Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 091758
AFDMKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
ISSUED BY NATIONAL WEATHER SERVICE CHICAGO IL
1158 AM CST TUE FEB 9 2016

.AVIATION/18Z TAFS/...

TERMINALS ARE IN A RELATIVE LULL IN SNOW SHOWER ACTIVITY EARLY
THIS AFTERNOON. WHILE SNOW SHOWERS WILL NOT COMPLETELY FILL BACK
IN THIS AFTERNOON AND EVENING...DO EXPECT SOME UPTICK IN COVERAGE
MID AFTERNOON THROUGH EARLY EVENING...ESPECIALLY EAST OF KMSN...AS
A SHORTWAVE IN NORTHERN MINNESOTA ROTATES SOUTHEASTWARD. CEILINGS
WILL HOVER IN THE MVFR TO LOW VFR RANGE THROUGH THE
AFTERNOON...TRENDING TOWARD MVFR. VSBY REDUCTIONS IN SNOW SHOULD
ALSO BE MVFR...WITH INFREQUENT IFR POSSIBLE. EXPECT COVERAGE TO
DIMINISH SIGNIFICANTLY MID TO LATE EVENING AS HIGH PRESSURE MOVES
IN FROM THE WEST. SKIES LOOK TO SCATTER FROM WEST TO EAST
OVERNIGHT...WITH BROKEN CLOUDS POSSIBLE AGAIN WEDNESDAY AFTERNOON
THAT LOOK TO LARGELY REMAIN VFR. GUSTY NW WINDS CONTINUE THROUGH
TONIGHT...EASING SOME DURING THE DAY WEDNESDAY.


&&

.PREV DISCUSSION... /ISSUED BY NATIONAL WEATHER SERVICE CHICAGO
IL/

UPDATE...

LOWERED POPS SOME TODAY TO ACCOUNT FOR SOME SUPPRESSION BEHIND THE
EARLIER MORNING SNOW SHOWER ACTIVITY. STILL CONTINUE TO CARRY
CHANCE TO LIKELY SNOW SHOWER WORDING AS THERE SHOULD STILL BE
OCCASIONAL FLURRIES/SHOWERS THROUGH THE DAY. STILL HANGING ONTO
THE BETTER CHANCES FOR SOME LIGHT ACCUMULATIONS BEGINNING MID TO
LATE AFTERNOON WITH REASONING FROM PREVIOUS DISCUSSION STILL
VALID. LAPSE RATES STEEPEN SOME DURING THIS PERIOD AHEAD OF THE
VORT MAX CURRENTLY ROTATING THROUGH NORTHERN MINNESOTA.

PREV DISCUSSION... /ISSUED 309 AM CST TUE FEB 9 2016/

TODAY AND TONIGHT...FORECAST CONFIDENCE IS HIGH.

THE MAIN FOCUS IS ON THE LIGHT SNOW AND HOW PESKY IT WILL BE
TODAY/THIS EVENING.

CURRENTLY...BROAD CYCLONIC FLOW ALOFT IS IN PLACE THROUGH THE
EASTERN HALF OF THE US THANKS TO A CLOSED 500MB LOW CENTERED OVER
THE CENTRAL GREAT LAKES.  AN ELONGATED SHORTWAVE TROUGH EXTENDS
NORTH OF THIS CLOSED LOW ALONG WESTERN LAKE MICHIGAN ON UP TO
ANOTHER CLOSED LOW OVER SOUTHWEST HUDSON BAY.  AT THE SURFACE...LOW
PRESSURE IS CENTERED TO THE EAST OF DETROIT WITH AN INVERTED TROUGH
EXTENDING WEST FROM THIS LOW INTO SOUTHERN LAKE MICHIGAN.  THIS
FEATURE HELPED TO CREATE SOME STRONGER SNOW SHOWERS EARLIER IN THE
NIGHT BUT HAS MAINLY PUSHED THEM TO THE SOUTH OF THE AREA. SURFACE
TEMPERATURES AND DEW POINTS HAVE BEEN DROPPING THROUGH THE NIGHT AS
THE POOL OF COLD LOW LEVEL AIR HAS BEEN PULLED SOUTH ACROSS SOUTH
CENTRAL CANADA ALONG THE WESTERN GRADIENT OF THE MID LEVEL TROUGH.

THE 09.06Z RAP SHOWS 850MB TEMPERATURES DROPPING FROM -13C AT 7Z TO -
19C BY 00Z THIS EVENING.  GIVEN THIS COLD AIR ADVECTION AND OVERCAST
CONDITIONS...EXPECT THAT TEMPERATURES WILL HAVE A DIFFICULT TIME
CLIMBING MUCH TODAY.  AS FOR SNOWFALL POTENTIAL...THE MID LEVEL
TROUGH LOOKS LIKE IT LINGERS IN WESTERN LAKE MICHIGAN THROUGH THIS
EVENING WITH SOME DECENT QG FORCING IN THE 850-500MB LAYER OVER THIS
PERIOD.  WITH THE COLDER AIR MOVING IN...THE SATURATED PORTION OF
THE THERMAL PROFILE FROM JUST ABOVE THE SURFACE ON UP TO AROUND
700MB WILL BE IN THE DENDRITIC GROWTH ZONE...SO AM EXPECTING THIS TO
CONTINUE TO BE A HIGH SNOW TO LIQUID RATIO SITUATION.  IF THERE IS
ONE PERIOD TO KEEP AN EYE ON IT IS THE AFTERNOON/EARLY EVENING
PERIOD WHEN IT LOOKS LIKE ANOTHER INVERTED SURFACE TROUGH WILL
ROTATE ALONG THE WESTERN PERIPHERY OF THE LOW AND COULD PROVIDE
ANOTHER PERIOD OF ACCUMULATING SNOW.  AS OF NOW...HAVE AN AROUND AN
INCH OF ACCUMULATION ALONG THE LAKE WITH LESSER AMOUNTS THE FURTHER
WEST YOU GET.

