955
FXUS63 KMQT 221110
AFDMQT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
710 AM EDT TUE JUL 22 2025
KEY MESSAGES
- SHOWERS AND THUNDERSTORMS ARE EXPECTED LATE TONIGHT INTO EARLY WEDNESDAY,
WITH POSSIBLY ADDITIONAL ROUNDS THROUGH THE DAY WEDNESDAY.
- STORMS LATE TONIGHT AND WEDNESDAY COULD PRODUCE HEAVY RAIN,
HAIL, AND STRONG TO DAMAGING WINDS. THERE IS A SLIGHT CHANCE
(AT LEAST 15%) OF EXCEEDING FLASH FLOOD GUIDANCE AND SEVERE
WEATHER ACROSS MOST OF UPPER MICHIGAN.
- ADDITIONAL SHOWERS AND THUNDERSTORMS ARE POSSIBLE WEDNESDAY
NIGHT THROUGH LATE THURSDAY.
- STRONG WINDS AND LARGE WAVES WILL RESULT IN DANGEROUS SWIMMING
CONDITIONS ON LAKE MICHIGAN BEACHES OF SCHOOLCRAFT COUNTY BY WEDNESDAY
AFTERNOON.
SHORT TERM /THROUGH WEDNESDAY/
ISSUED AT 310 AM EDT TUE JUL 22 2025
SURFACE HIGH PRESSURE OVER WESTERN QUEBEC HAS EXTENDED RIDGING SOUTH
AND SOUTHWESTWARD INTO THE GREAT LAKES OVERNIGHT. THIS HAS KEPT THE
EAST HALF MOSTLY CLOUD FREE WHILE MID AND UPPER LEVEL CLOUDS
STREAMED INTO THE WEST. THESE WERE ASSOCIATED WITH A DIMINISHING
SYSTEM FROM EARLIER AND THE HIGH HAS HELPED TO SCOUR OUT MOST SHOWER
ACTIVITY AS ITS MOVED INTO THE FORECAST AREA. SURFACE TEMPS UNDER
THIS CANOPY HAVE REMAINED IN THE UPPER 50S AND 60S SO FAR, WHILE THE
EAST HALF HAS DIPPED INTO THE 50S.
TODAY AND WEDNESDAY, THE HIGH TO OUR EAST WILL CONTINUE EXITING
WHILE A MID-UPPER LEVEL RIDGE AXIS SHIFTS THROUGH THE FORECAST AREA.
OVER THE CENTRAL PLAINS, A SURFACE LOW WILL ORGANIZE AND LIFT A WARM
FRONT INTO THE GREAT LAKES WEDNESDAY WHILE A COLD FRONT DESCENDS
THROUGH THE NORTHERN PLAINS AND MIDDLE CANADA. SOUTHERLY FLOW WILL
ESTABLISH ITSELF TODAY, RESULTING IN THE ADVECTION OF A WARM AND
MOIST ENVIRONMENT. DAYTIME HIGHS GROWING INTO THE LOW TO MID 80S
WEST AND UPPER 70S EAST ARE EXPECTED TODAY. BY THIS EVENING, NEAR 70
DEGREE DEWPOINTS IN THE WEST AND LOW 60S EAST WILL SUPPORT MUCAPE
VALUES EVENTUALLY OF 1500 J/KG OR GREATER WHILE 0-6KM SHEAR CLIMBS
TO 35-40KTS. CAMS SUGGEST ONGOING CONVECTION IN THE DAKOTAS WILL
GROW SCALE WITHIN AN AREA OF HIGHER INSTABILITY THIS MORNING AND
EARLY AFTERNOON, THEN PRESS INTO OUR FORECAST AREA LATE THIS
AFTERNOON OR EVENING. ITS A LITTLE UNCLEAR IF WE'LL BE ABLE TO
DESTABILIZE ENOUGH TO MAINTAIN SAID MCS FOR LONG, AND THE CAMS ALL
SUGGEST A GRADUALLY WEAKENING LINE MOVING INTO THE
WEST/KEWEENAW/LAKE SUPERIOR LATE AFTERNOON.
