Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 162328
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
528 PM CST SUN NOV 16 2014

.UPDATE...
ISSUED AT 528 PM CST SUN NOV 16 2014

LOSS OF DAYTIME HEATING HAS HELPED TO REALLY CLEAR SKIES OUT BACK
IN THE DAKOTAS AND PARTS OF WESTERN MN. THIS CLEARING AREA LOOKS
POISED TO MOVE INTO THE REGION OVERNIGHT...SO MAY HAVE TO ADJUST
SKY COVER DOWNWARDS. STILL LOOKS LIKE CLOUDS WILL GREATLY INCREASE
IN THE MORNING AS THE SUN DESTABILIZES THE ATMOSPHERE UNDER THE
UNSEASONABLY COLD AIR ALOFT.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 158 PM CST SUN NOV 16 2014

PRIMARY CHALLENGES INCLUDE LIGHT SNOW TONIGHT THROUGH MONDAY AND
STRONG NORTHWEST WINDS IN THE WAKE OF AN ARCTIC FRONT THROUGH THE
DAY ON MONDAY. 16.12Z GLOBAL MODELS ARE IN GOOD AGREEMENT THROUGH
19.12Z...DIVERGING SOMEWHAT THEREAFTER IN TIMING AND STRENGTH OF
SHORT-WAVES MOVING THROUGH PARENT NORTHWEST FLOW ALOFT...BECOMING
MORE ZONAL BY NEXT WEEKEND.

16.20Z SURFACE ANALYSIS SHOWS A STRONG ARCTIC/COLD FRONT DRAPED
FROM NEAR ROSEAU MN TO ABERDEEN SD. THIS FEATURE WILL SWEEP
ACROSS THE UPPER MISSISSIPPI RIVER VALLEY OVERNIGHT...BRINGING
WITH IT SCATTERED LIGHT SNOW SHOWERS AMOUNTING TO NO MORE THAN AN
INCH OF ACCUMULATION AND STRONG NORTHWEST WIND IN ITS WAKE.

SURFACE OBS BEHIND THE FRONT THIS AFTERNOON ACROSS ND SHOWING
GUSTS IN EXCESS OF 30 KTS AND ALTHOUGH THIS AIR MASS WILL MODIFY
SOMEWHAT AS IT DROPS SOUTH...16.19Z RAP BRINGS A NOSE OF 35 TO 40
KTS AT 0.5 KM INTO THE WESTERN FORECAST AREA BY MONDAY MORNING.
WITH A DEEPENING WELL-MIXED BOUNDARY LAYER...THIS SHOULD RESULT IN
WIDESPREAD 20 TO 25 MPH NORTHWEST WINDS WITH FREQUENT GUSTS UP TO
35 MPH. THESE WINDS COMBINED WITH 2 TO 4 INCHES OF NEW SNOWFALL
FROM SUNDAY AND SUNDAY NIGHT ACROSS PORTIONS OF SOUTHEAST MN AND
NORTHEAST IA WILL RESULT IN AREAS OF BLOWING AND DRIFTING SNOW...
REDUCING VISIBILITY AT TIMES TO ONE HALF MILE OR LESS. WILL ISSUE
A WINTER WEATHER ADVISORY FOR BLOWING SNOW FROM 17.12Z TO 18.00Z
ACROSS THE WESTERN THIRD OF THE FORECAST AREA. THE COMBINATION OF
POOR VISIBILITY AND BLOWING SNOW WILL CREATE DIFFICULT TRAVEL
CONDITIONS FOR THE MORNING COMMUTE AND CONTINUING THROUGH MUCH OF
THE DAY.

OTHERWISE...MONDAY WILL BE MOSTLY CLOUDY AND COLD WITH AFTERNOON
HIGHS ONLY IN THE TEENS. SCATTERED LIGHT SNOW SHOWERS WILL RESULT
IN MINOR ADDITIONAL ACCUMULATIONS.

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 158 PM CST SUN NOV 16 2014

850 HPA TEMPERATURES PLUNGE TO -18 C ACROSS THE FORECAST AREA BY
18.12Z (TUESDAY MORNING). THIS WILL RESULT IN THE COLDEST MORNING
SO FAR THIS SEASON. TEMPERATURES WILL FALL INTO THE SINGLE DIGITS
ABOVE ZERO WITH FAVORED COLD SPOTS DROPPING BELOW ZERO. COMBINED
WITH WESTERLY WINDS FROM 10 TO 15 MPH...WIND CHILL VALUES WILL BE
IN THE 10 TO 20 BELOW RANGE. THE REST OF TUESDAY WILL BE DRY AND
SHOULD SEE SOME PEAKS OF SUNSHINE LATE IN THE DAY AS MONDAY/S SNOW
MOVES OFF TO THE EAST. TEMPERATURES WILL TOP OUT IN THE MID TEENS.

