518
FXUS63 KDTX 271659
AFDDTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1259 PM EDT SUN SEP 27 2026
KEY MESSAGES
- DRY AND PLEASANT WEATHER CONDITIONS WILL PERSIST INTO TUESDAY.
- LOCALIZED FOG IS POSSIBLE THIS MORNING AND AGAIN MONDAY MORNING.
- RAIN CHANCES INCREASE DURING THE LATTER HALF OF NEXT WEEK WITH
COOLER TEMPERATURES EXPECTED.
AVIATION
FOG POTENTIAL LATE TONIGHT INTO MONDAY MORNING REMAINS THE MAIN
AVIATION CONCERN; OTHERWISE CLEAR TO MOSTLY CLEAR SKIES WILL BE THE
RULE. DENSE MORNING FOG AT FNT AND PTK FINALLY DISSIPATED LATE IN
THE MORNING/AROUND NOON. HOWEVER, SURFACE DEW PTS REMAIN ELEVATED IN
THE 50S (2-5 DEGREES HIGHER COMPARED TO 24 HOURS AGO). LOW LEVEL
NORTHEAST FLOW OFF LAKE HURON WILL PERSIST THROUGH TONIGHT. HOWEVER,
THE ACTUAL FLOW AT THE SURFACE LOOKS TO BECOME A BIT MORE NORTH-
NORTHWEST, WHICH ADDS UNCERTAINTY ON THE AREAL EXTENT OF THE
EXPECTED FOG, AS IT MAY BE MORE CONFINED TO THE THUMB REGION. WITH
SUPPORT FROM LAMP GUIDANCE, CONFIDENCE IN DENSE FOG IS HIGHEST AT
FNT ONCE AGAIN, WITH SOME POTENTIAL AT BOTH MBS/PTK. CONFIDENCE IN
FOG DEVELOPING OVER THE SOUTHERN TAFS REMAINS LOW, SO MENTION HAS
BEEN LEFT OUT.
D21/DTW CONVECTION...NO THUNDERSTORMS FORECAST THROUGH THE TAF
PERIOD.
DTW THRESHOLD PROBABILITIES
* NONE
PREV DISCUSSION
ISSUED AT 914 AM EDT SUN SEP 27 2026
UPDATE...
GIVEN THE DEPTH OF THE MORNING FOG AND LOW STRATUS PER SATELLITE, IT
WILL LIKELY TAKE UNTIL LATE MORNING FOR SOME AREAS TO CLEAR OUT
COMPLETELY. THERE HAS ALSO BEEN ENHANCED CONVERGENCE ALONG THE
SHORELINE OF SAGINAW BAY FROM THE MOUTH OF THE SAGINAW RIVER UP TO
SAND POINT WHICH HAS BEEN SUSTAINING A DECENT LOW CLOUD PLUME
DOWNWIND OF THE BAY. IT WILL TAKE DIURNAL MIXING OVER LAND TO
DIMINISH THIS ONGOING LAKESHORE CONVERGENCE REGION. WHILE THERE ARE
STILL A FEW SITES REPORTING LESS THAN 1/4 MILE VISIBILITY, ONGOING
DAYTIME HEATING WILL ALLOW STEADY SFC VISIBILITY IMPROVEMENT.
PREV DISCUSSION...
ISSUED AT 337 AM EDT SUN SEP 27 2026
DISCUSSION...
