997
FXUS63 KMQT 282343
AFDMQT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
743 PM EDT SUN JUN 28 2026
KEY MESSAGES
- HOT AND HUMID WEATHER IS EXPECTED THROUGH MUCH OF THE WEEK, WITH
THE HOTTEST PERIOD MONDAY THROUGH WEDNESDAY. THE HEAT INDEX WILL
REACH THE LOWER 100S OVER THE WEST AND SOUTH ON MONDAY AND MUCH OF
THE WESTERN AND CENTRAL U.P. ON TUESDAY. THE VERY HUMID AIRMASS WILL
OFFER LITTLE RELIEF AND COOLING MONDAY NIGHT, WITH THE HEAT INDEX
STAYING AT OR ABOVE 70F. A HEAT ADVISORY HAS BEEN ISSUED FOR THE
WESTERN AND SOUTHERN UP.
- SHOWERS AND THUNDERSTORMS ARE LIKELY TONIGHT ACROSS MUCH OF THE
UP. SOME STORMS COULD BE STRONG TO SEVERE WITH LARGE HAIL NEAR THE
MI/WI STATE LINE (5% CHANCE FOR SEVERE THUNDERSTORMS). THERE WILL BE
THE CHANCE FOR THUNDERSTORMS EVERY DAY NEXT WEEK ALONG WITH THE
POTENTIAL FOR STRONG TO SEVERE THUNDERSTORMS.
DISCUSSION
ISSUED AT 225 PM EDT SUN JUN 28 2026
WARM AIR AND MOISTURE ADVECTION IN THE MID LEVELS SET OFF A FEW
LIGHT SHOWERS AND SPRINKLES THIS MORNING BUT OTHERWISE IT WAS DRY
TODAY. A LARGE MCS PUSHED FROM MN TO IA AND FAR WESTERN WI BRINGING
A SHIELD OF HIGH CLOUDS NORTH OVER THE WESTERN HALF OF THE UP. A FEW
SHOWERS ASSOCIATED WITH THE DECAYING MCS COULD MOVE INTO THE WEST
THIS AFTERNOON BUT OVERALL ACTIVITY WILL BE ISOLATED. TEMPERATURES
HAD WARMED INTO THE 70S TO LOW 80S WITH SOUTHEASTERLY FLOW OVER THE
REGION IN RESPONSE TO LOW PRESSURE OVER THE PLAINS. UPSTREAM, AN
UPPER LEVEL LOW WAS OVER THE NORTHERN ROCKIES AND NORTH-CENTRAL MT,
WITH RIDGING CONTINUING TO BUILD OVER THE GREAT LAKES.
GULF MOISTURE SURGES NORTH INTO THE UP OVERNIGHT UNDER SOUTHERLY
FLOW. INSTABILITY WILL INCREASE THROUGH THE NIGHT AS A WARM FRONT
PUSHES NORTH INTO THE AREA. THE FRONT SEEMS TO BE SLOWING DOWN FROM
YESTERDAYS GUIDANCE WHICH MAY KEEP THE STRONGER AND ISOLATED SEVERE
THUNDERSTORMS SOUTH OF THE UP, OVER NORTH-CENTRAL WI. HREF UPDRAFT
HELICITY TRACKS ARE CONFINED MAINLY OVER WI BUT THERE ARE A FEW OVER
THE SOUTHERN UP, PARTICULARLY MENOMINEE COUNTY. PLENTY OF UPDRAFTS
ARE INDICATED ACROSS THE UP AND LIKELY WIDESPREAD SHOWERS AND
THUNDERSTORMS LATE TONIGHT INTO THE MORNING HOURS ON MONDAY. MUCAPE
WILL BE IN THE 1000-2000 J/KG RANGE WITH EFFECTIVE SHEAR OF 30-40KT.
SPC HAS SHIFTED THE MARGINAL RISK FOR SEVERE THUNDERSTORMS SOUTH,
WHICH NOW OVERLAPS ONLY PARTS OF THE UP NEAR THE MI/WI BORDER WHERE
LARGE HAIL CAN NOT BE RULED OUT WITH A STRONGER STORM. HEAVY RAIN
CAN ALSO BE EXPECTED WITH ANY THUNDERSTORMS THAT DEVELOP WITH A
DEEP, WARM AIRMASS.
THE UPPER LEVEL LOW WILL VERY SLOWLY MAKE ITS WAY FROM THE NORTHERN
ROCKIES TO NORTHERN MANITOBA THROUGH WEDNESDAY NIGHT. RIDGING WILL
CONTINUE TO BUILD AHEAD OF THE LOW PRESSURE BRINGING SOUTHERLY FLOW
AND INCREASING TEMPERATURES AND MOISTURE. BY TUESDAY AND WEDNESDAY
850MB TEMPS WARM UP TO 22-24C WHICH WILL TRANSLATE TO HIGHS WELL
INTO THE 80S TO MID 90S ACROSS MUCH OF THE UP. HUMIDITY ALSO BEGINS
TO INCREASE STARTING MONDAY WITH GULF MOISTURE SURGING NORTH,
BRINGING DEWPOINTS TO NEAR OR EXCEEDING 70F AT TIMES. HEAT IMPACTS
ARE EXPECTED THIS WEEK, ESPECIALLY OVER THE WEST MONDAY THROUGH
TUESDAY AS LOWS REMAIN WARM (60S TO LOW 70S) AND DAYTIME HIGHS
APPROACH OR BREAK THE 90F MARK, COMBINING WITH THE HUMID AIRMASS TO
BRING HEAT INDICES INTO THE 90-103F RANGE. HEAT ADVISORIES HAVE BEEN
ISSUED FOR THE SOUTH AND WEST AND MAY NEED TO BE EXPANDED TOMORROW
FOR THE HEAT TUESDAY INTO WEDNESDAY. WHILE THE HEAT INDEX REMAINS
BORDERLINE WITH RESPECTS TO CRITERIA, THE EXTENDED PERIOD OF HEAT AND
WARM NIGHTS WARRANTS THE HAZARD AND MESSAGING. THOSE WHO WILL BE
EXPOSED TO THE HEAT FOR PROLONGED PERIODS AND THOSE WHO ARE
SENSITIVE TO THE HEAT SHOULD HAVE A PLAN TO STAY COOL AND HYDRATED.
