Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 011709 AAA
AFDMKX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
1109 AM CST SUN FEB 1 2015

.UPDATE...

AFTER LOOKING AT 12Z NAM/GFS/CANADIAN MODELS AND LATEST MESOSCALE
MODEL OUTPUT...WILL LEAVE CURRENT HEADLINES/WINDS/SNOWFALL
AMOUNTS IN PLACE ACROSS THE AREA THIS AFTERNOON AND TONIGHT.
FOCUSED 600 MB WARM AIR ADVECTION/FRONTOGENESIS RESPONSE FIELDS
HELPING FOCUS BANDS OF MODERATE SNOW ACROSS SOUTHERN PORTIONS OF
THE AREA INTO NORTHERN ILLINOIS. THIS WILL GRADUALLY SHIFT EAST
THIS AFTERNOON...EAST OF THE AREA TONIGHT. ALSO HAVE 500 MB
SHORTWAVE TROUGH SLIDING EAST THROUGH THE AREA THIS AFTERNOON AND
EARLY EVENING...WITH A STRONG VORTICITY MAXIMUM PUSHING THROUGH AS
WELL.

THUS...WILL CONTINUE THE SNOW THIS AFTERNOON...TAPERING OFF THIS
EVENING FROM WEST TO EAST. FAR EASTERN/SOUTHEASTERN AREAS NEAR
LAKE MICHIGAN WILL BE AFFECTED BY SINGLE LAKE EFFECT SNOW BAND
THIS EVENING INTO THE OVERNIGHT HOURS. IT SHOULD MOVE SOUTHEAST OF
KENOSHA BY 12Z MONDAY AT THE LATEST.

TOTAL SNOW ACCUMULATIONS OF 3 TO 5 INCHES FAR NORTH...TO 7 TO 10
INCHES SOUTH HALF ARE EXPECTED. 8 TO 11 INCHES ARE EXPECTED IN
RACINE AND KENOSHA COUNTIES...WHERE GUSTY WINDS AND 1/4 MILE
VISIBILITIES WILL CONTINUE DURING BLIZZARD WARNING PERIOD. BLOWING
SNOW ELSEWHERE WILL OCCUR THIS AFTERNOON INTO TONIGHT.

&&

.AVIATION/18Z TAFS/...

EXPECT MODERATE SNOW AND BLOWING SNOW TO CONTINUE THIS AFTERNOON
INTO THE EVENING ACROSS TAF SITES. SNOW WILL END AT MADISON AROUND
04Z MONDAY...WAUKESHA AT 06Z MONDAY...WITH MILWAUKEE AND KENOSHA
AFFECTED BY A LAKE EFFECT SNOW BAND UNTIL 09Z TO 11Z MONDAY.

AN ADDITIONAL 1 TO 2 INCHES IS EXPECTED AT MADISON...AROUND 2
INCHES AT WAUKESHA...AND 4 TO 6 INCHES AT MILWAUKEE AND KENOSHA.
SNOWFALL RATES OF 1/2 TO 1 INCH PER HOUR ARE EXPECTED AS WELL.

VISIBILITIES BELOW ALTERNATE MINIMUMS ARE EXPECTED DURING THE
PERIOD OF SNOW...WITH SOME AT OR BELOW AIRPORT MINIMUMS AT
MILWAUKEE AND KENOSHA. CEILINGS WILL BE MAINLY IN THE IFR
CATEGORY. GUSTY NORTHEAST WINDS WITH GUSTS OF 28 TO 34 KNOTS ARE
EXPECTED THIS AFTERNOON AND EARLY THIS EVENING...HIGHEST AT
MILWAUKEE AND KENOSHA...CAUSING THE BLOWING SNOW.

THE WINDS WILL BACK NORTH TO NORTHWEST LATER TONIGHT AND MONDAY
MORNING...REMAINING GUSTY UNTIL LATER IN THE DAY. SKIES SHOULD
CLEAR OUT DURING THE MORNING ON MONDAY AND REMAIN SO THROUGH MOST
OF THE DAY.

&&

.MARINE...

GALE WARNING AND HEAVY FREEZING SPRAY WARNINGS REMAIN IN EFFECT
UNTIL 09Z MONDAY ACROSS THE NEARSHORE WATERS OF LAKE MICHIGAN.
STRONG PRESSURE GRADIENT WILL CONTINUE TO BRING GUSTY NORTHEAST
WINDS TO 35 KNOTS THIS AFTERNOON AND EARLY EVENING...BECOMING
NORTH LATER TONIGHT AND NORTHWEST ON MONDAY. PRESSURE GRADIENT
WILL SLOWLY WEAKEN TONIGHT INTO MONDAY...ALLOWING WINDS TO SLOWLY
SUBSIDE.

