427  
FXUS63 KMQT 101121  
AFDMQT  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MARQUETTE MI  
721 AM EDT SUN AUG 10 2025  
   
KEY MESSAGES
 
 
- CHANCES OF SHOWERS AND THUNDERSTORMS LINGER THROUGH TUESDAY.  
 
- HIGH TEMPERATURES REMAIN ABOVE-NORMAL TO NEAR-NORMAL  
THROUGHOUT THE NEXT WEEK.  
 

 
   
SHORT TERM /THROUGH TONIGHT/
 
 
ISSUED AT 405 AM EDT SUN AUG 10 2025  
 
EARLY MORNING RAP ANALYSIS AND GOES SATELLITE IMAGERY REVEAL A  
CLOSED UPPER LOW SITTING JUST NORTH OF THE MINNESOTA INTERNATIONAL  
BORDER WITH ITS SURFACE PRESSURE REFLECTION UNDERNEATH AROUND  
1006MB, EXTENDING A WEAK SFC TROUGH ACROSS THE UPPER MIDWEST. CLOSER  
TO HOME, A WEAK PERTURBATION IN THE LONGWAVE TROUGHING IS FIRING OFF  
CONVECTION ACROSS S-CENTRAL LAKE MICHIGAN. WITH THE MAIN FORCING  
DISPLACED AWAY FROM THE UP, MOSTLY CLEAR SKIES ARE OVERHEAD SAVE FOR  
SOME ANVIL CIRRUS PUSHING NORTHWARD. TEMPS HAVE COOLED INTO THE 60S  
AREA WIDE AND PATCHY FOG HAS BEEN OBSERVED IN THE S-CENTRAL WHERE  
RECENT RAINFALL HAS WET SOILS.  
 
THROUGH TODAY, THE AFOREMENTIONED CLOSED LOW TO OUR N BEGINS TO  
TRANSITION TO AN OPEN WAVE AS IT REACHES JAMES BAY. THE BROAD SW  
FLOW EXTENDING ACROSS THE MIDWEST AND NORTHERN GREAT LAKES WILL  
ALLOW FOR ANOTHER WARM AND HUMID DAY. THOUGH NOT AS HOT, DAYTIME  
TEMPS PUSHING THE LOW TO MID 80S COMBINED WITH UPPER 60S TO NEAR 70  
DEGREE DEWPOINTS SHOULD CREATE RELATIVELY UNCOMFORTABLE MUGGY  
CONDITIONS. THE MAIN FORECAST CHALLENGE FOR TODAY AIMS TO BE  
SCATTERED SHOWERS AND THUNDERSTORMS DEVELOPING THIS AFTERNOON ACROSS  
THE UP PROVIDED BY WEAK SYNOPTIC LIFT VIA A SUBTLE EMBEDDED  
SHORTWAVE WITHIN BROAD TROUGHING EXTENDING FROM THE PLAINS.  
DIURNALLY BUILDING INSTABILITY SHOULD BE SUFFICIENT FOR  
THUNDERSTORMS WITH THE HREF PROBABILITY FOR 1000 J/KG OF SBCAPE  
REACHING 60-70% BETWEEN 18-21Z. BULK SHEAR VALUES 25-35 KTS AND  
MOSTLY STRAIGHT HODOGRAPHS SUGGEST SOME GUSTY SMALL HAIL PRODUCING  
STORMS ARE POSSIBLE IN THE STRONGEST UPDRAFTS. THE LACK OF STRONG  
FORCING, HOWEVER, GIVES LOW CONFIDENCE TO ANYTHING REACHING SEVERE  
INTENSITY. ADDITIONALLY, CANT RULE OUT THE HEAVY RAINFALL POTENTIAL  
IN STRONG STORMS WITH PWATS >1.5" AND WARM CLOUD LAYER DEPTHS EXCEED  
10K FT. RECENT RAINFALL AND SATURATED SOILS MAY CONTRIBUTE TO  
LOCALIZED PONDING/FLOODING WHERE THE HEAVIEST RAINFALL OCCURS. CAMS  
ARE IN FAIR AGREEMENT ON A ROUND OF SCATTERED CONVECTION PUSHING N-  
NE INTO THE S-CENTRAL UP THIS AFTERNOON AND A SECOND SLUG REACHING  
THE WESTERN UP ALONG A SUBTLE COLD FRONTAL BOUNDARY IN THE EVENING.  
AS DIURNAL INSTABILITY WANES WITH SUNSET AND THE MAIN SYNOPTIC  
FORCING DEPARTS NE, WOULD EXPECT PRECIPITATION TO DIMINISH INTO THE  
OVERNIGHT HOURS, THOUGH SOME CAMS HOLD ONTO PRECIP IN THE EASTERN  
UP. OTHERWISE, TEMPS ONCE AGAIN COOL TO THE 60S AREA WIDE INTO  
MONDAY MORNING.  
 