A TRANQUIL FALL PATTERN CONTINUES FOR THE NEXT FEW DAYS AS HIGH
PRESSURE REMAINS IN CONTROL OVER SE MICHIGAN. THE ORIGIN OF THE
SURFACE HIGH HOWEVER TRANSITIONS AWAY FROM QUEBEC AND TOWARD THE
EMERGING HIGH PRESSURE CENTER OVER THE UPPER MIDWEST TODAY. THIS
WILL REINFORCE THE NORTHEASTERLY WINDS THAT WE HAVE SEEN FOR THE
PAST COUPLE OF DAYS TO MAINTAIN MOISTURE FLUX OFF OF LAKE HURON. A
SLIGHT INCREASE IN WIND SPEED AND UPSTREAM MOISTURE CONTENT OVER
ONTARIO SUGGESTS SLIGHTLY MORE AGGRESSIVE MOISTURE FLUX THAN
PREVIOUS MORNINGS. THAT SAID, SYNOPTIC SCALE MOISTURE IS STILL QUITE
MINIMAL WITH THE 27.00Z KDTX SOUNDING SAMPLING PWAT OF 0.38" (10TH
PERCENTILE PER SPC CLIMATOLOGY). THIS HAS ULTIMATELY KEPT
FOG/STRATUS LOCALIZED TO THE THUMB/SAGINAW VALLEY. SIMILAR FOG/LOW
STRATUS CONCERNS WILL PERSIST EACH MORNING UNTIL WINDS FLIP TO THE
SOUTH TUESDAY WITH THE DEPARTURE OF THE HIGH.
OTHERWISE, SEASONABLE TEMPERATURES HOLD IN THE LOW 70S OVER THE NEXT
SEVERAL DAYS AS THE PATTERN REMAINS AT A STANDSTILL DUE TO THE
STALLED NOR'EASTER. NO SIGNS OF ANY MEANINGFUL THICKNESS ADVECTION
UNTIL TUESDAY WHEN FLOW FLIPS SOUTHWEST AS THE EAST COAST SYSTEM
FILLS IN AND ABSORBS INTO THE MEAN FLOW. BY TUESDAY NIGHT, MID LEVEL
FLOW BECOMES ZONAL WHICH OPENS THE GREAT LAKES TO A LOW AMPLITUDE
SHORTWAVE BY EARLY WEDNESDAY MORNING. MAJORITY OF GUIDANCE BRINGS
THIS PACIFIC WAVE AND ITS ACCOMPANYING UPPER LEVEL MOISTURE ACROSS
THE STATE WELL AHEAD OF LOW LEVEL GULF MOISTURE. THIS KEEPS RAIN
CHANCES LOW (<30%) FOR MOST OF WEDNESDAY IN FAVOR OF JUST INCREASING
CLOUD COVER AND POSSIBLY SOME VIRGA. THERE REMAINS DISAGREEMENT IN
MODEL GUIDANCE REGARDING TIMING OF THE GULF MOISTURE SURGE, WHICH
WILL DICTATE WHEN RAIN CHANCES START TO RAMP UP. THIS LOOKS TO BE
SOMETIME WEDNESDAY EVENING WITH RAIN CHANCES THEN CONTINUING THROUGH
THURSDAY. RETURN FLOW WILL EVENTUALLY BE CUT OFF AS A COLD FRONT IS
DRAGGED ACROSS NORTHERN CONUS BY A NORTHERN STREAM LOW, WHICH ALSO
USHERS IN AN EVEN COOLER AIRMASS TO START OFF OCTOBER AS HIGHS WILL
ONLY BE IN THE MID-60S.
MARINE...
HIGH PRESSURE NOW SITUATED OVER THE GREAT LAKES WILL HOLD THROUGH
TUESDAY. SOME PERIODIC WIND GUST POTENTIAL AROUND 20 KNOTS WILL BE
POSSIBLE ACROSS SOUTHERN LAKE HURON THIS AFTERNOON AND EVENING, BUT
OTHERWISE, WIND GUST POTENTIAL TO OR BELOW 15 KNOTS IS EXPECTED FOR
MOST LOCATIONS. WIND DIRECTION WILL MAINLY HOLD FROM THE NORTH TO
NORTHEAST WITH HIGH PRESSURE IN PLACE.
DTX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
AVIATION.....SF
UPDATE.......SC
DISCUSSION...MV
MARINE.......AM
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