Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 261850
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1250 PM CST MON JAN 26 2015

.UPDATE...
ISSUED AT 1247 PM CST MON JAN 26 2015

STRONG WARM AIR ADVECTION/FORCING THAT PRODUCED A ROUND OF ACCUMULATING
SNOW TO MOST OF THE CWA THIS MORNING HAS JUST ABOUT EXITED OUR FAR
EASTERN COUNTIES. ACCUMULATIONS HAVE RANGED FROM 0.2 TO 1.3 INCHES
ACROSS THE CWA.

MEANWHILE...THE WESTERN EDGE OF THE CLOUDS WAS IN OUR FAR WESTERN
COUNTIES BUT THE CLOUDS WERE MOVING SOUTHWARD SO ANY CLEARING SHOULD
REMAIN IN OUR FAR WEST WITH CLOUDY SKIES ELSEWHERE.

&&

.SYNOPSIS...
ISSUED AT 328 AM CST MON JAN 26 2015

NORTHWEST FLOW ALOFT...WITH ANOTHER CLIPPER POISED IN NORTHERN
MINNESOTA IS IN PLACE EARLY THIS MORNING. AT THE SURFACE...A VERY
NARROW SURFACE RIDGE IS RIGHT OVER OUR CWA...WITH THE ONLY CALM
WINDS IN THE MIDWEST FOUND FROM SOUTHEAST IOWA THROUGH SOUTHEAST
WISCONSIN. UNDER A NARROW SLIVER OF CLEAR SKIES BETWEEN THE CIRRUS
TO THE SOUTHEAST...AND EXTENSIVE STRATUS TO THE WEST...WE HAVE
SHARPLY RADIATED OUT OVER THE FRESH SNOW FROM THE QUAD CITIES TO
DUBUQUE. AS OF 2 AM...LIKELY NEAR OUR LOWS...READINGS AS COLD AS THE
SINGLE DIGITS ARE TAKING PLACE ALONG THIS AXIS...WHILE TEMPERATURES
JUST TO THE WEST IN THE STRATUS ARE HOLDING NEAR 30.  THE STRATUS IS
FOUND ALONG A EXTREMELY SHARP WARM FRONT JUST TO OUR WEST ENHANCED
BY DOWN SLOPE CONDITIONS IN THE WESTERN PLAINS.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 328 AM CST MON JAN 26 2015

THE CLIPPER UPSTREAM WILL BE ACTING ON THIS STRONG FRONTAL
BOUNDARY...AND WITH STRATUS IN PLACE...AND STRONG LIFT ARRIVING IN A
NARROW AXIS ON THE COLD SIDE OF THE BOUNDARY TODAY...WE WILL LIKELY
SEE SNOW BREAKING OUT JUST ON THE COLD SIDE OF THE BOUNDARY. THAT
MEANS SNOW FOR EASTERN IOWA AND NORTHWEST ILLINOIS THIS MORNING. IT
SHOULD NOT LAST LONG...BUT WITH STRONG LIFT...SOME LIGHT TO MODERATE
SNOW MAY FALL FOR AROUND 1 TO 2 HOURS FOR LOCATION ALONG AND EAST OF
INTERSTATE 380. THE SNOW MAY FALL MODERATELY AND DENDRITIC BASED ON
MODEL DATA...BUT THE SHORT DURATION SHOULD MAKE MOST OF THE DAY DRY
FOR NEARLY ALL LOCATIONS. THAT SAID...WITH THE MORNING START OF THE
BAND OF SNOW...IT SHOULD ACCUMULATE...AND A HALF TO 1 INCH SEEMS
POSSIBLE. WE PLAN TO HANDLE THIS WITH SPS PRODUCTS AND SOCIAL MEDIA
POSTS GIVEN THE SHORT FUSED IMPACTS THIS MORNING.

AFTER THE WAVE MOVES THROUGH IN THE WEST...WE WILL SEE SIGNIFICANT
WARMING TODAY. HIGHS WILL BE A CHALLENGE...BUT WILL CONSERVATIVELY
GO WITH LOWER TO MID 40S WEST...AND HOLD THE EAST IN THE UPPER 20S.
HAVING A TIGHT BOUNDARY WITH CLOUDS OVER HEAD OFFERS UP A HUGE BUST
POTENTIAL BY DEFINITION...SO FOLLOW SHORT TERM TRENDS OF THE FRONT
LOCATIONS TODAY FOR CHANGES IN OUR FORECAST.

