331
FXUS63 KMKX 182113
AFDMKX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
313 PM CST WED DEC 18 2024
KEY MESSAGES
- SNOWFALL IS EXPECTED THURSDAY MORNING INTO THURSDAY NIGHT,
WITH WIDESPREAD ACCUMULATIONS OF 3 TO 6 INCHES. IMPACTS TO THE
MORNING COMMUTE ARE EXPECTED FROM MADISON NORTHWESTWARD, WITH
IMPACTS TO THE EVENING COMMUTE ACROSS ALL OF SOUTHERN
WISCONSIN. A WINTER WEATHER ADVISORY IS IN EFFECT FROM SAUK,
DANE, JEFFERSON, WAUKESHA, AND MILWAUKEE COUNTIES NORTHWARD.
- LAKE MICHIGAN COUNTIES WILL SEE LAKE EFFECT SNOW SHOWERS
LINGER INTO FRIDAY MORNING, POTENTIALLY IMPACTING THE MORNING
COMMUTE ACROSS SHEBOYGAN, WASHINGTON, OZAUKEE, WAUKESHA, AND
MILWAUKEE COUNTIES. A WINTER WEATHER ADVISORY REMAINS IN
EFFECT 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.
SHORT TERM
ISSUED 314 PM CST WED DEC 18 2024
TONIGHT THROUGH FRIDAY:
OVERCAST SKIES AND NORTHWESTERLY WINDS CONTINUE THROUGH THIS
EVENING, WITH WINDS CALMING OVERNIGHT AS A BRIEF RIDGE OF HIGH
PRESSURE MOVES OVERHEAD. EXPECT OVERNIGHT LOWS IN THE UPPER
TEENS TO LOWER 20S, WITH TRENDS A COUPLE DEGREES WARMER DUE TO
OVERCAST SKIES ACTING AS A BLANKET ACROSS THE REGION.
THURSDAY MORNING, A CLIPPER SYSTEM APPROACHES FROM THE NORTHEAST
AND SPREADS LIGHT TO MODERATE SNOWFALL ACROSS SOUTHERN
WISCONSIN. SNOW BEGINS IN SOUTHWESTERN WISCONSIN BETWEEN 6 AND 9
AM CST, IMPACTING THE MADISON AREA NORTHWESTWARD FOR THE MORNING
COMMUTE. BY MID-MORNING, SNOW SPREADS INTO THE REMAINDER OF
SOUTHERN WISCONSIN. THE HEAVIEST RATES UP TO 0.5 INCH PER HOUR
WILL DEVELOP MID-MORNING AND CONTINUE THROUGH THE LATE EVENING
HOURS, IMPACTING THE EVENING COMMUTE WITH SLIPPERY TRAVEL.
SNOW/LIQUID RATIOS ARE EXPECTED TO BE NEARING 16:1 DUE TO
TEMPERATURES IN THE 20S, WHICH IMPLIES FLUFFY, LIGHT SNOWFALL.
THAT BEING SAID, SLIPPERY TRAVEL IS EXPECTED ACROSS UNTREATED
ROADS AND AREAS SEEING THE HIGHEST RATES.
LIGHT SNOW BECOMES DOMINANT THURSDAY EVENING. HOWEVER, AS THE
CLIPPER EXITS TO THE EAST FRIDAY MORNING, A LOBE OF VORTICITY
PIVOTING AROUND THE NORTHWESTERN SIDE OF THE LOW MAY ENHANCE
SNOWFALL RATES ONCE AGAIN ACROSS SOUTHEASTERN WISCONSIN. AT THE
SAME TIME, WINDS SHIFT TO BECOME NORTHEASTERLY OFF LAKE
MICHIGAN, LEADING TO LAKE ENHANCEMENT AND LAKE EFFECT SHOWERS
ACROSS THE LAKE MICHIGAN COUNTIES. THE WINTER WEATHER ADVISORY
REMAINS IN EFFECT THROUGH NOON FRIDAY IN SHEBOYGAN, WASHINGTON,
OZAUKEE, WAUKESHA, AND MILWAUKEE COUNTIES FOR THESE CONCERNS.
SNOW ENDS AS WINDS TURN NORTHWESTERLY FRIDAY AFTERNOON.
MH
LONG TERM
ISSUED 314 PM CST WED DEC 18 2024
FRIDAY NIGHT THROUGH WEDNESDAY:
NLY WINDS WILL DIMINISH FRI NT AS A N-S SFC RIDGE APPROACHES FROM
MN AND IA. THE SFC RIDGE WILL THEN GRADUALLY MOVE ACROSS WI ON
SAT. POLAR AIR WILL RESIDE OVER SRN WI FOR THE WEEKEND WITH LOWS
IN THE SINGLE DIGITS, AND TEENS BY THE LAKE. HIGHS WILL ONLY WARM
TO NEAR 20F ON SAT BUT CLOSE TO 30F ON SUN AS SLY WINDS AND WARM
ADVECTION ENSUE. NO PCPN IS FORECAST ALTHOUGH ONE OR TWO
VORTICITY MAXIMUMS IN NNWLY FLOW ALOFT WILL SKIM BY TO THE WEST.