IN ADDITION TO THE HEAT, THUNDERSTORMS WILL BE POSSIBLE AT TIMES
THROUGH THE WEEK. POTENTIAL INSTABILITY WILL REMAIN MODERATE TO HIGH
THROUGH THE WEEK THOUGH THE ATMOSPHERE WILL LARGELY WILL REMAIN
CAPPED AND LARGE SCALE ASCENT WILL LIKELY BE NEEDED TO TRIGGER
CONVECTION. ECMWF CAPE EFI IS HIGH ON MONDAY THROUGH WEDNESDAY WITH
SHIFT-OF-TAILS OF 1 OVER THE GREAT LAKES TUE AND WED. VALUES ARE A
BIT LOWER WITH COMBINED CAPE/SHEAR BUT STILL NOTABLE AND A FEW AREAS
OF SOT OF 1 IS NOW SHOWING UP OVER THE UP. OVERALL, SHOULD
CONVECTION DEVELOP DURING THIS PERIOD IT COULD BE STRONG TO
POTENTIALLY SEVERE BUT IT IS TOO EARLY TO PIN DOWN DETAILS. SHOULD
MSC ACTIVITY OCCUR, OUTFLOW BOUNDARIES AND LINGERING CLOUD COVER
WILL LIKELY IMPACT THE EVOLUTION OF THE PROCEEDING DAY'S CONVECTION
AND HIGH TEMPERATURES.
AVIATION /00Z TAFS THROUGH 00Z TUESDAY/
ISSUED AT 742 PM EDT SUN JUN 28 2026
VFR CONDITIONS WILL PREVAIL AT ALL SITES THIS EVENING. SHOWERS WILL
BE A BIT LATER THAN ORIGINALLY FORECAST AS THE FIRST WAVE OF RIDGE-
RIDING SHOWERS PASSED TO THE SOUTH OF THE UP. MODELS STILL INDICATE
THAT CHANCES OF PRECIPITATION WILL INCREASE AT ALL SITES AROUND OR
SHORTLY AFTER SUNSET TONIGHT, FIRST EXCEEDING 30 PERCENT CHANCES AT
IWD AROUND 02-03Z WITH THE OTHER SITES FOLLOWING IN THE 04-08Z
WINDOW. PRECIPITATION INCREASES IN COVERAGE AFTER 06-08Z, SO PROB30S
BECOME PREVAILING GROUPS AT ALL SITES AS A RESULT. CHANCES OF
THUNDERSTORMS IN THE EARLY MORNING HOURS ARE AROUND 50%. AS
PRECIPITATION CHANCES AND COVERAGE INCREASE, THE CEILINGS WILL
DECREASE TO MVFR AND OVER 50% CHANCES OF IFR FOR SOME PERIOD IN THE
MORNING, EVEN AFTER THE PRECIPITATION ENDS. SKIES BEGIN TO LIFT AND
SCATTER IN THE AFTERNOON HOURS. WINDS WILL BE CONSISTENT OUT OF THE
SOUTH TO SOUTHEAST, THOUGH SOME GUSTS TO 20+ KT ARE FORECAST AT
TIMES AT IWD AND SAW.
MARINE
ISSUED AT 225 PM EDT SUN JUN 28 2026
LOW PRESSURE WILL CONTINUE TO DEEPEN OVER THE CENTRAL U.S, AHEAD OF
A UPPER LEVEL LOW PRESSURE THAT WILL SLOWLY MOVE FROM THE NORTHERN
ROCKIES TO NORTHERN MANITOBA THROUGH WEDNESDAY NIGHT. THIS WILL
RESULT IN A TIGHTENING PRESSURE GRADIENT OVER LAKE SUPERIOR AND
INCREASING WINDS. EASTERLY WINDS OF 20-30KT CAN BE EXPECTED TO
DEVELOP THIS AFTERNOON OVER THE OPEN WATER, TURNING SOUTH-SOUTHEAST
ON MONDAY. WINDS WILL REMAIN SOUTHERLY FOR TUESDAY AND WEDNESDAY BUT
GENERALLY 20KT OR LESS. THERE IS THE POTENTIAL FOR THUNDERSTORMS
STARTING TONIGHT, WITH CHANCES EACH DAY THROUGH THE WEEK.
PREDICTABILITY ON TIMING AND COVERAGE IS TOO LOW BUT THERE REMAINS A
CHANCE FOR STRONG TO SEVERE THUNDERSTORMS AT TIMES THROUGH THE WEEK.
MQT WATCHES/WARNINGS/ADVISORIES
UPPER MICHIGAN...
HEAT ADVISORY FROM NOON EDT /11 AM CDT/ MONDAY TO 8 PM EDT /7
PM CDT/ TUESDAY FOR MIZ002>004-009>011-084.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
DISCUSSION...NL
AVIATION...GS
MARINE...NL
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