174
FXUS63 KMKX 210417
AFDMKX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
1017 PM CST WED NOV 20 2024
KEY MESSAGES
- A BRIEF BUT HEAVY ROUND OF SNOW WILL TRACK ACROSS EAST-
CENTRAL AND SOUTHEASTERN WISCONSIN THURSDAY MORNING. EXPECTING
1-4 INCHES OF SNOW ACCUMULATION ACROSS EAST-CENTRAL AND
SOUTHEASTERN WISCONSIN ALONG WITH NORTHWESTERLY WINDS GUSTS OF
35-40 MPH. A WINTER WEATHER ADVISORY IS THEREFORE IN EFFECT
BETWEEN 6 AM AND NOON CST THURSDAY ACROSS EAST-CENTRAL AND
SOUTHEASTERN WISCONSIN.
- ALTHOUGH MADISON IS NOT INCLUDED IN THE WINTER WEATHER
ADVISORY, SNOWFALL ACCUMULATIONS AND GUSTY NORTHWESTERLY WINDS
ARE EXPECTED DURING THE MORNING COMMUTE AND MAY LEAD TO
HAZARDOUS TRAVEL CONDITIONS.
- A PROLONGED PERIOD OF GUSTY WINDS CONTINUES THROUGH THURSDAY
NIGHT. THE STRONGEST GUSTS ARE EXPECTED THURSDAY MORNING AND
AFTERNOON. SMALL CRAFT ADVISORIES AND GALE WARNINGS REMAIN IN
EFFECT IN NEARSHORE AND OPEN WATER ZONES OF LAKE MICHIGAN.
- THE NEXT WIDESPREAD PRECIPITATION CHANCES ARRIVES MONDAY,
WITH MOSTLY RAIN BEING FAVORED AT THIS TIME.
UPDATE
ISSUED 1017 PM CST WED NOV 20 2024
FORECAST REMAINS ON TRACK TONIGHT. SNOW SHOWERS HAVE
TRANSITIONED TO VERY LIGHT SNOW ACROSS SOUTHERN WISCONSIN AS THE
UPPER LEVEL LOW LINGERS JUST TO OUR NORTH. NOT ANTICIPATING MUCH
ADDITIONAL ACCUMULATION WITH THIS SNOWFALL, ALTHOUGH SLIPPERY
SPOTS ALONG ELEVATED SURFACES REMAIN POSSIBLE.
TIMING FOR THE SIGNIFICANT SNOWFALL REMAINS CONSISTENT ON THE
00Z MESOSCALE MODELING, WHICH ALLOWS FOR HIGH CONFIDENCE IN
VISIBILITY AND ACCUMULATION IMPACTS FOR THE MORNING COMMUTE
ACROSS SOUTHEASTERN WISCONSIN. ACCUMULATIONS OF 1-4 INCHES WITH
WIND GUSTS OF 35 TO 40 MPH ARE EXPECTED, SO TREE DAMAGE AND
POWER OUTAGES ARE ALSO POSSIBLE IN THE MORNING HOURS DURING THE
HEAVIEST ACCUMULATIONS.
SOUTHWESTERN TO SOUTH-CENTRAL WISCONSIN WILL STILL SEE IMPACTS
FROM THIS SYSTEM, BUT THESE IMPACTS ARE EXPECTED TO BE PRIMARILY
DUE TO SLICK SPOTS AND REDUCED VISIBILITY UNDER HEAVIER SNOW
SHOWERS. THE NAM SUITE LEANS TOWARD A WESTERLY SHIFT OF THE
DEFORMATION BAND PRECIPITATION, WHICH MAY IMPLY THAT
DANE/COLUMBIA/GREEN LAKE COUNTIES ARE UNDER THE THREAT FOR
HIGHER ACCUMULATIONS THAN THE CURRENT FORECAST OF 1-2 INCHES.
REGARDLESS OF EXACT AMOUNTS, THE FOCUS REMAINS ON LOWERED
VISIBILITY AND SLIPPERY TRAVEL ALONG THE I-90/I-94 CORRIDOR AT
PEAK MORNING COMMUTE TIME FRAMES.
