTO E IOWA/W ILLINOIS. BEST CHANCE FOR -RA/RA IS AT KCID DURING
THE LAST FEW HOURS OF THIS PERIOD WHERE VSBYS MAY FALL TO MVFR.
CHANCES FOR PRECIP ARE FORECAST TO INCREASE FRI AFTN AND EVENING.
UTTECH

&&

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

$$

SYNOPSIS...ERVIN
SHORT TERM...ERVIN
LONG TERM...08
AVIATION...UTTECH



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