Blizzard and Winter Storm in Wisconsin, February 1 to 2, 2015

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
848 PM CST SAT JAN 31 2015

.UPDATE...
THINGS ARE PROGRESSING NICELY THIS EVENING...THOUGH 2-4 HOURS
AHEAD OF SCHEDULE. THIS EARLY SNOW WAS IN RESPONSE TO SOME
RAPIDLY DEVELOPING LOW LEVEL FRONTOGENESIS. WE DID GET A FEW
REPORTS OF ICE PELLETS...BUT THAT THREAT APPEARS TO HAVE ENDED.
TYPICALLY IN THESE EVENTS WE HAVE TO WAIT A FEW HOURS FOR THE LOW
LEVELS TO SATURATE BEFORE THOSE FIRST RADAR ECHOES PRODUCE FLAKES
AT GROUND LEVEL. NOT TONIGHT...IT WAS NEARLY INSTANTANEOUS.

THE NEW NAM HAS ROLLED IN AND ISN/T PRODUCING ANY SURPRISES WITH
LOW TRACKS OR PRECIP AMOUNTS. IN FACT...THERE IS SURPRISING
CONSISTENCY. GIVEN THE FRONTOGENETIC FORCING DEPICTED THROUGH THE
EVENT...IT LOOKS LIKE WE/LL SEE PLENTY OF BANDED RADAR RETURNS
THAT WILL DEVELOP...DISSIPATE...SHIFT LOCATIONS...ETC.

WE/LL CONTINUE TO ASSESS THE SITUATION AS THE NEW GUIDANCE ROLLS
IN OVER THE NEXT FEW HOURS. THERE IS CONCERN WE COULD REACH
BLIZZARD CRITERIA WITH THE WIND SPEEDS NEAR LAKE MICHIGAN FOR A
TIME ON SUNDAY. JUST NOT CONFIDENT ENOUGH TO GO THAT
EXTREME...BUT IT IS A KEY FOCUS WITH THE NEW DATA. FOR
NOW...HEADLINES AND SNOW AMOUNTS WILL REMAIN UNCHANGED AND
CONFIDENCE IS INCREASING.

&&

.AVIATION/06Z TAFS/...

EXPECT A STEADY SNOWFALL THROUGH SUNDAY EVENING. IFR CONDITIONS
WILL OVERSPREAD THE AREA OVERNIGHT...FOR BOTH CIGS AND VSBYS.
NORTHEAST WINDS WILL ALSO STEADILY INCREASE...WITH GUSTS EXCEEDING
20KTS BY 09-12Z SUNDAY. WINDS WILL PEAK DURING THE DAY ON
SUNDAY...DIMINISHING SUNDAY NIGHT AS LOW PRESSURE TO OUR SOUTH
MOVES OFF TO THE EAST. FOR KMKE/KUES/KENW...WINDS MAY APPROACH
BLIZZARD CRITERIA FOR A TIME ON SUNDAY...GUSTS TO ABOUT 30KTS.
THIS SHOULD HAVE A BIG IMPACT ON AIRPORT OPERATIONS. IMPROVING
CIGS/VSBYS SHOULD BEGIN SUNDAY EVENING.

&&

.PREV DISCUSSION... /ISSUED 324 PM CST SAT JAN 31 2015/

SHORT TERM...

TONIGHT AND SUNDAY...FORECAST CONFIDENCE IS HIGH.

12Z MODELS IN GENERAL REMAIN SIMILAR TO PREVIOUS COUPLE OF RUNS WITH
REGARDS TO SYNOPTIC FEATURES ACROSS THE AREA FOR TONIGHT INTO
SUNDAY/SUNDAY NIGHT. BEST UPWARD VERTICAL MOTION IS EXPECTED LATER
TONIGHT INTO EARLY SUNDAY...WITH FOCUSED 600 MB WARM AIR ADVECTION
AND FRONTOGENESIS RESPONSE SHIFTING EAST ACROSS THE FAR SOUTHERN
COUNTIES. MOST OF THIS DOES REMAIN IN NORTHERN ILLINOIS.

ALSO HAVE RIGHT ENTRANCE REGION OF 250 MB JET STREAK OVER THE REGION
DURING THIS TIME. BEST UPWARD VERTICAL MOTION IN THE DENDRITE GROWTH
ZONE REMAINS IN NORTHERN ILLINOIS AS WELL...THOUGH STILL HAVE UP TO
5 MICROBARS/SECOND IN OUR AREA. MID LEVEL FRONTOGENESIS RESPONSE
THEN BRINGS ANOTHER SHOT OF UPWARD VERTICAL MOTION SUNDAY AFTERNOON.

