913
FXUS63 KMQT 152237
AFDMQT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
537 PM EST WED JAN 15 2025
KEY MESSAGES
- A CLIPPER LOW WILL BRING A QUICK BATCH OF LIGHT SNOW (1-2
INCHES) FOR MOST OF THE UP THIS EVENING THROUGH THE FIRST HALF
OF THE NIGHT. LAKE EFFECT SNOW LINGERS IN THE WEST TO
NORTHWEST WIND BELTS THE SECOND HALF OF THE NIGHT. ANOTHER 1-3
IN OF SNOW IS EXPECTED IN THOSE WIND BELTS, WITH LIGHTER
TOTALS MAINLY OF AN INCH OR LESS ACROSS THE REST OF THE UP.
- SW GALES OF 35-40KTS CONTINUE THE WEST HALF OF LAKE SUPERIOR
THIS AFTERNOON, ENDING BY MIDNIGHT THURSDAY.
- DANGEROUSLY COLD ARCTIC AIR SETTLES INTO THE AREA THIS
WEEKEND INTO EARLY NEXT WEEK, LEADING TO TEMPERATURES
REMAINING SUBZERO SATURDAY NIGHT THROUGH AT LEAST TUESDAY
MORNING OVER INTERIOR WESTERN UPPER MICHIGAN.
- WHILE WINDS WON'T BE STRONG, WHITEOUTS WILL BE COMMON IN THE AREAS
AFFECTED BY NORTHWEST FLOW LAKE EFFECT SNOW SHOWERS SATURDAY
THROUGH MONDAY DUE TO THE SNOW BEING A FINE, POWDERY TYPE
SNOW. AS A RESULT, TRAVEL CONDITIONS WILL BE VERY HAZARDOUS IN
THE LAKE EFFECT SNOW AREAS.
- NO WIDESPREAD, SIGNIFICANT SNOWFALLS FOR UPPER MI THROUGH
NEXT WEEK. NEARLY ALL OF THE SNOW THAT OCCURS WILL BE LAKE
EFFECT DRIVEN.
SHORT TERM /THROUGH THURSDAY/
ISSUED AT 317 PM EST WED JAN 15 2025
AFTERNOON RAP ANALYSIS AND WATER VAPOR IMAGERY DEPICT A CLIPPER
SYSTEM DIVING SOUTHEAST INTO THE UPPER GREAT LAKES WITH ASSOCIATED
ISENTROPIC LIFT KICKING OFF SNOW SHOWERS IN CENTRAL MINNESOTA. AS
THE SHORTWAVE NEARS CLOSER TO HOME, THESE SHOWERS WILL CONTINUE
THEIR EASTWARD MARCH INTO THE UP, EVENTUALLY REACHING THE FAR WEST
THIS EVENING BEFORE EXITING QUICKLY TO THE EAST BEFORE SUNRISE
TOMORROW MORNING. NOT EXPECTING ANY HEAVY SNOW ACCUMULATIONS WITH
THESE PASSING "SYSTEM" SNOW SHOWERS TONIGHT AS GUIDANCE ONLY
SUGGESTS LIGHT QPF GENERALLY <0.1" TIED WITH SLRS IN THE UPPER
TEENS:1, YIELDING LIGHT SNOW ACROSS THE UP 1-2" OR LESS THROUGH
TONIGHT.
BEHIND THE COLD FRONTAL PASSAGE EARLY THURSDAY MORNING,
WINDS VEER TO THE NORTHWEST AND 850MB TEMPERATURES ABOVE LAKE
SUPERIOR LOWER BETWEEN -10 TO -13C, SUPPORTING LIGHT LAKE EFFECT
SNOW FOR THE NW SNOWBELTS. LAKE EFFECT SNOW WILL BE SHORT LIVED,
HOWEVER, AS A BRIEF PERIOD OF RIDGING ALOFT AND DRIER AIR WORKS ITS
WAY IN ACROSS THE LAKE THURSDAY AFTERNOON, LOWERING INVERSION
HEIGHTS AND TAPERING OFF LES FROM WEST TO EAST. CONSIDERING LIGHT
QPF AND FLUFFIER SLRS CLOSER TO 20:1, AN ADDITIONAL 1-3" IS POSSIBLE
ACROSS THE KEWEENAW AND NW SNOWBELT BETWEEN MUNISING AND THE SOO.
