716
FXUS63 KMKX 152159
AFDMKX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
359 PM CST WED JAN 15 2025
KEY MESSAGES
- LIGHT SNOW EXPECTED TO BEGIN ROUGHLY 6-8 PM THIS EVENING,
BECOMING MORE SCATTERED / ISOLATED AROUND 1 AM, WITH CHANCES
FOR FLURRIES LINGERING THROUGH THURSDAY MORNING. SNOW
ACCUMULATIONS OF A TRACE TO 1 INCH POSSIBLE, WITH THE BEST
CHANCES FOR 0.5" TO 1" LOCATED EAST OF I-90 AND NORTH OF I-94.
- WELL ABOVE NORMAL TEMPERATURES THURSDAY AND FRIDAY.
- BITTERLY COLD TEMPERATURES AND WIND CHILLS RETURN SUNDAY,
CONTINUING INTO EARLY NEXT WEEK.
SHORT TERM
ISSUED 400 PM CST WED JAN 15 2025
TONIGHT AND THURSDAY:
METEOROLOGICAL SYNOPSIS:
AN OCCLUDING LOW OVER THE HUDSON BAY TONIGHT WORKS WITH A
500-300MB TROUGH TO FORM A TRIPLE-POINT LOW, WHICH WILL TRACK
EASTWARD ACROSS SOUTHERN ONTARIO CANADA AS A CLIPPER SYSTEM.
BOTH THE LEFT EXIT OF A 300MB JET STREAK AND PVA AHEAD OF THE
APPROACHING 500MB TROUGH ALIGN OVER OUR REGION THIS EVENING,
PROVIDING SYNOPTIC LIFT, CO-LOCATED WITH AN ENHANCEMENT IN THE
700MB MOISTURE FIELD. FORECAST SOUNDINGS AND MODEL CROSS
SECTIONS BOTH INDICATE A SATURATED DGZ WITH STEADY ASCENT,
ROUGHLY 6 PM THIS EVENING THROUGH 1 AM TONIGHT, FOLLOWED BY
ADDITIONAL (WEAKER) PERIODS OF 500MB PVA AND LINGERING SHALLOW
MOISTURE INTO THURSDAY MORNING.
EXPECTATIONS:
SNOW IS EXPECTED TO ARRIVE IN THE 6 PM TO 8 PM WINDOW THIS
EVENING (FROM NW TO SE), THOUGH DRY AIR AT THE SURFACE MAY DELAY
THE ARRIVAL AN EXTRA HOUR OR SO. MOST OF THE ACCUMULATING SNOW
WILL FALL BETWEEN THEN AND 1 AM TONIGHT. TOTAL ACCUMULATIONS
RANGING FROM A TRACE TO AN INCH, WITH THE BEST POTENTIAL FOR
1/2" TO 1" LOCATED EAST OF I-90 AND NORTH OF I-94. FROM 1 AM
THROUGH AN HOUR OR TWO AFTER SUNRISE THURSDAY, LINGERING
POTENTIAL FOR LIGHT SNOW SHOWERS / FLURRIES, THOUGH THIS
ACTIVITY WILL BE MORE SCATTERED / ISOLATED IN NATURE. DAYTIME
HIGHS CLIMB TO THE LOW 30S THURSDAY, CLOSER TO MID 30S EAST OF
THE KETTLE MORAINE HILLS / NEAR LAKE MICHIGAN.
SHEPPARD
LONG TERM
ISSUED 400 PM CST WED JAN 15 2025
THURSDAY NIGHT THROUGH WEDNESDAY:
DRY WEATHER LOOKING LIKELY THROUGH THE DAYTIME HOURS OF FRIDAY
AS A LOW PRESSURE SYSTEM TRACKS EASTWARD ACROSS ONTARIO CANADA. A
COLD FRONT EXTENDING SOUTHWEST OF THIS LOW WILL THEN CROSS OUR
REGION FRIDAY EVENING. SOUTHWESTERLY WAA AHEAD OF THE FRONT WILL
LEAD TO DAYTIME HIGHS AROUND 40 DEGREES ON FRIDAY (WELL ABOVE
AVERAGE). THE COLD FRONT ITSELF GENERALLY LACKS SUFFICIENT
MOISTURE FOR WIDESPREAD PRECIP, BUT A CHANCE FOR LIGHT RAIN
QUICKLY TRANSITIONING TO SNOW IS FEATURED IN THE FORECAST FRIDAY
EVENING FOR FAR SOUTHEASTERN WI. DRY AIR IS LIKELY TO ARRIVE
BEFORE SNOW BEGINS TO ACCUMULATE. DRY WEATHER APPEARS LIKELY
LATE FRIDAY NIGHT THROUGH EARLY NEXT WEEK.
