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000
FXUS63 KDVN 291731 AAB
AFDDVN

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1131 AM CST THU JAN 29 2015

.UPDATE...
ISSUED AT 1036 AM CST THU JAN 29 2015

MAIN CHANGE TO THE SHORT TERM FORECAST WAS WITH THE CLOUD COVER
TONIGHT. HELD ON TO THE CLOUDS A TAD BIT LONGER ACROSS WESTERN IL.
IT APPEARS THAT THERE ARE SOME BREAKS UP NORTH IN MN...HOWEVER THE
CLEARING IS STILL ACROSS N MN AND HEADING SOUTH. THE TOA TOOL
SUGGEST IT GETS TO US IN 13 HOURS...THINK WE WILL BREAK UP SOONER.
OTHERWISE...SOME TWEAKS TO TEMP AND TD TRENDS WERE MADE. NO OTHER
SIG UPDATES EXPECTED BEFORE AFTERNOON PACKAGE AS TODAY LOOKS
RATHER QUIET.

&&

.SYNOPSIS...
ISSUED AT 331 AM CST THU JAN 29 2015

THE LOW PRESSURE WORKING THROUGH IOWA HAS CHOSEN PATH DIRECTLY ALONG
THE SOUTHERN EDGE OF THE EXISTING SNOW PACK. THIS SNOW PACK WILL NOW
BE IN PLACE FOR THE FORESEEABLE FUTURE...AS NO PART OF THE FORECAST
WILL DO ANY MELTING. THUS...AS OF 2 AM...THE LOW IS OVER
DAVENPORT...AND MOVING EAST. STRATUS IS SPREADING IN BEHIND THE
LOW...WITH VERY PATCHY LIGHT DRIZZLE IN THE FAR NORTHWEST.
TEMPERATURES RADIATED OUT PRIOR TO THE STRATUS ARRIVAL INTO THE
UPPER 20S TO LOWER 30S IN SEVERAL LOCATIONS...BUT THROUGH MIXING
UNDER THE STRATUS...MOST SITES UNDER THE CLOUDS ARE HOLDING IN THE
32 TO 35 RANGE. DEWPOINTS ARE ALSO 32 TO 34...THUS THIS REMAINS A
SITUATION NOT LIKELY TO PRODUCE FREEZING PROBLEMS.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 331 AM CST THU JAN 29 2015

TODAY WILL BE CLOUDY AND WINDY...AND FLAT LINED ON TEMPERATURES.
SOME DRIZZLE REMAINS POSSIBLE EARLY IN THE NORTH...BUT AS REPORTED
BY OUR OFFICE TO THE WEST IN DES MOINES...THIS IS SO LIGHT AS TO NOT
EVEN DOT PARKING LOT WINDSHIELDS. IF VISIBILITIES DO NOT DROP MUCH
BELOW 5 MILES...I IMAGINE THERE IS NO CHANCE OF NOTICEABLE DRIZZLE.
IT WILL BE WINDY TODAY...AND WINDS APPEAR SUSTAINED NEAR 20 MPH
DURING THE MID DAY HOURS...GUSTING TO AROUND 30 FREQUENTLY.
LOOKING UPSTREAM AND AT MODEL SOUNDINGS TODAY...IT LOOKS LIKE THERE
MAY BE A PERIOD FROM AROUND 9 AM TO 1 PM...WHERE SOME GUSTS REACH
NEAR 40 MPH...BUT BY LATE AFTERNOON THIS THREAT GREATLY IS REDUCED.
CLOUDS SHOULD LAST THROUGH LATE AFTERNOON...AND BY EVENING
SUBSIDENCE IS FORECAST...AND ANY CYCLONIC FLOW ALOFT IS GONE.
THUS...THE MODELS FORECASTING CLEARING MAY BE CORRECT...AND WE WILL
SHOW CLEARING IN OUR FORECAST. THIS SHOULD ALLOW FOR A COOL
NIGHT...WITH MID TEENS OVER THE SNOW...AND UPPER TEENS TO NEAR 20
ELSEWHERE IN THE SOUTH 1/2.
ERVIN

