Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 261205
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
705 AM CDT SUN OCT 26 2014

.SYNOPSIS...
ISSUED AT 401 AM CDT SUN OCT 26 2014

LATEST SFC ANALYSIS WAS INDICATING A RIDGE OF HIGH PRESSURE CENTERED
FROM NORTHWESTERN MN...ACRS THE CWA AND DOWN INTO THE MOUTH OF THE
OH RVR VALLY. A FRONTAL SYSTEM WAS SHUNTED TO THE SOUTH OF THIS
FEATURE FROM KS AND UP THE OH RVR VALLEY...WHILE A WARM FRONT WAS
ORGANIZING AND ARCHING UP TO THE WEST ACRS THE HIGH PLAINS. ALOFT...
A RATHER SHARP RIDGE WAS PUSHING EASTWARD ACRS THE NORTHERN PLAINS
WHILE A L/W TROF WAS SEEN ON WATER VAPOR IMAGERY DIGGING ACRS THE
PACIFIC NORTHWEST AND INTO THE WESTERN INTERMOUNTAIN REGION. CLOSER
TO HOME...ENHANCED IR SATELLITE LOOP INDICATING SOME NOCTURNAL
STRATUS DEVELOPING ACRS SOUTHWESTERN IAN INTO NW MO.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 401 AM CDT SUN OCT 26 2014

TODAY..THE ABOVE MENTIONED STRATUS FIELD WILL TRY TO LIFT UP ACRS THE
WESTERN AND SOUTHWESTERN CWA THIS MORNING...BUT DIURNAL EFFECTS AND
DRY AIR ALOFT SHOULD DECAY IT AS IT DOES INTO JUST SOME SCTRD CU.
THUS THIS MORNING SUNNY TO MOSTLY SUNNY WITH BACKING SFC WINDS TO
THE SOUTHEAST AND INCREASING BEHIND DEPARTING RIDGE AXIS TO THE
EAST. SOUTHEASTERLY WINDS MAY GUST OVER 20 MPH IN THE AFTERNOON IN
TIGHTENING PRESSURE GRADIENT AROUND RETREATING WARM FRONT. WILL
KEEP ONGOING HIGHS AS THEY ARE ALREADY LEANING TOWARD THE WARMER OF
MODEL GUIDANCE/THE MAV/ WHICH DID THE BEST YESTERDAY. SOME AREAS IN
THE SOUTH TO WARM EVEN ABOVE THE WARMEST OF GUIDANCE HIGHS BACK
INTO THE MID 70S. LEAD ELEVATED WARM AIR ADVECTION WING DEVELOPING ON
NOSE OF INCREASING SOUTHWESTERLY LLJ ON TRACK TO SWEEP ACRS THE DVN
CWA FROM SOUTHWEST TO NORTHEAST FROM LATE MORNING AND ESPECIALLY
DURING THE AFTERNOON. WITH DRY AIRMASS IN PLACE...MAIN IMPACT
SHOULD ONLY BE TO PRODUCE A BAND OF AC/MID DECK OF CLOUDS THAT WILL
MIGRATE ACRS PORTIONS OF THE CWA AS THE DAY PROGRESSES. A LOW CHC
FOR SOME LATE AFTERNOON ELEVATED SHOWERS BREAKING OUT IN THE VCNTY
OF THE NORTHWESTERN CWA BUT FOR NOW WILL KEEP THE CWA DRY THROUGH
00Z.

