255
FXUS63 KAPX 121639
AFDAPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
1239 PM EDT SAT SEP 12 2026
KEY MESSAGES
- FEW SHOWERS/STORMS TODAY
- COOL AND SHOWERY SUNDAY FOLLOWED BY A CHILLY NIGHT SUNDAY NIGHT
- INCREASINGLY BREEZY WITH RAIN/STORM CHANCES MONDAY NIGHT INTO
TUESDAY
DISCUSSION
ISSUED AT 306 AM EDT SAT SEP 12 2026
PATTERN SYNOPSIS/FORECAST:
ZONAL FLOW ACROSS THE WESTERN US ATTM...WITH RIDGE AXIS HOLDING ON
ACROSS THE EASTERN US, INCLUDING THE GREAT LAKES. FLOW REMAINS A BIT
SPLIT ATTM...WITH A BEAUTIFUL SWIRL IN WATER VAPOR IMAGERY OVER THE
MID MS VALLEY ASSOCIATED WITH A TROUGH AXIS THERE...AND AN ELONGATED
POSITIVELY TILTED TROUGH AXIS STRETCHING FROM THE NORTHERN PLAINS TO
AN UPPER LOW OVER HUDSON BAY, WITH MANY-A PV MAXIMA IN THE FLOW
ACROSS MOST OF CANADA ATTM. DEEPEST MOISTURE REMAINS ACROSS THE SE
US AND LOWER MS VALLEY NEARER THAT FORMER FEATURE...WITH A MAXIMUM
IN PWATS (AROUND 2IN) ALONG THE TIGHTENING BAROCLINIC ZONE AND
DEFORMATION AXIS STRETCHING FROM CENTRAL ONTARIO BACK INTO
NEBRASKA...THOUGH THERE IS A LITTLE BIT OF MOISTURE HANGING BACK
ACROSS CENTRAL CANADA ALONG A SUBTLE TROUGH AXIS, NEAR AND NORTH OF
WHICH 850MB TEMPS DROP BACK TO 0-4C. PLUME OF WEAK STABILITY ALSO
STRETCHES ALONG THE AFOREMENTIONED BAROCLINIC ZONE, AND THIS IS
WHERE A LINE OF CONVECTIVE ACTIVITY FIRED LAST EVENING. LOW-LEVEL
FLOW IS PARALLEL TO THE UPSTREAM BOUNDARY AND MID-LEVEL FLOW HAS A
LITTLE BIT MORE OF A WESTERLY COMPONENT...SUCH THAT THE AIR MASS
WILL OVERALL BE MOISTENING HERE IN THE GREAT LAKES (DEWPOINTS AS OF
3Z ARE IN THE UPPER 40S TO LOWER 50S, WHICH IS WARMER THAN THIS TIME
YESTERDAY), BUT THE MOST NOTABLE WARM/MOIST ADVECTION SHOULD REMAIN
TO OUR NORTHWEST NEAR AND NORTH OF LAKE SUPERIOR TONIGHT. THIS IS
REFLECTED BY SURFACE WARM FRONT WELL TO OUR NORTH ALONG THE SOUTHERN
SHORE OF HUDSON BAY TO WESTERN QUEBEC. SOME MOISTURE IS SWIRLING
NORTHWARD THROUGH THE OH VALLEY, TOO, NORTH OF THE AFOREMENTIONED PV
SWIRLY IN THE MID MS VALLEY; ATTM, THIS IS SLOWLY ATTEMPTING TO
CREEP NORTHWARD/NORTHEASTWARD INTO SOUTHERN MICHIGAN.
PV MAXIMA SWINGS BY TO OUR NORTH TODAY, BUT WILL DRAG SOME SEMBLANCE
OF A BOUNDARY ACROSS THE AREA THROUGH THE DAY...WITH NW WINDS
PICKING UP AS COLD ADVECTION COMMENCES LATE. SUNDAY SHOULD BE
SEASONABLY COOL WITH A TROUGH AXIS PIVOTING OVERHEAD, MOST LIKELY IN
THE AFTERNOON/EVENING. BEHIND THIS...HIGH PRESSURE BUILDS IN SUNDAY
NIGHT, AND WITH THIS COLD AIR MASS IN PLACE, THINK SUNDAY NIGHT
COULD BE QUITE COOL INDEED. OUR QUIET WEATHER WILL BE SHORT-
LIVED...WITH AN UPPER LOW EJECTING FROM THE PACNW ACROSS THE
NORTHERN PLAINS MONDAY...TRACKING ACROSS THE UPPER MIDWEST INTO
SOUTHERN ONTARIO MONDAY NIGHT INTO TUESDAY. STILL HAVE CONCERNS THAT
THE GULF WILL BE OPEN FOR BUSINESS WITH THIS SYSTEM, AND PERHAPS
SOME TAP OF PACIFIC MOISTURE, TOO, WITH SOUTHWESTERLY FLOW
ALOFT...AND THUS, HAVE CONCERNS FOR HEAVY RAIN/STORM POTENTIAL
ACROSS THE REGION FOR THIS TIMEFRAME (MONDAY NIGHT INTO TUESDAY).