 
   
LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/
 
 
ISSUED AT 239 PM EDT SAT AUG 9 2025  
 
BY 00Z MONDAY, THE CUTOFF LOW FORCING THIS PERIOD OF DISTURBED  
WEATHER WILL HAVE WEAKENED SIGNIFICANTLY AS IT LIFTS INTO THE  
HUDSON BAY AREA. LONGWAVE TROUGHING WILL KEEP WARM, MOIST AIR  
OVER THE AREA AND THUS KEEPING HIGH TEMPERATURES MONDAY IN THE  
LOW 80S DESPITE FALLING 500MB HEIGHTS WITH LONGWAVE TROUGHING  
EXTENDS FROM THE ROCKIES INTO THE GREAT LAKES. REMNANT SURFACE  
TROUGHING WILL KEEP POPS IN THE FORECAST FOR MONDAY IN THE EAST  
HALF, THOUGH THE CHANCES OF RAINFALL RATES OVER A QUARTER INCH  
PER 6 HOURS IS ONLY AROUND 15 PERCENT PER THE LREF.  
 
ATTENTION TURNS TO A SHORTWAVE TROUGH RAPIDLY MOVING SOUTHEAST FROM  
THE NORTHWEST TERRITORIES AT 00Z MONDAY TO JUST NORTHWEST OF  
THE UPPER GREAT LAKES BASIN BY 18Z TUESDAY. THE LAST 24 HOURS OF  
ENSEMBLE GUIDANCE HAVE GRANTED MUCH IMPROVED AGREEMENT ON THE  
PLACEMENT OF THE PARENT TROUGH, THOUGH THE RESULTING SURFACE LOW  
WILL BE FAR ENOUGH NORTH THAT PRECIPITATION OVER THE UP MAY  
NEED A BOOST FROM DIURNAL INSTABILITY OR PERHAPS A LAKE BREEZE  
BOUNDARY. INSTABILITY LOOKS OK, AROUND 500 J/KG, AND WHILE BULK  
SFC-500MB SHEAR VALUES AROUND 40 KT LOOK IMPRESSIVE, HODOGRAPHS  
LOOK UNIDIRECTIONAL FOR THE MOST PART. WINDS ALOFT SHIFTING OUT  
OF THE NORTHWEST WILL BE A LITTLE LATE TO PROVIDE MUCH RELIEF  
FROM ABOVE AVERAGE TEMPERATURES AS TUESDAY'S HIGHS WILL BE  
AROUND 80 PER THE NBM, THOUGH OVERNIGHT LOWS IN THE MID 50S IN  
THE INTERIOR WILL BE A WELCOME RETURN TO NEAR-NORMAL FOR THIS  
TIME OF YEAR.  
 