OTHERWISE, SOUTHWEST WINDS OVERNIGHT WILL KEEP TEMPERATURES MOSTLY
ABOVE 10F TONIGHT, MUCH WARMER THAN THE PAST FEW NIGHTS. HIGH
TEMPERATURES TOMORROW ARE EXPECTED TO REMAIN IN THE MID TO UPPER
20S, POSSIBLE CLOSER TO OR ABOVE FREEZING NEAR LAKE MICHIGAN.
LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/
ISSUED AT 443 PM EST WED JAN 15 2025
MEDIUM RANGE MODEL GUIDANCE IS IN EXCELLENT AGREEMENT ON A LARGE
SCALE SURGE OF ARCTIC AIR INTO THE U.S. THIS WEEKEND INTO EARLY NEXT
WEEK. THIS WILL BE DRIVEN BY A BUILDING RIDGE OVER THE NE PACIFIC
THAT BECOMES HIGHLY AMPLIFIED NORTHWARD THRU ALASKA/NW CANADA INTO
THE HIGH ARCTIC OVER THE WEEKEND, FORCING A SIGNIFICANTLY DEEPENING
TROF DOWNSTREAM ACROSS CENTRAL TO EASTERN N AMERICA. NEGATIVE HEIGHT
ANOMALIES AT 500MB IN THIS TROF SETTLE AT ABOUT 300M (2-2.4 SIGMA)
OVER WI AND UPPER MI SUN NIGHT. THUS, THE LARGE SCALE SURGE OF
ARCTIC AIR SOUTHWARD INTO THE U.S. OVER THE LAST 48HRS, ENSEMBLES
HAVE SLIGHTLY LOWERED 850MB TEMPS IN THE CORE OF THE COLD AIR AS IT
REACHES UPPER MI. MEDIAN 850MB TEMPS REACH -30 TO -31C INTO WESTERN
UPPER MI FOR SUN/MON WITH MON LIKELY THE COLDEST DAY. 850MB TEMPS
THAT LOW AT THIS TIME OF YEAR VERY EASILY SUPPORT 2M TEMPS REMAINING
SUBZERO DURING THE DAYLIGHT HRS ACROSS INTERIOR WESTERN UPPER MI AND
LIKELY THRU MUCH OF CENTRAL UPPER MI AS WELL. NOW, WITH 850MB TEMPS
FORECAST TO BE DOWN TO -30C OR LOWER, WOULD EXPECT TEMPS DURING THE
DAYLIGHT HRS OVER INTERIOR WESTERN UPPER MI TO STRUGGLE TO GET ABOVE
-10F SUN/MON, MON IN PARTICULAR. ONCE TEMPS FALL BLO 0F OVER
INTERIOR WESTERN UPPER MI SAT NIGHT, THEY WON'T RISE ABOVE 0F UNTIL
SOMETIME TUE AFTN AT THE EARLIEST. MIN TEMPS WILL RANGE DOWN THRU
THE NEGATIVE TEENS AND -20S F AWAY FROM LAKE SUPERIOR. SOME RECORD
LOW MIN AND RECORD LOW MAX TEMPS MAY BE SET ACROSS UPPER MI WITH
THIS ARCTIC OUTBREAK. HOMEOWNERS AND PROPERTY MANAGERS WHO HAVE HAD
ISSUES WITH WATER PIPES FREEZING DURING PERIODS OF VERY COLD
CONDITIONS SHOULD MAKE PREPARATIONS NOW. AREAS THAT HAVE VERY LITTLE
SNOW COVER COULD ALSO BECOME AT RISK FOR FREEZING OF WATER SUPPLY
LINES EARLY NEXT WEEK AS GROUND FROST DEPTHS DEEPEN RAPIDLY. AS FOR
PCPN, THIS PATTERN WILL NOT SUPPORT ANY WIDESPREAD, SIGNIFICANT
SNOWFALLS FOR UPPER MI FOR THE REMAINDER OF THIS WEEK AND THROUGH