THROUGHOUT THE TIME PERIOD OF HEAVIEST PRECIPITATION, A "PINCH
OFF" AREA WILL BE SEEN BETWEEN THE LOWER TEMPERATURES/WETBULBS
WORKING THEIR WAY IN FROM THE WEST AND THE HIGHER
TEMPERATURES/WETBULBS WORKING IN FROM THE NORTH. AS LOW PRESSURE
PIVOTS AND NORTHERLY FLOW BECOMES DOMINANT AT THE SURFACE,
TEMPERATURES WILL RISE AND SNOW WILL TURN TO A MIX OF RAIN AND
SNOW BY MIDDAY AND FINALLY TRANSITION TO PURE RAIN IN THE
AFTERNOON.
MH
SHORT TERM
ISSUED 302 PM CST WED NOV 20 2024
TONIGHT THROUGH THURSDAY NIGHT:
SYNOPSIS/MESOANALYSIS: SURFACE OBSERVATIONS PLACE A TROUGH/SECONDARY
COLD FRONT ALONG AN APPROXIMATE DUBUQUE, IA - MADISON - STEVENS
POINT AXIS EARLY THIS AFTERNOON. THE SURFACE BOUNDARY IS POSITIONED
BENEATH AN AREA OF LOW PRESSURE IN THE MID-LEVELS OF THE ATMOSPHERE,
WITH GOES WATER VAPOR IMAGERY SHOWING THE FEATURE ADVANCING TOWARD
THE SOUTHERN HALF OF LAKE MICHIGAN AS OF 2:30 PM. LIFT FROM THE TWO
FEATURES WILL SUPPORT SCATTERED SNOW SHOWERS THROUGH THE REMAINDER
OF THE AFTERNOON AND THIS EVENING, WHICH COULD BRING ABRUPT
REDUCTIONS IN VISIBILITY DURING THE EVENING DRIVE HOME. TO OUR EAST,
DPVA AHEAD OF THE AFOREMENTIONED UPPER DISTURBANCE IS ENCOURAGING
SURFACE CYCLOGENESIS OVER SOUTHERN LAKE HURON, WHERE AN AREA OF SUB-
1000 MB SURFACE PRESSURES HAS BEEN NOTED IN RECENT OBSERVATIONS.
SAID SURFACE LOW WILL CONTINUE TO DEEPEN THIS AFTERNOON AND TONIGHT,
GRADUALLY RETROGRADING NORTHWEST TOWARD NORTHERN LAKE MICHIGAN AND
THE UPPER PENINSULA OF MICHIGAN. THE FEATURE WILL PROGRESS SOUTH
DOWN THE EASTERN HALF OF LAKE MICHIGAN DURING THE DAY ON TUESDAY.
THE LOW'S APPROACH FROM THE NORTHWEST, IN ADDITION TO INCREASING WAA
AND DPVA IN THE LOW-MID LEVELS, WILL DRIVE A ROUND OF BRIEF BUT
HEAVY SNOWFALL THURSDAY MORNING, PARTICULARLY OVER EAST-CENTRAL AND
SOUTHEASTERN WISCONSIN. THE TIMING OF SAID SNOWFALL WILL BRING
IMPACTS TO THE MORNING COMMUTE. A WINTER WEATHER ADVISORY IS IN
EFFECT BETWEEN 6 AM AND NOON THURSDAY, WHEN THE HEAVIEST SNOWFALL
RATES WILL BE MOVING ACROSS EAST-CENTRAL AND SOUTHEASTERN PORTIONS
OF THE AREA. PRECIPITATION WILL TRANSITION TO A RAIN-SNOW MIX LATE
THURSDAY MORNING, AND EVENTUALLY ALL RAIN BY THURSDAY AFTERNOON.
PRECIPITATION WILL TAPER BY THURSDAY EVENING. NORTHWEST WINDS
WILL BE GUSTY THROUGH THE DAY ON THURSDAY, WITH WIDESPREAD
35-40 MPH WINDS ANTICIPATED.
REST OF THIS AFTERNOON & THIS EVENING: THE ONGOING SCATTERED SNOW
SHOWERS WILL CONTINUE TO ADVANCE INTO & PERSIST ACROSS THE REGION.