THESE WINDS WILL CAUSE HIGH WAVES OF 8 TO 12 FEET THIS
AFTERNOON...SLOWLY SUBSIDING TONIGHT INTO MONDAY MORNING. WILL
NEED A SMALL CRAFT ADVISORY BETWEEN 09Z AND 18Z OR SO ON
MONDAY...AS WINDS AND WAVES REMAIN ABOVE SMALL CRAFT ADVISORY
THRESHOLDS. HEAVY FREEZING SPRAY IS EXPECTED WITH THE WINDS AND
WAVES THIS AFTERNOON INTO THIS EVENING...WITH MODERATE FREEZING
SPRAY POSSIBLE FOR A TIME LATER THIS EVENING AND OVERNIGHT.

&&

.PREV DISCUSSION... /ISSUED 558 AM CST SUN FEB 1 2015/

SHORT TERM...

TODAY AND TONIGHT...FORECAST CONFIDENCE IS HIGH.

FIRST ROUND OF ENHANCED FORCING WITH OMEGA WITH 850-700 MB WAA
MOVING ACROSS SRN WISCONSIN NOW...WITH ENHANCED BANDS ON REGIONAL
RADAR FROM S CNTRL IA TO WRN IL IN LINE WITH STRONGER FRONTOGENETIC
RESPONSE THAT LIFTS NORTH TO THE IL/WI BORDER REGION AROUND 12Z.
THOUGH THIS STRONGER FORCING REMAINS JUST TO THE SOUTH WITH THE 700
MB BAROCLINIC ZONE...MODELS SHOW A SECOND FRONTOGENETIC BAND IN
RESPONSE TO THE DEFORMATION ZONE TO THE NORTH OF THE 700 MB LOW
MOVING OVER SRN WI ROUGHLY ALONG THE I-94 CORRIDOR THIS AFTERNOON.

WIND NOW BECOMING A MAJOR FACTOR AS ALL MODELS HAVE DEEPENED LOW AND
INCREASED WIND SPEEDS AT/BELOW 1000 FT. THAT ARE MIXING DOWN TO THE
SURFACE. WILL BE SEEING GUSTS OF 30 TO 35 MPH. WHILE WINDS AND TREES
WILL LIMIT VSBY REDUCTIONS FROM FALLING TO 1/4 MILE FOR A PROLONGED
DURATION...OVER MOST OF SOUTHERN WISCONSIN THE HIGHER GUSTS ALONG
LAKESIDE COUNTIES AND THE HEAVIER SNOW SOUTH OF MILWAUKEE...PUT
RACINE AND KENOSHA INTO A BLIZZARD WARNING WHERE PROLONGED 1/4 MILE
VSBYS ARE EXPECTED.

WILL BE ADDING IOWA...DANE...AND JEFFERSON TO WINTER STORM
WARNING...AS WELL AS SHEBOYGAN AND OZAUKEE FOR HIGHER SNOW AMOUNTS
AS WELL AS WINDS. ALSO ADDED MARQUETTE...GREEN LAKE AND FOND DU LAC
COUNTIES TO THE ADVISORIES FOR THE HIGHER SNOW/WIND COMBINATION.

SNOW WILL BE TAPERING OFF FROM NW TO SOUTHEAST THROUGH THE LATE
AFTERNOON AND EVENING...WITH SNOW ENDING AROUND 06Z WITH
FORCING SHIFTING EAST AS MID-UPPER LEVEL TROUGH AXES .

LONG TERM...

MONDAY AND MONDAY NIGHT... FORECAST CONFIDENCE MEDIUM.

NORTHWEST FLOW ALOFT WILL RESUME OVER THE UPPER MIDWEST AND SURFACE
HIGH PRESSURE WILL DRIFT ACROSS THE MID MISSISSIPPI RIVER VALLEY ON
MONDAY. PLAN ON QUIET WEATHER... LIGHTER WESTERLY WINDS AND A PERIOD
OF SUNNY SKIES.

A 500MB SHORTWAVE TROUGH WILL TREK ALONG AN 850MB BAROCLINIC ZONE
THROUGH EASTERN IOWA... NORTHERN IL AND SOUTHWEST WI MON NIGHT AND
BRING A CHANCE FOR LIGHT SNOW TO SOUTHERN WI. THE LIFT WILL BE WEAK
AND BRIEF SO LESS THAN AN INCH EXPECTED. PLUS... THE NAM IS THE ONLY
MODEL SPREADING SNOW VERY FAR INTO THE MKX AREA- THE GFS AND ECMWF
ARE FURTHER SOUTH.

TUESDAY AND TUESDAY NIGHT... FORECAST CONFIDENCE MEDIUM.