SLY WINDS AND WARM ADVECTION WILL THEN CONTINUE INTO MON WITH A
SHORTWAVE TROUGH APPROACHING FROM SD AND MN. THE TROUGH WILL PASS
DURING THE DAY WITH LIGHT SNOW BECOMING LIKELY VIA WARM ADVECTION
AND PVA. THE LIGHT SNOW MAY LINGER INTO MON EVENING.
A QUASI-ZONAL FLOW AND WEAK SFC WINDS WILL THEN PREVAIL INTO
CHRISTMAS DAY WITH ABOVE NORMAL TEMPS.
GEHRING
AVIATION
ISSUED 314 PM CST WED DEC 18 2024
CEILINGS CONTINUE TO BOUNCE BETWEEN MVFR AND VFR NEAR LAKE
MICHIGAN, WITH MVFR CONDITIONS REMAINING FIRMLY IN PLACE INLAND.
WITH SUNSET APPROACHING, EXPECTING MVFR CONDITIONS TO LINGER
THROUGH MUCH OF THE OVERNIGHT HOURS, ASIDE FROM A BRIEF BREAK
UNDER HIGH PRESSURE BEFORE A CLIPPER SYSTEM APPROACHES FROM THE
NORTHWEST.
A CLIPPER SYSTEM WILL SPREAD SNOWFALL AND 1000-2000 FT CEILINGS
ACROSS SOUTHERN WISCONSIN FROM WEST TO EAST THURSDAY MORNING,
WITH IFR CEILINGS AND LOWERED VISIBILITIES PROGRESSING EASTWARD
THROUGH THURSDAY AFTERNOON.
NORTHWESTERLY WINDS CONTINUE THROUGH THIS EVENING, BECOMING
LIGHT AND VARIABLE TO CALM OVERNIGHT BEFORE SOUTHEASTERLY WINDS
INCREASE THURSDAY MORNING AHEAD OF THE CLIPPER SYSTEM.
SOUTHEASTERLY WINDS CONTINUE THROUGH MUCH OF THE DAY
THURSDAY, BEGINNING TO SHIFT SOUTHWESTERLY GOING INTO THURSDAY
EVENING.
MH
MARINE
ISSUED 314 PM CST WED DEC 18 2024
BRISK NORTHWEST WINDS CONTINUE HIGH PRESSURE BUILDS INTO THE
UPPER MISSISSIPPI RIVER VALLEY. WINDS WILL DIMINISH TONIGHT AND
REMAIN LIGHT INTO THURSDAY MORNING AS HIGH PRESSURE MOVES ACROSS
LAKE MICHIGAN. WINDS WILL SHIFT TO BECOME SOUTHEASTERLY DURING
THE DAY THURSDAY AS LOW PRESSURE APPROACHES LAKE MICHIGAN FROM
THE UPPER MISSISSIPPI VALLEY. EXPECT RAIN AND SNOW SHOWERS
THROUGHOUT THE DAY THURSDAY INTO THURSDAY NIGHT. WINDS AND WAVES
IN NEARSHORE REGIONS WILL BECOME ELEVATED, LEADING TO A SMALL
CRAFT ADVISORY THURSDAY AFTERNOON THROUGH FRIDAY EVENING.
LOW PRESSURE MOVES SOUTHEASTWARD ACROSS THE SOUTHERN HALF OF
THE OPEN WATERS OVERNIGHT THURSDAY, BRINGING A LULL IN WINDS TO
THE SOUTHERN HALF AND SLOWLY BACKING WINDS TO BECOME NORTHERLY
IN THE NORTHERN HALF. THE LOW WILL PROGRESS EAST OF THE OPEN
WATERS INTO FRIDAY MORNING, RESULTING IN GUSTY NORTH WINDS
ACROSS THE LAKE. NORTHERLY WINDS CONTINUE INTO SATURDAY, SLOWLY
DIMINISHING AS LOW PRESSURE EXITS EASTWARD.
MH
MKX WATCHES/WARNINGS/ADVISORIES
WI...WINTER WEATHER ADVISORY...WIZ046-WIZ047-WIZ051-WIZ056-WIZ057-
WIZ058-WIZ063-WIZ064...6 AM THURSDAY TO 6 AM FRIDAY.
WINTER WEATHER ADVISORY...WIZ052-WIZ059-WIZ060-WIZ065-
WIZ066...9 AM THURSDAY TO NOON FRIDAY.
LM...SMALL CRAFT ADVISORY...LMZ643-LMZ644...3 PM THURSDAY TO 6 PM
FRIDAY.
SMALL CRAFT ADVISORY...LMZ645-LMZ646...3 PM THURSDAY TO
MIDNIGHT SATURDAY.
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