Small Craft Advisory 13, NWS Milwaukee, WI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
1108 AM CST SUN JAN 20 2013

.AVIATION/18Z TAFS/...VFR THIS PERIOD. WATER VAPOR SHOWS BROAD
CYCLONIC FLOW ACROSS THE UPPER MIDWEST. ELONGATED SHEAR VORT/JET
STREAK ENHANCED SNOWS WILL STAY TO OUR WEST AND SOUTHWEST WHILE
A VORT MAX SHIFTS EAST FROM NRN MN INTO LAKE SUPERIOR. REINFORCING
WAVE SLIDES THROUGH MONDAY MORNING WITH ELONGATED VORT AXIS
STAYING SOUTHWEST. GRADIENT TIGHTENS BACK UP ON MONDAY SO LOOK FOR
NW WINDS TO RAMP BACK UP AGAIN...BUT NOTHING CLOSE TO SATURDAY
NIGHT.

PC

&&

.MARINE...NW WINDS EASING BELOW CRITERIA SO WILL ALLOW BOTH SMALL
CRAFT AND HEAVY FREEZING SPRAY WARNING TO EXPIRE AT NOON.

PC

&&

.PREV DISCUSSION... /ISSUED 435 AM CST SUN JAN 20 2013/

TODAY AND TONIGHT...FORECAST CONFIDENCE...MEDIUM TO HIGH

NWLY WINDS AND COLD ADVECTION WILL WEAKEN THROUGHOUT THE DAY AS THE
STRONG LOW MOVES AWAY ACROSS QUEBEC CANADA. A SHORTWAVE TROUGH AND
ASSOCIATED LOW TO MID LEVEL FRONTOGENESIS WILL TAKE A SWATH OF LIGHT
SNOW FROM THE NRN PLAINS TO ACROSS IA INTO WEST CENTRAL IL THIS
AFTERNOON. SHOULD SEE A PERIOD OF BROKEN MID LEVEL CLOUD COVER FROM
THIS SYSTEM BUT WILL ALSO SEE SOME SUNSHINE AS WELL. 925 MB TEMPS
SUGGEST HIGHS IN THE TEENS TODAY...SIMILAR TO THE GFS MOS GUIDANCE.

FOR TNT...A NLY 140 KT JET WILL DIVE SWD INTO THE PLAINS WITH AN
ASSOCIATED UPPER TROUGH REACHING A LINE FROM LAKE SUPERIOR TO IA BY
12Z MON. THIS WILL HELP ENHANCE THE DIABATIC LOW PRESSURE AREA THAT
IS PRESENT OVER THE RELATIVELY WARM GREAT LAKES. THUS NWLY WINDS
WILL INCREASE TOWARD MON AM WITH AN INCREASE IN COLD ADVECTION. 850
MB TEMPS WILL DROP ON AVERAGE TO -25C BY 12Z MON. SFC LOW TEMPS WILL
RANGE FROM SLIGHTLY BELOW ZERO NORTH AND WEST CWA TO SINGLE DIGITS
SOUTHEAST. WIND CHILL TEMPS BARELY REACH -20F AROUND 12Z MON IN THE
FAR NRN AND WRN CWA SO NO WIND CHILL ADVISORY YET.

MONDAY THROUGH WEDNESDAY...FORECAST CONFIDENCE...MEDIUM TO HIGH

COLD WEATHER WILL CONTINUE MONDAY WITH HIGHS ONLY IN THE SINGLE
DIGITS AND WIND CHILLS IN THE -10F TO -20F RANGE. WILL SEE THE
COLDEST TEMPS OF THE SEASON MONDAY NIGHT...WITH SUB ZERO LOWS
EXPECTED ACROSS THE FORECAST AREA. WIND CHILLS WILL LIKELY DROP TO
THE -20F TO -30F RANGE OVERNIGHT INTO EARLY TUE MORNING. HIGH TEMPS
TUESDAY WILL GENERALLY BE AS COLD AS MONDAY...THOUGH WINDS WILL AT
LEAST BE A BIT LIGHTER. STILL...WILL PROBABLY SEE BELOW ZERO WIND
CHILLS CONTINUE THROUGH THE DAY.

MAY SEE HIGHS WEDNESDAY JUMP A GOOD 10 DEGREES FROM TUESDAY...THOUGH
WILL STILL BE WELL BELOW NORMAL. LOOKS LIKE WIDESPREAD WIND CHILLS
ABOVE ZERO BY AFTERNOON FOR THE FIRST TIME SINCE LAST EVENING.