WARM ANTECEDENT SURFACE AND PAVEMENT TEMPERATURES WILL PREVENT ANY
ACCUMULATION FROM OCCURRING, HOWEVER, BRIEF BOUTS OF MODERATE
SNOWFALL RATES ARE POSSIBLE AS ACTIVITY MOVES THROUGH. COMBINED WITH
THE GUSTY WEST/NORTHWEST WINDS IN PLACE ACROSS THE REGION, THIS
COULD RESULT IN ABRUPT DROPS IN VISIBILITY TO ONE MILE OR LESS.
THOSE DRIVING HOME THIS EVENING SHOULD THUS BUDGET EXTRA TIME AND
ALLOW FOR EXTRA FOLLOWING DISTANCE IN THE EVENT SCATTERED SNOW
SHOWERS ARE ENCOUNTERED.
THURSDAY MORNING & EARLY AFTERNOON: AN ABUNDANCE OF SYNOPTIC FORCING-
---NAMELY INCREASING WAA/ISENTROPIC ASCENT IN THE 850-700 MB
LAYER & DPVA ALOFT---WILL SUPPORT A PERIOD OF BRIEF BUT HEAVY
SNOWFALL OVER EAST-CENTRAL AND SOUTHEASTERN WISCONSIN AS LOW
PRESSURE MOVES DOWN LAKE MICHIGAN. SAID SYNOPTIC FORCING WILL
BE WELL-POSITIONED WITH RESPECT A DEEP AND SATURATED DGZ,
SUPPORTING EFFICIENT TO HEAVY (1- 1.5"+/HR) SNOWFALL RATES AS
ACTIVITY MOVES THROUGH. SATURATION OF THE DGZ, AS WELL AS
PRECIPITABLE WATERS AROUND 0.5", WILL ALSO SUPPORT A VERY WET
NATURE TO THE SNOW THAT FALLS. THE END RESULT WILL BE QUICK
ACCUMULATION OF SNOW ON GRASSY SURFACES. WHILE PAVEMENT
TEMPERATURES WILL STILL BE WELL-ABOVE FREEZING PRIOR TO THE
ONSET OF SNOW, THE HEAVY RATE OF SNOWFALL IS LIKELY TO LEAD TO
SOME SLUSH ACCUMULATION ON ROADS. IMPACTS TO THE THURSDAY
MORNING COMMUTE ARE THUS ANTICIPATED WITH THIS SNOWFALL, WITH A
WINTER WEATHER ADVISORY IN EFFECT BETWEEN 6 AM AND NOON CST
THURSDAY OVER EAST- CENTRAL AND SOUTHEASTERN WISCONSIN.
GENERALLY 1-4" OF SNOW ARE EXPECTED WITHIN THE ADVISORY AREA,
WITH THE LOWEST TOTALS BEING NEAR THE WARMER WATERS OF LAKE
MICHIGAN AND THE HIGHER TOTALS BEING ALONG THE KETTLE MORAINE.
A FEW TOTALS APPROACHING OR EVEN EXCEEDING 5" CAN'T BE RULED
OUT ALONG THE SHEBOYGAN-FOND DU LAC CO LINE, WHERE SNOW WILL
BEGIN TO FALL PRIOR TO SUNRISE & THE ONSET OF THE DIURNAL
CYCLE. PRECIPITATION WILL GRADUALLY TRANSITION TO A RAIN-SNOW
MIX BY LATE MORNING, AND EVENTUALLY ALL RAIN BY EARLY AFTERNOON
AS A MILDER AIR MASS FUNNELS INTO SOUTHERN WISCONSIN FROM THE
NORTHEAST. GIVEN THAT THIS IS THE FIRST APPRECIABLE SNOWFALL IN
SEVEN MONTHS, AND THE ANTICIPATED OVERLAP OF HEAVY SNOWFALL
RATES WITH THE MORNING COMMUTE, THOSE WITH THURSDAY MORNING
TRAVEL PLANS ARE STRONGLY ENCOURAGED TO BUDGET EXTRA TIME AND
ALLOW FOR PLENTY OF FOLLOWING DISTANCE. QUIGLEY
LONG TERM
ISSUED 302 PM CST WED NOV 20 2024
FRIDAY THROUGH WEDNESDAY:
FRIDAY THROUGH WEDNESDAY:
FRIDAY: AS THE DEPARTED LOW PRESSURE WEAKENS AND MERGES INTO
DEEPENING LOW PRESSURE OVER PENNSYLVANIA, NORTHWEST WINDS
CONTINUE, BUT AT A SLOWER PACE (15-20 MPH GUSTING TO 25-30). DRY
WEATHER LIKELY FOR ALL LAND AREAS, WITH A FEW LINGERING BANDS OF
RAIN OVER LAKE MICHIGAN. DAYTIME HIGHS IN THE MID 40S WITH MOSTLY
CLOUDY SKIES. FRIDAY NIGHT LOWS AROUND 30 DEGREES.
