235
FXUS63 KMQT 200218
AFDMQT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
918 PM EST TUE NOV 19 2024
KEY MESSAGES
- SCATTERED SHOWERS THIS AFTERNOON DIMINISH THROUGH LATE TONIGHT
FROM SOUTHWEST TO NORTHEAST.
- A SLOW MOVING SYSTEM WILL USHER IN A WET PATTERN INTO THE
WEEKEND. PRECIP WILL MAINLY BE RAIN, BUT SOME SNOW WILL BE
POSSIBLE WEDNESDAY NIGHT INTO THURSDAY MORNING ACROSS THE WEST
HALF.
- NORTHERLY GALES TO 35 KNOTS WILL BE POSSIBLE THURSDAY.
UPDATE
ISSUED AT 917 PM EST TUE NOV 19 2024
INCREASINGLY QUIET WEATHER IS EXPECTED TONIGHT. THE FORECAST HAS
BEEN ADJUSTED TO ACCOUNT FOR LINGERING SPOTTY SPRINKLES AND LIGHT
RAIN SHOWERS - MAINLY ACROSS THE NORTHERN AND EASTERN UP. OTHERWISE,
WE REMAIN UNDER A BLANKET OF LOW CLOUDS WITH WINDS QUICKLY FALLING
OFF. THIS SHOULD HELP TO CONTAIN OVERNIGHT LOWS IN THE 30S TO LOWER
40S THE REST OF TONIGHT.
SHORT TERM /THROUGH TONIGHT/
ISSUED AT 310 PM EST TUE NOV 19 2024
AT THE MID LEVELS, A NEGATIVELY TILTED TROUGH IS SITUATED OVER THE
NORTHERN PLAINS WITH A RIDGE OVER THE SOUTHEASTERN STATES. THE SFC
LOW PRESSURE SYSTEM RESPONSIBLE FOR THE SCT RAIN SHOWERS CURRENTLY
DECORATING THE UPPER GREAT LAKES RADAR MOSAIC IS CENTERED OVER
NORTHERN MN THIS AFTERNOON AT 985 MB PER THE LATEST RAP ANALYSIS; AN
ASSOCIATED OCCLUDED FRONT IS APPROACHING THE MI/WI STATE LINE. THIS
SFC LOW IS PROGGED TO LIFT NORTH TOWARD, SLIGHTLY RETROGRADING TO
SOUTHEASTERN MANITOBA AT 994 MB AS THE MID LEVEL TROUGH DEVELOPS
INTO A CLOSED LOW OVER THE UPPER MIDWEST. THIS HELPS THE OCCLUDED
FRONT PUSH NORTHEAST OVER THE AREA THROUGH THIS EVENING.
GUSTY SOUTHEAST WINDS (OBSERVED UP TO 30-50 MPH EARLIER IN THE DAY)
AHEAD OF THE FRONTAL BOUNDARY CAUSED PLENTY OF POWER OUTAGES IN THE
KEWEENAW AS WELL SCATTERED AREAS OF POWER OUTAGE IMPACTS ACROSS THE
UP. THESE WINDS HAVE ALREADY STARTED WEAKENING, ESPECIALLY CLOSE TO
THE FRONT. AS THE FRONT PUSHES NORTH OVER THE AREA THROUGH THIS
EVENING, THE LULL IN WINDS WILL MOVE NORTH WITH IT, SHIFTING WINDS
OUT OF THE SOUTHWEST FOR TONIGHT. 11/19 12Z HREF INDICATES A 30-60%
CHANCE FOR SOME GUSTS UP TO 30 MPH AGAIN THIS EVENING AS A 35-40 KT
LOW LEVEL JET INCREASES OVER WESTERN LAKE SUPERIOR AND THE WESTERN
SHORES. MODEL SOUNDINGS ALSO SUPPORT THIS MIXING DOWN EARLY ON THIS
EVENING BEFORE WINDS WEAKEN TO 5 TO 15 MPH BY WEDNESDAY MORNING
CALMER WINDS IN THE EAST. WITH WINDS AND RESULTING WAVES
DIMINISHING, OPTED TO ALLOW WIND AND LAKESHORE FLOOD ADVISORIES TO
FALL OFF AS SCHEDULED.