THURSDAY THROUGH SATURDAY...FORECAST CONFIDENCE...LOW TO MEDIUM

STILL NOT A LOT OF CONFIDENCE IN THE LATE WEEK FORECAST. THE LATEST
ECMWF AND CANADIAN HAVE COME BACK NORTH A BIT...PUTTING A LITTLE
MORE ACCUMULATING SNOW INTO SOUTHERN WISCONSIN. THE GFS IS STILL
PRETTY FAR SOUTH THOUGH WITH THE SFC LOW...JUST BRINGING A DUSTING
WITH THE UPPER WAVE. KEPT CHANCE POPS FOR NOW THURSDAY AND THURSDAY
NIGHT...AS MODELS HAVE NOT REALLY SETTLED DOWN YET.

LOOKS MAINLY DRY THEN FRIDAY AND SATURDAY WITH TEMPS A FEW DEGREES
BELOW NORMAL FOR LATE JANUARY.

AVIATION/12Z TAFS/...MID TO HIGH CLOUDS WILL OVERSPREAD SRN WI LATE
THIS AM AND AFTERNOON BUT THE SNOWFALL WILL REMAIN TO THE SOUTH OVER
IA AND IL. COLD ADVECTION WILL INCREASE AGAIN TNT WITH LOW LEVEL
INSTABILITY INCREASING ONCE AGAIN. THIS COULD RESULT IN MAINLY
SCATTERED STRATOCUMULUS CLOUDS BUT CANNOT RULE OUT LOCAL MVFR CIGS.

MARINE...A SMALL CRAFT ADVISORY AND HEAVY FREEZING SPRAY WARNING
ARE IN EFFECT UNTIL NOON. BRISK NWLY WINDS AND HIGH WAVES WILL
LINGER THIS AM BEFORE SUBSIDING THIS AFTERNOON AS STRONG LOW
PRESSURE CONTINUES TO MOVE AWAY ACROSS SRN CANADA. THE BRISK
WINDS...HIGH WAVES AND COLD TEMPERATURES WILL LEAD TO HEAVY FREEZING
SPRAY THIS AM. BRISK NWLY WINDS WILL DEVELOP ONCE AGAIN FOR MONDAY
AND MONDAY NIGHT WITH ANOTHER SMALL CRAFT ADVISORY POSSIBLE.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...HEAVY FREEZING SPRAY WARNING UNTIL NOON CST TODAY FOR LMZ643>646.

     SMALL CRAFT ADVISORY UNTIL NOON CST TODAY FOR LMZ643>646.

&&

TODAY/TONIGHT AND AVIATION/MARINE...GEHRING
MONDAY THROUGH SATURDAY...DDV

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
130 PM CST SUN JAN 20 2013

WIZ046-047-051-052-056>060-062>072-211100-
MARQUETTE-GREEN LAKE-FOND DU LAC-SHEBOYGAN-SAUK-COLUMBIA-DODGE-
WASHINGTON-OZAUKEE-IOWA-DANE-JEFFERSON-WAUKESHA-MILWAUKEE-
LAFAYETTE-GREEN-ROCK-WALWORTH-RACINE-KENOSHA-
130 PM CST SUN JAN 20 2013

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

.DAY ONE...TODAY AND TONIGHT

WIND CHILL TEMPERATURES OF 10 BELOW TO 20 BELOW ZERO WIND CHILLS ARE
EXPECTED FOR LATE TONIGHT.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

ARCTIC AIR WILL PREVAIL OVER SOUTHERN WISCONSIN THROUGH WEDNESDAY.
BITTERLY COLD TEMPERATURES ARE EXPECTED WITH WIND CHILL
TEMPERATURES RANGING FROM 10 BELOW TO 30 BELOW ZERO. WIND CHILL
ADVISORIES MAY BE NEEDED AT TIMES MONDAY THROUGH TUESDAY MORNING.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED IN THE NEXT SEVEN DAYS

LMZ643>646-211100-
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-
130 PM CST SUN JAN 20 2013

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF LAKE MICHIGAN.

.DAY ONE...TODAY AND TONIGHT

THE PROBABILITY OF WIDESPREAD HAZARDOUS WEATHER IS LOW.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

A SMALL CRAFT ADVISORY AND HEAVY FREEZING SPRAY WARNING MAY BE
NEEDED MONDAY INTO MONDAY NIGHT AS BRISK AND GUSTY NORTHWEST WINDS
RETURN WITHIN AN ARCTIC AIRMASS.

COLLAR
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