Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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000
FXUS63 KMKX 110909
AFDMKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
309 AM CST THU FEB 11 2016

.TODAY AND TONIGHT...FORECAST CONFIDENCE IS HIGH.

THE MAIN FOCUS IS ON THE SMALL CHANCES FOR SOME LIGHT SNOW IN
SOUTHWEST WISCONSIN LATE TONIGHT.

CURRENTLY...AN ELONGATED RIDGE OF HIGH PRESSURE EXTENDS FROM NORTH
CENTRAL CANADA DOWN TO THE SOUTHEASTERN US.  NORTHWESTERLY FLOW
ALOFT HAS USHERED IN A COLD AIR MASS FROM NORTHERN CANADA WITH
SURFACE TEMPERATURES IN THE SINGLE DIGITS TO AROUND 0F.  THE CORE OF
THIS RIDGE WILL TRACK TO THE SOUTHEAST TODAY ALONG THE UPPER
MISSISSIPPI RIVER VALLEY AND CREATE A SUNNY AND CLEAR DAY WITH LIGHT
WINDS.

GOING INTO TONIGHT...THERE IS A FAIRLY CONSISTENT SIGNAL IN THE
11.00Z GUIDANCE WITH SHOWING A QUICK MOVING LOW PRESSURE SYSTEM THAT
GOES FROM WESTERN SOUTH DAKOTA THIS AFTERNOON TO CENTRAL MISSOURI
OVERNIGHT.  SNOW IS EXPECTED TO DEVELOP TO THE NORTH OF THIS
LOW...MAINLY DUE TO THE LIFT PROVIDED BY THE LEFT EXIT REGION OF THE
250MB JET STREAK.  THE QUESTION IS HOW FAR NORTHEAST WILL THE SNOW
MAKE IT AS THERE DOES NOT APPEAR TO BE AS MUCH LOW LEVEL LIFT THAT
GETS INTO SOUTH CENTRAL WISCONSIN.  11.00Z FORECAST THERMAL PROFILES
SHOW A 200 TO 300MB DEEP LAYER WHERE THE TEMP/DEW POINT IS IN THE
DENDRITIC GROWTH ZONE...BUT SATURATION IS SOMEWHAT SPORADIC. IF LIFT
WAS A LITTLE BIT STRONGER...WOULD HAVE HIGHER CONFIDENCE IN SOME
ACCUMULATING SNOW...PARTICULARLY IN SOUTHWEST WISCONSIN.  FOR
NOW...IT MAINLY LOOKS LIKE FLURRIES OR A POSSIBLE DUSTING THERE.

.FRIDAY AND FRIDAY NIGHT - CONFIDENCE...MEDIUM
NORTHWEST 500 MILLIBAR FLOW STRENGTHENS AND BECOMES INCREASINGLY
CYCLONIC ACROSS THE GREAT LAKES REGION. EMBEDDED SHORTWAVE WITHIN
THIS FLOW HEADS SOUTHEAST INTO LWR MI WITH CYCLOGENESIS ACROSS THE
EASTERN GRT LAKES REGION. THIS WILL DRAG A COLD FRONT THROUGH SRN
WI. 925 TEMPS WILL DROP THROUGH THE NEGATIVE TEENS CELSIUS WITH
NEGATIVE LOW AND EVEN POSSIBLE MID 20S CELSIUS INTO FRIDAY NIGHT.
THIS WILL LEAD TO A BITTERLY COLD AIRMASS WITH WIND CHILLS GETTING
NEAR OR IN SOME CASES REACHING ADVISORY CRITERIA. SOME UNCERTAINTY
ON WIND STRENGTH LATER FRIDAY NIGHT. 925 WINDS PROGGD TO BE 20
KNOTS OR HIGHER THOUGH GRADIENT DOES SLACKEN AFTER 06Z. SO HAVE
LOWERED TEMPS A BIT MORE IN THE WESTERN CWA. STILL LOOKING AT
PARTS OF THE AREA VULNERABLE FOR WIND CHILL ADVISORY.

.SATURDAY - CONFIDENCE...MEDIUM
AFTER A BITTERLY COLD START 1045 MILLIBAR HIGH AND SUBSIDING
INFLUENCE SHOULD RESULT IN A DECENT AMOUNT OF SUNSHINE. MID LEVEL
FLOW REMAINS STRONG FROM THE NORTHWEST THOUGH TRENDING MORE
ANTICYCLONIC. CORE OF LOW LEVEL THERMAL TROUGH REMAINS ACROSS SRN
WI WITH 925 TEMPS AOB -20C IN THE MORNING MODIFYING ONLY INTO THE
MID OR UPPER TEENS CELSIUS DURING THE AFTERNOON. SO THE SUPERBLEND
GUID SHOWING MANY HIGHS STRUGGLING TO GET OUT OF THE SINGLE DIGITS
CONTINUES TO LOOK PLAUSIBLE.