ALL OF NEXT WEEK AS ONLY A FEW CLIPPER TYPE WAVES WILL GENERATE SOME
BRIEF PERIODS OF -SN. SO, SNOWFALL WILL BE ALMOST EXCLUSIVELY LAKE
EFFECT DRIVEN. WHILE THE ARCTIC AIR ARRIVING OVER THE WEEKEND/EARLY
NEXT WEEK WILL LEAD TO EXTREME OVERLAKE INSTABILITY, THE COLD WILL
ALSO SUPPRESS THE DGZ TOWARD THE SFC OR ELIMINATE IT ALTOGETHER,
LEADING TO A FINE/POWDERY TYPE SNOW (LOW SLR) THAT DOES NOT
ACCUMULATE AS EFFICIENTLY. ON THE FLIP SIDE, THIS TYPE OF SNOW IS
HIGHLY EFFECTIVE AT REDUCING VIS, LEADING TO FREQUENT WHITEOUTS EVEN
WITH WINDS NOT PARTICULARLY STRONG/GUSTY. THIS TYPE OF SNOW IS ALSO
EASILY KICKED UP ON ROADS BY VEHICLES, LEADING TO MINI WHITEOUTS AS
VEHICLES PASS EACH OTHER. TRAVEL IN THE AREAS AFFECTED BY NW FLOW
LES SAT THRU EARLY NEXT WEEK WILL BE VERY HAZARDOUS DUE TO POOR
VISIBILITY. FROM TUE ONWARD, FLOW ACROSS N AMERICA DEAMPLIFIES, BUT
THERE WILL CONTINUE TO BE RIDGING IN THE NE PACIFIC/ADJACENT N
AMERICA FORCING TROFFING IN CENTRAL AND EASTERN N AMERICA. THE
DEAMPLIFICATION WILL ALLOW FOR MODERATION TUE ONWARD, BUT THE
PATTERN WILL STILL SUPPORT THE POTENTIAL FOR COLDER AIR TO AT LEAST
GRAZE UPPER MI WITH THE PASSAGE OF CLIPPER TYPE SHORTWAVES. EXPECT
TEMPS ON MOST DAYS NEXT WEEK TO BE BLO NORMAL.
BEGINNING THU NIGHT/FRI, A CLIPPER SHORTWAVE WILL TRACK VCNTY OF THE
INTERNATIONAL BORDER AND WILL PASS ACROSS UPPER MI FRI NIGHT. THIS
WAVE WILL INITIATE THE START OF THE ARCTIC AIR SURGE. WAA/ISENTROPIC
ASCENT WILL NEED TO OVERCOME DRIER AIR. WITH BULK OF GUIDANCE
SUGGESTING SUFFICIENT SATURATION OCCURRING DEEPER INTO THE
RETREATING COLDER AIR WHERE IT IS EASIER TO ACHIEVE, FORECAST ONLY
REFLECTS MAINLY CHC POPS FROM THE KEWEENAW INTO EASTERN UPPER MI,
BEGINNING VERY LATE THU NIGHT OVER THE KEWEENAW AND SPREADING TO THE
E QUICKLY FRI MORNING. ANY SNOW ACCUMULATION WILL BE LESS THAN 1
INCH. CENTER OF PRES FALLS OF 6-7MB/3HR PASSING JUST N OF UPPER MI
ON FRI WILL ENHANCE S TO SW SFC WINDS ON FRI. EXPECT GUSTS OF 25 TO
35MPH. DOWNSLOPING NEAR LAKE SUPERIOR MAY YIELD GUSTS OF 40-45MPH
FOR A FEW HRS FROM MARQUETTE COUNTY EASTWARD PER FCST SOUNDINGS. 180-
190 WIND DIRECTION IS FAVORABLE FOR STRONG WINDS IN SCHOOLCRAFT/LUCE
COUNTIES AS WELL. HIGH TEMPS ON FRI SHOULD REACH THE LOW/MID 30S F.