PROGRESSIVE REGIME WILL KEEP THIS NIBLET MOVING, TOO, AS ANOTHER
LOBE OF ENERGY MAKES ITS WAY EASTWARD ACROSS THE CENTRAL CONTINENT.
TIMING OF THIS NEXT FEATURE REMAINS A BIT UNCLEAR ATTM, BUT APPEARS
WEDNESDAY NIGHT INTO THURSDAY WILL BE THE BROAD TIMEFRAME FOR
ANOTHER ROUND OF ACTIVITY. EVEN MORE UNCERTAINTY IN THE PATTERN FOR
THE END OF THE WEEK INTO NEXT WEEKEND, DEPENDING ON HOW STRONG THE
SOUTHERN STREAM RIDGE AXIS WILL BE, AND WHERE IT WILL BE FOCUSED.
FORECAST DETAILS...
RAIN/STORM CHANCES TODAY...FRONT CROSSES THE REGION BETWEEN 15-21Z
ISH TODAY FROM W-E AND THINK THERE WILL BE AN UPTICK IN LOW-LEVEL
FORCING AND MOISTURE POOLING ALONG THIS BOUNDARY TO PRODUCE AT LEAST
CLOUD COVER, IF NOT SHOWERS, ESPECIALLY TOWARD THE EUP AND TIP OF
THE MITT WHERE THERE IS A LIKELIHOOD OF BETTER FORCING AND DEEPER
MOISTURE...THOUGH INSTABILITY SHOULD BE LESSER HERE (MINUS THAT
THERE SHOULD BE CONVECTIVE INSTABILITY PRESENT ALONG THE EDGE OF THE
DRY SLOT). THERE IS A BETTER SHOT AT SLIGHTLY (SLIGHTLY) DEEPER
INSTABILITY ACROSS NORTHERN LOWER MI (MORE LIKELY TO BE UNDERNEATH
THE PLUME OF WEAKEST STABILITY), THOUGH THIS WILL BE FURTHER REMOVED
FROM THE BETTER MOISTURE AND FORCING. NOT IMPOSSIBLE THERE COULD BE
A FEW SHOWERS OR EVEN A RUMBLE OF THUNDER THIS AFTERNOON AS THE
FRONT PASSES THROUGH...BUT LESSER MOISTURE HERE SIGNALS LESS
CONFIDENCE IN SHOWER/STORM DEVELOPMENT HERE. DEEP LAYER SHEAR PICKS
UP THIS AFTERNOON/EVENING, GENERALLY IN THE WAKE OF THE FRONT, BUT
NOT IMPOSSIBLE IT COULD BE A LITTLE BETTER RIGHT WITH THE FRONT, AND
IF WE DO END UP WITH MORE ACTIVITY ALONG THE FRONT THAN PREVIOUSLY
EXPECTED...NOT IMPOSSIBLE A FEW CELLS COULD GET A LITTLE BETTER
ORGANIZED AND A LITTLE SPICIER. IT'S POSSIBLE THE BOUNDARY MAY STALL
OVER THE REGION TONIGHT, IN AN EAST-WEST FASHION, BEFORE THE NEXT
NIBLET COMES ROLLING IN FOR SUNDAY, AND THIS IDEA SUGGESTS SOME
SHOWER ACTIVITY WILL HANG ON INTO AT LEAST PART OF THE NIGHT.
COOL WITH SHOWERS SUNDAY; CHILLY SUNDAY NIGHT...TEMPS WILL CONTINUE
TO FALL SATURDAY NIGHT INTO SUNDAY, PARTICULARLY ALOFT, WITH 850MB
TEMPS AT OR BELOW 5C ACROSS A GOOD CHUNK OF THE AREA BY THE
AFTERNOON. THIS WILL BE BORDERLINE FOR OVERLAKE INSTABILITY
GENERATION, AND COMBINED WITH AN INCOMING PV MAX PUNTING SATURDAY'S
BOUNDARY OUT OF THE AREA, THINK THERE IS A SHOT WE SEE LAKE ENHANCED
SHOWER ACTIVITY SUNDAY (PARTICULARLY WITH THE PASSAGE OF THE PV MAX
AROUND MIDDAY/AFTERNOON). WITH THE COOLER AIR AND WEAKER WINDS
SUNDAY, NOT IMPOSSIBLE THERE COULD BE A ROGUE WATERSPOUT, THOUGH
CLOUD DEPTHS AND LAKE-850MB DELTA-TS ARE A LITTLE ON THE LOW SIDE
FOR ANY GREAT AMOUNT OF CONFIDENCE. ASSUMING SKIES CLEAR AS HIGH
PRESSURE MOVES OVERHEAD SUNDAY NIGHT, SOME LOCALES COULD DROP DOWN
INTO THE UPPER 30S AND LOWER 40S AGAIN, SIMILAR TO LAST
NIGHT...THOUGH A LITTLE UNCLEAR ATTM IF THE AIR MASS THEN WILL BE
QUITE AS DRY AS IT WAS LAST NIGHT, WHEN WE DID DROP DOWN INTO THIS
RANGE. IF IN FACT WE ARE AS DRY...A 30 DEGREE (GIVE OR TAKE) DIURNAL
TEMPERATURE SWING FROM THE LOWER TO MIDDLE 60S COULD DROP TEMPS INTO
THE MID 30S OR COLDER IN SOME INTERIOR LOCALES BY MONDAY
MORNING...SO WILL BE SOMETHING TO KEEP AN EYE ON.