TONIGHT...LIFT IN THE FAR NORTHEAST SHOULD END BY 9 PM...WITH
FLURRIES OR FREEZING DRIZZLE AT THE TAIL END OF THE EVENT AS WE LOSE
ICE INTRODUCTION INTO THE LOWER CLOUDS. THIS SETS UP A MAINLY DRY
NIGHT...WITH MIXING CONTINUING THROUGH THE NIGHT AND MAINLY CLOUDY
SKIES EAST. THUS...LOWS SHOULD ONLY FALL TO THE MID 20S EAST TO
LOWER 30S WEST OVERNIGHT.
ERVIN

.LONG TERM...(TUESDAY THROUGH NEXT SUNDAY)
ISSUED AT 328 AM CST MON JAN 26 2015

TUESDAY AND WEDNESDAY...LATEST SUITE OF 00Z RUN MEDIUM RANGE MODEL
SOLUTIONS SFC RIDGE TO PASS EAST ACRS THE AREA TUE INTO TUE
EVENING...WITH STRATOCU FIELD ALONG AND EAST OF THE MS RVR ALSO
MAKING HEADWAY EAST OR DECREASING SOME DIURNALLY TO ALLOW FOR SOME
INSOLATION. BUT FCST SOUNDINGS SUGGEST WEAK FLOW/MIXING
SCENARIO...AND ALONG WITH LINGERING SNOW COVER WILL SIDE WITH COOLER
TEMP GUIDANCE ACRS THE EAST/NORTHEAST...BUT WILL GO CLOSER TO THE
WARMER ECMWF MOS IN THE WEST AND SOUTH WHERE SOME AFTERNOON RETURN
FLOW MAY HAVE AN EFFECT. BACKING LOW TO MID LEVEL FLOW REALLY STARTS
TO TAP INTO PLAINS THERMAL RIDGE AND WAA TUE NIGHT MAKING FOR A
POTENTIALLY BROAD WARM WEDGE/INVERSION ALOFT IN THE H9-H65 MB LAYER
INTO WED MORNING. WILL KEEP THE FCST DRY...BUT SIGNS OF AT LEAST A
WARM AIR ADVECTION WING OF MID DECK CLOUDS MOVING ACRS THE REGION
AHEAD OF THE WARM PUSH ALOFT.

WESTERN RIDGE-RIDING WAVE WILL LOOK TO DIG DOWN ACRS THE PLAINS LATE
TUE NIGHT INTO WED...TRYING TO PHASE WITH SOUTHERN STREAM ENERGY. OF
COURSE THE VARIOUS 00Z MODEL RUNS ALL HAVE THEIR DIFFERENCES IN
HANDLING OF THIS PROCESS...BUT THE GENERAL IDEA IS THAT WHAT EVER
WAVE DEVELOPS AND PROPAGATES ACRS THE MO RVR VALLEY...IT WILL INDUCE
A STRENGTHENING LLVL WARM AIR ADVECTION MODE ACRS THE LOCAL AREA BY
WED. FOR NOW WILL SIDE WITH THE MORE MODEST OF WARM UP POTENTIAL. BUT
THIS STILL SUGGESTS WIDESPREAD UPPER 30S TO MID 40S ACRS THE
NORTHEASTERN HALF OF THE CWA...WITH THE FAR SOUTHWEST BREACHING THE
50 DEGREE MARK. THE 00Z ECMWF TAKES THE DEVELOPING SFC LOW ASSOCIATED
WITH THE APPROACHING UPPER TROF RIGHT ACRS CENTRAL IA INTO NORTHERN
IL...WITH THE 00Z GFS A BIT FURTHER SOUTH ALONG THE IA/MO BORDER INTO
CENTRAL IL WED INTO THU MORNING. MODELS STILL HAVING A TIME PICKING
UP ON EVENTUAL MOISTURE RETURN AND SATURATION THAT THIS WAVE WILL BE
ABLE TO UTILIZE...BUT CURRENTLY INDICATED LIFT/STRENGTH SWEEPING ACRS
THE AREA SUGGESTS THAT EVEN MODEST MOISTURE RETURN SHOULD BE ABLE TO
PRODUCE LIGHT TO POCKETS OF MODERATE PRECIP. TIMING LOOKS TO BE
MAINLY WED NIGHT WITH MAINLY RAIN IN WAA PATTERN FOR FIRST HALF OF
THE NIGHT. THEN DEPENDING ON WAVE PASSAGE TIMING...LLVL COLD
CONVEYOR WRAP IN BEHIND THE SYSTEM...AS WELL AS DYNAMICAL TOP-DOWN
COOLING FOR A POTENTIAL SWITCH OVER TO A WINTRY MIX IN THE
NORTHWESTERN THIRD TO HALF OF THE DVN CWA TOWARD THU MORNING. WILL
KEEP LOW TO MODERATE CHC POPS THIS PERIOD TO MARK THE WINDOW OF
PRECIP POTENTIAL. CURRENT SYSTEM TIMING SUGGESTS LOWS WED NIGHT WILL
OCCUR AT DAWN...AFTER HOLDING UP WELL ABOVE FREEZING FOR MOST OF
THE NIGHT.

