305
FXUS63 KMQT 220818
AFDMQT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
318 AM EST WED JAN 22 2025
KEY MESSAGES
- CLIPPER PASSING THROUGH THE AREA TODAY TO BRING MAINLY LIGHT
SNOW DURING THE DAY AND HIGH TEMPERATURES IN THE TEENS ABOVE
ZERO.
- LAKE EFFECT SNOW OVERNIGHT INTO THURSDAY MORNING TO BRING 2-4
INCHES OF FLUFFY SNOW TO THE NORTH-NORTHWEST WIND SNOW BELTS,
LOCALLY UP TO 6 INCHES IN THE HIGH TERRAIN ALONG THE SPINE OF
THE KEWEENAW.
- MODERATING AIRMASS WILL SEE TEMPERATURES TRENDING MORE OR
LESS TOWARDS NORMAL VALUES FROM MIDWEEK ONWARDS.
- PASSING CLIPPER SYSTEMS WILL BRING IN ROUNDS OF LIGHT LAKE
EFFECT/ENHANCED SNOW THROUGH THE EXTENDED PERIOD, BUT
WIDESPREAD SIGNIFICANT SNOWFALL IS NOT EXPECTED.
SHORT TERM /THROUGH TONIGHT/
ISSUED AT 316 AM EST WED JAN 22 2025
RAP ANALYSIS SHOWS PRIMARILY DIRECT NORTHWEST FLOW AT 500MB OVER THE
UP WITH BROAD SCALE TROUGHING OVER MUCH OF THE GREAT LAKES
REGION. UPSTREAM, A SHORTWAVE AXIS IS PIVOTING AROUND THE
WESTERN PERIPHERY OF THE LONGWAVE TROUGH, CURRENTLY APPROACHING
THE INTERNATIONAL BORDER AT EASTERN MT/ND. THIS TROUGH IS
SUPPORTING A CLIPPER LOW THAT THE RAP HAS AT 1003MB CENTERED
OVER THE NORTHWEST ANGLE AT 07Z. BROAD WARM ADVECTION IS
PROVIDING ENOUGH ASCENT FOR -SHSN TO BE OBSERVED AT THE OFFICE
AND LIGHT RADAR RETURNS CAN BE SEEN ACROSS AT LEAST THE WEST
HALF OF THE UP, SPREADING EAST QUICKLY. PWAT VALUES OF AROUND
0.1" WILL LIMIT QPF POTENTIAL, WITH THE HREF ONLY SHOWING
ISOLATED POCKETS OF THE UP WITH ~30% POTENTIAL OF EXCEEDING 0.1"
OF PRECIPITATION BY NOON TODAY. THE WARM ADVECTION WILL ALSO
ALLOW HIGHS TO CLIMB INTO THE TEENS TODAY, WHICH WHILE STILL AT
LEAST A HANDFUL OF DEGREES BELOW NORMAL FOR THIS TIME OF YEAR
(AROUND 20), THIS WILL BE A WELCOME RESPITE FROM THE FRIGID COLD
OF THE PAST FEW DAYS. WIND GUSTS OF 20-30 MPH WILL STILL KEEP
WIND CHILLS IN AT LEAST THE NEGATIVE TEENS THIS MORNING AND
BELOW ZERO THIS AFTERNOON, BUT WIND CHILLS ARE NOT EXPECTED TO
BE AT COLD WEATHER ADVISORY AFTER THE SUN RISES THIS MORNING.