WEDNESDAY - CONFIDENCE...MEDIUM
PRIMARY MID LEVEL TROUGH AXIS SHIFTS INTO THE EASTERN LAKES
THOUGH BROAD EXPANSE OF THE TROUGH STILL FELT HERE WITH MAINLY
SHEARED VORT RIDING SE IN THE FLOW. COLD LOW LEVEL THERMAL TROUGH
IN PLACE WITH 925 TEMPS -16C TO -18C. WIND CHILLS PROGGD TO BE
WELL BELOW ZERO EARLY ON BUT NOT QUITE REACHING ADVISORY LEVELS.
BUFKIT SHOWS ABUNDANT DRY AIR IN PLACE WITH PRONOUNCED SUBSIDENCE.
WILL RETAIN DRY FORECAST. LLVL RH PROGS AND MOS SUGGEST SOME CLOUD
COVER WILL LINGER WITHIN THIS CYCLONIC FLOW AND CHILLY THERMAL TROUGH.

THURSDAY - CONFIDENCE...MEDIUM
ELONGATED SHEAR AXIS ON WESTERN PERIPHERY OF 500 MILLIBAR TROUGH
WILL SHIFT EAST WITH STRONG NW UPPER FLOW PERSISTING. VERY CHILLY
AIRMASS REMAINS IN PLACE WITH 925 TEMPS SHOWING ONLY SUBTLE
MODIFICATION. SURFACE HIGH SHIFTS INTO IA AND RIDGES INTO THE MID
MISS VLY.

THURSDAY NIGHT AND FRIDAY - CONFIDENCE...LOW TO MEDIUM
250 MILLIBAR SPEED MAX DRIVES INTO THE UPPER MIDWEST WITH MODELS
SHOWING A QUICK HITTING SYSTEM WITH LIGHT QPF AHEAD OF NEXT ARCTIC
SURGE. WEAK SHOT OF WAA WITH MOSTLY SHEARED VORT. 00Z ECMWF
CONTINUED TREND OF 12Z RUN TO GENERATE A BIT MORE QPF AREA WIDE
THAN THE GFS OR GEM. WILL GO WITH BLENDED POPS FOR NOW AS GFS/GEM
IN AGREEMENT WITH LESS QPF AND CONFINED MORE TO THE SW AND SRN PTN
OF THE CWA.

FRIDAY NIGHT AND SATURDAY - CONFIDENCE...MEDIUM
BITTERLY COLD AIRMASS EXPECTED WITH 1045 MILLIBAR HIGH BUILDING
IN FROM THE DAKOTAS THIS PERIOD. WILL LIKELY SEE WIND CHILLS WELL
BELOW ZERO FRI NGT INTO SAT MRNG. 925 TEMPS PROGGD TO -20C TO
-24C.

SUNDAY - CONFIDENCE...LOW TO MEDIUM
FAIRLY STRONG SHORTWAVE SHIFTS ESE FROM THE NORTHERN AND CENTRAL
PLAINS. MEANWHILE SOME MODEL DIVERGENCE ON PLACEMENT OF LOW LEVEL
FEATURES. THE GFS SHOWS A MORE PROGRESSIVE NORTHERN TROUGH WHILE
THE ECMWF CARVES OUT A STRONGER MORE SOUTHERN LOW VCNTY MO. THERE
IS SOME AGREEMENT THAT 850 WAA WILL BE ENOUGH TO GENERATE SNOW
ACROSS THE AREA DESPITE THESE DIFFERENCES IN SFC/850 LOW
PLACEMENT. SO WILL BE USING SUPERBLEND POPS AS THESE SEEM
REASONABLE AT THIS TIME.

SUNDAY NIGHT AND MONDAY - CONFIDENCE...LOW TO MEDIUM
THE ECMWF CONTINUES TO SHOW A MORE SRN SOLUTION WITH RESPECT TO
SFC/850 LOW TRACKS WHILE THE GFS TRACKS SFC LOW/TROUGH ACROSS WI.
SO AGAIN DESPITE SOME DIFFERENCES THE MAIN MESSAGE WILL BE SNOW
CHANCES CONTINUING AT LEAST THROUGH MONDAY MORNING.


MARINE...OFFSHORE WINDS WILL BE ON THE INCREASE OUT OF THE NORTHWEST
INTO WEDNESDAY AS A LOW PRESSURE SYSTEM DRIFTS EAST THROUGH THE GREAT
LAKES AND A RIDGE OF HIGH PRESSURE SETS UP ACROSS THE EASTERN HIGH
PLAINS. WITH GUSTS IN THE 20 TO 30 KT RANGE THROUGH WEDNESDAY...A
SMALL CRAFT ADVISORY IS IN EFFECT FOR THIS PERIOD. WAVES WILL BE
THE HIGHEST TOWARD THE OPEN WATERS OF THE LAKE AS WELL GIVEN THE
NORTHWEST WINDS.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL MIDNIGHT CST WEDNESDAY NIGHT FOR
     LMZ643>646.

&&

$$

UPDATE...KMD
AVIATION...KMD
TODAY/TONIGHT...HALBACH
THROUGH MONDAY...COLLAR


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