Area Forecast Discussion
Issued by NWS La Crosse, WI

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000
FXUS63 KARX 190952
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
352 AM CST WED NOV 19 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 352 AM CST WED NOV 19 2014

AT 3 AM...LIGHT SNOW OR FLURRIES WAS FALLING ALONG AND NORTH OF
AUSTIN MINNESOTA TO WISCONSIN RAPIDS LINE. THIS WAS IN RESPONSE TO
SYNOPTIC LIFT ASSOCIATED WITH A SHORT WAVE TROUGH MOVING EAST
THROUGH WESTERN WISCONSIN. THE 19.00Z MODELS ARE IN GOOD AGREEMENT
THAT THIS SYSTEM WILL MOVE EAST OF THE AREA THIS MORNING. THIS
WILL BRING AN END TO ACCUMULATING SNOW. HOWEVER WITH CYCLONIC FLOW
ALOFT AND 950 TO 900 MB LAPSE RATES RUNNING AROUND 9C/KM...WE WILL
LIKELY SEE FLURRIES OR SCATTERED SNOW SHOWERS THROUGHOUT THE
REMAINDER OF TODAY. IN ADDITION TO THIS...THE NORTHWEST WINDS WILL
GUST INTO THE 25 TO 35 MPH RANGE THIS AFTERNOON. THIS MAY RESULT
IN SOME PATCHY AREAS OF BLOWING SNOW. THIS WILL BE MORE LIKELY IN
SOUTHEAST MINNESOTA AND NORTHEAST IOWA...AND ON THE RIDGE TOPS AND
OPEN AREAS OF WESTERN WISCONSIN.

FOR TONIGHT...IT CONTINUES TO LOOK LIKE WE WILL SEE CYCLONIC FLOW
ALOFT AND YET ANOTHER SHORT WAVE TROUGH MOVING THROUGH NORTHERN
MINNESOTA AND WISCONSIN. HOWEVER THE MODELS CONTINUE TO SHOW THAT
CLEARING WILL TAKE PLACE THIS EVENING. AM A BIT CONCERNED THAT THE
CLOUDS MAY STICK AROUND A LOT LONGER THAN WE CURRENTLY HAVE IN OUR
FORECAST GRIDS. IN ADDITION...SOME OF THE SOUNDINGS SUGGEST THAT
THERE WILL BE SOME WEAK OMEGA IN THE DENDRITIC ZONE AND STILL SOME
STEEP LAPSE RATES IN THE 950 TO 900 MB LATER. THIS WOULD SUGGEST
THE POTENTIAL FOR AT LEAST SOME FLURRIES. LOOKING UPSTREAM...THERE
IS SOME LIGHT SNOW ASSOCIATED WITH ACROSS NORTHERN MANITOBA.  IF
THIS TREND CONTINUES...THE DAY SHIFT MAY HAVE TO ADD THESE TO THE
FORECAST.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 352 AM CST WED NOV 19 2014

ON THURSDAY...THE MODELS CONTINUE TO SHOW THAT ANOTHER OF VERY
COLD AIR WILL MOVE SOUTHEAST INTO THE UPPER MISSISSIPPI VALLEY AND
GREAT LAKES. 850 MB TEMPERATURES WILL RANGE FROM -14 TO -18C.
NAEFS SHOWS THAT THIS IS 2 TO 3 STANDARD DEVIATIONS BELOW NORMAL.
THIS WILL LIKELY RESULT IN ANOTHER DAY WITH TEMPERATURES IN THE
TEENS.

LATE FRIDAY NIGHT INTO SATURDAY...A NEGATIVELY TITLED SHORT WAVE
TROUGH IN THE SOUTHERN STREAM WILL MOVE FROM THE MID MISSISSIPPI
RIVER VALLEY NORTHEAST INTO THE GREAT LAKES. STRONG WARM AIR
ADVECTION WILL MOVE INTO THE AREA ON FRIDAY NIGHT AND THEN
CONTINUE INTO SATURDAY MORNING. 850 MB TEMPERATURES CLIMB FROM
BETWEEN 0C TO -4C AT 00Z SATURDAY TO BETWEEN 2 AND 6C BY 18Z
SATURDAY. WITH DRY AIR ABOVE 850 MB...SOUNDINGS CONTINUE TO SHOW
THAT THERE WILL BE NO ICE CRYSTAL SEEDING FROM ALOFT. AS A
RESULT...THE PRECIPITATION WILL BE PRIMARILY IN THE FORM OF
LIQUID. THERE WILL BE THE POTENTIAL FOR FREEZING RAIN WHERE
TEMPERATURES HAVE NOT SUFFICIENTLY WARMED. IN ADDITION...MAY HAVE
TO CONTEND WITH COLD ROADS TOO INITIALLY. IN ADDITION TO THE
FREEZING RAIN THREAT...SOUNDINGS SUGGEST THAT THERE MAY BE SLEET
DUE TO THE VERY COLD NEAR THE GROUND ALONG AND NORTH OF INTERSTATE
90. FORTUNATELY...IT LOOKS LIKE THE PRECIPITATION WILL BE ARRIVING
MUCH LATER /BETWEEN 3 AM AND 6 AM/ THAN ORIGINALLY
ANTICIPATED...SO THIS WILL ALLOW FOR A CHANCE TO WARM UP BEFORE
ITS ARRIVAL. WITH VERY WARM ALOFT LATER ON SATURDAY MORNING AND
DURING THE AFTERNOON...EXPECT THE WINTRY MIX TO TRANSITION QUICKLY
OVER TO RAIN.