STRONG CAA CONTINUES THROUGH THE WEEKEND INTO EARLY NEXT WEEK,
FORCED BY A STRONG "ARCTIC" HIGH PRESSURE IN SOUTHERN CANADA /
MIDWEST USA. HIGH TEMPS PLUMMET TO THE 20S BY SATURDAY, THEN
POSSIBLY TO THE SINGLE DIGITS / NEAR ZERO EARLY NEXT WEEK. SOME
OF THE MORE AGGRESSIVE ENSEMBLE SYSTEM MEMBERS HAD SHOWN
OVERNIGHT LOWS SUNDAY/MONDAY NIGHT IN THE VICINITY OF 20 BELOW
ZERO, THOUGH WITH A DISTINCT LACK OF SNOW COVER IN THE FORECAST,
CLIMATOLOGY WOULD SUGGEST THIS IS UNLIKELY. OUR FORECAST
(INSTEAD) AIMS FOR THE NEGATIVE SINGLE DIGITS TO AROUND 10 BELOW
ZERO FOR SUNDAY AND MONDAY NIGHT LOWS. PRESSURE GRADIENT FROM
THE ARCTIC HIGH PRESSURE IS LIKELY TO KEEP NORTHWEST WINDS
MOVING, RESULTING IN BITTER COLD WIND CHILLS LATE THIS WEEKEND
INTO EARLY NEXT WEEK.
SHEPPARD
AVIATION
ISSUED 400 PM CST WED JAN 15 2025
EXPECTING LIGHT SNOW SHOWERS TO ARRIVE ROUGHLY 6 TO 8 PM THIS
EVENING (THOUGH ONSET MAY BE DELAYED AN EXTRA HOUR OR SO WITH
DRY AIR IN PLACE), ACCOMPANIED BY GRADUALLY DECREASING (MVFR)
CLOUD CEILINGS. GENERALLY EXPECTING TRACE TO 1 INCH
ACCUMULATIONS, WITH THE MAJORITY OF IT FALLING BETWEEN ONSET AND
1 AM TONIGHT. BREEZY SOUTHWEST WINDS THIS EVENING GRADUALLY
TURNING NORTHWEST INTO THURSDAY AM. SNOW FLURRIES CONTINUE INTO
THURSDAY AM, BECOMING MORE ISOLATED / BRIEF IN NATURE BEFORE
DISSIPATING. CLOUD CEILINGS MAKE A GRADUAL IMPROVEMENT THROUGH
THURSDAY.
SHEPPARD
MARINE
ISSUED 400 PM CST WED JAN 15 2025
LOW PRESSURE OF 29.3 INCHES REMAINS OVER THE HUDSON BAY TONIGHT,
WHILE A FASTER MOVING LOW PRESSURE (CLIPPER SYSTEM) OF 29.6
INCHES MOVES EAST ACROSS SOUTHERN ONTARIO CANADA, DRAGGING A COLD
FRONT ACROSS LAKE MICHIGAN. GUSTY SOUTHWEST WINDS ARE EXPECTED
ACROSS THE LAKE AHEAD OF THE FRONT THIS EVENING, WITH A FEW GUSTS
TO GALE FORCE POSSIBLE ACROSS THE NORTHERN HALF OF THE LAKE BEFORE
MIDNIGHT. WINDS BEGIN TO VEER AFTERWARDS, BECOMING NORTHWEST
AROUND DAWN THURSDAY AND PICKING BACK UP TO AROUND 25-30 KT.
NORTHWEST WINDS SETTLE THURSDAY EVENING AS WEAK HIGH PRESSURE
MOVES EASTWARD THROUGH THE OHIO RIVER VALLEY. LOW PRESSURE AROUND
29.1 INCHES MOVING EAST THROUGH ONTARIO ON FRIDAY WILL THEN LEAD
TO GUSTY SOUTH TO SOUTHWEST WINDS, WITH GALES POSSIBLE. AS THIS
LOW LIFTS NORTHEASTWARD AND STRONG ARCTIC HIGH PRESSURE MOVES INTO
SOUTHERN CANADA / MIDWESTERN US-STATES THIS WEEKEND, A PROLONGED
PERIOD OF GUSTY NORTHWEST WINDS IS EXPECTED SATURDAY THROUGH EARLY
NEXT WEEK, WITH FALLING TEMPERATURES. FREEZING SPRAY (HEAVY AT
TIMES) WILL BECOME A CONCERN FROM SATURDAY NIGHT ONWARDS AS THE
COLD AIR ARRIVES, PARTICULARLY OVER EASTERN AREAS OF THE LAKE
(CO-LOCATED WITH THE LARGEST WAVES).
SHEPPARD
MKX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
LM...SMALL CRAFT ADVISORY...LMZ643-LMZ644-LMZ645-LMZ646 UNTIL 3 PM
THURSDAY.
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