TONIGHT, AS THE LOW PASSES, WEAKENING TO ABOUT 1013MB, CAMS SHOW
SOME MESOLOW TYPE FEATURES MAKING LANDFALL AROUND THE PICTURED ROCKS
NATIONAL LAKESHORE AROUND 07Z. WHILE SOME LOCALIZED LOWER
VISIBILITY IS POSSIBLE WITH THIS, ANY ENHANCED SNOWFALL FROM
THIS WILL BE SHORT-LIVED, SO WINTER WEATHER ADVISORIES ARE NOT
ANTICIPATED AT THIS TIME. NORTH-NORTHWEST LAKE EFFECT SNOW BANDS
SET UP IN THE WAKE OF THIS SYSTEM AS 850MB TEMPERATURES REMAIN
AROUND -20 C AND LAKE SUPERIOR REMAINS AT LEAST 90% OPEN DESPITE
THE RECENT COLD. THE HIGHEST SNOW TOTALS ARE EXPECTED ALONG THE
SPINE OF THE KEWEENAW, WHERE UPSLOPING WILL HELP ENHANCE THE
BANDS TO PRODUCE AROUND A THIRD OF AN INCH OF QPF PER THE HREF
MEAN BY THURSDAY MORNING, WHICH AT NEAR 20:1 RATIOS COULD MEAN
LOCALLY UP TO 6 INCHES OF FLUFFY SNOW POSSIBLE (THOUGH MORE
WIDESPREAD TOTALS OF 2-4 INCHES WILL BE THE NORM). OVERNIGHT
LOWS IN THE SINGLE DIGITS ABOVE ZERO AND WINDS GUSTING TO AROUND
25 MPH WILL LEAD TO WIND CHILLS AROUND -10, WHICH IS COLD, BUT
WILL NOT BE ENOUGH TO WARRANT ANY HEADLINES.
LONG TERM /WEDNESDAY THROUGH MONDAY/
ISSUED AT 257 PM EST TUE JAN 21 2025
A MORE ACTIVE PATTERN LOOKS TO SET UP FOR THE MIDWEEK AND BEYOND AS
THE FIRST IN A SERIES OF SHORTWAVES TRANSITS THROUGH THE MIDWEST
REGION ON WEDNESDAY. WHILE DETAILS IN TIMING AND INTENSITY OF THE
FOLLOWING SHORTWAVES IS STILL HIGH, THERE IS A GENERAL AGREEMENT ON
A BRIEF PERIOD OF LOCAL RIDGING FOR FRIDAY BEFORE ANOTHER SHORTWAVE
PASSES FRIDAY INTO THE WEEKEND. FROM THERE, MORE SHORTWAVES (WITH
PLENTY OF SPREAD AMONG MODELS, AND VARYING DEGREES OF
STRENGTH/TIMING) ARE EXPECTED THROUGH THE REST OF THE PERIOD. THESE
ARE EMBEDDED IN BROAD TROUGHING OVER THE GREAT LAKES AS A SPLIT FLOW
PATTERN SETS UP WITH A CUTOFF LOW OVER THE DESERT SOUTHWEST.
WEDNESDAY MORNING, A WEAKENING CLIPPER LOW WILL BE MOVING ALONG THE
BORDER OF NORTHERN MN, SET TO TRACK ALONG/NORTH OF LAKE SUPERIOR
THROUGH THE AFTERNOON. HIGH PRESSURE EXTENDING FRO THE MID ATLANTIC
SOUTHWEST TO TEXAS WILL CUT US OFF FROM THE GULF OF MEXICO (AND ITS
MUCH-NEEDED MOISTURE), AND GIVEN PRIOR SIMILAR SETUPS IN MOISTURE-
STARVED CLIPPERS THIS SEASON, ONLY A COUPLE TO A FEW TENTHS OF
SNOWFALL ARE EXPECTED WITH THIS SYSTEM AS IT PASSES WEDNESDAY. ONE
FEATURE TO WATCH WITH THE WEDNESDAY SYSTEM IS ANY POTENTIAL
SOUTHERLY TO SOUTHWESTERLY LAKE EFFECT/ENHANCED SNOWFALL AS DESPITE
THE RELATIVELY WARM ADVECTION, 850MB TEMPERATURES ARE STILL EXPECTED
TO BE IN THE NEGATIVE TEENS ABOVE AN OPEN LAKE MICHIGAN. CAMS
CONTINUE TO SHOW STRONGER BANDING EXTENDING INTO MACKINAC AND
CHIPPEWA COUNTIES, JUST EAST OF OUR CWA. HOWEVER, IF FUTURE FORECAST
CYCLES SHIFT THIS MORE WESTERLY, AT LEAST LUCE COUNTY COULD BE
CLIPPED BY SOME ADVISORY AMOUNTS.