MESOSCALE MODELS CONTINUE TO SHOW THE BEST SIMULATED REFLECTIVITY
VALUES REMAINING JUST TO THE SOUTH OF THE AREA LATER TONIGHT INTO
SUNDAY MORNING. THEY DO BRING LIGHT TO MODERATE SNOW INTO THE AREA
FROM THE SOUTHWEST DURING THE EVENING...LINGERING LATER TONIGHT AND
SUNDAY. FETCH MODEST FOR LAKE ENHANCEMENT UNTIL SUNDAY NIGHT.

THE 12Z SYNOPTIC MODELS ARE GENERALLY SHOWING TOTAL QPF FOR THE
EVENT OF 0.75 INCHES IN THE FAR SOUTH...TO 0.25 INCHES IN THE FAR
NORTHERN COUNTIES. GIVEN THE BEST UPWARD VERTICAL MOTION FIELDS
BEING JUST TO OUR SOUTH...THESE QPF AMOUNTS MAY BE A BIT TOO HIGH.
LOWERED QPF AMOUNTS A BIT FROM THESE AMOUNTS IN THE FORECAST. SNOW
AMOUNTS ARE SIMILAR TO PREVIOUS FORECAST...6 TO 9 INCHES FAR SOUTH
AND 6 TO 10 INCHES FAR SOUTHEAST...TO 2 TO 4 INCHES FAR NORTH.

OVERALL...THIS WILL BE A GOOD LONG DURATION SNOW EVENT FOR THE AREA
TONIGHT INTO SUNDAY/SUNDAY NIGHT. ADDED ILLINOIS BORDER COUNTIES TO
THE WINTER STORM WARNING...GIVEN EXPECTED SNOW AMOUNTS AND
WINDS/BLOWING SNOW POTENTIAL. ADJUSTED START TIMES OF THE REST OF
THE HEADLINES A BIT TO MATCH ONSET OF SNOW. KEPT MARQUETTE...GREEN
LAKE AND FOND DU LAC COUNTIES OUT OF AN ADVISORY FOR NOW...DUE TO 2
TO 4 INCH AMOUNTS EXPECTED THERE.

SUNDAY NIGHT THROUGH TUESDAY NIGHT...FORECAST CONFIDENCE MEDIUM.

INTENSIFYING LOW PRESSURE WILL CONTINUE ALONG OR JUST NORTH OF THE
OHIO RIVER SUN NT. THE BACK END OF THE LIFT FROM JET
DYNAMICS...PVA...AND FRONTOGENESIS WILL LINGER IN THE EVE. LES
WILL CONTINUE WITH THE BACKING FLOW TO NNELY MAKING FOR A SINGLE
LES BAND THAT WILL BE TRANSIENT AS IT MOVES DOWN THE LAKE. AN
ADDITIONAL 1-3 INCHES IS EXPECTED OVER FAR SE WI WITH LESS THAN AN
INCH INLAND. WIND GUSTS CLOSE TO 30 KTS WILL CONTINUE NEAR THE
LAKE WELL INTO THE EVENING WITH SOME GUSTINESS INLAND AS WELL.
THUS BLOWING AND DRIFTING SNOW WILL CONTINUE SUN EVE. WINDS AND
BLOWING SNOW WILL CEASE FROM WEST TO EAST ACROSS THE AREA DURING
THE OVERNIGHT AS POLAR HIGH PRESSURE APPROACHES.

THE HIGH WILL QUICKLY SHIFT EWD FOR LATER ON MON WITH A SHORTWAVE
TROUGH EXPECTED TO TRACK FROM THE NRN PLAINS TO NRN IL TO S OHIO
BY 12Z TUE. LOW TO MID LEVEL WARM ADVECTION WILL OCCUR BUT MOISTURE
IS LIMITED AND THE SHORTWAVE IS MAINLY TO THE SOUTH SO ONLY SMALL
CHANCES OF LGT SNOW AT THIS TIME. ANOTHER SHORTWAVE TROUGH WILL
TRACK TO E IA BY 00Z WED AND ACROSS IL TUE NT. THIS WILL KEEP
CHANCES OF LGT SNOW IN THE FORECAST WITH BETTER CHANCES TOWARD THE
SOUTH. BELOW NORMAL TEMPS TO PREVAIL DURING THIS PERIOD.