.LONG TERM...(FRIDAY THROUGH NEXT WEDNESDAY)
ISSUED AT 331 AM CST THU JAN 29 2015

FRIDAY THROUGH SUNDAY...PASSING BOUT OF BOTH SFC AND UPPER RIDGING
STILL ON TRACK TO MAKE FOR A FAIR WX BUT COOL FRI ACRS THE
REGION...ALTHOUGH SOME INSOLATION AND LIGHT RETURN FLOW BY MID TO
LATE AFTERNOON MAY WIPE OUT THAT COOL DESCRIPTOR FOR THE SOUTHWESTERN
CWA WITH HIGHS BACK INTO THE MID 30S. LOWS FRI NIGHT MAY BE IN THE
EVENING THROUGH 1 AM...BEFORE STEADY TO SLOW RISE TREND COMMENCES
INTO EARLY SAT MORNING WITH INCREASING RETURN FLOW AND POSSIBLY SOME
CIRRUS APPROACHING FROM THE SOUTHWEST.

ALL EYES THEN TURN TO THE POTENTIAL STORM SYSTEM FOR THE REST OF THE
WEEKEND...AS GULF OF AK WAVE ENERGY RIDGE-RIDES AND DIGS DOWN
SOUTHEASTWARD ACRS THE PLAINS. THIS OFF-SHORE WAVE STILL YET TO BE
SAMPLED BY THE UPPER AIR NETWORK...AND MODEL VARIANCES A PLENTY STILL
THERE WITH THE 00Z RUNS IN THE WAY THIS WAVE TRIES TO PHASE AND
INTERACT WITH SOUTHERN STREAM WAVE ENERGY TRYING TO EJECT OUT OF A
CUT-OFF UPPER LOW COMPLEX/THAT IS ALSO CURRENTLY OFF-SHORE OF
SOUTHERN CA AND THE BAJA/...THAT WILL BE MOVING ACRS THE SOUTHWESTERN
CONUS FRI NIGHT INTO SAT. THE PHASING WILL BE EVERYTHING...ALONG WITH
EXTENT OF GULF MOISTURE INJECTION OUT AHEAD AND UP INTO WHATEVER
TROF/WAVE SYSTEM THAT CAN DEVELOP. FEEL THE MEDIUM RANGE MODELS WILL
CONTINUE TO HAVE THEIR PROBLEMS/DIFFERENCES OVER THE NEXT 24 HRS OF
RUNS UNTIL THE DRIVING SYSTEMS MAKE IT ONSHORE. ASSESSING THE 00Z
RUNS...THE GEM AND NAM APPEAR THE MOST PHASED AND PRODUCE WIDESPREAD
ACCUMULATING SNOWS ACRS THE ENTIRE CWA FROM LATE SAT NIGHT AND INTO
SUNDAY. THE 00Z GFS PHASES THE SYSTEM FURTHER SOUTH AND TARGETS
GENERALLY THE SOUTH HALF OF THE DVN CWA WITH A QUICKER INCOMING SPEED
FROM SAT AFTERNOON THROUGH MIDDAY SUNDAY...WITH A RANGE OF 2-4 INCHES
ALONG AND JUST SOUTH OF I80...TO 5-7 INCHES IN THE SOUTHERN CWA. THE
00Z ECMWF IS THE LEAST DEVELOPED OF THE SOLUTIONS WITH PARTIAL
PHASING OF LESS SEPARATED AND WEAKER UPPER WAVES...ONE PROGRESSIVE
VORT MAX BY SAT EVENING AND ANOTHER ON SUNDAY. EITHER REALLY ARE
STRONG ENOUGH TO PULL A SINGULAR STRONGER LLVL SYSTEM FURTHER TO THE
NORTH THAT WOULD IMPACT THE LOCAL FCST AREA AS HARD AS THE OTHER
MODEL SOLUTIONS. THE 00Z ECMWF SNOW ALGORITHM ONLY PRODUCES 1-3
INCHES OF SNOW ACRS THE SOUTH HALF OF THE CWA BY SUNDAY EVENING.

