357
FXUS63 KAPX 302337
AFDAPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
737 PM EDT THU JUL 30 2026
KEY MESSAGES
-SHOWER AND STORM CHANCES THIS AFTERNOON / EVENING ACROSS
EASTERN UPPER AND PORTIONS OF NORTHEAST LOWER.
-ADDITIONAL SHOWER AND THUNDER CHANCES FRIDAY, AGAIN FAVORING
NORTHEAST LOWER AND EASTERN UPPER. RAIN CHANCES CONTINUE INTO
SATURDAY. LIMITED FOOTPRINT OF APPRECIABLE RAINFALL SUGGESTS
THAT RAINFALL AMOUNTS IN EXCESS OF 1-2" WILL REMAIN HIGHLY
LOCALIZED THROUGH THE WEEKEND.
-DRIER AND COOLER TO START NEXT WEEK, WITH WARMER WEATHER AND
RAIN CHANCES BUILDING BY NEXT TUESDAY.
DISCUSSION
ISSUED AT 235 PM EDT THU JUL 30 2026
PATTERN / FORECAST SYNOPSIS:
CONVOLUTED WEATHER PATTERN LOCALLY COURTESY OF A PAIR OF
DISTURBANCES RIDING A WEAK POINT IN JET STREAM FLOW. NORTHERN WAVE,
MUCH MORE ROBUST WITH ATTENDANT 998MB SURFACE LOW, WILL
CONTINUE A SOUTH AND EAST PROGRESSION OVER HUDSON BAY INTO THE
WEEKEND. SOUTHERN WAVE SET TO MANIFEST AS A CONVECTIVELY CHARGED
WAVE OVER SOUTH DAKOTA AND NEBRASKA LATER TODAY, RIDING A
REGIME OF NW FLOW INTO IOWA AND ILLINOIS BY THE WEEKEND. COLD
FRONTAL BOUNDARY FROM THE NORTHERN WAVE WILL SLOWLY PROGRESS
SOUTH AND EAST FRIDAY INTO SATURDAY AS THE SOUTHERN WAVE PASSES
TO OUR SOUTH AND WEST. NOSE OF DEEPER MOISTURE ALONG THE FRONT
WILL BE DRAWN SOUTHWARD FROM THE FRONTAL BOUNDARY INTO NORTHERN
LOWER, RESULTING IN BUDDING INSTABILITY DEVELOPMENT IN AN
ENVIRONMENT THAT WILL ESSENTIALLY BECOME THE NEUTRAL POINT OF
THE TROUGH FROM FRIDAY INTO SATURDAY. WEAK SYNOPTIC FLOW MAY
LEAD TO LAKE BREEZE PROCESSES BECOMING THE LIFTING MECHANISM IN
NORTHEAST LOWER FRIDAY AFTERNOON, WITH OUTFLOW DRIVEN CONVECTION
SPREADING WESTWARD ACROSS THE REGION. MEANWHILE, THE APPROACH
OF THE COLD (AND SOON TO BE STATIONARY) FRONT WILL PROVIDE
ENOUGH FORCING TO GENERATE CONVECTION ACROSS EASTERN UPPER.
EVENTUALLY, THIS FRONT WILL SLOWLY DRIFT SOUTHWARD INTO
SATURDAY, AND SHOULD EXIT BY SUNDAY, WITH RISING (BUT STILL LOW)
500MB HEIGHTS SUPPORTING A PERIOD OF DRIER AND COOLER WEATHER
INTO EARLY NEXT WEEK BEFORE THE NEXT WAVE PASSAGE IS PROGGED TO
TRANSPIRE ACROSS THE GREAT LAKES.
DETAILS:
TODAY - TONIGHT: SUBTLE PRE-FRONTAL TROUGH CURRENTLY ANALYZED FROM
ROUGHLY THUNDER BAY TO ESCANABA WILL PROVIDE JUST ENOUGH FORCING TO
CONTINUE SHOWER AND THUNDER DEVELOPMENT THROUGH THE EVENING ACROSS
THOSE REGIONS, PERHAPS SENDING A FEW SHOWERS INTO NW LOWER
OVERNIGHT, BUT REALISTICALLY THE BETTER SHOT OF RAIN BY THE EVENING
INTO THE OVERNIGHT WILL FIRST BE DRIVEN BY LAKE BREEZE CONVERGENCE
PROCESSES OVER EASTERN UPPER, AND TO A LESSER EXTENT, NORTHEAST
LOWER. SURFACE DEWPOINTS IN THE LOW TO MID 60S SHOULD PROVIDE JUST
ENOUGH TO FORCE SOME DIURNAL INSTABILITY. STORM COVERAGE MAY
INCREASE IN EASTERN UPPER LATER TONIGHT AS THE STATIONARY FRONT
INCREASES.
