Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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000
FXUS63 KMKX 170929
AFDMKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
330 AM CST MON NOV 17 2014

.TODAY AND TONIGHT...CONFIDENCE - HIGH.

THE INITIAL ONSET OF A DEEPENING UPPER TROUGH AND PVA HAS RESULTED
IN SCT-BKN STRATOCUMULUS OVER SRN WI WITH SCT FLURRIES POSSIBLE THIS
AM. FOR THIS AFTERNOON AND TNT THE LARGE CORE OF A 500 DM THICKNESS
TROUGH WILL MOVE ACROSS THE REGION WHILE A LARGE AREA OF SFC LOW
PRESSURE STRENGTHENS OVER SE CANADA. BROKEN STRATOCUMULUS WITH
FLURRIES OR VERY LIGHT SNOW SHOWERS ARE EXPECTED IN THE AFTERNOON
AND EVENING. THE STRONG COLD ADVECTION ON BRISK WLY WINDS TODAY WILL
KEEP TEMPS MAINLY IN THE TEENS TODAY WITH PERHAPS LOWER 20S IN FAR
SE WI. FOR TNT...TEMPS WILL DROP TO MAINLY THE SINGLE DIGITS WITH
CONTINUED BRISK WINDS. WIND CHILLS IN THE SINGLE DIGITS TODAY AND
BELOW ZERO FOR TNT.

.TUESDAY THROUGH WEDNESDAY...CONFIDENCE - MEDIUM.

SHORT TERM GUIDANCE IN GOOD AGREEMENT ON MORE AGRESSIVE SHORT WAVE
TROUGH CAUGHT IN BRISK NORTHWEST FLOW MOVING ACROSS WI LATER TUE NGT
INTO WED MRNG.  STRONG WARM AIR ADVECTION IN THE LOW TO MID-LEVELS
WL OCCUR AHEAD OF THIS FEATURE AS 850H LOW LEVEL JET OF 30-35KTS
BRUSHES SRN WI.  STRONG PUSH OF ISENTROPIC OMEGA ON 280 THETA
SURFACE SHOULD RESULTS IN RAPID MOISTENING OF THE COLUMN AFT
06Z/WED.  STRONG LAYER Q-VECTOR CONVERGENCE OF 20 TO 30 UNITS ALSO
PASSES RAPIDLY ACROSS SRN WI DURING THIS PERIOD.  ENOUGH AGREEMENT
IN SHORT TERM GUIDANCE TO BUMP UP POPS TO LIKELY FOR A PERIOD OF -SN
AFFECTING THE ENTIRE AREA BETWEEN 06Z AND 15Z/WED.

NAM CROSS SECTIONS YIELD A PERIOD OF OMEGA OCCURRING IN THE
FAVORABLE DENDRITIC GROWTH ZONE WHICH ALSO INTERSECTS A BURST OF
FRONTOGENETICAL FORCING.  SNOW TO LIQUID RATIO OF AROUND 20 TO 1
DURING THIS PERIOD.  HENCE DESPITE LESS THAN A TENTH OF AN INCH OF
QPF...MOST AREAS LIKELY TO RECEIVE 1 TO 2 INCHES OF DRY SNOW BY MID-
MRNG WED.  THIS SNOW WL HAVE A GREATER IMPACE AND AFFECT WED MRNG
RUSH HOUR. WL MENTION IN HWO FOR NOW. -SN WILL TAPER OFF FROM WEST
TO EAST LATE TUE NGT THRU WED MRNG AS WARM AIR SURGE AND SHARP TROF
AXIS SHIFT TO THE EAST.

.WEDNESDAY NIGHT THROUGH FRIDAY NIGHT...CONFIDENCE - MEDIUM.

POSSIBLE A FEW FLURRIES LINGERING INTO WEDNESDAY NIGHT AS COLD AIR
GETS REINFORCED ALONG WITH LOW LEVEL CYCLONIC FLOW.  HOWEVER COLUMN
RH CONTINUES TO DECREASE DURING LOW LEVEL COLD AIR ADVECTION EARLY
IN THE PERIOD AS HIGH PRESSURE GRADUALLY BUILDS INTO THE WRN
GTLAKES.  VERY COLD NIGHT ANTICIPATED THU NIGHT AS SFC HIGH PRESSURE
PASSES ACROSS WI.  WITH FRESH SNOW COVER AND 85H TEMPS IN THE MID-
TEENS...TEMPS LIKELY TO FALL INTO THE SINGLE DIGITS BY EARLY FRI
MRNG AWAY FROM THE LAKE.