WEEKEND: TEMPERATURES NEAR OR JUST ABOVE SEASONAL NORMS SATURDAY
AND SUNDAY (HIGHS IN THE 40S, LOWS IN THE 30S). DRY WEATHER
THROUGH SUNDAY AFTERNOON. 15-30% RAIN CHANCE SUNDAY EVENING /
NIGHT AS A WEAK LOW PRESSURE TRACKS NORTHEASTWARD THROUGH IL.
MONDAY: AS WEAK LOW PRESSURE CONTINUES NORTHEASTWARD FROM IL AND
HIGH PRESSURE BUILDS INTO SOUTHERN CANADA MONDAY, PRECIP CHANCES
INCREASE TO 25-40%, MAINLY ON ACCOUNT OF COOLER AIR PUSHING IN
ALOFT (FROM THE WEST) AND SOME ASSOCIATED FGEN. OUR FORECAST
CALLS FOR RAIN TO REMAIN THE DOMINANT PRECIP TYPE THROUGHOUT THE
EVENT, BUT FORECAST SOUNDINGS DO SHOW THE POSSIBILITY THAT THE
LATTER HALF COULD SEE A TRANSITION TO WET SNOW. A HARD FREEZE IS
EXPECTED MONDAY NIGHT, BUT THE CURRENT FORECAST CALLS FOR PRECIP
CHANCES DIMINISH BELOW 15% BEFORE FREEZING SURFACE AIR TEMPS
ARRIVE.
REST OF THE PERIOD: SEASONABLY COOL TEMPERATURES (HIGHS IN THE
30S TO AROUND 40, LOWS IN THE 20S) ARE LOOKING LIKELY. MOSTLY
QUIET WEATHER THROUGH MID NEXT WEEK WITH HIGH PRESSURE BUILDING
JUST NORTH OF THE REGION.
SHEPPARD
AVIATION
ISSUED 1017 PM CST WED NOV 20 2024
CEILINGS RANGE FROM VFR TO 1500 FT ACROSS THE REGION, WITH THE
PRIMARY DETERMINER BEING THE LOCATION OF LIGHT SNOWFALL.
GENERALLY EXPECTING VFR CONDITIONS TO BE LOCALIZED AND BRIEF,
WITH SNOWFALL AND CEILINGS IN THE 1500 TO MVFR RANGE DOMINATING
THROUGH THE EARLY MORNING HOURS THURSDAY. SNOWFALL CONTINUES TO
LOWER VISIBILITY TO THE 3 TO 5 SM RANGE TONIGHT, WITH THIS LIGHT
SNOWFALL EXITING INTO THE EARLY MORNING HOURS. HOWEVER, AS LIGHT
SNOW EXITS, MORE SIGNIFICANT SNOWFALL ENTERS THE REGION FROM THE
NORTHEAST AROUND SUNRISE.
EXPECTING HIGH SNOWFALL RATES ON THE ORDER OF 1 INCH PER HOUR
ACROSS SOUTHEASTERN WISCONSIN BETWEEN 12Z AND 15Z THIS MORNING,
TRANSITIONING TO A MIX OF RAIN AND SNOW BY MIDDAY AND
TRANSITIONING TO RAIN BY THE AFTERNOON HOURS. DURING THE
MORNING, EXPECT VISIBILITIES AND CEILINGS TO DIP INTO THE IFR
CATEGORY, WITH 1 SM OR LESS VISIBILITY POSSIBLE ALONG LAKE
MICHIGAN AND KETTLE MORAINE TERMINALS. MEANWHILE, EXPECT A WIND
SHIFT TO NORTH-NORTHWEST WITH GUSTS AROUND 35 KT. GUSTY WINDS
CONTINUE OVERNIGHT AND INTO FRIDAY, ALTHOUGH PRECIPITATION ENDS
BY THE EVENING HOURS THURSDAY.