ON SATURDAY NIGHT...ANOTHER NEGATIVELY TILTED SHORT WAVE TROUGH
IN THE SOUTHERN STREAM WILL MOVE TO OUR SOUTHEAST. SOUNDINGS
CONTINUE TO SUGGEST THAT THIS PRECIPITATION WILL BE LIQUID. LIKE
YESTERDAY...THE CONSOLIDATED MINIMUM TEMPERATURE GRID LOOKS TOO
COLD...SO RAISE THEM A COUPLE OF DEGREES ABOVE FREEZING. THIS IS
LIKELY NOT ENOUGH YET...BECAUSE 6 OF THE LAST 7 COBB RUNS SHOW
THAT THE TEMPERATURES WILL BE IN THE LOWER TO MID 40S ACROSS
NORTHEAST IOWA AND SOUTHWEST WISCONSIN...AROUND 40 ALONG
INTERSTATE 90...AND IN THE MID AND UPPER 30S ACROSS THE REMAINDER
OF THE AREA. WITH TEMPERATURES ABOVE FREEZING...REMOVED THE WINTRY
MIX FROM THE FORECAST.

FROM SUNDAY NIGHT INTO MONDAY...TWO WAVES /ONE IN THE SOUTHERN
STREAM AND YET ANOTHER ONE IN THE NORTHERN STREAM/ WILL BRING YET
ANOTHER ROUND OF PRECIPITATION. THIS PRECIPITATION WILL LIKELY
START OUT AS RAIN AND THEN TRANSITION OVER TO SNOW AS COLDER AIR
MOVES INTO THE REGION.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1125 PM CST TUE NOV 18 2014

SWATH OF WARM AIR ADVECTION ADVANCING EASTWARD ACROSS THE REGION AT
LATE EVENING...SERVING TO HELP SATURATION RATHER THAN PRODUCE
PCPN...ALTHOUGH SOME SPOTTY -SN WAS NOTED. MOST OF THE CLOUD DECK
WAS VFR IN THE 5-7 KFT RANGE.

THE RESPONSIBLE UPPER LEVEL SHORTWAVE TROUGH WILL SPIN ACROSS THE
REGION OVERNIGHT...DRAGGING ITS ASSOCIATED SFC FRONT ACROSS THE TAF
SITES NEAR 12Z. BUFKIT SOUNDINGS ARE ADAMANT THAT CIGS WILL LOWER
AHEAD OF THE FRONT...MOSTLY 1.5-2.5 KFT. SFC OBS VERIFYING A DROP IN
THE CLOUD HEIGHTS...AND WILL CONTINUE THIS TREND AT KRST/KLSE. -SN
ALSO DEVELOPING IN THIS LOWERING CLOUD DECK...AND SOME VSBYS
DROPPING INTO MVFR. A FEW 21/2SM. CONFIDENCE SHAKY ON WHETHER SUB
3SM -SN WILL SLIDE ACROSS KRST/KLSE...BUT IF IT WOULD...SHOULD BE
SHORT-LIVED. THE WHOLE SYSTEM IS A QUICK MOVER...AND EXPECT UNDER AN
INCH OF SNOW.

WINDS ARE GOING TO INCREASE FROM THE NORTHWEST AND BECOME GUSTY AS
THE SYSTEM/S SFC FRONT SWEEPS THROUGH. DEPENDING ON HOW MUCH SNOW
FALLS SOME MVFR VSBY RESTRICTIONS POSSIBLE DUE TO BLSN AT KRST WED
MORNING. HOW LONG THAT STICKS AROUND IS UNCERTAIN...ALTHOUGH
GENERALLY CONDITIONS SHOULD IMPROVE AFTER THE FIRST FEW HOURS OF
BLOWING SNOW - IF NO NEW SNOW IS ADDED TO THE MIX.


&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&

$$

SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION....RIECK



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