COLD FRONT PASSES FRI NIGHT, INITIATING LES AND LEADING TO
PROGRESSIVELY COLDER AIR FLOWING INTO THE AREA THRU THE WEEKEND ON
PREDOMINANTLY NW LOW-LEVEL FLOW. THE INCREASINGLY COLDER AIR
SURROUNDING THE LAKE WILL PROGRESSIVELY STRENGTHEN LAKE INDUCED
THERMAL TROFFING, LEADING TO WINDS DEVELOPING AN OFFSHORE COMPONENT.
THIS WILL BE MORE NOTABLE OFF OF NW WI, OFF OF MARQUETTE COUNTY AND
OFF OF ONTARIO ALONG THE E SIDE OF LAKE SUPERIOR. THIS WILL FAVOR
ENHANCED CONVERGENCE FROM N OF IRONWOOD INTO ONTONAGON/SOUTHERN
HOUGHTON COUNTIES AND ALSO INTO ALGER/LUCE COUNTIES. EXPECT LES TO
BE MOST PERSISTENT/HEAVIER IN THOSE AREAS. HOWEVER, BY LATER SAT AND
THRU MON, THE COLD WILL SUPPRESS THE DGZ TOWARD NEAR THE SFC OR
ELIMINATE IT ALTOGETHER, LEADING TO A FINE/POWDERY TYPE SNOW THAT
DOES NOT ACCUMULATE AS EFFICIENTLY AS TYPICAL LES. INITIAL THOUGHTS
ARE THAT SNOW ACCUMULATIONS WILL END UP IN A GENERAL 1-3 TO ISOLD 4-
5 INCHES/12HR RANGE. BIGGER ISSUE WILL BE WHITEOUTS AS THIS TYPE OF
SNOW IS HIGHLY EFFICIENT AT REDUCING VISIBILITY AND IS EASILY BLOWN
AROUND. WINDS WILL BE STRONGER ON SAT AFTER FROPA, BUT DURING THE
COLDEST PERIOD SUN/MON, WINDS WON'T BE PARTICULARLY STRONG, GUSTING
TO 25 TO AT TIMES 30MPH NEAR THE LAKE SUPERIOR SHORE AND KEWEENAW
AND UP TO AROUND 20MPH ELSEWHERE. EVEN SO, THE FINE/POWDERY SNOW
WILL BE EASILY LOFTED BY THESE WINDS TO FURTHER REDUCE THE ALREADY
POOR VIS FROM THE FALLING SNOW. AS FOR TEMPS, MAX TEMPS IN THIS FCST
ISSUANCE ARE PROBABLY A BIT ON THE HIGH SIDE FOR SUN/MON GIVEN HOW
LOW THE 850MB TEMPS WILL BE. IT'S QUITE PLAUSIBLE THAT HIGH TEMPS
WILL STRUGGLE TO GET ABOVE -10F OVER MUCH OF THE INTERIOR W ON
SUN/MON, MON IN PARTICULAR. MUCH OF THE FCST AREA MAY REMAIN BLO 0F
BOTH DAYS. FORTUNATELY, THE WINDS WON'T BE STRONG TO REALLY DRIVE
WIND CHILLS DOWN. NONETHELESS, THE COLD WILL BE DANGEROUS, AND
EXPECT CONDITIONS TO WARRANT COLD WEATHER ADVISORIES AND POSSIBLY
EXTREME COLD WARNINGS ACROSS THE AREA. EXTREME COLD WARNING CRITERIA
ARE AIR TEMPS OR WIND CHILL -35 OR LOWER OVER INTERIOR WESTERN UPPER
MI AND -30 OR LOWER ELSEWHERE.