THE MODELS ARE IN FAIR AGREEMENT FOR ANOTHER ROUND OF SNOW ACROSS
SOUTHERN WI TUE EVENING WITH A CLIPPER. BUMPED UP POPS TO LIKELY FOR
PORTIONS OF MKX AREA. SNOW AMOUNTS WILL BE LIGHT... IN THE 0.5 TO 2
INCH RANGE. THE OMEGA WILL BE STRONGER WITH THIS CLIPPER THAN THE
TUE NIGHT ONE BECAUSE OF SOME HELP FROM 850MB WARM AIR ADVECTION AND
UPPER DIVERGENCE WITH AN APPROACHING UPPER JET STREAK... BUT A
WEAKER 500MB SHORTWAVE.

WEDNESDAY THROUGH SATURDAY... FORECAST CONFIDENCE MEDIUM.

ARCTIC AIR WILL SETTLE OVER THE UPPER GREAT LAKES IN THE WAKE OF THE
TUE NIGHT SYSTEM. A LINGERING TIGHT PRESSURE GRADIENT AND COLD AIR
ADVECTION WILL LEAD TO LOW WIND CHILL TEMPS WED THROUGH THU NIGHT.
WIND CHILLS WILL FALL INTO THE NEGATIVE UPPER TEENS. WEATHER WILL BE
QUIET THROUGH FRIDAY.

SOUTHWEST WINDS WILL MODIFY TEMPS FRIDAY AND SATURDAY. THE WARM AIR
ADVECTION WILL BRING OUR NEXT CHANCE FOR PRECIP INTO SOUTHERN WI
OVER THE WEEKEND AS WELL. THE GFS IS WARMER AND WOULD SUGGEST A
CHANCE FOR A WINTRY MIX. THE ECMWF REMAINS COLD ENOUGH FOR SNOW
CHANCES.

AVIATION/12Z TAFS/...

STEADY LIGHT TO MODERATE SNOW WILL CONTINUE INTO THE AFTERNOON
WITH SMALL FLAKE SIZE LIMITING ACCUMULATIONS BUT WILL SEE TOTALS
AROUND 7 INCHES AT KMSN...8-9 INCHES AT KUES...AROUND 10 INCHES AT
KMKE AND 11-12 INCHES AT KENW BY THE TIME IT ENDS AT KMSN AROUND
06Z AND FAR EASTERN TAF SITES BETWEEN 06Z AND 09Z MONDAY.

COMPLICATING FACTOR WILL BE INCREASING NORTHEAST WINDS...WITH LOW
PRESSURE DEEPER THAN PREVIOUSLY FORECAST BRINGING WIND GUSTS OF
30-35 KTS WITH THE HIGHER GUSTS AT KMKE AND KENW. THIS WILL REDUCE
VSBYS TO 1/2 TO 3/4 MILES WITH BLOWING SNOW...EVEN AS THE FALLING
SNOW BECOMES LESS INTENSE LATE THIS AFTERNOON AND EVENING.
DRIFTING SNOW WILL MAKE KEEPING RUNWAYS CLEAR DIFFICULT. WINDS
WILL LOWER DURING THE OVERNIGHT AS THE GRADIENT RELAXES WITH THE LOW
PULLING AWAY...AND SOME CLEARING TOWARD THE END OF THE FORECAST
PERIOD ALLOWING SURFACE WINDS TO DECOUPLE.

MARINE...

HAVE ISSUED A GALE WARNING TO START AT 15Z AS NORTHEAST WINDS
INCREASE TO GALE FORCE AND CONTINUE INTO THE EVENING. THE
NORTHEAST GALES...HIGH WAVES AND COLD TEMPERATURES WILL PRODUCE
HEAVY FREEZING SPRAY...SO ALSO ISSUED A HEAVY FREEZING SPRAY
WARNING TO COINCIDE WITH THE GALE WARNING.

WINDS WILL LOWER BELOW GALE FORCE AROUND 06Z...BUT A SMALL CRAFT
ADVISORY WILL BE NEEDED AFTER THE WARNING EXPIRES FOR WINDS
REMAINING AT SMALL CRAFT LEVELS INTO MONDAY MORNING AS THEY BACK
TO THE NORTH AND THEN NORTHWEST...WITH HIGH WAVES SLOWER TO
SUBSIDE UNTIL MONDAY AFTERNOON/EVENING.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR
     WIZ052-060-066.

     WINTER STORM WARNING UNTIL 9 PM CST THIS EVENING FOR
     WIZ062-063-067-068.

     WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR
     WIZ064-065-069-070.

     WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR
     WIZ046-047-056-057.

     BLIZZARD WARNING UNTIL MIDNIGHT CST TONIGHT FOR WIZ071-072.

     WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR WIZ051-
     058-059.

LM...HEAVY FREEZING SPRAY WARNING UNTIL 3 AM CST MONDAY FOR
     LMZ643>646.

     GALE WARNING UNTIL 3 AM CST MONDAY FOR LMZ643>646.

&&

$$

UPDATE...WOOD
TODAY/TONIGHT AND AVIATION/MARINE...REM
MONDAY THROUGH SATURDAY...MRC


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