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

A LARGE...DIGGING UPPER TROUGH WILL PROGRESS ACROSS WI AND THE W
GREAT LAKES ON WED FOLLOWED BY A WEAK SHORTWAVE TROUGH FOR THU
NT. NNWLY SFC WINDS WILL BRING ARCTIC AIR INTO THE REGION ON WED
WITH HIGH PRESSURE TO FOLLOW LATE WED NT AND THU. WED NT-THU NT
WILL BE THE COLDEST PERIOD WITH BELOW ZERO LOWS AND HIGHS BARELY
IN THE TEENS. WIND CHILLS COULD APPROACH 20 BELOW FOR LATE WED NT
AND THU AM. SW WINDS WILL THEN MODIFY TEMPS FOR FRI AND SAT.

AVIATION/00Z TAFS/...MVFR CEILINGS ARE EXPECTED INTO EARLY THIS
EVENING...EXCEPT KENOSHA WHERE THEY MAY REMAIN TO THE NORTH.
COLD FRONT SLIDING SOUTH ACROSS THE AREA INTO EARLY EVENING WILL
ALLOW LIGHT WEST TO NORTHWEST WINDS TO SHIFT NORTHEAST BY MID
EVENING. THESE WINDS WILL BECOME GUSTY DURING THE NIGHT AND REMAIN
SO ON SUNDAY...BECOMING NORTH SUNDAY NIGHT. GUSTS OF 25 TO 28
KNOTS ARE EXPECTED AT TIMES SUNDAY INTO SUNDAY NIGHT.

SNOW WILL SPREAD NORTHEAST INTO TAF SITES BETWEEN 03Z AND 05Z
SUNDAY...AND REMAIN LIGHT TO MODERATE IN INTENSITY LATER TONIGHT AND
SUNDAY. THE SNOW SHOULD END AT MADISON BETWEEN 02Z AND 05Z
MONDAY...LINGERING AT THE EASTERN SITES UNTIL BETWEEN 09Z AND 12Z
MONDAY DUE TO LAKE EFFECT SNOW BAND MOVING THROUGH THAT AREA.

EXPECT HOURLY SNOW RATES OF 1/4 TO 1/2 INCH PER HOUR LATER TONIGHT
INTO SUNDAY...WITH RATES UP TO 1 INCH PER HOUR POSSIBLE IN ANY
MODERATE SNOW BANDS. TOTAL AMOUNTS OF 5 TO 6 INCHES AT MADISON...6
TO 8 INCHES AT WAUKESHA...7 TO 9 INCHES AT MILWAUKEE...AND 8 TO 10
INCHES AT KENOSHA ARE ANTICIPATED.

EXPECT CEILINGS AND VISIBILITIES AROUND OR BELOW ALTERNATE MINIMUMS
DURING THE PERIOD OF SNOW...APPROACHING AIRPORT MINIMUMS AT TIMES
LATER TONIGHT INTO SUNDAY. BLOWING SNOW IS ALSO ANTICIPATED SUNDAY
INTO SUNDAY NIGHT WITH THE GUSTY WINDS. THIS MAY REDUCE VISIBILITIES
AT TIMES...AND AFTER THE SNOW ENDS.

MARINE...

SMALL CRAFT ADVISORY REMAINS IN EFFECT FROM LATER THIS EVENING INTO
MONDAY MORNING ACROSS THE NEARSHORE WATERS OF LAKE MICHIGAN. TIGHT
PRESSURE GRADIENT WITH THE PASSING LOW PRESSURE SYSTEM TO THE SOUTH
WILL RESULT IN GUSTY ONSHORE WINDS TONIGHT INTO SUNDAY...BECOMING
MORE OFFSHORE SUNDAY NIGHT. GUSTS TO 30 KNOTS ARE EXPECTED AT TIMES.

THIS WILL GENERATE HIGH WAVES UP TO 6 TO 10 FEET SUNDAY INTO SUNDAY
NIGHT...SLOWLY SUBSIDING MONDAY MORNING. FREEZING SPRAY IS ALSO
EXPECTED...WITH HEAVY FREEZING SPRAY POSSIBLE SUNDAY NIGHT. A HEAVY
FREEZING SPRAY WATCH MAY BE NEEDED FOR SUNDAY NIGHT IF CONDITIONS
CONTINUE TO BE FAVORABLE.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER WEATHER ADVISORY UNTIL 9 PM CST SUNDAY FOR WIZ056-057-062-
     063.

     WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST SUNDAY NIGHT FOR
     WIZ052-058>060-064-065.

LM...SMALL CRAFT ADVISORY UNTIL NOON CST MONDAY FOR LMZ645-646.

     SMALL CRAFT ADVISORY UNTIL 9 AM CST MONDAY FOR LMZ643-644.

