346
FXUS63 KDTX 150757
AFDDTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
357 AM EDT MON SEP 15 2025
KEY MESSAGES
- EXTENDED STRETCH OF DRY CONDITIONS WITH HIGHS WELL ABOVE AVERAGE
THIS WEEK.
DISCUSSION
HIGH MAGNITUDE UPPER LEVEL HIGH PRESSURE SYSTEM CENTERED SQUARELY
OVER THE GREAT LAKES DURING THE EARLY WEEK PERIOD. THIS EXISTS ATOP
A SPRAWLING SURFACE ANTICYCLONE ANCHORED ACROSS WESTERN QUEBEC THAT
MAINTAINS A LIGHT EAST/NORTHEAST LOW LEVEL FLOW. ASSOCIATED WELL
ABOVE AVERAGE WARMTH FIRMLY ENTRENCHED LOCALLY. LITTLE EVIDENCE OF
ANY MEANINGFUL THERMAL ADVECTION TODAY AND TUESDAY, WITH EXPECTATION
FOR A WELL MIXED PROFILE UNDER FULL INSOLATION TO YIELD A VIRTUAL
CARBON COPY OF T/TD BOTH MON & TUE OF THAT NOTED YESTERDAY. INHERENT
STABILITY RESIDING THROUGHOUT THE COLUMN WITHIN THIS STAGNANT PATTERN
ENSURES CONTINUED DRY CONDITIONS. CONDUCIVE ENVIRONMENT GIVEN THE
LIGHT ONSHORE FLOW FOR SOME DEGREE OF NOCTURNAL NEAR SURFACE MOISTURE
FLUX OFF THE GREAT LAKES, MAINTAINING POTENTIAL EACH NIGHT FOR
PATCHY TO AREAS OF FOG DEVELOPMENT DURING THE EARLY MORNING HOURS.
UPPER RIDGING MAINTAINS INFLUENCE THROUGH THE LATTER HALF OF THE
WEEK, AS NORTHERN STREAM HEIGHT FALLS ASSOCIATED WITH SHORTWAVE
ENERGY SHEARING ACROSS HUDSON BAY SIMPLY GLANCES ACROSS THE NORTHERN
GREAT LAKES. THIS MAINTAINS THIS EXTENDED STRETCH OF BENIGN WEATHER.
TEMPERATURES EDGE UPWARD SLIGHTLY MIDWEEK, LIKELY PEAKING THURSDAY
IN THE MID/UPPER 80S AS THE CORE OF THE THERMAL RIDGE MARKED BY 850
MB TEMPS OF MID TEENS EASES OVERHEAD. A BROAD AREA OF HEIGHT FALLS
SETTLING ACROSS THE PLAINS WILL ATTEMPT TO ORGANIZE BEFORE LIFTING
TOWARD THE GREAT LAKES SOMETIME NEXT WEEKEND. MIXED SIGNAL YET ACROSS
THE MODEL ENSEMBLE ENVELOP IN TERMS OF DEFINING THE DOWNSTREAM PACE
AND EFFECTIVE INFLUENCE ON CONDITIONS. LATEST NBM GUIDANCE OFFERS
SOME INTRODUCTORY LOWER END PRECIP CHANCES FOR THE WEEKEND PERIOD,
WITH TEMPERATURES EASING BACK TOWARD AVERAGE.
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 THIS AFTERNOON AND 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.
PREV DISCUSSION
ISSUED AT 1157 PM EDT SUN SEP 14 2025
AVIATION...
NE SURFACE WIND IS SHOWING SOME TENDENCY TO HOLD NEAR 5 KNOTS SINCE
SUNSET, LESS AT DTW AND MORE TOWARD MBS WHERE REINFORCEMENT OF THE
SAGINAW BAY MARINE LAYER IS EVIDENT. THIS IS OCCURRING UNDER CLEAR
SKY TO MAINTAIN A FAVORABLE SETUP FOR RADIATIONAL COOLING AND FOG
AND/OR STRATUS LATE TONIGHT AND EARLY MORNING. THERE ARE HINTS OF
LIFR STRATUS FARTHER NORTH TOWARD OSC, ON THE EDGE OF A LARGER MID
CLOUD AREA OVER INTERIOR NORTHERN LOWER MI. THE OSC CLOUD TRENDS
LEAN THE MBS FORECAST IN THAT DIRECTION AND MORE TOWARD MVFR FOG IN
THE FNT TO PTK AREA, IFR IF THE WIND DROPS OFF LATE. THE NE
DIRECTION IS MORE OF A LIMITING FACTOR FOR BOTH CLOUDS AND FOG AT
DTW, AT LEAST INITIALLY AS LAKE ERIE OBSERVATIONS ARE CONVINCINGLY
NE AT FORECAST ISSUANCE. THERE IS A LATE DEVELOPING VEERING TREND IN
MODEL GUIDANCE FOR THE DTW CORRIDOR TOWARD SUNRISE BUT WITH LOW
PREDICTABILITY ON FOG/STRATUS OUTCOMES AS A RESULT. THE MORNING THEN
STARTS OFF WITH FULL SUN TO ENSURE A STANDARD MID SEPTEMBER PACE OF
FOG/STRATUS DISSIPATION LEADING INTO ANOTHER AFTERNOON OF JUST FAIR
WEATHER CUMULUS THAT LINGERS INTO MONDAY EVENING.
FOR DTW/D21 CONVECTION... NO THUNDERSTORMS THROUGH THE EARLY WEEK
PERIOD.
THRESHOLD PROBABILITIES...
* LOW FOR CEILING AT OR BELOW 200 FT, OR VISIBILITY BELOW 1/2 SM
EARLY IN THE MORNING.
DTX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
DISCUSSION...MR
MARINE.......MR
AVIATION.....BT
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FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT.
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