A REINFORCING SHOT OF ARCTIC AIR WILL DROP SOUTH TUESDAY NIGHT
BEHIND THE NEXT COLD FRONT. MOST SNOW WILL FALL TO THE NORTH AND
EAST NEAREST THE BEST MID-LEVEL FORCING AND HIGHEST MOISTURE...
ALTHOUGH SOME SCATTERED LIGHT SNOW IS POSSIBLE ACROSS THE FORECAST
AREA WITH ACCUMULATIONS LESS THAN ONE INCH.

WEDNESDAY THROUGH FRIDAY WILL BE DRY AND UNSEASONABLY COLD. BROAD
SURFACE HIGH PRESSURE DRIFTS ACROSS THE UPPER MISSISSIPPI RIVER
VALLEY THROUGH THIS PERIOD...CENTERED ACROSS NORTHERN MO BY 12Z
FRIDAY. THE REGION REMAINS FULLY ENTRENCHED WITHIN ARCTIC AIR
MASS THROUGH FRIDAY WITH DAILY HIGHS IN THE MID TEENS AND 20S AND
LOWS IN THE SINGLE DIGITS TO TEENS. DEPENDING ON CLOUD COVER...
THURSDAY NIGHT LOWS COULD RIVAL THOSE FROM TUESDAY MORNING.

MID-LEVEL THERMAL RIDGE FINALLY MAKES SOME EASTWARD PROGRESS BY
THE WEEKEND. WARM AIR ADVECTION REGIME SHOULD ALLOW TEMPERATURES
TO CLIMB BACK INTO THE 30S. HOWEVER...BOTH THE 16.12Z GFS AND
ECMWF SHOW THE NEXT STORM SYSTEM LIFTING NORTH FROM THE SOUTHERN
PLAINS OVER THE WEEKEND. THE ECMWF IS FARTHER WEST WITH ITS
PRECIP THAN THE GFS...SO FOR NOW WILL FOLLOW A BLENDED APPROACH
WITH 20 TO 30 POPS AND THE POTENTIAL FOR MIXED PRECIP GIVEN WARMER
TEMPERATURES ALOFT.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 528 PM CST SUN NOV 16 2014

LOSS OF DAYTIME HEATING OVER THE LAST 2 HOURS HAS REALLY HELPED
GET RID OF A LOT OF MVFR CLOUDS ACROSS THE DAKOTAS AND MINNESOTA.
THIS TREND HAS RESULTED IN A MUCH MORE OPTIMISTIC TAF
FORECAST...ESPECIALLY FOR TONIGHT. AN ARCTIC COLD FRONT TRACKING
THROUGH MINNESOTA IS POISED TO CROSS THE TAF SITES TONIGHT. THERE
IS A BRIEF BAND OF LIGHT SNOW WITH VFR TO MVFR VISIBILITIES AHEAD
OF THE FRONT IN CENTRAL MN...WHICH COULD AFFECT BOTH TAF SITES.
RST BEING A HIGHER TERRAIN SITE AND MORE EXPOSED HAS THE BEST SHOT
OF SEEING THESE LOWER VISIBILITIES. CLOUDS THEN LOOK TO CLEAR OUT
AS WINDS SHIFT WEST TO NORTHWESTERLY AT 10-15 KT. ONCE THE SUN
COMES UP...ANTICIPATING MVFR STRATOCUMULUS TO FORM QUICKLY...
FOLLOWED BY SCATTERED-NUMEROUS SNOW SHOWERS A FEW HOURS
THEREAFTER. WITH WINDS BECOMING GUSTY AT 20-30 KT...STRONGEST AT
RST...BLSN WITH MVFR CONDITIONS ARE LIKELY AT RST. LATE IN THE
AFTERNOON...LOSS OF DAYTIME HEATING SHOULD ALLOW CEILINGS TO
CLIMB.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...WINTER WEATHER ADVISORY FROM 6 AM TO 6 PM CST MONDAY FOR MNZ086-
     087-094-095.

IA...WINTER WEATHER ADVISORY FROM 6 AM TO 6 PM CST MONDAY FOR IAZ008-
     009-018-019.

&&

$$

UPDATE...AJ
SHORT TERM...ROGERS
LONG TERM...ROGERS
AVIATION...AJ



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