&&

UPDATE...DAVIS
TONIGHT/SUNDAY AND AVIATION/MARINE...WOOD
SUNDAY NIGHT THROUGH SATURDAY...GEHRING

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
334 PM CST SAT JAN 31 2015

WIZ046-047-051-052-056>060-062>072-012145-
MARQUETTE-GREEN LAKE-FOND DU LAC-SHEBOYGAN-SAUK-COLUMBIA-DODGE-
WASHINGTON-OZAUKEE-IOWA-DANE-JEFFERSON-WAUKESHA-MILWAUKEE-
LAFAYETTE-GREEN-ROCK-WALWORTH-RACINE-KENOSHA-
334 PM CST SAT JAN 31 2015

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EAST CENTRAL
WISCONSIN...SOUTH CENTRAL WISCONSIN AND SOUTHEAST WISCONSIN.

.DAY ONE...TONIGHT

A WINTER STORM WARNING GOES INTO EFFECT FOR FAR SOUTHEAST
WISCONSIN AND FAR SOUTHERN WISCONSIN THIS EVENING...WITH WINTER
WEATHER ADVISORIES FOR MOST OF THE REST OF SOUTHERN WISCONSIN.

SNOW WILL OVERSPREAD THE AREA GRADUALLY FROM THE SOUTH THROUGH THE
EVENING AND CONTINUE INTO SUNDAY EVENING...AS LOW PRESSURE
INTENSIFIES FROM THE CENTRAL GREAT PLAINS TO ACROSS THE OHIO
RIVER VALLEY. SNOW WILL BECOME HEAVY AT TIMES OVER FAR
SOUTHEASTERN WISCONSIN WHERE LAKE EFFECT SNOW WILL COMBINE WITH
THE SNOW FROM THE LOW PRESSURE AREA. BLOWING AND DRIFTING SNOW IS
EXPECTED OVER ALL OF THE AREA WITH GUSTS BETWEEN 25 MPH AND 30
MPH...AND A FEW GUSTS TO 35 MPH ALONG THE LAKE MICHIGAN SHORE.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH SATURDAY

THE WINTER STORM WARNING AND WINTER WEATHER ADVISORIES WILL
CONTINUE UNTIL THE SNOW WINDS DOWN LATE SUNDAY NIGHT. HEAVY SNOW
TOTALS ARE EXPECTED NEAR THE LAKE AND NEAR THE ILLINOIS BORDER...WITH
MODERATE AMOUNTS INLAND. BLOWING AND DRIFTING SNOW WILL CONTINUE
THROUGH SUNDAY NIGHT.

WIND CHILL TEMPERATURES WILL APPROACH 20 BELOW ZERO LATE WEDNESDAY
NIGHT AND THURSDAY MORNING AS BRISK NORTHWEST WINDS BRING ARCTIC
AIR TO THE REGION. WIND CHILL VALUES WILL APPROACH 20 BELOW ZERO AGAIN
THURSDAY NIGHT INTO FRIDAY MORNING.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED...BUT SNOWFALL REPORTS ARE
APPRECIATED.

LMZ643>646-012145-
SHEBOYGAN TO PORT WASHINGTON WI-
PORT WASHINGTON TO NORTH POINT LIGHT WI-
NORTH POINT LIGHT TO WIND POINT WI-
WIND POINT WI TO WINTHROP HARBOR IL-
334 PM CST SAT JAN 31 2015

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF LAKE MICHIGAN.

.DAY ONE...TONIGHT

A SMALL CRAFT ADVISORY GOES INTO EFFECT THIS EVENING INTO SUNDAY
FOR INCREASING NORTHEAST WINDS AS DEEPENING LOW PRESSURE MOVES
FROM THE GREAT PLAINS TO ACROSS THE OHIO RIVER VALLEY. THE STRONG
WINDS WILL BUILD HIGH WAVES. THE BRISK WINDS...HIGH WAVES AND COLD
AIR TEMPERATURES WILL PRODUCE FREEZING SPRAY TONIGHT.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH SATURDAY

THE SMALL CRAFT ADVISORY CONTINUES SUNDAY INTO MONDAY MORNING AS BRISK
NORTHEAST WINDS AND HIGH WAVES CONTINUE THROUGH SUNDAY...BEFORE
WINDS BECOME NORTHWESTERLY ON SUNDAY NIGHT INTO MONDAY AS THE LOW
PRESSURE WILL PASS TO THE SOUTH OF THE REGION SUNDAY INTO EARLY
MONDAY.

FREEZING SPRAY IS ALSO EXPECTED...WITH HEAVY FREEZING SPRAY
POSSIBLE SUNDAY NIGHT.

WWW.WEATHER.GOV/MKX