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000
FXUS63 KMPX 220546 AAB
AFDMPX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1146 PM CST SAT DEC 21 2013

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 224 PM CST SAT DEC 21 2013

EARLY AFTERNOON WATER VAPOR IMAGERY TOGETHER WITH GFS 21.12 500MB
WINDS AND HEIGHTS IDENTIFIED THE POWERFUL MID LATITUDE CYCLONE WITH
A TEXTBOOK BAROCLINIC LEAF CLOUD AND COMMA SHAPE APPEARANCE. THIS
STORM WAS WILL BE RESPONSIBLE FOR THE HEAVY SNOW ACROSS THE UPPER
MIDWEST...AND RECORD RAINFALL/FLOODING ACROSS THE OHIO RIVER VALLEY.
CLOSER TO HOME...THE ONLY INDICATION OF THIS STORM WAS THE GRADUAL
NORTHERLY ALIGNMENT OF THE SURFACE WINDS IN RESPONSE TO THE LOW
TRACKING NORTHEAST TOWARDS THE GREAT LAKES.

UPSTREAM A SHORTWAVE EMBEDDED IN THE NORTHWEST FLOW WILL DIVE
SOUTHWARD ALONG THE EASTERN SPINE OF THE ROCKIES...WITH A PV ANOMALY
ON THE POLEWARD SIDE SET TO MOVE ACROSS THE UPPER MISSISSIPPI RIVER
VALLY ON SUNDAY. THIS WILL PRODUCE A FEW LIGHT SNOW SHOWERS...AND
BUFR SOUNDINGS ALSO SHOW INCREASING NORTHERLY WINDS AS AN ARCTIC
FRONT MOVES THROUGH THE REGION LATE SUNDAY. SNOWFALL TOTALS WILL
GENERALLY BE AROUND AN INCH OR LESS FOR MOST LOCATIONS...WITH
SLIGHTLY HIGHER AMOUNTS ACROSS WESTERN WISCONSIN.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 224 PM CST SAT DEC 21 2013

EINSTEIN SUPPOSEDLY SAID THAT THE DEFINITION OF INSANITY IS DOING
THE SAME THING OVER AND OVER AGAIN AND EXPECTING DIFFERENT
RESULTS. CAN/T SAY IF IT HAS EXPECTED DIFFERENT RESULTS... BUT IF
SO THEN IT APPEARS THE ATMOSPHERE MAY BE SUFFERING FROM A FORM OF
INSANITY. A COMPARISON OF THE CURRENT 500MB LARGE SCALE FLOW WITH
THAT THE GFS AND ECMWF ARE SHOWING 10 DAYS FROM NOW SHOWS LITTLE
CHANGE IN THE LONGWAVE FEATURES. THE RIDGE OFF THE WEST COAST AND
UPPER LOW OVER EASTERN CANADA LOOK TO REMAIN IN ESSENTIALLY THE
SAME POSITIONS... WITH THE WESTERN ATLANTIC RIDGE SLIDING SLIGHTLY
EASTWARD. FOR US... THIS MEANS MORE OF THE SAME... WITH
TEMPERATURES GENERALLY BELOW NORMAL AS WE SEE AN ALBERTA CLIPPER
BRING REINFORCING SHOTS OF COLD AIR EVERY FEW DAYS ALONG WITH
MAINLY LIGHT SNOWFALL AND PERIODS OF BLOWING SNOW. THERE ARE SOME
DIFFERENCES IN THE DETAILS BETWEEN THE MODELS... BUT THEY ARE
FAIRLY MINOR... AND THE GFS AND ECMWF ENSEMBLES DON/T SHOW MUCH
SPREAD... SO THERE WOULD APPEAR TO BE DECENT CONFIDENCE IN A MORE
OF THE SAME FORECAST.