WIND BEGIN TO BACK WESTERLY MON NIGHT/TUE WITH ONSET OF WAA,
SHIFTING LES TO MAINLY THE KEWEENAW OVER THE W AND CLOSER TO SHORE
OVER THE E. CLIPPER TYPE SHORTWAVE WILL PASS AT SOME POINT LATER
TUE/WED TO PROVIDE A CHC OF -SN. HIGH TEMPS WILL BE BACK TO THE
TEENS F ON WED.
AVIATION /00Z TAFS THROUGH 00Z FRIDAY/
ISSUED AT 537 PM EST WED JAN 15 2025
CLIPPER SYSTEM SNOW WILL MOVE THROUGH THE AREA TONIGHT AND WILL TAKE
THE VFR CONDITIONS DOWN TO IFR AS IT MOVES THROUGH AT ALL SITES.
MVFR CONDITIONS WILL REUTRN TO ALL SITES THU AFTERNOON.
MARINE
ISSUED AT 443 PM EST WED JAN 15 2025
A COUPLE OF PASSING CLIPPERS WILL RESULT IN A STRONG PRESSURE
GRADIENT OVER THE LAKE AT TIMES IN THIS PERIOD, FOLLOWED BY
DEEPENING ARCTIC COLD THIS WEEKEND AND EARLY NEXT WEEK.
ONGOING SW 35-40KT GALES OVER THE W HALF OF LAKE SUPERIOR WILL FALL
BACK TO 30KT TONIGHT AS WINDS SHIFT W TO NW. EXPECT WINDS UP TO 30KT
OVER THE E WITH A FEW GALE FORCE GUSTS POSSIBLE DURING THE EVENING.
THE NW WINDS WILL INCREASE ACROSS THE E HALF OF LAKE SUPERIOR ON THU
MORNING. EXPECT GALE GUSTS TO 35KT FOR A TIME MORNING THRU EARLY
AFTN. PROBABILITY OF GALES IS 40-60PCT. WINDS BRIEFLY SETTLE DOWN TO
AROUND 20KT LAKEWIDE THU EVENING AS HIGH PRES RIDGE QUICKLY PASSES.
WINDS THEN INCREASE AS THE NEXT CLIPPER APPROACHES. ENHANCED BY PRES
FALLS PASSING EASTWARD OVER AND N OF LAKE SUPERIOR, S TO SW WINDS
WILL RAMP UP TO 35-40KT GALES OVER MUCH OF LAKE SUPERIOR, STRONGEST
OVER THE E HALF. THE POTENTIAL OF WINDS TO REACH HIGH END GALES IS
25-45PCT OVER THE E HALF OF THE LAKE. THESE WINDS WILL SHIFT TO THE
NW FRI NIGHT. AIDED BY INCOMING PRES RISES AND COLDER AIR, EXPECT
GALES OF 35-40KT ACROSS CENTRAL AND EASTERN LAKE SUPERIOR INTO SAT
MORNING. VERY COLD AIR POURING OVER THE UPPER GREAT LAKES AFTERWARDS
AND LINGERING INTO NEXT WEEK WILL LIKELY SUPPORT WINDS OF 25-30KT
ACROSS MUCH OF THE LAKE.
THE INCREASINGLY COLDER AIR ARRIVING OVER WEEKEND WILL SUPPORT
PERIODS WHERE ICE GROWTH FROM FREEZING SPRAY WILL BECOME MDT TO HVY
AT TIMES.
MQT WATCHES/WARNINGS/ADVISORIES
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING UNTIL 10 PM EST /9 PM CST/ THIS EVENING FOR
LSZ162.
GALE WARNING UNTIL 1 AM EST /MIDNIGHT CST/ THURSDAY FOR
LSZ241>244-263-264.
GALE WATCH FROM FRIDAY MORNING THROUGH SATURDAY AFTERNOON FOR
LSZ241>244-263-264.
GALE WATCH FROM FRIDAY MORNING THROUGH SATURDAY AFTERNOON FOR
LSZ249>251-266-267.
LAKE MICHIGAN...
NONE.
SHORT TERM...BW
LONG TERM...ROLFSON
AVIATION...07
MARINE...ROLFSON
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