Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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000
FXUS63 KMKX 212130
AFDMKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
330 PM CST WED JAN 21 2015

.TONIGHT AND THURSDAY...FORECAST CONFIDENCE - HIGH.

500 MB SHORTWAVE TROUGH WILL SHIFT TOWARDS THE EAST TONIGHT OVER
MICHIGAN. AMPLE LOW LEVEL MOISTURE WILL LINGER OVER THE
AREA...PROVIDING ENOUGH SATURATION TO KEEP SKIES MOSTLY CLOUDY
DURING THE EVENING AND OVERNIGHT HOURS. CHANCES OF SNOW WILL
DECREASE AS THE MID-LEVEL SUPPORT SHIFTS TO THE EAST. SFC WINDS WILL
BACK WITH TIME FROM THE NORTH TO THE NORTHWEST TONIGHT...AND WILL
CONTINUE TO TURN DURING THE DAY THURSDAY TO A MORE SOUTHEASTERLY
DIRECTION BY 21Z THURSDAY. GFS40 AND NAM12 MODELS ARE SHOWING GOOD
AGREEMENT OF A BAND OF NVA TRANSLATING OVER WISCONSIN THURSDAY
MORNING AND AFTERNOON. SUBSIDENCE FROM THIS NVA BAND...COUPLED WITH
DECENT DRYING OF THE 1000-850MB LAYER WILL HELP SUPPORT CLEARING
OVER S WI BY 21Z THURSDAY.

.SHORT TERM...THURSDAY NIGHT THROUGH SATURDAY.

THURSDAY NIGHT AND FRIDAY...FORECAST CONFIDENCE HIGH

NOT A HUGE DROP IN TEMPERATURES OVERNIGHT WITH SLOWLY RISING 925-
850MB AHEAD OF SHORT WAVE MOVING ACROSS SRN CANADA...AND INCREASING
SWLY SURFACE WINDS IN TIGHTENING GRADIENT AS SURFACE RIDGE SAGS
SOUTH AND SURFACE LOW MOVES INTO WESTERN ONTARIO. AFTER LOWS IN THE
LOWER TO MID 20S...HIGHS EXPECTED TO NUDGE INTO THE MID-UPPER 30S IN
SPITE OF INCREASING CLOUDS.

FRIDAY NIGHT...FORECAST CONFIDENCE MEDIUM.

PAIR OF SHORT WAVES MOVE THROUGH LATE FRIDAY NIGHT AND LATE
MORNING/AFTERNOON SAT. MODELS AGREE THAT DEEPER MOISTURE AND BETTER
FORCING ACCOMPANY THE FRIDAY NIGHT WAVE...BUT DRY LAYER BETWEEN 2K
FT AND 6K FT ON FORECAST SOUNDINGS DURING PERIOD OF BEST LIFT WILL
LIMIT/PREVENT MUCH IN THE WAY OF ACCUMULATING PRECIPITATION. 12Z NAM
WAS DRY...POSSIBLY CLIPPING SHEBOYGAN COUNTY...WITH THE 18Z NAM NOW
BRINGING A BAND OF LIGHT QPF DOWN THE EASTERN-MOST COUNTIES WITH
GEM AND ECMWF BRUSHING THE NRN COUNTIES WITH QPF. WILL GO WITH A
CONSENSUS BLEND THAT BRINGS A SLIGHT CHANCE OF SNOW IN THE EVENING
ALONG AND NORTH OF THE DELLS TO PORT WASHINGTON. TOP-DOWN METHOD
INDICATES THE POTENTIAL FOR A PERIOD OF FREEZING RAIN OR FREEZING
DRIZZLE...ESPECIALLY AFTER MIDNIGHT..BUT POTENTIAL TOO LOW TO
MENTION AT THIS TIME.

SATURDAY...FORECAST CONFIDENCE MEDIUM

FORECAST SOUNDINGS SHOW A DRY COLUMN ABOVE 5K FT IN UNIDIRECTIONAL
NW FLOW. SOME OMEGA NOTED AS SHORT WAVE MOVES THROUGH IN THE LATE
MORNING AND AFTERNOON. WEAK SURFACE RIDGING AND LACK OF MOISTURE
MEANS NO MORE THAN PATCHY DRIZZLE...IF ANYTHING AT ALL. WILL LEAVE
ANY MENTION OF PCPN OUT FOR NOW. HIGHS AGAIN REACH THE MID 30S.


.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY...FORECAST
CONFIDENCE MEDIUM.

WISCONSIN UNDER NW FLOW WITH OVERALL WESTERN RIDGE/EASTERN TROUGH
UPPER PATTERN THROUGH THE EXTENDED. STATE ON THE CYCLONIC SIDE OF
UPPER JET AT THE BEGINNING OF THE PERIOD...WITH THE JET SLOWLY
SHIFTING OVER THE STATE BY NEXT WEDNESDAY.

MAIN STORY THIS PERIOD IS POTENT CLIPPER SYSTEM THAT BRINGS A GOOD
POTENTIAL FOR ADVISORY-LEVEL SNOW ACCUMULATIONS SATURDAY NIGHT
THROUGH SUNDAY. MODEL QPF TOTALS AROUND 0.30 OF AN INCH. THERMAL
PROFILES SUGGEST THERE MAY BE SOME RAIN MIXING IN WITH THE SNOW AT
THE OUTSET SATURDAY EVENING...AND AGAIN SUNDAY AFTERNOON THAT COULD
HOLD DOWN OVERALL SNOW TOTALS. STILL LOOKING TO SEE AT LEAST A 1 TO
3 INCH ACCUMULATIONS BEFORE SNOW TAPERS OFF SUNDAY EVENING. WILL
ALSO HAVE TO WATCH POTENTIAL FOR LAKE-EFFECT SNOW IN THE WAKE OF THE
CLIPPER SUNDAY NIGHT ALONG THE LAKESHORE COUNTIES.

GFS MOST BULLISH WITH A SHORT WAVE ON MONDAY...WITH THE ECMWF
DROPPING ANOTHER SHORT WAVE THROUGH THE REGION TUESDAY. BLENDED
SOLUTION BRINGS JUST A SLIGHT CHANCE OF LIGHT SNOW TO THE NW CWA
MONDAY...AND TOT HE FAR NE TUESDAY. HIGH PRESSURE BRINGS QUIET
WEATHER FOR NEXT WEDNESDAY.

NW TO SE ORIENTATION OF 850 MB BAROCLINIC ZONE...PARALLEL TO THE
UPPER FLOW MEANS ONLY SLIGHT WARMING/COOLING VARIATIONS TO THE TEMPS
WITH EACH WAVE. SHOULD SEE AT OR ABOVE NORMAL TEMPERATURES IN THE SW
HALF OF THE CWA...WITH AT OR BELOW NORMAL READINGS IN THE NE.

&&

.AVIATION/00Z TAFS/...

LIGHT SNOW IS SLOWLY MOVING SOUTH ACROSS SOUTHWESTERN WISCONSIN THIS
AFTERNOON...RESULTING IN ONLY A DUSTING. MVFR CONDITIONS WILL
PERSIST THIS AFTERNOON WITH CIGS NEAR 2000 FT. THESE MVFR CONDITIONS
WILL PERSIST THROUGH THE EVENING AND INTO THE THURSDAY MORNING
HOURS. CONDITIONS WILL LIKELY IMPROVE TO VFR TOMORROW AFTERNOON.&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&

$$

TONIGHT/THURSDAY AND AVIATION/MARINE...JTS
THURSDAY NIGHT THROUGH WEDNESDAY...REM



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