NEEDLESS TO SAY WITH THE ONGOING MODEL UNCERTAINTIES...WILL NOT MAKE
MUCH CHANGES FROM THE CURRENT PHILOSOPHY AND KEEP HIGH CHC TO LIKELY
POPS GOING ACRS THE SOUTH HALF SAT NIGHT AND SUNDAY. IF INCOMING
PRECIP SLOWS AND DOES NOT ARRIVE UNTIL LATER SAT NIGHT/AS WHAT WILL
HAPPEN WITH A MORE PHASED SYSTEM/...SAT MAY GET RATHER MILD WITH WAA
AHEAD OF THE DEVELOPING SYSTEM PRODUCING HIGHS WELL UP IN THE 30S OR
EVEN SOME 40S POSSIBLE. DEPENDING ON THE EXIT SPEED AND PATH OF
WHATEVER SYSTEM CAN DEVELOP AND IMPACT THE CWA OVER THE WEEKEND...A
COLD CANADIAN HIGH PRESSURE SYSTEM LOOMS ON THE NORTHERN HORIZON TO
DUMP DOWN ACRS THE UPPER MIDWEST. PRESSURE BATTLE ZONE BETWEEN THE
TWO SYSTEMS MAY DRIVE STRONG NORTH WINDS BY LATE SUNDAY AND COMPOUND
ANY ONGOING WINTERY CONDITIONS. ASSESSING THE CURRENT UPPER AND
MIDDLE JET FLOWS CURRENTLY ONGOING ACRS THE EASTERN PACIFIC INTO THE
WEST COAST...AND EARLY HUNCH WOULD BE THAT A SOLUTION IN BETWEEN THE
00Z ECMWF AND THE 00Z RUN GFS MAY BE THE WAY TO GO.

MONDAY THROUGH NEXT WEDNESDAY...IN GENERAL THE ENSEMBLES AND LATEST
RUN MEDIUM RANGE SOLUTIONS ADVERTISE AMPLIFYING NORTHWESTERLY FLOW
DURING THE PERIOD...BECOMING ACTIVE WITH EMBEDDED WEAK TO MODERATE
STRENGTH CLIPPER SYSTEMS RIPPLING DOWN ACRS SOMEWHERE THRU THE
MIDWEST ALMOST EVERY OTHER DAY. SOME SOLUTIONS EVEN SUGGEST A DAY-TO-
DAY THREAT THROUGH AT LEAST NEXT FRI. IN BETWEEN THE WAVES THERE
WILL BE COLD AIR MASS UNDULATIONS...AND THEN RECOVERY AGAIN AHEAD OF
THE NEXT CLIPPER LOW. BUT OVERALL WILL ADVERTISE A COLDER WEEK AHEAD
WITH LOWS AT NIGHT BEHIND ANY PASSING CLIPPER POSSIBLY DOWN IN THE
SINGLE DIGITS OR NEAR ZERO. HIGHS IN THE TEENS OR 20S UNLESS A
STRONGER CLIPPER CAN DRAW UP PORTION OF SOUTHERN PLAINS MILDER
THERMAL POOL. BUT TIMING THESE SYSTEMS AND THEIR IMPACT ON DAY TO DAY
TEMPS VERY CHALLENGING AT THIS POINT AND WILL KEEP GENERAL MODEL
BLENDS ONGOING.    ..12..

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1120 AM CST THU JAN 29 2015

MVFR CONDITIONS WILL DOMINATE THROUGH THE EARLY EVENING HOURS AS
THE STRATUS DECK MOVES OUT OF THE AREA. SOME BREAKS IN THE DECK
ARE POSSIBLE TODAY BEFORE THE DECK MOVES OUT COMPLETELY. SOME
DRIZZLE IS POSSIBLE AT MLI AND BRL FOR THE NEXT FEW
HOURS...HOWEVER CONFIDENCE IS LOW WITH THAT. VFR CONDITIONS SHOULD
TAKE HOLD OVERNIGHT AND THROUGH THE END OF THE TAF PERIOD.

&&

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

$$

UPDATE...GIBBS
SYNOPSIS...ERVIN
SHORT TERM...ERVIN
LONG TERM...12
AVIATION...GIBBS