WE WILL SEE SOME LINGERING LIGHT SNOW/FLURRIES ON SUNDAY NIGHT
INTO MONDAY ON THE BACKSIDE OF SUNDAY/S SYSTEM... WITH CYCLONIC
FLOW LINGERING OVER THE AREA FOR MOST OF THE DAY. TEMPERATURES
WILL BE COLD... DROPPING QUICKLY SUNDAY NIGHT... THEN MOVING LITTLE
IF AT ALL UPWARD DURING THE DAY ON MONDAY. WILL LIKELY NEED A WIND
CHILL ADVISORY/WARNING FOR MUCH OF THE AREA DURING PARTS OF THE
SUNDAY NIGHT THROUGH MONDAY NIGHT PERIOD... BUT WILL WAIT A BIT TO
GET A BETTER HANDLE ON TIMING AND LOCATIONS... PARTICULARLY SINCE
THE COLD SHOULDN/T COME AS TOO MUCH OF A SHOCK/SURPRISE TO ANYONE
AT THIS POINT. HOWEVER... MONDAY NIGHT WILL BE ONE OF THE COLDEST
WE/VE SEEN IF THE CLOUDS DEPART... WHICH IT APPEARS THEY WILL AS
THE SURFACE RIDGE BUILDS OVER THE AREA. EVEN THE TWIN CITIES METRO
SHOULD MANAGE TO GET INTO THE 10 TO 15 BELOW ZERO RANGE FOR LOWS
MONDAY NIGHT. HOWEVER... TEMPERATURES WILL RISE ON TUESDAY AS WARM
ADVECTION ON THE BACKSIDE OF THE SURFACE HIGH WORKS INTO THE AREA.
THIS SHOULD LEAD TO SOME SNOWFALL TUESDAY AFTERNOON INTO TUESDAY
NIGHT AHEAD OF A CLIPPER WHICH WILL BE MOVING EAST ALONG THE
CANADIAN BORDER. SHOULD SEE SOME LIGHT ACCUMULATIONS OF FLUFFY
SNOW OCCUR... LEAVING A BLANKET OF HALF INCH TO AS MUCH AS TWO
INCH AMOUNTS OVER THE AREA FOR CHRISTMAS MORNING. WINDS WILL PICK
UP ACROSS THE AREA ON CHRISTMAS DAY AS COLDER AIR SURGES BACK INTO
THE REGION. WITH A FRESH COVERING LIGHT FLUFFY SNOW EXPECTED OVER
MUCH OF THE AREA... THIS COULD MAKE FOR LOCALLY HAZARDOUS DRIVING
CONDITIONS DUE TO BLOWING AND DRIFTING SNOW.

HIGH PRESSURE WILL BUILD OVER THE AREA ON THURSDAY... WITH
GENERALLY COLD AND DRY WEATHER TO CLOSE OUT THE WEEK. ANOTHER
CLIPPER LOOKS TO DROP TOWARD THE REGION OVER THE UPCOMING
WEEKEND... BUT KEPT THINGS DRY AT THIS POINT... SINCE THE ECMWF IS
A BIT SLOWER THAN THE GFS ON TIMING BOTH MODELS FOCUS THE BETTER
FORCING NORTH OF OUR AREA. THE MAIN FEATURE ASSOCIATED WITH THE
WEEKEND CLIPPER LOOKS TO BE THE STRONGER WARM ADVECTION AHEAD OF
IT... WHICH COULD PUSH TEMPERATURES BACK UP INTO THE 20S AND
PERHAPS NEAR 30 OVER THE SOUTHWEST PORTION OF THE AREA ON
SATURDAY. HOWEVER... COLDER AIR LOOKS TO DROP SOUTHEAST INTO THE
REGION ONCE AGAIN BEHIND IT AS WE MOVE TOWARD THE END OF THE
MONTH.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1137 PM CST SAT DEC 21 2013

MVFR CONDITIONS EXPECTED THROUGH THE PERIOD. SNOW WILL DEVELOP
LATE TONIGHT AND PERSIST INTO SUNDAY NIGHT FOR ALL TAF SITES
EXCEPT FOR RWF WHICH WILL BE TOWARD THE SOUTHERN FRINGE OF THE
STEADIER SNOW. SOME IFR VISIBILITIES ARE POSSIBLE AT TIMES...BUT
SHOULD BE SOMEWHAT BRIEF IN NATURE.

KMSP...HIGH END MVFR CIGS WILL DETERIORATE TO CIGS LESS THAN
FL017 BY AROUND 08Z. SNOW WILL BEGIN OVERNIGHT...BUT THE BEST
CHANCE FOR STEADY SNOW WILL OCCUR SUNDAY WHEN IFR CONDITIONS ARE
POSSIBLE FOR A TIME LATE SUNDAY MORNING.

/OUTLOOK FOR KMSP/
MON...VFR. WINDS NW AT 10-15 KTS.
TUE...MVFR/IFR WITH SNOW LIKELY AFTERNOON AND EVENING. WINDS S AT
10-15 KTS.
WED...MVFR WITH -SN/BLSN POSSIBLE. WIND W 15G25KT.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&

$$

SHORT TERM...JRB
LONG TERM...
AVIATION...BORGHOFF