TONIGHT...MOST OF SHORT RANGE MODELS SUGGEST IMPRESSIVE 40-50+ KT
SOUTHWESTERLY H85 LLJ TO STREAK ACRS THE CWA WITH ONGOING CONVERGENT
NOSE PUSHING WEST-TO-EAST ACRS THE NORTHERN TWO THIRD OF THE LOCAL
FCST AREA DURING THE EVENING AND INTO THE OVERNIGHT. STRENGTH OF
CONVERGENT SIGNAL AND PLUME OF ADEQUATE MID LEVEL LAPSE RATES WITH
SOME ELEVATED MUCAPES SUGGEST SCTRD SHOWERS AND A FEW THUNDERSTORMS
TO DEVELOP AND MOVE ACRS THE NORTHERN THIRD TO QUARTER OF THE CWA.
THE MODELS DO VARY ON ELEVATED INSTABILITY WITH THE NAM MUCH MORE
BULLISH ON MID LAYER PLUME OF CAPES AND MID LAYER DRY WEDGE WHICH
WOULD SUPPORT MORE THUNDER COVERAGE AND VIGOROUS THUNDERSTORMS
CAPABLE OF PRODUCING AT LEAST SOME SMALL HAIL. BUT THE 00Z GFS AND
ECMWF NOT AS AGGRESSIVE AND FEEL THE NAM OVERDOING THESE PARAMETERS
AGAIN AND WILL JUST KEEP ISOLATED EMBEDDED THUNDER EMBEDDED IN THE
SCTRD SHOWER ACTIVITY THAT DOES MANAGE TO DEVELOP OR MOVE ACRS THE
FCST AREA TONIGHT. WITH WAA CLOUD COVER...BACKING SFC WINDS TO THE
SOUTH/SOUTHEAST AND ENOUGH OF A SFC PRESSURE GRADIENT MAINTAINING
THEM AT 7-14KTS OVERNIGHT...LOW TEMPERATURES TONIGHT TO OCCUR DURING
THE MID EVENING WITH STEADY TO SLOW RISE TEMP TRENDS INTO DAWN MONDAY
MORNING/NON-TYPICAL DIURNAL TEMP TRENDS.    ..12..


.LONG TERM...(MONDAY THROUGH NEXT SATURDAY)
ISSUED AT 401 AM CDT SUN OCT 26 2014

LIGHT TO MODERATE RAIN EVENT WITH ISOLATED STORMS POSSIBLE THE
PRIMARY FORECAST CHALLENGE.

LONG TERM FORECAST CONFIDENCE...OVERALL GOOD OR ABOVE AVERAGE WITH
FAIR OR AVERAGE WITH PRECIPITATION EVENT.  SOLUTIONS NOW PHASING
MOISTURE BETTER...SIMILAR TO AS DISCUSSED LAST NIGHT...SUPPORTING
AREAS OF SHOWERS AND POSSIBLY EMBEDDED STORMS WITH LIKELY TO
CATEGORICAL POPS.  LOCAL MOISTURE FORCING TOOLS SUGGEST STILL
LOCALLY HALF INCH AMOUNTS ARE POSSIBLE IN TRAINING OF SHOWERS ALONG
AND BEHIND FRONT.  RISK OF ISOLATED ELEVATED THUNDERSTORMS IS STILL
MARGINAL AS STRATIFICATION TO QUICKLY OCCUR WITH ANY CONVECTIVE
UPDRAFTS...COUPLED WITH WEAK INSTABILITY AND HIGH RH LEVELS. THEN...
TYPICAL SLIGHTLY WIDER DAILY DIURNAL TEMPERATURES MOST DAYS WEDNESDAY
INTO NEXT WEEKEND.

OVERVIEW...INITIALIZATION EXCELLENT WITH UPPER TROUGH NOW ONSHORE
IN PACIFIC NORTHWEST CONUS.  VERIFICATION AT 06Z CONTINUES TO
SUPPORT HI-RES ECMWF BEST OF MOISTURE AND RAIN TOTALS AND ALSO
COOLING WITH RISK OF INSTABILITY PRECIPITATION OF RAIN AND EVEN
WET SNOW LATE NEXT WEEK. USE OF D_PROG_DT TOOL WITH ENERGY SUPPORTS
A 80/20 MIX OF HI-RES ECMWF TO GFS.