SHOWERS WILL CONTINUE LIFTING NORTHEAST THROUGH THIS EVENING WITH A
DRY SLOW BEHIND THE FRONT RESULTING IN DRY WEATHER RETURNING LATE
THIS AFTERNOON THROUGH LATE TONIGHT FROM SOUTHWEST TO NORTHEAST.
ADDITIONAL ACCUMULATIONS SHOULD REMAIN BELOW 0.25 INCHES. OTHERWISE,
LOWS ARE EXPECTED IN THE LOW 30S TO LOW 40S, WARMER IN THE EAST
WHERE SHOWERS HOLD ON THE LONGEST.
LONG TERM /WEDNESDAY THROUGH MONDAY/
ISSUED AT 234 PM EST TUE NOV 19 2024
THERE CONTINUES TO BE VERY GOOD AGREEMENT AMONG THE DETERMINISTIC
MODELS AND THEIR RESPECTIVE ENSEMBLE PACKAGES THIS MORNING,
SUGGESTING THE MAIN ITEM OF INTEREST WILL BE THE EVOLUTION OF A
CLOSED MID-LEVEL LOW AND MULTIPLE SURFACE LOWS THROUGH THE GREAT
LAKES INTO THE WEEKEND. CURRENT WATER VAPOR IMAGERY FROM GOES 16,
MSAS ANALYSIS, AND RAP HEIGHT ANALYSIS SHOW THE INITIAL CLOSED
CIRCULATION OVER MINNESOTA, WITH AN OCCLUDED FRONT EXTENDING
SOUTHEAST FROM THE SURFACE FEATURE ACROSS NORTHERN WISCONSIN.
TONIGHT, THE MID-LEVEL LOW WILL PROGRESS SOUTHEAST WHILE THE DRY
SLOT OF THIS SYSTEM MOVES OVERHEAD BEHIND THE NORTHWARD LIFTING
FRONT AND THE SURFACE FRONT FIZZLES. AS THE MID-LEVEL FEATURE
MIGRATES EAST, IT WILL AGAIN AMPLIFY, RESULTING IN A SECOND SURFACE
LOW DEVELOPING NEAR MICHIGAN'S THUMB BY WEDNESDAY AFTERNOON. THE LOW
WILL LIFT NORTH TO THE NORTHERN SHORES OF LAKE HURON IN THE EVENING,
BEFORE RETROGRADING WESTWARD, AND THEN BACK SOUTH DOWN LAKE MICHIGAN
OR WESTERN LOWER MICHIGAN. THIS SURFACE REFLECTION WILL WEAKEN LATE
THURSDAY WHILE A THIRD SURFACE LOW DEVELOPS OFF THE MID-ATLANTIC
COAST IN RESPONSE TO THE MID-LEVEL LOW AGAIN, AMPLIFYING AS IT
SHIFTS EASTWARD. THE SYSTEM WILL OCCLUDE FRIDAY THEN SLOWLY EXIT
THROUGH NEW ENGLAND ON SATURDAY, PERHAPS DEEPENING AGAIN SATURDAY
EVENING AS IT LIFTS INTO THE CANADIAN MARITIMES. THIS WILL SUPPORT A
PROLONGED WET PERIOD ACROSS THE FORECAST AREA WITH SYNOPTIC PRECIP
SHIFTING OVER TO LAKE ENHANCED AND EVENTUALLY LAKE EFFECT THROUGH AT
LEAST SATURDAY. THE MAIN FORECASTING CHALLENGES IN THIS PERIOD
CONTINUE TO REVOLVE AROUND THE EXACT WESTWARD EDGE THE SECOND
SURFACE LOW'S POSITION WHILE IT WOBBLES AROUND THE GREAT LAKES AND
THE SUBSEQUENT POSITION OF THE LOW'S DEFORMATION AXIS/INVERTED
TROUGH WHILE COOLING OCCURS WEDNESDAY NIGHT.