QUASI-ZONAL FLOW ALOFT IS THEN EXPECTED FOR THE MIDWEEK PERIOD,  
KEEPING PRIMARILY DRY WEATHER IN THE FORECAST WITH NEAR- TO SLIGHTLY  
ABOVE-NORMAL TEMPERATURES, THOUGH THIS PATTERN MAY ALLOW FOR SOME  
LAKE BREEZE SHOWERS IF THE CONDITIONS LINE UP CORRECTLY. MODEL  
SPREAD THEN INCREASES FOR THE FRIDAY AND BEYOND PERIOD AS THE  
VARIOUS GLOBAL DETERMINISTIC AND ENSEMBLE SUITES DISAGREE ON THE  
BREAKDOWN OF SOUTHERN US RIDGING AND THE ARRIVAL OF A CUTOFF LOW  
OVER THE CANADIAN PRAIRIE. LOTS OF VARIANCE IN THE RESULTING WEATHER  
IS SEEN IN THE ENSEMBLES, THOUGH ON A CONCEPTUAL LEVEL, WARM  
SOUTHWESTERLY FLOW SEEMS PROBABLE TO RETURN WITH CHANCES OF SHOWERS  
AND THUNDERSTORMS PROBABLY DEPENDENT ON UPSTREAM CONVECTIVE  
DEVELOPMENT OVER THE UPPER MIDWEST.  
 

 
   
AVIATION /12Z TAFS THROUGH 12Z MONDAY/
 
 
ISSUED AT 721 AM EDT SUN AUG 10 2025  
 
PATCHY DENSE FOG HAS BLANKETED MUCH OF THE INTERIOR UP THIS MORNING,  
SAVE FOR THE KEWEENAW WHERE CMX HAS RECENTLY SCATTERED OUT. GUIDANCE  
FAVORS THIS PATCHY FOG LINGERING AT SAW THROUGH THE MORNING HOURS,  
BUT CLEARING BY AT LEAST 15Z. THE MAIN AVIATION CONCERN TODAY WILL  
BE THE DEVELOPMENT OF SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE  
UP THIS AFTERNOON/EVENING, AS WELL AS GUSTY S-SW WINDS 15-20 KTS.  
THE GENERAL CONSENSUS BETWEEN RECENT CAM GUIDANCE FAVORS -SHRA/TSRA  
LIFTING NORTHWARD AROUND PEAK DIURNAL HEATING BETWEEN 18-00Z,  
POTENTIALLY LINGERING ACROSS THE EASTERN HALF OF THE UP AND SAW AS  
LONG AS 04-06Z. HAVE OPTED TO TIME OUT THIS CONVECTION WITH THE USE  
OF PROB30 GROUPS GIVEN THE SCATTERED NATURE OF STORMS. LATER  
TONIGHT, PATCHY FOG IS NOT OUT OF THE QUESTION AGAIN AS SOILS REMAIN  
SATURATED FROM RECENT RAINFALL AND WINDS LIGHTEN UP.  
 

 
   
MARINE
 
 
ISSUED AT 405 AM EDT SUN AUG 10 2025  
 
BREEZY SOUTHERLY FLOW WILL KEEP AFTERNOON GUSTS 15-20 KTS IN THE  
FORECAST THROUGH TODAY, CALMING BELOW 15 KTS DURING THE OVERNIGHT  
HOURS INTO THE WORK WEEK. THUNDERSTORMS PRESSING N-NE THIS AFTERNOON  
AND EVENING MAY CAUSE GUSTY AND ERRATIC WINDS, PRIMARILY OVER THE  
EASTERN HALF OF THE LAKE. A STRONG SHORTWAVE PASSING THROUGH THE  
NORTHERN GREAT LAKES TUESDAY LOOKS TO INCREASE SW WINDS UPWARDS OF  
25 KTS FUNNELING BETWEEN ISLE ROYALE AND THE KEWEENAW, ELSEWHERE 20  
KTS OR LESS.  
 

 
   
MQT WATCHES/WARNINGS/ADVISORIES
 
 
UPPER MICHIGAN...  
NONE.  
LAKE SUPERIOR...  
NONE.  
LAKE MICHIGAN...  
NONE.  
 

 
 

 
 
SHORT TERM...BW  
LONG TERM...GS  
AVIATION...BW  
MARINE...BW  
 
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