Area Forecast Discussion
Issued by NWS La Crosse, WI

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000
FXUS63 KARX 221002
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
402 AM CST SAT NOV 22 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 251 AM CST SAT NOV 22 2014

CHALLENGES INCLUDE PRECIP TYPE/CHANCES/AMOUNTS THROUGH MONDAY AS A
STRONG LOW PRESSURE SYSTEM MOVES ACROSS THE UPPER MIDWEST. 22.00Z
GLOBAL MODELS INITIALIZED WELL AND ARE IN GOOD AGREEMENT THROUGH
AT LEAST 25.00Z (MONDAY NIGHT)...DIVERGING A BIT THEREAFTER IN
TIMING AND STRENGTH OF SHORT-WAVES IN NORTHWEST FLOW ALOFT.

22.09Z WATER VAPOR LOOP SHOWS A STRONG WAVE CRASHING ON THE PACIFIC
NORTHWEST SHORE AND THIS FEATURE WILL BE THE PRIMARY PLAYER FOR
THE NEXT FEW DAYS. LIGHT DRIZZLE/FREEZING DRIZZLE EARLY THIS MORNING
WILL DISSIPATE AND PUSH EAST AS THE DEEPEST MOISTURE MOVES INTO IL
AND SOUTHEAST WI. WILL KEEP 20 POPS ACROSS THE EASTERN HALF OF THE
FORECAST AREA TODAY FOR ANY LINGERING DRIZZLE...BUT ADDITIONAL
ACCUMULATION WILL BE A HUNDREDTH OR TWO AT BEST. OTHERWISE...TODAY
WILL BE MOSTLY CLOUDY AND WARM WITHIN THE WARM AIR ADVECTION
REGIME AS THE +10 C 850 HPA ISOTHERM APPROACHES THE FORECAST AREA
BY 23.00Z. AFTERNOON HIGHS WILL CLIMB INTO THE UPPER 30S TO MID
40S.

FOR TONIGHT...A STRONG WARM FRONT WILL SURGE NORTHWARD WITH THE
NEXT SLUG OF MOISTURE IN ITS WAKE. SATURATION ONLY EXPECTED TO
AROUND 2 KM OVERNIGHT WITH DRY AIR ALOFT...SO ANY PRECIP WILL
LIKELY STILL BE IN THE FORM OF DRIZZLE. TEMPERATURES BY THEN WILL
BE WELL ABOVE ZERO SO FREEZING WILL NOT BE AN ISSUE. THE BIGGER
CONCERN WILL BE WIDESPREAD FOG WITH THE 22.03Z SREF SHOWING A 100
PERCENT PROBABILITY THAT VISIBILITY WILL DROP BELOW 1 MILE
TONIGHT. THERE IS A CHANCE A DENSE FOG ADVISORY WILL BE NEEDED...
BUT WILL WAIT UNTIL CURRENT FREEZING RAIN ADVISORY HAS EXPIRED
AND/OR CANCELLED BEFORE MAKING ANY DECISIONS.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 251 AM CST SAT NOV 22 2014

ATMOSPHERIC COLUMN SATURATES TO AT LEAST 500 HPA BY SUNDAY
RESULTING IN DRIZZLE CHANGING OVER TO RAIN. STRONG FORCING/LIFT
FROM THE SURFACE TO 850 HPA ALONG AND AHEAD OF AN APPROACHING COLD
FRONT WILL RESULT IN WIDESPREAD RAIN THROUGH THE DAY. STILL SOME
UNCERTAINTY AS TO WHERE THE WESTERN EDGE OF THE PRECIP SHIELD WILL
SET-UP...BUT AT THIS TIME APPEARS TO BE NEAR A LINE FROM HUDSON WI
TO MASON CITY IA. RAINFALL AMOUNTS SUNDAY WILL GENERALLY RANGE
FROM OVER A HALF INCH ACROSS THE SOUTHEAST TO AROUND A TENTH
ACROSS THE NORTHWEST.