FOLLOWING THE EROSION OF THE DRY SLOT WEDNESDAY MORNING, INCREASING
MID-LEVEL CONVERGENCE WILL SUPPORT AND PRECIP SPREADING INTO EASTERN
UPPER MICHIGAN WHILE THE SECOND SURFACE LOW DEVELOPS. THE CONSENSUS
AMONG THE GEPS, GEFS, AND EPS SURFACE LOW CLUSTERING IS THAT THE LOW
WILL DRIFT NORTH THEN RETROGRADE WEST, BEFORE MIGRATING SOUTH.
CURRENT TIMING OF THIS EVOLUTION WILL BE OVERNIGHT WEDNESDAY INTO
THURSDAY WHEN SURFACE TEMPERATURES DIP NEAR OR BELOW FREEZING AND
WETBULB ZERO HEIGHTS FALL LESS THAN 600FEET, WHICH WILL SUPPORT A
RAIN TO WET SNOW TRANSITION OVER WESTERN UPPER MICHIGAN. THERE'S
ENOUGH SPREAD AMONG THESE SYSTEMS ON THE NORTHWARD AND WESTWARD
POSITION TO QUESTION HOW FAR WEST HIGHER QPF AXIS WILL BE, WHICH
IMPACTS SNOWFALL AMOUNTS. MIDDLE OF THE ROAD OPTION CONFORMS TO MOST
DETERMINISTIC SOLUTIONS, WHILE THE MOST NOTABLE OUTLIER IS THE
EASTWARD NAMNEST. THIS FORECAST REPRESENTS THE CONSENSUS OPTION
WHERE CONFIDENCE IS HIGHEST. ENSEMBLES SUGGEST A 50% CHANCE OR
HIGHER OF A MAJORITY OF THE FORECAST AREA GETTING ANOTHER 0.5" OF
QPF AND THE EPS SUGGESTS A 20-60% CHANCE OF EXCEEDING 1.0" IN THE
HIGHER TERRAIN REGIONS OF BARAGA AND MARQUETTE COUNTIES. WITH
ANTICIPATED SNOW RATIOS APPROXIMATELY 10:1 OR LESS, THIS WOULD YIELD
A COUPLE INCHES OF WET SNOW. SNOW AMOUNTS AMONG THE VARIOUS ENSEMBLE
AND DETERMINISTIC ARE MIXED AND LARGELY DEPEND ON THE RATE OF
COOLING, THE POSITION OF THE LOW, AND THE QPF SPREAD. CURRENT
FORECAST REFLECTS ~1 INCH ACROSS MOST OF WESTERN UPPER MICHIGAN AWAY
FROM THE LAKESHORES AND A SWATH OF 2 TO 4 INCHES FROM THE HURON
MOUNTAINS SOUTHWESTWARD TOWARD SIDNAW/WATTON. TIMING CURRENTLY LOOKS
LIKE IN THE OVERNIGHT PERIOD AFTER MIDNIGHT FOR THE BULK OF THE
POTENTIAL.
EVENTUALLY, THE MID-LEVEL LOW EXITS EAST, LEAVING BEHIND CONTINUED
CYCLONIC FLOW WITH 850MB TEMPS OF -4 TO -1C. THIS SHOULD KEEP LAKE
EFFECT RAIN/SNOW SHOWERS DOWNWIND OF LAKE SUPERIOR INTO SATURDAY
WHEN ITS POSSIBLE A COOLER AIRMASS MAY BUILD IN. MID-LEVEL RIDGING
WILL EVENTUALLY FILTER IN FROM WEST TO EAST LATE SATURDAY/SUNDAY,
WITH A MORE UNCERTAIN PATTERN DEVELOPING AFTERWARDS. A BRIEF, PSEUDO-
ZONAL FLOW PATTERN LOOKS TO DEVELOP ACROSS CONUS AFTERWARDS BUT THIS
LOOKS SHORT LIVED AS AN EASTWARD MIGRATING SHORTWAVE INTERRUPTS THIS
FOR OUR FORECAST AREA SUNDAY NIGHT INTO EARLY NEXT WEEK. THERE
CONTINUES TO BE PLENTY OF UNCERTAINTY WITH THIS WAVE, BUT GUIDANCE
CONTINUES TO SUGGEST THE AIRMASS BEHIND IT OF 850MB TEMPS IN THE -10
TO -5C FOR THE START OF NEXT WEEK.
