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000
FXUS63 KDVN 051745
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1145 AM CST THU MAR 5 2015

.UPDATE...
ISSUED AT 1140 AM CST THU MAR 5 2015

ARCTIC HIGH PRESSURE OVER THE REGION PROVIDING SUNNY SKIES BUT
COLD TEMPERATURES. CURRENT READINGS WERE MAINLY IN THE SINGLE
DIGITS AND SEEM ON TARGET TO RISE INTO THE TEENS THIS AFTERNOON.
WARM AIR ADVECTION DEVELOPS LATER TONIGHT AS WINDS TURN SOUTHERLY
ON THE BACK SIDE OF THE DEPARTING HIGH PRESSURE RIDGE. A BAND OF
MID LEVEL CLOUDS SHOULD ALSO MOVE ACROSS THE CWA LATE TONIGHT.
THEREFORE...THE COLDEST READINGS TONIGHT SHOULD OCCUR THIS EVENING
WITH SLOWLY RISING TEMPERATURES AFTER MIDNIGHT.

&&

.SYNOPSIS...
ISSUED AT 255 AM CST THU MAR 5 2015

ARCTIC AIR...IS FULLY ESTABLISHED OVER IOWA AND ILLINOIS TODAY...AND
WILL PROVIDE ONE LAST FULL ON MID WINTER DAY IN MARCH. AFTER THAT
HOPE OF SPRING ARRIVES ON THE HEELS OF A CHILLY BREEZY TOMORROW.
ALOFT EARLY TODAY...850 TEMPERATURES ARE REMARKABLE FOR NEARLY ONE
WEEK INTO MARCH...WITH -18 OVER THE QUAD CITIES AND -24 OVER
MINNESOTA AND SOUTH DAKOTA. WINDS HAVE BEEN DECREASING AS THE LOW
LEVELS STABILIZE EARLY TODAY...ALLOWING TEMPERATURE TO DROP BELOW
ZERO IN NORTHEAST IOWA...AND THE SINGLE DIGITS CENTRAL...AND LOWER
TEENS SOUTH. THE REDUCED WIND IS HELPING WIND CHILLS REMAIN
GENERALLY ABOVE -20...THOUGH SOME ISOLATED SPOTS ARE HITTING THAT
LEVEL AS OF 2 AM. WE ARE HANDLING THAT WITH SPS PRODUCTS AND WILL
CONTINUE TO DO SO.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 255 AM CST THU MAR 5 2015

COLD...THAT REALLY SUMS UP TODAYS WEATHER IN A THE MOST BROAD
ACCURATE SENSE. WINDS TODAY WILL BE LIGHT NORTHWEST GENERALLY 10 MPH
OR LESS AS THE HIGH PRESSURE SOUTHEAST. THERE IS A SMALL PLUME OF
MOISTURE LOCATED BETWEEN DES MOINES AND KIRKSVILLE MISSOURI...WHICH
HAS PRODUCED A FEW FLURRIES AND SNOW SHOWERS OVERNIGHT...BUT THIS
SHOULD CONTINUE TO DROP SOUTH...AND DISSIPATE TODAY...LEAVING OUR
CWA IN MAINLY CLEAR SKIES. THUS...WE WILL MAKE THE MOST OF OUR
ARCTIC AIR WITH RESPECT TO HIGHS TODAY...STRONG MARCH SUN ON OLD
SNOW SHOULD HELP US BOOST OUR HIGHS A FEW DEGREES ABOVE
GUIDANCE...WHICH WAS THE CASE YESTERDAY AS WELL. HIGHS TODAY WILL
TOP OUT 12 OVER THE NORTH AND WAPSI VALLEY...WHERE THE CENTER OF THE
HIGH WILL TRACK...AND IN THE MID TO UPPER TEENS SOUTH...WHERE SNOW
PACK IS LESS OF A NEGATIVE FACTOR.  TONIGHT...THE NORTHWEST PATTERN
WILL BRING A DRY SHORT WAVE ALOFT THROUGH IOWA OVERNIGHT. THE HIGH
MOVING EAST AND FALLING PRESSURES OVER THE PLAINS WILL INDUCE A
CHANGE TO SOUTHERLY WINDS. WINDS SHOULD PICK UP TO 10 TO 15 MPH
AFTER MIDNIGHT...IN RESPONSE TO THIS CHANGE. THE INCREASED
MIXING...AS MID CLOUDS ASSOCIATED WITH THE SHORT WAVE TROF...SHOULD
CREATE RISE TEMPERATURES AFTER MIDNIGHT...FOLLOWING THE LOWS OF
AROUND ZERO IN THE EAST 1/2 TO 5 TO 10 IN THE FAR WEST.  BY
SUNRISE...TEMPERATURES AROUND 5 NORTHEAST TO 15 SOUTHWEST ARE
EXPECTED...ALONG WITH THE WIND...THAT WILL STILL PROVIDE A WIND
CHILL OF ZERO TO -12...SO THIS REALLY IS ANOTHER FULL 24 HOURS OF
COLD COMING OUR WAY.
ERVIN