RAIN/STORM CHANCES MONDAY NIGHT INTO TUESDAY; INCREASINGLY BREEZY...
STILL LOOKING FOR AN ANOMALOUS WAD OF MOISTURE (PWATS PUSHING THE 95-
99TH PERCENTILE VS CLIMO) TO PIVOT INTO THE AREA MONDAY NIGHT INTO
TUESDAY AHEAD OF A LIFTING SHORTWAVE TROUGH (SUGGESTING POTENTIAL
FOR BETTER SYNOPTIC FORCING) AND ATTENDANT TIGHTLY-WOUND SURFACE
CYCLONE, PER DETERMINISTIC GUIDANCE. THIS SETS THE STAGE FOR A)
STORM DEVELOPMENT, AND B) HEAVY RAIN POTENTIAL WITH ANY STORMS.
BETTER INSTABILITY PARAMETERS MAY SET UP TO OUR SOUTHWEST AS FAR AS
STORMS ARE CONCERNED...AND WITH STRONGER WINDS ALOFT, THINK SOME
STORMS COULD BECOME ORGANIZED, ESPECIALLY DOWN IN THIS REGION,
ASSUMING THIS IDEA PERSIST, WITH MUCH LESS CERTAINTY IN THIS IDEA
FOR NORTHERN MICHIGAN. HOWEVER, WE WILL BE NEAR/NORTH OF THE WARM
FRONT AS IT LIFTS IN, WHICH COULD SIGNAL A BETTER POSITION FOR HEAVY
RAINFALL FOR US. CERTAINLY SOMETHING WE WILL NEED TO MONITOR...WITH
PROBABILISTIC GUIDANCE STILL POINTING TOWARD UPWARDS OF A 40-50
PERCENT CHANCE OF AN INCH OF RAIN IN 24HRS ENDING TUESDAY EVENING.
WORTH NOTING THAT PROB GUIDANCE IS MORE CONFIDENT ON THE HIGHEST
RAINFALL TOTALS TO OUR SOUTH AND WEST, WHICH IS A REASONABLE IDEA
BASED ON THE SETUP...BUT THERE IS STILL POTENTIAL FOR HEAVIER RAINS
TO SNEAK UP INTO OUR AREA ALONG THE BOUNDARY AS IT DRAPES IN.
PRESSURE GRADIENT CURRENTLY LOOKS TO STRENGTHEN QUITE DRAMATICALLY
MONDAY NIGHT INTO TUESDAY AHEAD OF THE INCOMING SURFACE LOW, AND
THINK WE HAVE A SHOT AT OUR FIRST GALES OF THE SEASON WITH
THIS...GIVEN SOUNDING-DERIVED WIND GUST PROBABILITIES AROUND 30
PERCENT FOR GUSTS OF AT LEAST 34KTS. 850MB WINDS ARE ON THE HIGHER
SIDE...+3 STANDARD DEVIATIONS FROM THE MEAN...SUGGESTING WE COULD BE
IN FOR SOME STRONGER WINDS IF THEY CAN MIX DOWN; THE CAVEAT BEING
THAT WARM ADVECTION TYPICALLY DOES NOT SUPPORT FULL MIXING, AND
COULD KEEP THE STRONGER WINDS TRAPPED ALOFT.
AVIATION /18Z TAFS THROUGH 18Z SUNDAY/
ISSUED AT 1239 PM EDT SAT SEP 12 2026
LARGELY VFR CONDITIONS THROUGH THE FORECAST PERIOD. GUSTY S TO SSW
WINDS THIS AFTERNOON FLIP MORE NW BY EVENING WITH A COLD FRONTAL
PASSAGE. SOME GUSTS AS HIGH AS 25KTS POSSIBLE THROUGH THE EVENING.
POTENTIAL FOR A PASSING SHOWER OR TWO GENERALLY 19-23Z, PRIMARILY AT
PLN AND CIU... THOUGH COULD SCRAPE TVC AND APN, BUT NOT LIKELY. BEST
SHOT FOR ANY FLIGHT CATEGORY RESTRICTIONS FROM SHOWERS WILL BE AT
CIU, GRADUALLY DECREASING THE FARTHER SOUTH ONE GOES. WINDS TAPER
SOME OVERNIGHT WITH CIGS RISING AGAIN. BREEZY NW FLOW CONTINUES INTO
SUNDAY, WITH VFR DIURNAL CUMULUS CLOUDS SPROUTING THROUGH THE
DAY.
APX WATCHES/WARNINGS/ADVISORIES
MI...BEACH HAZARDS STATEMENT UNTIL 8 PM EDT THIS EVENING FOR MIZ025-
031-095-096-098.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR
LHZ345>347.
SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LMZ323-
341-342-344>346.
SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LSZ321-
322.
DISCUSSION...FEF
AVIATION...HAD
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