653
FXUS63 KDTX 152313
AFDDTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
713 PM EDT MON SEP 15 2025
KEY MESSAGES
- PATCHY-AREAS OF FOG, LOCALLY DENSE LATE TONIGHT.
- ABOVE NORMAL HIGH TEMPERATURES CONTINUE INTO THE WEEKEND.
- DRY WEATHER THROUGH THE FIRST HALF OF THE WEEKEND.
AVIATION
SURFACE HIGH PRESSURE CENTERED ON SOUTHERN QUEBEC HAS A RIDGE
EXTENDING INTO NORTHERN LOWER MI TONIGHT. THIS CONFIGURATION RESULTS
IN CONTINUATION OF STEADY BUT LIGHT NE WIND ACROSS LAKE HURON INTO
SE MI THIS EVENING THAT MAINTAINS MARINE BOUNDARY LAYER MOISTURE
INFLUENCE THROUGH TONIGHT AND EARLY TUESDAY. WIND SPEED AFTER SUNSET
WILL BE MONITORED FOR TENDENCY TO REMAIN NEAR 5 KNOTS TO HELP
DIAGNOSE FOG/STRATUS DISTRIBUTION. AS IT STANDS AT THE 00Z FORECAST
ISSUANCE, WIND SPEED IS EXPECTED TO DROP OFF LATE TONIGHT FOR
ANOTHER ROUND OF IFR/LIFR FOG ONCE AGAIN CONCENTRATED MORE IN THE
THUMB INTO THE MBS AREA WHERE MARINE INFLUENCE IS GREATER. POINTS
SOUTH TOWARD THE DTW CORRIDOR ARE ALSO UNDER FAVORABLE RADIATIONAL
COOLING CONDITIONS FOR MVFR FOG AS LONG AS LIGHT WIND REMAINS FROM
THE NE DIRECTION, AND THIS WILL BE CAREFULLY MONITORED FOR ANY
CHANGES THAT INCREASE LAKE ERIE INFLUENCE. THE GOOD THING ABOUT THE
LAST FEW DAYS OF FOG ISSUES IS THE FULL SUN MORNINGS THAT HELPED
DISSIPATE FOG/STRATUS QUICKLY AND TUESDAY MORNING WILL BE THE SAME.
SCATTERED TO BROKEN VFR CUMULUS ALSO DEVELOPS ONCE AGAIN IN THE
AFTERNOON INTO TUESDAY EVENING.
FOR DTW/D21 CONVECTION... NO THUNDERSTORMS THROUGH THE EARLY WEEK
PERIOD.
THRESHOLD PROBABILITIES...
* NONE.
PREV DISCUSSION
ISSUED AT 251 PM EDT MON SEP 15 2025
DISCUSSION...
UPPER LEVEL RIDGE CENTERED OVER THE CENTRAL GREAT LAKES WILL
CONTINUE TO HOLD OVER THE NEXT COUPLE DAYS. 12Z DTX SOUNDING
INDICATED A 500 MB HEIGHT OF 591 DAM, NEAR RECORD HIGH FOR MID
SEPTEMBER PER SPC CLIMATOLOGY PAGE. MORNING FOG, ENHANCED BY
LIGHT EASTERLY FLOW OFF LAKE HURON, IS THE ONLY THE NOTEWORTHY
WEATHER DURING THE NEXT COUPLE DAYS, AS WARM DAYTIME TEMPERATURES
PUSH INTO THE 80S. 12Z DTX SOUNDING INDICATED A SIMILAR PROFILE TO
YESTERDAY, AND THUS NO SURPRISE MAX TEMPS ARE/OR WILL BE BACK INTO
THE LOWER 80S. 850 MB TEMPS STILL LOOKING TO BE AOA 13 C TOMORROW,
BUT THEN EVEN SLIGHTLY WARMER FOR WEDNESDAY AND ESPECIALLY THURSDAY,
SUPPORTING MID 80S FOR WEDNESDAY AND UPPER 80S FOR THURSDAY.
ELEVATED SURFACE DEW PTS THIS AFTERNOON INTO THE 55-60 DEGREE RANGE
WILL SET THE STAGE FOR FOG ONCE AGAIN, AND WILL CONTINUE TO FAVOR
AREAS OF FOG NORTH OF M-59 AND PATCHY FOG SOUTH.
THE UPPER-LEVEL RIDGE WILL WEAKEN TO END THE WORK WEEK, WITH ITS
AXIS POSITIONING MORE TOWARD THE WESTERN GREAT LAKES. A WEAK COLD
FRONT WILL DROP SOUTH THROUGH THE CENTRAL GREAT LAKES THURSDAY NIGHT,
BUT IS EXPECTED TO COME THROUGH DRY WITH LITTLE TO NO UPPER LEVEL
SUPPORT. STRONG HIGH PRESSURE (1030+ MB) BUILDS INTO NORTHERN ONTARIO
FRIDAY AND INTO QUEBEC ON SATURDAY. THIS WILL LEAD TO A SUBSTANTIAL
EAST-SOUTHEAST PRESSURE GRADIENT, WHICH WILL LIKELY KEEP DAYTIME
TEMPS A BIT COOLER, ESPECIALLY WITH AN INCREASE IN MID TO HIGH
CLOUDS FOR SATURDAY.
MARINE...
A RIDGE OF HIGH PRESSURE WILL CONTINUE TO BRING AN EXTENDED PERIOD
OF DRY WEATHER AND LIGHTER WINDS TO THE GREAT LAKES THROUGH THE
WEEK. SOME LOCALIZED HIGHER WIND SPEEDS NEARING 15 TO 20 KNOTS WILL
AGAIN BE POSSIBLE THROUGH THE SAGINAW BAY INTO THE EVENING GIVEN THE
FAVORABLE NORTHEAST FETCH. OTHERWISE, THE NEXT CHANCE FOR MORE
ACTIVE WEATHER WILL ENTER THIS WEEKEND AS A LOW PRESSURE SYSTEM
NEARS THE REGION.
DTX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
AVIATION.....BT
DISCUSSION...SF
MARINE.......AM
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AT WWW.WEATHER.GOV/DETROIT.
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