MEDIUM RANGE GUIDANCE IN AGREEMENT ON LONG WAVE TROF OVER ERN CONUS
SUCCUMBING TO MORE ZONAL FLOW LATE IN THE PERIOD AS UPSTREAM LARGE
HIGH PRESSURE RIDGE OVR WRN CONUS WEAKENS.  THIS WL ALLOW RECOVERY
IN TEMPS OVER THE WEEKEND.

SATURDAY THROUGH SUNDAY...CONFIDENCE - LOW.

AS STEERING FLOW BECOMES MORE ZONAL...SEVERAL PIECES OF SHORT WAVE
ENERGY ARE EXPECTED TO MOVE ACROSS THE SOUTHWEST CONUS AND THEN TAKE
A MORE NORTHEAST TRACK INTO THE WESTERN GTLAKES OVER THE
WEEKEND...ON INTO EARLY NEXT WEEK.  MEDIUM RANGE GUIDANCE IN GENERAL
AGREEMENT ON THESE SYSTEMS EVENTUALLY AFFECTING SRN WI...BUT TIMING
AND STRENGTH OF SYSTEM IN LARGER DISAGREEMENT.  12Z ECMWF HAD BEEN
MORE AGRESSIVE WITH FIRST SYSTEM MOVING INTO THE REGION SAT
NGT...WHILE NEW 00Z GFS SLOWER WITH THIS SYSTEM.  NEW 00Z ECWMF IN
BETTER AGREEMENT WITH SLOWER SOLUTION WITH THIS LOW PRESSURE SYSTEM
MOVING THRU WRN GTLAKES SUN/SUN NGT.

BOTH HOWEVER DO AFFECT THE REGION COINCEDENT WITH WARMER LOW LEVEL
AIR IN PLACE OR GETTING REINFORCED.  HENCE WL CONTINUE MIXED PRECIP
THREAT CHANGING TO MAINLY LIQUID.

BOTH GFS AND ECWMF ALSO KEEP SECOND SHORT WAVE TROUGH WEAKER AND
REMAINING TO THE SOUTH.  COLDER AIR WILL RETURN EARLY NEXT WEEK WITH
THE THREAT FOR -RA CHANGING BACK TO -SN.

&&

.AVIATION/12Z TAFS/...

SCT-BKN STRATOCUMULUS EXPECTED THIS AM AND BECOMING MORE WIDESPREAD
BROKEN THIS AFTERNOON AS THE COLD CORE ALOFT ARRIVES. CIGS TODAY AND
TNT WILL RANGE FROM 2-4 KFT...SO MVFR CIGS ARE EXPECTED AT TIMES
ESPECIALLY THIS AFTERNOON AND TNT. FLURRIES ARE EXPECTED AT TIMES.

&&

.MARINE...A SMALL CRAFT ADVISORY IS IN EFFECT FROM 9 AM THIS MORNING
THROUGH TUESDAY EVENING. BRISK WEST WINDS OF 15 TO 25 KNOTS WITH
GUSTS UP TO 30 KTS WILL PREVAIL DURING THIS PERIOD DUE TO
STRENGTHENING LOW PRESSURE OVER SE CANADA. A BRIEF SLOW DOWN IN THE
WINDS WILL OCCUR LATE TUE NT AND WED AM BUT THE PASSAGE OF ANOTHER
COLD FRONT WILL RESULT IN BRISK AND GUSTY WLY WINDS FOR WED
AFTERNOON AND NIGHT. THUS A SMALL CRAFT ADVISORY MAY BE NEEDED FOR
THIS TIME PERIOD.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...

WI...NONE.
LM...SMALL CRAFT ADVISORY FROM 9 AM TODAY TO MIDNIGHT CST TUESDAY
     NIGHT FOR LMZ643>646.

$$
TODAY AND TONIGHT/AVIATION/MARINE...MG
TUESDAY THROUGH SUNDAY...MBK



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