AVIATION /00Z TAFS THROUGH 00Z THURSDAY/
ISSUED AT 613 PM EST TUE NOV 19 2024
A BLANKET OF LOW STRATUS REMAINS OVER THE UP THIS EVENING, WITH IFR
TO LIFR CEILINGS LINGERING AT CMX AND SAW. MEANWHILE, CEILINGS HAVE
ALREADY LIFTED TO MVFR AT IWD. A SLOW IMPROVEMENT TO MVFR IS
EXPECTED OVER THE NEXT SEVERAL HOURS AT CMX AND SAW, THEN IWD AND
CMX SHOULD LIFT TO VFR BEFORE DAYBREAK WEDNESDAY. MVFR CEILINGS
LINGER THROUGH THE DAYTIME HOURS AT SAW, WITH RAIN SPREADING IN FROM
THE EAST LATER IN THE DAY AND BRINGING IN A DROP IN VISIBILITY AS
WELL. OTHERWISE, WINDS TURNING OVER TO THE SW CONTINUE TO GUST TO
AROUND 20-25KTS THIS EVENING, BUT SHOULD TURN CALMER THE SECOND HALF
OF THE NIGHT.
MARINE
ISSUED AT 234 PM EST TUE NOV 19 2024
STRONG GALES WITH SOME STORM FORCE GUSTS WILL SETTLE DOWN THIS
AFTERNOON AND EVENING FROM SOUTH TO NORTH WITH THE PASSAGE OF AN
OCCLUDED FRONT. EXPECT THE SOUTHEAST WINDS TO SHIFT TO SOUTHWEST
IMMEDIATELY AFTER THE FRONT AND CONTINUE TO BLOW GALES OF 35KTS OVER
THE WEST HALF INTO THE EVENING HOURS. WINDS WILL SETTLE FURTHER
OVERNIGHT, FALLING TO NEAR 20KTS BY MORNING LAKE-WIDE. ATTENTION
THEN TURNS TO A DEVELOPING SURFACE LOW OVER LAKE HURON THAT WILL
LIFT NORTH WEDNESDAY NIGHT THEN SHIFT WEST AND SOUTH OVER LOWER
MICHIGAN INTO THURSDAY. THERE CONTINUES TO BE DIFFERENCES IN THE
DETERMINISTIC AND ENSEMBLE GUIDANCE PACKAGES OF WHERE EXACTLY THE LOW
WILL WOBBLE AND HOW DEEP IT WILL BE, AND THUS THE IMPACT OF THE
INCREASING PRESSURE GRADIENT FORCES. HOWEVER, CONFIDENCE CONTINUES
TO GROW THAT A WIDESPREAD GALE EVENT TO AT LEAST 35KNOTS WILL BE
POSSIBLE THURSDAY. INTERNAL PROBABILISTIC GUIDANCE SUGGESTS 30-50%
CHANCE OF AT LEAST 34KTS WHICH IS REINFORCED BY EPS PROBABILITIES
SUGGESTING >50% ACROSS LAKE SUPERIOR. ITS POSSIBLE THAT A GALE WATCH
MAY BE ISSUED LATER THIS EVENING OR BY WEDNESDAY MORNING.
WINDS SHOULD LIGHTEN LATE THURSDAY BUT REMAIN GENERALLY NORTH AT 20-
30KTS INTO THE WEEKEND. CURRENT THINKING IS FOR WINDS TO FALL BELOW
20KTS FROM WEST TO EAST SATURDAY INTO THE EVENING HOURS. LIGHT WINDS
LOOK TO REMAIN INTO EARLY NEXT WEEK, BUT A SYSTEM MOVING THROUGH THE
REGION LATE SUNDAY/MONDAY WITH TRAILING COLD AIR MAY RESULT IN
INCREASING WINDS AGAIN MONDAY/TUESDAY.
MQT WATCHES/WARNINGS/ADVISORIES
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING UNTIL 11 PM EST /10 PM CST/ THIS EVENING FOR
LSZ162-263.
LAKE MICHIGAN...
NONE.
UPDATE...LC
SHORT TERM...JABLONSKI
LONG TERM...JTP
AVIATION...LC
MARINE...JTP
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