MONDAY THROUGH MONDAY NIGHT...MINOR CHANGES MADE WITH HIGHER POPS
MAIN UPDATE.  MILD SOUTH WINDS OF 10 TO 20+ MPH SHOULD ALLOW WITH
PARTLY SUNNY SKIES UNTIL MID AFTERNOON FOR HIGHS MID/UPPER 70S SE
SECTIONS AND AROUND 70 DEGREES NORTHWEST. FORCING TO INCREASE WITH
MID AFTERNOON WITH POPS TO BLOOM OVER AREA TOWARD EVENING. NAM-WRF
TOO UNSTABLE WITH POOR BL INITIALIZATION.  OTHER SOLUTIONS MORE
REASONABLE WITH LIMITED INSTABILITY OF SBCAPE AOB 400J/KG AND
HIGH WBZ AOA 10K AGL AND CAP THROUGH 10K AGL TO PRECLUDE ANY
RISK OF HAIL OR GUSTY CONVECTIVE WINDS.  MONDAY NIGHT...A BAND OR
TWO OF RAIN AND RAIN SHOWERS AND ISOLATED STORMS...AHEAD OF VORT
MAX AND ALONG AND BEHIND FRONT WITH RAIN TOTALS MOSTLY .1 OF AN INCH
TO QUARTER INCH...AND LOCALLY AROUND A HALF INCH.  LOWS...INDICATIONS
OF CLEARING NW SECTIONS LOW TO MID 40S NW WITH FASTER CLEARING SKIES
AND LOW/MIDDLE 50S SE.

TUESDAY THROUGH SATURDAY...NW FLOW TO KEEP AREA MOSTLY BELOW NORMAL
WITH WEAK DISTURBANCE THURSDAY THAT MAY PRODUCE LIGHT SPRINKLES OR A
SHOWER FOR LATER SHIFTS TO CONSIDER.  FRIDAY AND SATURDAY...STRONGER
SHORT WAVE DIVING SOUTH FROM CANADA RESULTING IN COLDER TEMPERATURES
THAT ONCE AGAIN APPEAR WILL NEED LOWERING. LOCAL TOOLS SUPPORTS MINS
WITH SFC HIGH IN THE MID 20S MOST LOCATIONS FOR A HARD FREEZE AND
HIGHS THAT MAY MAKE ONLY THE MIDDLE 40S.  AXIS OF JET WITH SHORT
WAVE SUGGEST LATER MAY NEED TO ADD CHANCE POPS WITH FREEZING LEVELS
CLOSE TO A MIX OR EVEN A WET SNOW.  THIS ISSUE SHOULD BE CONFIRMED OR
CLARIFIED NEXT 24 HOURS.     NICHOLS

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 644 AM CDT SUN OCT 26 2014

A VFR TAF FCST TODAY THROUGH EARLY EVENING WITH JUST PASSING MID
AND HIGH LEVEL CLOUDS AS A WARM FRONT ORGANIZES AND LIFTS NORTH
THROUGH THE REGION. SFC WINDS WILL GO SOUTHEASTERLY THIS MORNING
AND INCREASE TO 10-15 KTS THIS AFTERNOON WITH SOME GUSTS. A LOW
CHC FOR SOME ISOLATED TO SCTRD ELEVATED SHOWERS AND POSSIBLY A
THUNDERSTORM IN THE VCNTY OF CID AND DBQ FROM LATE AFTERNOON
THROUGH THE EVENING. COVERAGE OF THIS ACTIVITY CURRENTLY EXPECTED
TO BE LIMITED AND MAY BE EVEN FURTHER TO THE NORTH...SO FOR NOW
WILL LEAVE MENTION OUT OF THE TAFS. ROUNDS OF VFR CLOUDS TONIGHT
WITH SOUTHEAST WINDS BECOMING MORE SOUTH TOWARD MON MORNING.
STRONG SOUTHWEST WINDS OF 40-50 KTS FROM 2-5K FT AGL LATE
TONIGHT...BUT EXPECT SFC WINDS TO MAINTAIN AT 10-15 KTS ENOUGH TO
LIMIT A TRUE LOW LEVEL WIND SHEAR SCENARIO.    ..12..

&&

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

$$

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






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