.SATURDAY NIGHT - CONFIDENCE...MEDIUM
EXPECTING MAINLY CLEAR SKIES DURING THE EVENING WITH SURFACE
RIDGE AXIS ACROSS THE STATE. WENT WITH A NON-DIURNAL TEMP CURVE AS
WAA INCREASES LATER IN THE NIGHT WITH INCREASING MID DECK. BUFKIT
SOUNDINGS IN THE FAR WEST SHOW A MASSIVE DRY LAYER TO OVERCOME
WITH THE GFS SHOWING BETTER LOW LEVEL MOISTENING WITH TIME. THE
NAM KEEPS THE DRY LAYER ALL NIGHT AND THUS SHOWS NO QPF WITH THE
APPCH SHORTWAVE. WENT WITH SOME SMALL POPS IN OUR FAR SW CWA AFTER
MIDNIGHT AS BOTH THE GFS AND ECMWF SHOW QPF ARRIVING WITH THE WAA
WING AHEAD OF THE APPCH SYSTEM.

.SUNDAY AND SUNDAY NIGHT - CONFIDENCE...MEDIUM TO HIGH
PRETTY SOLID AGREEMENT IN PLACE FOR FAIRLY POTENT SHORTWAVE TO
MOVE INTO THE GREAT LAKES THIS PERIOD WITH ASSOC DCVA AND WAA OUT
AHEAD TO GENERATE ACCUMULATING SNOWS. THE 00Z ECMWF HAS COME A BIT
MORE IN LINE WITH THE CONSISTENTLY WETTER LOOK OF THE GFS
SOLUTION. PER COLLAB WITH SURROUNDING OFFICES HAVE NUDGED BOTH
POPS AND QPF OVER WHAT THE SUPERBLEND OFFERED. LOOKS LIKE A FEW
INCHES AT THIS TIME WITH STILL SOME UNCERTAINTY WITH QPF AND HOW
QUICK DRY AIR CAN ERODE. STILL POTENTIAL FOR A FEW INCHES WITH
SOME IMPACT DUE TO THE COLDER AIR TEMPS IN THE TEENS. THE SFC/850
TROUGH SWINGS THROUGH SUNDAY NIGHT WITH ADDITIONAL SNOW CHANCES.
BEST DCVA PROGGD TO ARRIVE LATER IN THE AFTN INTO THE ERLY EVE
HRS.

.MONDAY - CONFIDENCE...MEDIUM
ACTIVE NORTHWEST FLOW CONTINUES WITH A SECONDARY MID LEVEL TROUGH
SWINGING THROUGH WITH CYCLONIC LOW LEVELS RESULTING IN MORE SNOW
CHANCES WITH BOTH THE GFS AND ECMWF SHOWING LIGHT QPF WITH THIS
SYSTEM.

.TUESDAY AND WEDNESDAY - CONFIDENCE...LOW
TIMING DIFFERENCES NOT THAT ATYPICAL WITH A FAST MOVING NW FLOW
REGIME THIS FAR OUT. THE ECMWF WRAPS UP A FAIRLY IMPRESSIVE LOW
TUESDAY NIGHT AND WEDNESDAY TO OUR SOUTH WITH APPRECIABLE QPF.
MEANWHILE THE GFS SHOWS A WEAKER SYSTEM WITH PRECIP MOSTLY
ASSOCIATED WITH SOME WAA AND A LESS PRONOUNCED SHORTWAVE AND MUCH
LESS QPF THAN THE ECMWF. WILL BE GOING WITH THE SUPERBLEND GUID
THIS PERIOD.

&&

.AVIATION/12Z TAFS/...MAINLY CLEAR SKIES CAN BE EXPECTED FOR MUCH
OF THE DAY BEFORE HIGH LEVEL CLOUDS MOVE IN TONIGHT. MSN MAY BE
ON THE EDGE OF SOME FLURRIES AFTER MIDNIGHT...BUT AM NOT EXPECTING
ANY VISIBILITY DROPS THERE DUE TO SNOW WITH THE HIGHER CHANCES
BEING IN IOWA/ILLINOIS. CAN NOT RULE OUT SOME MVFR CEILINGS AT
MSN...BUT EXPECT THAT IT WILL MORE LIKELY STAY VFR. WINDS WILL BE
ON THE LIGHT SIDE TODAY BEFORE SWITCHING AROUND TO THE SOUTHWEST
LATER THIS AFTERNOON.

&&

.MARINE...THE MAIN CONCERNS FOR OVER THE LAKE ARE FOR THE FRIDAY
INTO EARLY SATURDAY PERIOD AFTER A COLD FRONT PASSES THROUGH THE
WESTERN GREAT LAKES AREA. A LARGE AREA OF HIGH PRESSURE WILL BE
PUSHING DOWN INTO THE HIGH PLAINS AND WILL CREATE A TIGHT PRESSURE
GRADIENT ACROSS THE GREAT LAKES. OFF SHORE NORTHWEST WINDS ARE
EXPECTED TO INCREASE INTO THE SUSTAINED 20KT-GUST 30KT RANGE...
PARTICULARLY FRIDAY NIGHT. SO...A SMALL CRAFT ADVISORY WILL BE
NEEDED FOR THIS PERIOD ONCE IT GETS A LITTLE CLOSER. ALSO...THE
COMBINATION OF STRONG WINDS...WAVES OVER 4 FEET...AND COLD AIR
MOVING ACROSS THE LAKE WILL LEAD TO SOME MODERATE FREEZING SPRAY
OVER THIS PERIOD.

&&

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

$$
TODAY/TONIGHT AND AVIATION/MARINE...HALBACH
FRIDAY THROUGH WEDNESDAY...COLLAR


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