THIS EVENING, TONIGHT AND WEDNESDAY, THERE CONTINUES TO BE
CONSIDERABLE DIFFERENCES AMONG THE VARIOUS GUIDANCE PACKAGES ON THE
TIMING AND POSITION OF ADDITIONAL RAIN/STORMS. THE TABLE INCLUDES
MULTIPLE ROUNDS OF THUNDERSTORM CLUSTERS MOVING THROUGH THE REGION
TO BEING MISSED ENTIRELY. GIVEN THAT GUIDANCE VARIES WILDLY ON THE
PLACEMENT, INTENSITY, AND STRUCTURE IN THESE WAVES OF SHOWERS AND
STORMS, MESOANALYSIS TONIGHT AND AGAIN WEDNESDAY WILL LIKELY PLAY A
HEAVY ROLE IN ANTICIPATING WHERE CONVECTION OCCURS A FEW HOURS
LATER. AT THE EARLIEST THE NEXT WAVE COULD MOVE INTO THE WEST 0-6Z
TONIGHT, BUT AGAIN, THIS IS VERY UNCLEAR AT THE MOMENT.
THERE IS, THOUGH, A CONSISTENT SIGNAL FOR CONTINUED ADVECTION OF A
WARM AND MOIST AIRMASS. IN FACT, LATEST NAEFS SUGGEST PWATS CLIMBING
TO NEAR CLIMATOLOGICAL MAXIMUMS ON WEDNESDAY. AT THE SURFACE, THIS
COULD EQUATE TO DEWPOINTS IN THE MID 70S OR HIGHER WHILE DAYTIME
TEMPERATURES CLIMBING INTO THE UPPER 80S ACROSS THE WEST HALF AND
SOUTH. THIS SUGGESTS A HEAT RISK FOR SENSITIVE GROUPS AS HEAT INDEX
VALUES CLIMB POTENTIALLY CLIMB INTO THE 90S. THE HEAT AND MOISTURE
WILL ALSO RESULT IN THE GRADUAL DESTABILIZATION OF THE REGION TO
>2000 J/KG AS A 30-40KT 925-850MB LLJ SIT OVERHEAD. THIS LOOKS TO
OCCUR AS THE WARM FRONT MOVES INTO THE REGION AND UPSTREAM COLD
FRONT MOVES INTO MINNESOTA. COINCIDENT WILL BE GROWING DCAPE TO 1000
J/KG OR HIGHER AND MID LEVEL LAPSE RATES ABOVE 6 OR 7C/KM. THERE IS
ALSO TRAINING POTENTIALLY, WHICH IS HIGHLIGHTED WELL BY THE HRRR'S
MULTI-HOUR WEST TO EAST TRAIN OF HEAVY RAINFALL ACROSS ISLE ROYALE.
TOGETHER THESE SUGGEST HEAVY OR VERY HEAVY RAIN, POTENTIAL FLASH
FLOODING, HAIL, AND STRONG TO DAMAGING WINDS WITH THESE
THUNDERSTORMS. SPC AND WPC POSITION MARGINAL RISKS (AT LEAST 5
PERCENT) TONIGHT AND SLIGHT RISKS (AT LEAST 15 PERCENT CHANCE)
WEDNESDAY FOR SEVERE WEATHER (WIND AND HAIL) AND EXCEEDING FLASH
FLOOD GUIDANCE, RESPECTIVELY, FOR OUR FORECAST AREA.
ADDITIONALLY, THE LLJ MOVING OVER THE AREA ON WEDNESDAY WILL MAKE
FORE BREEZIER WINDS, PARTICULARLY ACROSS EASTERN UPPER MICHIGAN. THIS
IS LIKELY TO RESULT IN LARGER WAVE GROWTH ON LAKE MICHIGAN AND THE
DEVELOPMENT OF DANGEROUS SWIMMING CONDITIONS ON LAKE MICHIGAN
BEACHES OF SCHOOLCRAFT COUNTY.
LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/
ISSUED AT 310 AM EDT TUE JUL 22 2025
THE ACTIVE PERIOD CONTINUES THROUGH MUCH OF THE WORK WEEK AS
MULTIPLE MID LEVEL SHORTWAVES TRACKING E ALONG FAIRLY ZONAL FLOW
OVER THE GREAT LAKES BRING ROUNDS OF SHRA/TSRA TO THE REGION. WITH
SUFFICIENT CAPE AND BULK SHEAR WITHIN THE ENVIRONMENT THROUGH THU,
SEVERAL ROUNDS OF TSRA ARE LIKELY WITH THE INCOMING SHORTWAVES. A
PASSING WEAK SFC HIGH PRESSURE BRINGS A BRIEF BREAK FROM THE
ACTIVITY FRI/SAT, BUT LOW RAIN CHANCES RETURN SAT NIGHT/SUN AS THE
TROUGHING RETURNS. OTHERWISE, ABOVE NORMAL TEMPS DOMINATE THE FCST
WITH HIGHS IN THE MID 70S TO UPPER 80S AND LOWS IN THE MID 50S TO
60S.
AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/
ISSUED AT 710 AM EDT TUE JUL 22 2025
VFR CONDITIONS LOOK TO HOLD THROUGH THE DAY TODAY; HOWEVER, THERE
ARE MANY QUESTIONS ABOUT CONVECTION THAT WILL DEVELOP UPSTREAM TODAY
AND TONIGHT. PROB30 GROUPS ARE INCLUDED TO HIGHLIGHT THIS
UNCERTAINTY. CAM GUIDANCE STILL DOESN'T OFFER MUCH CONFIDENCE ON THE
TIMING AND LOCATION OF THESE STORMS, BUT THERE HAS BEEN A PERSISTENT
SIGNAL FOR A LINE OF SHOWERS/STORMS TO MOVE THROUGH OR NEAR
KIWD/KCMX THIS AFTERNOON. AFTERWARDS TONIGHT, CONFIDENCE IS MUCH
LOWER. WHAT IS KNOWN THOUGH, IS THAT ANY THUNDERSTORM THAT DOES MOVE
OVER THE TERMINAL WILL BE CAPABLE OF HEAVY DOWNPOURS AND COULD BE
STRONG TO SEVERE. STRONGER WINDS ALOFT AND DAYTIME MIXING WILL ALSO
SUPPORT GUSTY WINDS NEAR 20KTS AT KIWD/KSAW AND THEN TONIGHT LOW
LEVEL WIND SHEAR AT KSAW AND MAYBE KCMX.
MARINE
ISSUED AT 332 PM EDT MON JUL 21 2025
LIGHT WINDS OF GENERALLY 20 KNOTS OR LESS ARE EXPECTED TO DOMINATE
THE REST OF THIS WEEK, ALTHOUGH SOME SOUTHERLY WINDS OF 20 TO 25
KNOTS ARE POSSIBLE OVER THE EASTERN HALF OF THE LAKE TUESDAY NIGHT
AS THE SFC LOW MOVES THROUGH LAKE SUPERIOR. SOME SHOWERS AND
THUNDERSTORMS ARE EXPECTED ACROSS THE LAKE THIS EVENING AND ONCE
AGAIN TUESDAY THROUGH THURSDAY. SOME THE STORMS MAY BE STRONG TO
SEVERE TUESDAY THROUGH THURSDAY, BRINGING ERRATIC/DAMAGING WINDS AND
LARGE HAIL TO THE SFC.
MQT WATCHES/WARNINGS/ADVISORIES
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
SHORT TERM...JTP
LONG TERM...JABLONSKI/JTP
AVIATION...JTP
MARINE...TAP
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