710
FXUS63 KMKX 191846
AFDMKX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
1246 PM CST THU DEC 19 2024
KEY MESSAGES
- WIDESPREAD LGT TO MDT SNOWFALL IS ON TRACK FOR TODAY WITH MUCH
LESSER SNOW TOWARD THE IL BORDER. WIDESPREAD LGT TO MDT SNOW
TNT OVER ALL OF SRN WI, HEAVIEST OVER ERN SHEBOYGAN AND ERN
OZAUKEE COUNTIES VIA LAKE ENHANCEMENT.
- LAKE MICHIGAN COUNTIES WILL SEE LAKE EFFECT SNOW SHOWERS
LINGER INTO FRIDAY MORNING, POTENTIALLY IMPACTING THE MORNING
COMMUTE. HENCE, A WINTER WEATHER ADVISORY REMAINS IN EFFECT
LONGER (THROUGH MIDDAY FRIDAY) FOR THESE REGIONS.
- THE NEXT ROUND OF ARCTIC AIR SETTLES INTO SOUTHERN WISCONSIN
THIS WEEKEND, WITH TEMPERATURES SETTLING BACK TOWARD NORMAL
INTO EARLY NEXT WEEK.
- THE NEXT CHANCES FOR ACCUMULATING SNOWFALL DEVELOP MONDAY INTO
MONDAY NIGHT, BUT PRECIP TYPE IS UNCERTAIN. MAY FALL AS RAIN
DEPENDING ON SYSTEM TRACK.
UPDATE
ISSUED 1245 PM CST THU DEC 19 2024
A WELL DEFINED VORTICITY MAXIMUM OVER SOUTH CENTRAL WI WILL
CONTINUE ENEWD THIS AFTERNOON WHILE THE 700MB TROUGH AND 850-700
MB WARM ADVECTION AND EMBEDDED FRONTOGENESIS WILL FOLLOW. MORE
SPECIFICALLY, THE SLY 30-35 KT 850 MB FLOW OVER WRN WI WILL
SHIFT EWD THROUGH THE AFTERNOON BUT RETREAT SWD, WHILE THE 700
MB BAROCLINIC ZONE WILL MOVE TO CENTRAL WI BY EARLY EVENING THEN
STALL. AN ADDITIONAL SHORTWAVE TROUGH CURRENTLY OVER SW MN WILL
DIVE SEWD TO WEST CENTRAL IL BY 06Z FRI, WHILE ANOTHER UPPER
WAVE OVER SRN MANITOBA WILL REACH THE SAME REGION BY 12Z FRI.
AT THE SFC, THE LOW PRESSURE AREA ALONG THE MN/IA BORDER WILL
TRACK TO CENTRAL IN BY 12Z FRI WITH NO DEEPENING EXPECTED. AS
THE LOW PASSES TO THE SOUTH, THE BAROCLINIC ZONE OVER CENTRAL WI
WILL SHIFT BACK SWD WITH LOW TO MID LEVEL FRONTOGENESIS
EXPECTED AS IT DOES SO. LAKE ENHANCEMENT VIA SELY BOUNDARY LAYER
FLOW BACKING NELY WILL LIKELY ADD A FEW INCHES OR MORE OF SNOW
TO ERN SHEBOYGAN COUNTY THROUGH 15Z FRI, AND A WINTER STORM
WARNING MAY BE NEEDED AS HIGH SNOWFALL RATES MAY OCCUR
FREQUENTLY TNT. ELSEWHERE, A LGT-MDT SNOW WILL CONTINUE THROUGH
TNT GIVEN THE SUSTAINED CYCLONIC FLOW AND PVA THROUGH THE DEPTH
OF THE TROPOSPHERE AND THE AFOREMENTIONED FRONTOGENESIS
SHIFTING BACK SWD THROUGH THE AREA.
ADDITIONAL SNOWFALL TOTALS OF 3-6 INCHES ARE FORECAST IN THE
WINTER WX ADVISORY AREA WITH 5-9 INCHES OVER ERN SHEBOYGAN
COUNTY.
GEHRING
SHORT TERM
ISSUED 400 AM CST THU DEC 19 2024
TODAY THROUGH FRIDAY:
CHANGES:
NOT MUCH HAS CHANGED SINCE THE PRIOR FORECAST ITERATION.