OTHERWISE, MAINLY LIGHT NORTHWESTERLY LAKE EFFECT SNOWFALL IS
EXPECTED IN THE WAKE OF THE TROUGH'S PASSAGE WITH LREF 6-HOURLY
PRECIP RATES FOR WEDNESDAY EVENING THROUGH THURSDAY ARE ONLY AROUND
0.01-0.05", AND SOME LOCALLY HIGHER AMOUNTS UP TO 0.10" WEDNESDAY
NIGHT WHERE ANY LOCALIZED TERRAIN ENHANCEMENT CAN OCCUR IN THE
WESTERN UP. WILL ALSO NOTE THAT SOME OF THE LATEST CAM GUIDANCE IS
HINTING AT SOME LOCALLY HIGHER AMOUNTS IN THE EASTERN UP WEDNESDAY
EVENING/NIGHT WITH SOME LOCALIZED CONVERGENCE OR MESO-LOW
DEVELOPMENT MOVING ONSHORE FROM EASTERN LAKE SUPERIOR. WITH SNOW
RATIOS ONLY PEAKING AT AROUND 20:1, AROUND AN AN INCH OF SNOW PER
SIX HOURS IS EXPECTED FOR THE MOST PART ACROSS THE NW WIND SNOW
BELTS WED-THURS, WITH LOCALLY HIGHER AMOUNTS TO 1-2IN/6HRS WEDNESDAY
EVENING AND NIGHT IN THOSE AREAS OF LOCALIZED ENHANCEMENT. INTO
THURSDAY, SLOWLY BACKING WINDS AND A DRIER AIRMASS WORKING IN AS A
RIDGE SLOWLY BUILDS INTO THE GREAT LAKES WILL CUT BACK ON SNOWFALL
ACCUMULATIONS THROUGHOUT THE DAY.
MEANWHILE, TEMPERATURES CONTINUE TO COME IN SLIGHTLY BELOW AVERAGE
WEDNESDAY THROUGH THURSDAY, BUT MORE SEASONABLE AIR IS EXPECTED TO
RETURN TO THE AREA LATE WEEK WITH HIGHS GENERALLY IN THE TEENS AND
20S AND LOWS IN THE SINGLE DIGITS. AS LONG AS LAKE SUPERIOR REMAINS
IN ITS CURRENT MAINLY ICE-FREE STATE, TEMPERATURES ALOFT CONTINUE TO
SUPPORT LAKE EFFECT SNOW IN THE WAKE OF ANY PASSING SHORTWAVES. FOR
THE WEEKEND AND BEYOND, THE MOST COMMON 925MB WIND DIRECTION REMAINS
NWERLY, SO THAT WILL CONTINUE TO BE THE EXPECTED REGIME FOR LES
BANDS TO SET UP IN FOLLOWING ANY CLIPPERS. HOWEVER, STRONG SYNOPTIC
SNOWS LOOK UNLIKELY UNTIL AT LEAST NEXT WEEK, WHEN THERE'S A WEAK
SIGNAL IN THE ENSEMBLES FOR A SUB-900MB LOW TO PASS...SOMEWHERE
THROUGH OR NEAR THE GREAT LAKES. SPREAD IS HIGH AT THIS TIME PERIOD,
SO THIS PROSPECTIVE SYSTEM IS JUST AS LIKELY TO MISS THE UP AS IT IS
TO PROVIDE ANY WINTER IMPACTS. CPC OUTLOOKS FOR EARLY FEBRUARY
HIGHLIGHT SLIGHT FAVORING OF COOLER THAN NORMAL TEMPERATURES AND
HIGHER PRECIPITATION THAN NORMAL FOR THE UPPER GREAT LAKES REGION.