COLD FRONT WILL SWING ACROSS THE FORECAST AREA SUNDAY NIGHT
RESULTING IN A GRADUAL CHANGE OVER FROM RAIN TO SNOW. DEFORMATION
AXIS SNOW BAND WILL ROTATE AROUND THE BACKSIDE OF THE DEPARTING
LOW ON MONDAY GENERALLY RESULTING IN 1 TO 3 INCHES OF SNOW WITH
THE HIGHER AMOUNTS FURTHER NORTH AND EAST. NORTHWEST WIND WILL
ALSO INCREASE WITH GUSTS AS HIGH AS 30 MPH ACROSS PORTIONS OF
SOUTHEAST MN AND NORTHEAST IA...POSSIBLY CREATING SOME BLOWING AND
DRIFTING SNOW.

TUESDAY THROUGH FRIDAY WILL SEE A RETURN OF A SUB-FREEZING AIR
MASS WITH TEMPERATURES GENERALLY IN THE 20S DURING THE DAY AND
TEENS AT NIGHT. THE NEXT BEST CHANCE FOR LIGHT SNOW WILL BE
TUESDAY NIGHT THROUGH WEDNESDAY AS THE NEXT SHORT-WAVE DROPS SOUTH
IN NORTHWEST FLOW ALOFT. THANKSGIVING DAY INTO THE HOLIDAY WEEKEND
SHOULD BE DRY...BUT COLD AS SURFACE HIGH PRESSURE BUILDS ACROSS
THE NATION/S MID-SECTION.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1120 PM CST FRI NOV 21 2014

-RA/-DZ PUSHING NORTHEAST ACROSS EASTERN IA...HEADING INTO
WESTERN/SOUTHERN WI LATE THIS EVENING. LOW CIGS HAVE ALREADY SPREAD
ACROSS KRST/KLSE...AND WITH PUSH OF LOW LEVEL MOISTURE/WARM AIR
ADVECTION...ANTICIPATE SOME -DZ DEVELOPMENT AT KLSE. KRST WILL
LIKELY STAY WEST OF THE PCPN. WHILE AIR TEMPS SHOULD STEADY OR
SLOWLY RISE...ROAD TEMPS ARE FREEZING...AND THUS -FZDZ WILL BE THE
LIKELY PCPN TYPE FOR AT LEAST A FEW HOURS. WITH THE CONTINUED
WARMING EXPECT MOST PCPN TO SWITCH OF TO -RA/-DZ EARLY/MID MORNING
SAT.

IFR/MVFR CIGS ARE LIKELY TO STICK AROUND WELL INTO SUNDAY...PER
RAP/HRRR/GFS/NAM BUFKIT SOUNDINGS. THAT SAID...SOME HINTS THAT THERE
COULD BE SOME IMPROVEMENT...PERHAPS EVEN BRIEF SCATTERING...FOR LATE
AFTERNOON/EARLY EVENING. CONFIDENCE NOT HIGH HERE...SO WILL HOLD
ONTO THE LOW CIGS FOR NOW.

-RA/DZ LOOKS TO BECOME WIDESPREAD SAT NIGHT WITH ANOTHER SURGE OF
LOW LEVEL MOISTURE COUPLED WITH ISENTROPIC UPGLIDE ON THE 280-290 K
SFCS. CIGS SHOULD LOWER AND FOG BECOMES A GREATER
LIKELIHOOD...ADDING ANOTHER VSBY RESTRICTOR IN ADDITION TO THE
EXPECTED PCPN.

925 MB WINDS AT KDVN AT 35 KTS BUT UP TO 45 KTS AT KGRB. RAP/NAM12
BUFKIT SOUNDINGS HAVE WINDS IN THE 45-50 KT RANGE BY 2 KFT THROUGH
09Z...IMPROVING AFTER THAT. WILL CONTINUE MENTION FOR KLSE IN
FORECAST.


&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...FREEZING RAIN ADVISORY UNTIL 8 AM CST THIS MORNING FOR
     WIZ041>044-053>055-061.

MN...FREEZING RAIN ADVISORY UNTIL 8 AM CST THIS MORNING FOR MNZ096.

IA...FREEZING RAIN ADVISORY UNTIL 8 AM CST THIS MORNING FOR
     IAZ008>011-018-019-029-030.

&&

$$

SHORT TERM...ROGERS
LONG TERM...ROGERS
AVIATION....RIECK



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