MH
MARINE
ISSUED 302 PM CST WED NOV 20 2024
AN ACTIVE PERIOD FEATURING WINTRY PRECIPITATION AND GUSTY NORTH-
NORTHWEST WINDS BEGINS OVERNIGHT AS 992 MB LOW PRESSURE
DEVELOPS OVER THE UPPER PENINSULA OF MICHIGAN. SAID LOW WILL
RETROGRADE INTO THE NORTHERN OPEN WATERS OF LAKE MICHIGAN BY
SUNRISE BY DAYBREAK THURSDAY, CONTINUING TO DEEPEN TO NEAR 990
MB IN THE PROCESS. THE DEVELOPMENT AND APPROACH OF THE SURFACE
LOW WILL RESULT IN INCREASING WIND GUSTS TONIGHT, WITH READINGS
RANGING BETWEEN 30-40 KNOTS ANTICIPATED BY SUNRISE OVER THE
WESTERN HALF OF THE LAKE. SIMILAR GUSTS WILL CONTINUE THROUGH
THURSDAY AFTERNOON AS THE AFOREMENTIONED SURFACE LOW DRIFTS
SOUTH ACROSS THE LAKE AND FILLS TOWARD 996 MB. GALE WARNINGS
THUS REMAIN IN EFFECT BETWEEN 12 AM AND 7 PM CST THURSDAY OVER
THE NORTHERN HALF OF THE OPEN WATERS, AND BETWEEN 3 AM CST
THURSDAY AND 12 AM CST FRIDAY ACROSS THE SOUTHERN HALF OF THE
OPEN WATERS. WAVE HEIGHTS BETWEEN 7-14 FEET WILL ACCOMPANY
THURSDAY AFTERNOON'S GUSTS.
GUSTY WEST TO NORTHWEST WINDS ARE ONGOING IN NEARSHORE ZONES THIS
AFTERNOON, SUPPORTING CONTINUED SMALL CRAFT ADVISORY CONDITIONS
THROUGH THIS EVENING. THE APPROACH OF RETROGRADING LOW PRESSURE FROM
THE NORTH WILL RESULT IN EVEN GREATER, NORTHWESTERLY GUST READINGS
APPROACHING DAYBREAK THURSDAY, WITH A GALE WARNING GOING INTO EFFECT
FROM SHEBOYGAN SOUTH TO WINTHROP HARBOR AT 3 AM CST THURSDAY
MORNING. 30-40 KNOT WINDS WILL BE ACCOMPANIED BY WAVE HEIGHTS
RANGING BETWEEN 4-10 FEET THURSDAY AFTERNOON. GUSTY WINDS AND
ELEVATED WAVE HEIGHTS WILL CONTINUE INTO THURSDAY EVENING, WITH THE
GALE WARNING REMAINING IN EFFECT UNTIL 12 AM FRIDAY. GUSTY NORTHWEST
WINDS---ALBEIT LIGHTER THAN THE READINGS EXPECTED ON THURSDAY---WILL
CONTINUE THROUGH FRIDAY IN NEARSHORE ZONES. AN ADDITIONAL SMALL
CRAFT ADVISORY WILL LIKELY BE NEEDED AS THIS PORTION OF THE PERIOD
DRAWS CLOSER.
QUIGLEY
MKX WATCHES/WARNINGS/ADVISORIES
WI...WINTER WEATHER ADVISORY...WIZ051-WIZ052-WIZ058-WIZ059-WIZ060-
WIZ064-WIZ065-WIZ066-WIZ070-WIZ071-WIZ072...6 AM THURSDAY
TO NOON THURSDAY.
LM...GALE WARNING...LMZ080-LMZ643-LMZ644-LMZ645-LMZ646-LMZ669-
LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ870-LMZ872-LMZ874-
LMZ876-LMZ878...3 AM THURSDAY TO MIDNIGHT FRIDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ868 UNTIL 6 PM THURSDAY.
SMALL CRAFT ADVISORY...LMZ643-LMZ644-LMZ645-LMZ646 UNTIL 3 AM
THURSDAY.
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