THIS LIKELY STEMS FROM ENSEMBLE MEAN 500MB HEIGHT CHARTS FAVORING
TROUGHING STRETCHING FROM NORTHEAST CANADA TO THE GREAT LAKES AND
RIDGING OVER WESTERN NORTH AMERICA, FAVORING TRANSPORT OF COOLER AIR
OVER STILL-OPEN WATERS OF THE GREAT LAKES (SAVE FOR BAYS, ETC THAT
ARE ICING OVER CURRENTLY) WHICH SHOULD SUPPORT CONTINUED LES.
AVIATION /06Z TAFS THROUGH 06Z THURSDAY/
ISSUED AT 1243 AM EST WED JAN 22 2025
MVFR CEILINGS SHOULD DEVELOP OVERNIGHT AND THIS MORNING AS A LOW
PRESSURE MOVES THROUGH THE REGION. THIS SYSTEM WILL SPREAD SNOW
THROUGH THE REGION, BRINGING CHANCES TO ALL TERMINALS. GUSTY
SOUTHWESTERLY WINDS OF 25-30KTS ARE EXPECTED, BUT SHOULD IMPROVE
THROUGH THE DAY WEDNESDAY AND EVENTUALLY SHIFT TO MORE WESTERLY
AT KCMX/KIWD AS LAKE EFFECT SNOW SHOWERS SPREAD TO THE
TERMINALS. VISIBILITIES DURING THIS MORNING'S SNOW IS EXPECTED
TO PREVAIL MVFR, BUT SOME IFR CAN'T BE RULED OUT.
MARINE
ISSUED AT 257 PM EST TUE JAN 21 2025
FOR TODAY, WESTERLY WINDS WILL BACK SOUTHWESTERLY AHEAD OF AN
APPROACHING CLIPPER LOW. A FEW ISOLATED GALE FORCE GUSTS ARE
EXPECTED LATE THIS EVENING THROUGH TONIGHT, ESPECIALLY ACROSS THE
WEST HALF OF THE LAKE, BUT CONFIDENCE OF MORE WIDESPREAD COVERAGE AT
ANY GIVEN TIME IS TOO SMALL TO ISSUE A GALE WARNING. AN APPROACHING
CLIPPER LOW ON WEDNESDAY WILL BRING SOUTHWESTERLY WIND GUSTS UP TO
NEAR 30 KT, VEERING TO THE NW OVERNIGHT, WITH CHANCES OF GALES OF
AROUND 30-50% WEDNESDAY TO WEDNESDAY NIGHT ACROSS THE EASTERN HALF
OF THE LAKE. AS HIGH PRESSURE INFLUENCES THE FORECAST FOR THURSDAY,
MAINLY WESTERLY WINDS AROUND 20-25 KT ARE EXPECTED. FOR FRIDAY INTO
THE WEEKEND, PRIMARILY WESTERLY AND SOUTHWESTERLY WINDS AROUND 25 KT
ARE EXPECTED, BUT GALES TO 35 KNOTS ARE POSSIBLE INTO EARLY SUNDAY
(AROUND 30-50% CHANCE) AS WINDS SHIFT TO THE NW AGAIN BEHIND A
PASSING CLIPPER SYSTEM. NW WINDS REMAIN ELEVATED AT AROUND 20-30KTS
INTO EARLY NEXT WEEK. WITH SOME OF THE MOST FRIGID AIR OF THE LAST
FEW YEARS OVER LAKE SUPERIOR, HEAVY FREEZING SPRAY WARNINGS ARE IN
EFFECT THROUGH AT LEAST WEDNESDAY MORNING AS WAVES OF UP TO 10 FEET
FEET WILL ALLOW FOR SUPERCOOLED SPRAY TO FORM.
MQT WATCHES/WARNINGS/ADVISORIES
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST /6 AM CST/ THIS
MORNING FOR LSZ162-240>251-263>265.
HEAVY FREEZING SPRAY WARNING UNTIL 1 PM EST THIS AFTERNOON FOR
LSZ266-267.
LAKE MICHIGAN...
HEAVY FREEZING SPRAY WARNING UNTIL 1 PM EST THIS AFTERNOON FOR
LMZ248-250.
SHORT TERM...GS
LONG TERM...LC
AVIATION...JTP
MARINE...LC
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