FRIDAY-SATURDAY: INFLUX OF DEEPER MOISTURE (DEWPOINTS ANYWHERE FROM
64 TO 70) MAKES ITS PRESENCE KNOWN BY FRIDAY AS THE DOUBLE
BARRELED SYSTEMS MOVE CLOSER. WEAK WESTERLY FLOW COUPLED WITH
AMPLE DAYTIME HEATING SHOULD BE ENOUGH TO DRUM UP A LAKE HURON
LAKE BREEZE. AS INSTABILITY BUILDS THROUGH THE DAY, COULD SEE A
VERY OUTFLOW DOMINANT BATCH OF CONVECTION, LIKELY VERY PULSEY IN
NATURE, MANIFEST THROUGH LATE MORNING INTO THE AFTERNOON. WITH
THE STATIONARY FRONT DRAWING CLOSER TO EASTERN UPPER, GREATLY
INSTABILITY POTENTIAL SUPPORTS A BETTER SHOT AT RAIN UP THERE
THROUGH THE DAY FRIDAY. RESULTANT STRATIFORM RAIN WITH EMBEDDED
DOWNPOURS TO SAG SOUTHWARD INTO NORTHERN LOWER WITH THE ADVANCE
OF THE FRONT FRIDAY NIGHT INTO SATURDAY... WHICH MAY TREND A BIT
MORE SHOWERY THROUGH THE DAY (ESPECIALLY AREAS SOUTH OF THE
FRONT, LOOKING AT M-55 IN PARTICULAR) BEFORE ACTIVITY WANES INTO
THE OVERNIGHT HOURS. WILL NEED TO WATCH HOW ANY EMBEDDED
DOWNPOURS BEHAVE OVER THIS TIMEFRAME.
AFOREMENTIONED DEEPER MOISTURE PLUME WILL BALLOON PWATS POTENTIALLY
AS HIGH AS 1.75 AT THE ZENITH OF MOISTURE CONCENTRATION, WHICH
SUGGESTS VERY EFFICIENT RAINFALL POTENTIAL. AS SUCH, LOOKING AT
PROBABILISTIC GUIDANCE, MOST AREAS HAVE A 48HR (THROUGH 00Z
SUNDAY) 50TH PERCENTILE VALUE OF 0.40-0.75" OF QPF, WITH THE
HIGHEST VALUES FAVORING AFOREMENTIONED M-55 CORRIDOR, UP THE
LAKE HURON COAST AND INTO EASTERN UPPER. 48HR (THRU 00Z SUNDAY)
90TH PERCENTILE (I.E, ONLY A 10% CHANCE THIS MUCH RAIN OR MORE
FALLS OVER THAT PERIOD) TOPS OUT AT 1 TO 2.50" AREA WIDE, WITH
HIGHEST AMOUNTS FOCUSED ON NORTHEAST LOWER AND EASTERN UPPER,
WHICH TO ME, SUGGESTS THAT FRIDAY'S CONVECTIVE POTENTIAL MAY
DRIVE ROBUST RAINFALL IN THE EVENT THE ENVIRONMENT SUPPORTS
REPEATED CONVECTION. IN ADDITION, THE LACK OF FORCING CONVEYS
THAT NOT EVERYONE IS SET TO SEE HIGH RAINFALL RATES. THESE
PATTERS ARE EXTREMELY FICKLE, AND AREA-WIDE, IT WOULD BE
UNSURPRISING TO SEE SOME AREAS SEE LESS THAN 0.05" OF RAIN,
WHILE SOME LOCALIZED AREA SEES RAINFALL IN EXCESS OF 2.50" OVER
48 HOURS. AT THIS JUNCTURE, SEVERE POTENTIAL LOOKS LIMITED TO
STORM CORE COLLAPSE PROCESSES ON FRIDAY WHEN THE MOST ROBUST
CONVECTION IS ANTICIPATED, AND A WIDESPREAD ORGANIZED SEVERE
THREAT SEEMS UNLIKELY.
REST OF THE PERIOD: COOLER CANADIAN AIR FILTERS IN BEHIND THE FRONT
BY SUNDAY, WITH COOLER AND DRIER WEATHER TO KICK OFF NEXT WEEK.
SEASONABLE TO PERHAPS ABOVE NORMAL TEMPS RETURN TUESDAY-WEDNESDAY AS
THE NEXT WAVE APPROACHES, BRINGING WITH IT, THE NEXT RAIN CHANCES
AFTER THIS WEEKEND.
AVIATION /00Z TAFS THROUGH 00Z SATURDAY/
ISSUED AT 737 PM EDT THU JUL 30 2026
PLENTY OF (PARTLY THIN) HIGH CLOUDS OVERHEAD. CU WILL DECREASE
THIS EVENING. CIU/PLN COULD SEE SOME SHOWERS IN THE VICINITY
OVERNIGHT, WITH A SOMEWHAT BETTER CHANCE ACROSS MORE OF NORTHERN
MI DURING THE DAY FRIDAY.
MAINLY LIGHT WINDS.
APX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
MARINE...NONE.
DISCUSSION...HAD
AVIATION...JZ
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