Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 270951
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
351 AM CST THU NOV 27 2014

.SYNOPSIS...
ISSUED AT 319 AM CST THU NOV 27 2014

AT 3 AM CST...LOW CLOUDS LINGERED ACROSS EASTERN IOWA AND
NORTHWEST ILLINOIS...HELPING KEEP TEMPERATURES UP IN THE 20S MOST
LOCATIONS. FARTHER WEST IN CENTRAL IOWA...READINGS WERE IN THE
SINGLE DIGITS UNDER A CLEAR SKY.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 319 AM CST THU NOV 27 2014

THE MAIN FORECAST ISSUE IN THE SHORT TERM PERIOD IS TEMPERATURES.

ADJUSTMENTS TO THE TIMING OF THE CLEARING FROM WEST TO EAST TODAY
HAS NECESSITATED SOME CHANGES TO THE TEMPERATURE TRENDS. LOW
CLOUDS WILL KEEP READINGS FROM DROPPING SHARPLY EARLY THIS
MORNING...WITH THE EXCEPTION OF THE FAR NORTHWEST FRINGE. TODAY`S
HIGHS...IN THE TEENS TO LOWER 20S...WILL OCCUR SHORTLY AFTER DAYBREAK
MOST LOCATIONS...FOLLOWED BY FALLING TEMPS MID TO LATE MORNING
AND A SLIGHT REBOUND THIS AFTERNOON AS CLOUDS SCATTER OUT. CANNOT
RULE OUT A FEW FLURRIES THIS MORNING BEFORE THE CLEARING...BUT
HAVE OPTED TO KEEP OUT OF FORECAST AND WILL MONITOR THE TRENDS
OVER THE NEXT SEVERAL HOURS.

FOR TONIGHT...SURFACE HIGH PRESSURE WILL MOVE EAST ACROSS THE
FORECAST AREA. WINDS WILL GO CALM DURING THE EVENING AND
TEMPERATURES WILL PLUMMET QUICKLY INTO THE SINGLE DIGITS AND TEENS.
HAVE UNDERCUT GUIDANCE FOR TONIGHT...ESPECIALLY ACROSS THE NARROW
ENHANCED SNOW BAND IN THE SOUTH...AND ADDITIONAL DOWNWARD
ADJUSTMENTS MAY BE NEEDED. EXPECT STEADY TO SLOWLY RISING TEMPS
AFTER MIDNIGHT AS THE HIGH MOVES EAST FOLLOWED BY SOUTHEAST WINDS
AND INCREASING MID LEVEL CLOUDS.     RP KINNEY


