Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 251710
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1210 PM CDT SAT OCT 25 2014

.SYNOPSIS...
ISSUED AT 338 AM CDT SAT OCT 25 2014

LATEST SFC ANALYSIS WAS INDICATING THE MAIN SFC TROF PUSHING ACRS
THE NORTHWESTERN THIRD OF THE CWA FROM THE NORTHWEST...PRESSURE
FALLS MAX AHEAD OF THIS FEATURE ACRS THE WESTERN GRT LKS/MI AND
RISES BEHIND IT INCREASING ACRS THE NORTHEAST PLAINS INTO IA. WEST
WINDS STARTING TO INCREASE IN THESE PRESSURE RISE FIELDS...AND THIS
WILL HELP MIX OUT THE FOG ONGOING ACRS THE AREA. THIS PROCESS SEEN
ON IR FOG SATELLITE LOOP WORKING INTO THE FAR NORTHERN CWA AND JUST
UPSTREAM TO THE WEST ATTM. ALOFT...CURRENT WATER VAPOR LOOP AND 00Z
UPPER AIR ANALYSIS WAS INDICATING VORT LOBE OVERHEAD STARTING TO GET
SPILLED OFF TO THE SOUTHEAST AS UPSTREAM UPPER RIDGE AXIS ACRS THE
WESTERN ROCKIES IS UNDER AMPLIFICATION.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 338 AM CDT SAT OCT 25 2014

TODAY...WILL LET ONGOING FOG ADVISORIES RIDE FOR NOW...AND WILL
EITHER LET EXPIRE OR CHOP AWAY FROM THE NORTHWEST AS NEEDED AS WEST
TO NORTHWEST WINDS INCREASE AND MIX UP/IMPROVE VISIBILITIES. AFTER
MORNING STRATUS/FOG LAYER CLEARS OFF THIS MORNING...REST OF DAY TO
BE SUNNY/MOSTLY SUNNY. BUT MID DECK SEEN ACRS THE NORTHERN PLAINS ON
SOUTHERN FRINGE OF UPPER JET MAX DUMPING INTO THE GRT LKS...WILL
PROBABLY MAKE IT INTO PORTIONS OF THE NORTHERN AND NORTHEASTERN CWA
TODAY. BUT IT WILL BE TEMPORARY AND MAY DECREASE SOME AS IT
STREAKS DOWN INTO THE AREA SO AS NOT TO RUIN MOSTLY SUNNY WORDING.
LLVL THERMAL LAYER TIGHTENS ACRS THE AREA BUT STILL MILD ENOUGH
THAT MIXING NORTHWESTERLY FLOW WILL HELP TEMPS WARM WELL ABOVE
NORMAL TODAY WITH HIGHS IN THE MID TO UPPER 60S IN THE NORTH...TO
THE LOWER TO MID 70S IN THE SOUTH.

TONIGHT...WITH SFC RIDGE ADJUSTING OVERHEAD AND SFC DPTS DIURNALLY
DRY DOWN MIXING INTO THE 40S AND EVEN 30S...THE STAGE WILL BE SET
FOR A COOL NIGHT. LIGHT WINDS...DRIED SFC LAYER AND MAINLY CLEAR
SKIES TO ALLOW FOR SOME UPPER 30S NORTH OF I80...AND LOW TO MID 40S
IN THE SOUTH. WITH DRIED OUT SFC LAYER...EXPECT FOG DEVELOPMENT
TONIGHT TO BE LIMITED TO RIVER/STREAM VALLEYS AND SIMILAR LOW LYING
AREAS AND WILL NOT MENTION IN THE GRIDS.     ..12..

.LONG TERM...(SUNDAY THROUGH NEXT FRIDAY)
ISSUED AT 338 AM CDT SAT OCT 25 2014

INCREASING RAIN LATE MONDAY MAIN FORECAST ISSUE.

LONG TERM FORECAST CONFIDENCE...OVERALL FAIR OR AVERAGE WITH POOR OR
BELOW AVERAGE WITH PRECIPITATION EVENT AS WIDE MOISTURE LEVELS
VARIANCE INDICATING INTER/INTRA SOLUTION QPF FIELDS DISCREPANCIES.
LARGE SCALE FORCING AND MOISTURE LEVELS CONTINUE TO SUGGEST A
WIDESPREAD LIGHT TO LOCALLY MODERATE AMOUNTS OF A TENTH TO LOCALLY
AROUND A HALF INCH POSSIBLE.  RISK OF ISOLATED ELEVATED THUNDERSTORMS
REMAIN MARGINAL AND ISOLATED AS STRATIFICATION TO OCCUR WITH ANY
CONVECTIVE UPDRAFTS WITH WEAK INSTABILITY AND HIGH RH LEVELS.
OTHERWISE...DAILY DIURNAL TEMPERATURES MOST DAYS MAY STILL BE A
DEGREE OR TWO WIDER.  COOLING TREND LATE IN THE WEEK PROBABLY STILL
TOO MILD FOR LATER SHIFTS WITH STRONG COLD AIR MASS FOR LATE OCTOBER.