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 255 AM CST THU MAR 5 2015

MAIN FORECAST CONCERN FOR THE EXTENDED IS THE CLIPPER SYSTEM PROG TO
MOVE THROUGH THE AREA SUNDAY.  AT THIS TIME THERE IS LOW CONFIDENCE
THAT THIS SYSTEM WILL RESULT IN MUCH MORE THAN SOME SPRINKLES OR
LIGHT WINTRY MIX ACROSS EXTREME NORTHEAST ZONES.  AFTER THIS...THE
WARM IS STILL ON WITH DISCREPANCIES IN THE GFS AND ECMWF MODELS
TOWARDS THE END OF THE PERIOD.

LOOKS LIKE THE BEGINNING OF THE SNOW MELT WILL START FRIDAY IN
SOUTHERN ZONES AND OVERTAKE THE REST OF THE CWA BY SATURDAY WITH
HIGH TEMPERATURES FINALLY ABOVE FREEZING.  OVERNIGHT THE
TEMPERATURES WILL STILL GET COLD ENOUGH TO HAVE THE SNOW
REFREEZE...SO THE MELT COULD AFFECT UNTREATED SURFACES AT NIGHT WITH
SOME ICE.

NOW FOR THE CLIPPER ON SUNDAY.  MODELS ARE IN GOOD AGREEMENT WITH
THE VORT COMING THROUGH THE AREA.  THE 00Z GFS IS THE ODD MAN OUT
WITH NO PRECIP.  LOOKING AT DPROG/DT...IT APPEARS THAT THE 12Z AND
18Z RUNS HAD PRECIP MUCH LIKE THE 00Z GEM.  IT APPEARS THAT THE 00Z
GEFS MEAN IS LESS DEEP THAN THE GFS OPERATIONAL.  WITH THIS
SAID...WOULDNT BE SURPRISED TO SEE THE GFS SHIFT SOUTH AGAIN AS IT
WAS TRENDING THAT WAY LAST NIGHT.  AT THIS TIME IT APPEARS A WINTRY
MIX IS POSSIBLE IN THE AM...CHANGING OVER TO A COLD RAIN IN THE
AFTERNOON.

THEN THE WARM UP.  IT IS STILL FORECAST.  THE GFS AND ECMWF ARE BOTH
IN AGREEMENT WITH THIS.  THE LAST PERIOD OF THE FORECAST...THE LARGE
SCALE FLOW COULDNT BE ANY DIFFERENT BETWEEN THE MODELS...WITH THE
ECMWF BEING WARM...LIKE 60S WARM AND THE GFS BRINGING IN A COLD
FRONT AND COOLER.  RIGHT NOW THE SUPERBLEND LOOKED TO BE MORE
WEIGHTED TO THE COOLER GFS.  WE SHALL SEE WHAT LATER RUNS BRING.  IF
YOU LIKE SPRING...NEXT WEEK IS OUR FIRST GLANCE.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1140 AM CST THU MAR 5 2015

VFR CONDS THROUGH THIS TAF CYCLE. ARCTIC HIGH PRESSURE OVER THE
REGION THIS AFTERNOON WILL SHIFT OFF TO OUR EAST TONIGHT. NORTHWEST
TO WEST WINDS THIS AFTERNOON THEN SOUTH TONIGHT AND FRIDAY. WIND SPEEDS
WILL BE AROUND 10 KNOTS OR LESS.

&&

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

$$

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