EXPECTED STORM TOTALS ARE ON TRACK: 2 TO 4 INCHES SOUTH OF THE
I-94 CORRIDOR, 3 TO 5 INCHES NORTH OF IT, AND 4-7 INCHES ACROSS
THE NORTHERN TIER OF OUR CWA WITH ISOLATED AREAS TO 9 INCHES
POSSIBLE IN THE VICINITY OF SHEBOYGAN COUNTY (DUE TO SHORELINE
CONVERGENCE AND LAKE ENHANCEMENT). THE MAIN CHANGE IS A SLIGHT
DELAY IN ARRIVAL TIMES (NOTE THE NEW START TIME OF THE WINTER
WEATHER ADVISORY IN YOUR AREA IF APPLICABLE). MORNING COMMUTE
IMPACTS STILL POSSIBLE FOR AREAS NORTHWEST OF MADISON, EXPECTING
AN ARRIVAL CLOSER TO MID-DAY FURTHER EAST AND SOUTH, LEADING TO
EVENING COMMUTE IMPACTS ACROSS THE ENTIRE AREA.
EVENT EVOLUTION:
SNOW WILL BATTLE DRY AIR AS IT APPROACHES AREAS NORTH AND WEST
OF MADISON THIS MORNING, BUT COULD STILL IMPACT THE MORNING
COMMUTE THERE. WIDESPREAD LIGHT TO MODERATE SNOW THIS AFTERNOON,
GENERALLY 1/2-INCH PER HOUR RATES. LATE IN THE EVENING /
OVERNIGHT TONIGHT, SNOW BEGINS TO TAPER OFF IN THE WESTERN HALF
OF THE CWA. FOR 1-2 COUNTIES DISTANCE AWAY FROM THE LAKE MI
SHORELINE, EXPECTING LAKE EFFECT SNOW SHOWERS TO CONTINUE
OVERNIGHT INTO FRIDAY MORNING. THESE LAKE-ENHANCED SHOWERS HAVE
POTENTIAL TO PRODUCE > 1/2-INCH PER HOUR RATES (TOUGH TO PREDICT
UNTIL THEY BEGIN TO DEVELOP AND REVEAL THEIR INTENSITY), BUT
WILL ONLY BE "OFF AND ON" IN NATURE. THIS ACTIVITY PERSISTS INTO
FRIDAY MORNING, BECOMING WEAKER / LESS FREQUENT AND EVENTUALLY
DISSIPATING BY AROUND NOON (HENCE THIS IS WHEN WE CURRENTLY
EXPIRE THE EASTERN TIER OF THE WINTER WX ADVISORY).
SHEPPARD
LONG TERM
ISSUED 400 AM CST THU DEC 19 2024
FRIDAY NIGHT THROUGH WEDNESDAY:
SYNOPSIS: ARCTIC HIGH PRESSURE WILL SETTLE INTO THE WESTERN GREAT
LAKES FRIDAY NIGHT, WITH CLEARING SKIES AND TAPERING SURFACE WINDS
ALLOWING LOW TEMPERATURES TO FALL INTO THE SINGLE DIGITS AWAY FROM
LAKE MICHIGAN. CHILLY LOWS IN THE TEENS AND SINGLE DIGITS WILL
CONTINUE SATURDAY NIGHT AS THE ARCTIC HIGH MIGRATES TOWARD THE
ONTARIO-QUEBEC BORDER. SOUTH-SOUTHEAST WINDS WILL BECOME ESTABLISHED
IN THE WAKE OF THE ARCTIC HIGH, ALLOWING FOR TEMPERATURES TO
MODERATE FROM SUNDAY INTO THE BEGINNING OF NEXT WEEK. AN UPPER
DISTURBANCE WILL APPROACH THE WESTERN GREAT LAKES FROM THE NORTHERN
PLAINS ON MONDAY, BRINGING THE NEXT ROUND OF PRECIPITATION CHANCES
TO SOUTHERN WISCONSIN. DESPITE SOUTHERLY WINDS, TEMPERATURES ARE
LIKELY TO REMAIN COOL ENOUGH TO SUPPORT SNOW IN THIS SYSTEM. WITH NO
SIGNIFICANT PUSH OF NORTHERLY SURFACE FLOW/ATTENDANT ARCTIC AIR
OCCURRING IN THE WAKE OF MONDAY'S SYSTEM, RELATIVELY MILD
TEMPERATURES APPEAR POISED TO REMAIN ENTRENCHED THROUGH CHRISTMAS
ACROSS SOUTHERN WISCONSIN.
MONDAY & MONDAY NIGHT: THE NEXT CHANCES FOR PRECIP ARRIVE AHEAD OF
AN UPPER DISTURBANCE. WHILE SURFACE TEMPS WILL BE MODERATING THANKS
TO SOUTH-SOUTHEAST SURFACE FLOW, CURRENT PROGS SUGGEST THAT THE LOW
LEVEL AIR MASS WILL STILL BE COLD ENOUGH TO SUPPORT PRIMARILY SNOW
IN THIS ACTIVITY.