OVERVIEW...INITIALIZATION GOOD TO EXCELLENT OVER CONUS WITH PACIFIC
ENERGY SAMPLED OK ALLOWING FOR A SLIGHTLY DEEPER TROUGH EARLY NEXT
WEEK.  D_PROG_DT TOOL SUGGEST SOME ADDITIONAL CHANGES TO A DEEPER
TROUGH LIKELY NEXT 12-24 HOURS AS SYSTEM COMES ONSHORE.  VERIFICATION
AT 06Z COMBINED WITH RUN TO RUN VARIANCE CLEARLY SUGGEST HI-RES ECMWF
STILL SHOULD RECEIVE HIGHEST WEIGHT WITH 70/30 SUGGESTED.  WHEN
TIMING IS BETTER CONFIRMED LATE MONDAY...CATEGORICAL POPS REASONABLE
OF MOST LIGHT RAINFALL AMOUNTS AND POSSIBLY REMOVING ISOLATED THUNDER
IN NW SECTIONS.

SUNDAY...NICE...SEASONABLE LATE OCTOBER WEATHER WITH FAIR SKIES AND
HIGHS MID/UPPER 60S NE 2/3 OF AREA TO LOW 70S SW 1/3  UNDER A FAIR
SKY AND SE WINDS OF 5 TO 15 MPH.  GOOD DAY FOR RAKING FALL LEAVES AND
OTHER OUTSIDE ACTIVITIES. SUNDAY NIGHT...INCREASING CLOUDS AND
ISOLATED ELEVATED SHOWER AND POSSIBLY A BRIEF RUMBLE OF THUNDER
ALONG HIGHWAY 20 CORRIDOR AHEAD OF NEXT DISTURBANCE. BEST FORCING
SUGGEST LATER SHIFTS MAY BE ABLE TO REMOVE POPS.  MINS MILD IN THE
50S TO NEAR 60F SOUTH SECTIONS AND INCREASING CLOUDS BY MORNING.

MONDAY THROUGH MONDAY NIGHT...NEXT DISTURBANCE AND FRONT TO ARRIVE
MONDAY AFTERNOON.  MILD SOUTH WINDS OF 10 TO 20+ MPH SHOULD ALLOW
WITH PARTLY SUNNY SKIES FOR HIGHS MID/UPPER 70S SE SECTIONS.  NW
SECTIONS WITH FRONT ARRIVAL EARLIER SUGGESTS AROUND 70F. FORCING TO
INCREASE WITH POPS TO BLOOM OVER AREA SUGGESTED AROUND 3 PM INTO
EVENING HOURS FOR LATER SHIFTS TO REASSESS.  SHEAR AND MOISTURE AND
INSTABILITY PROFILES SUGGESTS ANY ISOLATED THUNDER IN PM WOULD BE
MOSTLY ALONG ADVANCING COLD FRONT.  MONDAY NIGHT...A FEW BANDS OF
SHOWERS AND ISOLATED STORMS SUGGESTED...ALONG AND BEHIND FRONT WITH
RAIN TOTALS MOSTLY .1 OF AN INCH TO LOCALLY AROUND A HALF INCH.  WHEN
TIMING OF FRONT BETTER ASCERTAINED...THEN LIKELY TO CATEGORICAL
POPS ARE REASONABLE.  LOWS...UPPER 40S NW WITH CLEARING SKIES AND
MIDDLE 50S SE.

TUESDAY THROUGH FRIDAY...MINOR CHANGES MADE.  NW FLOW TO USHER IN
COOLER AIR WITH FAIR SKIES AND DRY TO GENERALLY DRY CONDITIONS AND
BIT WIDER DIURNAL RANGES. DEEPENING TROUGH THURSDAY INTO FRIDAY.
HIGHS HAVE BEEN LOWERED INTO THE 40S FRIDAY WITH A HARD FREEZE LIKELY
REQUIRING LOWS STILL 2 TO 5 DEGREES TOO MILD PER LOW LEVEL THERMAL
FIELDS. MAY HAVE ENOUGH COLD AIR ALOFT WITH DIGGING UPPER TROUGH FROM
NW FOR LIGHT PRECIPITATION NEEDING TO BE INTRODUCED FOR LATER SHIFTS
TO RECONSIDER.      NICHOLS

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1209 PM CDT SAT OCT 25 2014

HIGH PRESSURE CENTERED OVER THE PLAINS WILL SLIDE EAST ACROSS IOWA
AND ILLINOIS TONIGHT THROUGH SUNDAY PROVIDING MOSTLY CLEAR SKIES
AND VFR CONDITIONS. NORTHERLY WINDS TODAY WILL BECOME LIGHT AND
VARIABLE TONIGHT...THEN SOUTHEAST AROUND 10 KTS BY MIDDAY SUNDAY.

&&

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

$$

SYNOPSIS...12
SHORT TERM...12
LONG TERM...NICHOLS
AVIATION...SHEETS






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