THURSDAY AND FRIDAY...THU COULD BE A RAW DAY WITH SCTRD SNOW SHOWERS
AND FLURRIES IN THE WAKE OF THE PASSING LOW PRESSURE SYSTEM AND IN
INCREASING LLVL COLD AIR ADVECTION PATTERN. TIGHT PRESSURE GRADIENT
BEHIND THE DEPARTING WAVE MAY ALSO MAKE FOR A BLUSTERY DAY WITH
BRISK NW SFC WINDS GUSTING WELL OVER 30 MPH. MORNING HIGHS MID TO
UPPER 30S...THEN FALLING AS THE DAY PROGRESSES. THEN IT APPEARS A
PASSING BOUT OF BOTH SFC AND UPPER RIDGING TO MAKE FOR DRY AND
SEASONABLE CONDITIONS FOR THE END OF THE WEEK.

NEXT SATURDAY AND SUNDAY...LONGER RANGE INDICATIONS/ENSEMBLE TRENDS
SUGGEST WEST COAST UPPER RIDGE AMPLIFICATION AND ALMOST A TYPE OF
TEMPORARY REX BLOCK DEVELOPMENT TO CARVE OUT A COLD CORE L/W TROF
ACRS THE GRT LKS AND INTO THE NORTHEASTERN CONUS. LATEST RUNS
SUGGEST BRUNT OF POTENTIAL ARCTIC AIR SURGE TO THE NORTHEAST OF THE
REGION OR JUST CLIPPING THE MID/UPPER MS RVR VALLEY OVER THE
WEEKEND...WITH A CLIPPER TYPE SYSTEM RIPPLING ALONG THE PROCESS
SOMEWHERE ACRS THE UPPER MIDWEST. TIMING PROBLEMATIC AT THIS POINT
BUT THE LATEST SOLUTIONS SUGGEST A POTENTIAL SNOW CHC IN OR
NEAR THE LOCAL FCST AREA EITHER SAT OR SAT NIGHT. ANOTHER ONE SUNDAY
NIGHT INTO MON...THEN SIGNS OF ANOTHER ARCTIC SURGE FURTHER WEST
AND SOUTH WHICH MAY TARGET THE REGION EARLY NEXT WEEK...THE LATEST
ECMWF HAS -22 TO -26C BY MON EVENING...THE 00Z GFS NOT QUITE AS
COLD BUT STILL TARGETS MON INTO NEXT TUE WITH A CANADIAN AIR MASS
DUMP.   ..12..

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1247 PM CST MON JAN 26 2015

MVFR CIGS THROUGH THIS TAF CYCLE. SOUTH WINDS BECOMING NORTHWEST
THIS AFTERNOON AND TONIGHT...THEN NORTH TO NORTHEAST ON TUESDAY.
WINDS SPEEDS 5 TO 15 KNOTS.

&&

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

$$

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






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