CHRISTMAS EVE & CHRISTMAS DAY: WITH NO MAJOR PUSH OF NORTHERLY FLOW
EXPECTED BEHIND THE MONDAY SYSTEM, A RELATIVELY MILD AIR MASS WILL
REMAIN ENTRENCHED REGIONALLY. THE OVERNIGHT UPDATE SUGGESTS HIGHS IN
THE MID-30S ON CHRISTMAS EVE, WITH A FEW LOCATIONS POTENTIALLY
PUSHING INTO THE UPPER 30S ON CHRISTMAS DAY.
QUIGLEY
AVIATION
ISSUED 1245 PM CST THU DEC 19 2024
WIDESPREAD LGT TO MDT SNOW WILL CONTINUE THIS AFTERNOON INTO FRI
AM. CIGS OF 600-1900 FEET AND VSBYS OF 1/2-1 MILE WILL BE
PREVALENT. PERIODS OF SLIGHTLY HIGHER OR LOWER VSBYS WILL OCCUR.
THE SNOW WILL END AND THE LOW CIGS WILL CLEAR AFTER 15Z FRI AWAY
FROM LAKE MI.
GEHRING
MARINE
ISSUED 400 AM CST THU DEC 19 2024
OPEN WATERS:
29.8 INCH LOW PRESSURE OVER THE NORTHERN GREAT PLAINS WILL
TRACK INTO THE UPPER MISSISSIPPI RIVER VALLEY TODAY AS IT FILLS
THROUGH 29.9 INCHES. THE APPROACH OF THE AFOREMENTIONED LOW
PRESSURE WILL RESULT IN BREEZY SOUTH TO SOUTHEAST WINDS ACROSS THE
OPEN WATERS TODAY, WITH GUSTS UP TO 25 KNOTS POSSIBLE DURING THE
AFTERNOON HOURS. WINDS WILL SHIFT OUT OF THE NORTH- NORTHEAST BY
DAYBREAK FRIDAY AS THE AREA OF LOW PRESSURE MIGRATES INTO THE OHIO
RIVER VALLEY. NORTHERLY GUSTS UP TO 30 KNOTS WILL BE POSSIBLE
THROUGH EARLY FRIDAY AFTERNOON. PERIODS OF SNOW WILL ACCOMPANY THE
LOW PRESSURE SYSTEM, WITH THE BEST CHANCES FOR PRECIPITATION OVER
LAKE MICHIGAN FORECAST FROM THURSDAY AFTERNOON THROUGH FRIDAY
MORNING. WINDS WILL GRADUALLY TAPER FRIDAY NIGHT AS 30.6 INCH
HIGH PRESSURE BUILDS IN FROM THE NORTHERN GREAT PLAINS. SAID AREA
OF HIGH PRESSURE WILL MOVE OVER LAKE MICHIGAN DURING THE DAY ON
SATURDAY, ALLOWING FOR WINDS TO TURN OUT OF THE SOUTH- SOUTHEAST
BY EARLY SUNDAY.
NEARSHORE ZONES:
APPROACHING LOW PRESSURE WILL RESULT IN GUSTY SOUTHEAST WINDS,
ELEVATED WAVE HEIGHTS, AND RESULTANT SMALL CRAFT ADVISORY
CONDITIONS IN ALL NEARSHORE ZONES BY EARLY THIS AFTERNOON.
ADVISORY-LEVEL CONDITIONS WILL CONTINUE THROUGH THE DAY ON
FRIDAY AS WINDS TURN NORTH-NORTHEASTERLY IN THE WAKE OF
DEPARTING LOW PRESSURE.
QUIGLEY
MKX WATCHES/WARNINGS/ADVISORIES
WI...WINTER WEATHER ADVISORY...WIZ046-WIZ047-WIZ051-WIZ056-WIZ057-
WIZ058-WIZ063-WIZ064 UNTIL 6 AM FRIDAY.
WINTER WEATHER ADVISORY...WIZ052-WIZ059-WIZ060 UNTIL NOON
FRIDAY.
WINTER WEATHER ADVISORY...WIZ065-WIZ066-WIZ071-WIZ072 UNTIL
NOON FRIDAY.
LM...SMALL CRAFT ADVISORY...LMZ643-LMZ644...2 PM THURSDAY TO 6 PM
FRIDAY.
SMALL CRAFT ADVISORY...LMZ645-LMZ646...2 PM THURSDAY TO
MIDNIGHT SATURDAY.
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