.LONG TERM...(FRIDAY THROUGH NEXT WEDNESDAY)
ISSUED AT 319 AM CST THU NOV 27 2014

FRIDAY THROUGH SUNDAY...ELEVATED WARM AIR ADVECTION WING ALONG
TIGHTENING NORTHWEST-TO-SOUTHEAST ORIENTED BAROCLINICITY TO LEE
ORGANIZING HIGH PLAINS LLVL CYCLOGENESIS REGION...TO BE ONGOING AT
THE START OF THE PERIOD ACRS THE REGION. WILL KEEP THE FCST DRY WITH
DRY SUB H7 MB LAYERS IN FRI MORNING...BUT THERE COULD BE A FEW
FLURRIES NORTHEAST OF THE HWY 30 CORRIDOR. LLVL RETURN FLOW TO
STRENGTHEN DURING THE DAY WITH LATE AFTERNOON HIGHS. COLD GROUND/
LINGERING SNOW COVER AND ANY KIND OF WAA STRATOCU TO TEMPER WARM UP
POTENTIAL...BUT MUCH OF THE CWA TO RETURN TO THE 30S BY AFTER NOON
WITH EVEN A FEW 40S POSSIBLE SOUTH OF I80 AWAY FROM THE SOUTHEASTERN
IA INTO WEST CENTRAL IL COLD SINK ENHANCED SNOW COVER RIBBON. WAA TO
CONTINUE OVERNIGHT FRI NIGHT INTO SAT AM...WITH A FEW MODEL
SOLUTIONS TRYING TO BREAK OUT MORE LIGHT PRECIP ACRS THE NORTHERN
CWA FRI EVENING IN A CONVERGENT WING. IF THIS HAPPENS WITH WARMER
TEMPS ALOFT...MAY BE SOME LIGHT FREEZING PRECIP ISSUES ALONG THE HWY
20 CORRIDOR BUT WITH ADEQUATE LAYER SATURATION FOR PRECIP TO FORM
STILL AT QUESTION WILL KEEP THE FCST DRY FOR NOW. WITH SF LAYER
MOISTURE INCREASE ACRS LINGERING SNOW COVER OR AT LEAST COLD
GROUND...FRI NIGHT MAY BE ANOTHER FOG OPPORTUNITY WINDOW TO WATCH AND
WILL AT LEAST INTRODUCE PATCHY FOG IN THE GRIDS FOR NOW...BUT IF
ENOUGH MIXING SOUTHERLY BREEZE MAINTAINS IT COULD LIMIT WIDESPREAD
DENSE OCCURRENCE. WARM SIGNAL CONTINUES TO BE ADVERTISED IN ROBUST
WAA REGIME FOR SAT...TEENS ABOVE ZERO C H85 TEMPS ADVECTED ACRS THE
REGION IN LOW TO MID LVL SOUTHWESTERLIES TO POSSIBLY MAKE FOR A VERY
STOUT INVERSION ALOFT IN THAT LAYER. FOG OR LOW STRATUS COULD GET
TRAPPED UNDER IT AND MAKE FOR A CLOUDY COOLER SAT THAN WHAT THE WARM
UP POTENTIAL COULD BE. MAY ACTUALLY TEMPER THE ADVERTISED MILD HIGHS
SOME ESPECIALLY NORTH OF I80 FOR NOW WITH THESE CONCERNS...BUT IF
SOME AFTERNOON BREAKS OCCUR AND MIX DEEPER INTO BASE OF INVERSION
OVER H95 MB...SOME MID TO UPPER 50S MAY OCCUR IN PORTIONS OF THE CWA.
THE WARM UP TO BE ENDED BY PASSING SFC FRONTAL COMPLEX AND FOLLOWING
STRONG 1040+ MB LLVL CANADIAN RIDGE DUMPING DOWN THE UPPER MIDWEST
SUNDAY INTO MONDAY. ENSEMBLE FROPA THRU THE CWA GENERALLY BY MIDDAY
SUNDAY WITH FALLING TEMPS IN THE AFTERNOON. PREFER THE DRY 00Z GFS
FOR SUNDAY NIGHT INTO MON TAKING INTO ACCOUNT THE STRENGTH OF THE
RIDGE WHICH WOULD DEFLECT ANY OVERRUNNING PRECIP PROCESS TRYING TO
EJECT OUT OF THE SOUTHERN PLAINS SOUTH OF THE DVN CWA. INTERESTINGLY
THE 00Z ECMWF IS THE MOST BULLISH MODEL OF OVERRUNNING PRECIP MAKING
IT FAR ENOUGH TO THE NORTH TO STREAM ACRS SOUTHEASTERN PORTIONS OF
THE FCST AREA SUNDAY NIGHT INTO EARLY MON MORNING.

MONDAY THROUGH NEXT WEDNESDAY...CANADIAN HIGH TO MAINTAIN DRY AND
COLDER CONDITIONS MON INTO EARLY TUE...THEN UPSTREAM WAVE PHASING
INTERACTING WITH A BOUT OF RETURN FLOW WILL HAVE TO BE MONITORED
FOR A POSSIBLE PRECIP EVENT BY LATE TUE OR NEXT WED. THE LATEST 00Z
RUN MEDIUM RANGE SOLUTIONS ACTUALLY BLOCK MUSH OF ANY MOISTURE RETURN
BY SOUTHERN PLAINS LLVL RIDGING FOR MUCH OF ANY PRECIP GENERATION IF
A TROF CAN DIG ACRS THE MIDWEST AND SWEEP ANOTHER FRONT THROUGH THE
UPPER MS RVR VALLEY/WESTERN GRT LKS BY MID NEXT WEEK.    ..12..

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1115 PM CST WED NOV 26 2014

MVFR CIGS AND 4 TO 6 MILE VISIBILITIES IN VERY LIGHT SNOW AND
LIGHT FOG WILL END BEFORE 12Z THURSDAY AS DRY AIR POURS INTO THE
REGION BEHIND A COLD FRONT. WINDS WILL BE NORTH AROUND 12 TO 15
KTS...AND WILL ONLY WEAKEN LATE THURSDAY AFTERNOON AS WINDS
DECOUPLE. AFTER THE EARLY MVFR PERIOD...THE REST OF THE PERIOD
WILL BE VFR / CLEAR.
ERVIN

&&

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

$$

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








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