041
FXUS63 KDTX 310400
AFDDTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1200 AM EDT FRI OCT 31 2025
KEY MESSAGES
- SEASONALLY COOL CONDITIONS WILL PREVAIL THROUGH THE WEEKEND.
BREEZY CONDITIONS WILL ADD A SLIGHT WIND CHILL TO THE COOL
TEMPERATURES TODAY. THERE IS A CHANCE OF RAIN SHOWERS ON SATURDAY.
- WINDY CONDITIONS ARE POSSIBLE ON MONDAY. THERE IS A CHANCE THAT
PEAK GUSTS MAY FALL INTO THE 35 TO 45 MPH RANGE.
AVIATION
VFR SKIES PREVAILS THROUGH THE EARLY MORNING HOURS UNDER A NW WIND
AT LESS THAN 10 KNOTS. WINDS BECOME MORE WNW TODAY AND WILL ACTIVATE
LAKE MICHIGAN CLOUDS WHICH WILL PRODUCE MOSTLY SCT/BKN LOWER VFR
DIURNAL CU MOSTLY BETWEEN 3 TO 6 KFT. LOWER LEVEL FLOW DOES INCREASE
TO NEAR 30 KNOTS AND DAYTIME MIXING SHOULD TAP INTO SOME OF THIS
INCREASED FLOW AND PRODUCE WIND GUSTS BETWEEN 20-25 KNOTS DURING THE
AFTERNOON TOMORROW. FAIR DEGREE OF CLOUD COVERAGE SHOULD HOLD ON
THROUGH THIS EVENING.
FOR DTW/D21 CONVECTION...NO THUNDERSTORM ACTIVITY EXPECTED THROUGH
THE TAF PERIOD.
DTW THRESHOLD PROBABILITIES...
* LOW FOR CEILINGS AT OR BELOW 5000 FEET TONIGHT AND TOMORROW.
PREV DISCUSSION
ISSUED AT 302 PM EDT THU OCT 30 2025
DISCUSSION...
THE BACK EDGE OF THE MID LEVEL DEFORMATION ASSOCIATED WITH THE UPPER
LOW NOW LIFTING UP THE UPPER OHIO VALLEY/CENTRAL APPALACHIANS WILL
CONTINUE TO BRUSH THE EASTERN PORTION OF THE FORECAST AREA LATE THIS
AFTERNOON AND EVENING. AMPLE MID LEVEL DRY AIR HAS EFFECTIVELY KEPT
MOST OF THE FORECAST AREA DRY THIS AFTERNOON. ONGOING COLD AIR
ADVECTION ACROSS LAKE HURON WILL RESULT IN SOME LAKE ENHANCED RAIN
SHOWERS ACROSS THE SOUTHERN BASIN TONIGHT. WHILE THE FLOW WILL BACK
FROM NNE TO NW DURING THE NIGHT, THERE WILL BE A PERIOD THIS EVENING
WHEN SOME OF THIS ENHANCEMENT MAY DRIVE SOME OF THESE SHOWERS INTO
PORT HURON BEFORE THE CONVERGENCE AXIS SHIFTS EAST WITH THE BACKING
FLOW. THE DRY AIR IN THE WAKE OF THE DEPARTING MID LEVEL DEFORMATION
TONIGHT WILL OFFER SOME PERIODS OF CLEARING. NOCTURNAL COOLING WILL
BE LIMITED BY THE GRADIENT FLOW, WARRANTING FORECAST LOWS FROM THE
UPPER 30S TO LOW 40S GIVEN THE DEGREE OF COLD AIR OVERHEAD.
THERE WILL BE A BACKING OF THE LOW LEVEL FLOW TOWARD THE WNW ON
FRIDAY. 850MB TEMPS FORECAST IN THE 0 TO -2C RANGE WILL BE COLD
ENOUGH TO SUPPORT A DECENT MOISTURE FLUX OFF LAKE MICHIGAN. SUBTLE
MID LEVEL RIDGING/CONFLUENCE WILL MAINTAIN A SUBSIDENCE INVERSION
THROUGH THE BULK OF THE DAY. THE INSTABILITY OFF LAKE MICHIGAN WILL
RESULT IN AMPLE CLOUDS DUCTED UNDER THE SUBSIDENCE INVERSION. THE
DEGREE OF MID LEVEL SUBSIDENCE AND DRY AIR WILL LIKELY LIMIT THE
EXTENT OF LAKE EFFECT RAIN SHOWERS (IF ANY) INTO SE MI FRI AFTERNOON.
THE COLD AIR AND CLOUD COVERAGE WILL WARRANT AFTERNOON HIGHS IN THE
LOW 50S. MODEL SOUNDINGS INDICATE 20 TO 25 KNOTS IN THE MIXED LAYER
FRIDAY, WHICH WILL RESULT IN RATHER BRISK CONDITIONS IN THE
AFTERNOON AND EVENING.
THE COMPACT MID LEVEL LOW SHOWN ON LATEST SATELLITE OVER SOUTH
CENTRAL CANADA IS FORECAST TO ROTATE INTO NRN IL AND THE MID
MISSISSIPPI VALLEY REGION SATURDAY. MID LEVEL COOLING WITH THE
APPROACH OF THIS SYSTEM WILL BEGIN RAISING INVERSION HEIGHTS FRI
NIGHT INTO SATURDAY. MODEL SOUNDINGS SUGGEST INVERSION HEIGHTS UP TO
8K FEET WITH DECENT MOISTURE ADVECTING INTO THE AREA BELOW THE
INVERSION. ALTHOUGH THERE HAS BEEN SUBTLE PLACEMENT DIFFERENCES WITH
RESPECT TO THE POSITION/TRACK OF THE UPPER LOW, GROWING AGREEMENT IN
SHOWING A SFC TROUGH AND/OR AREA OF LOW PRESSURE OVER SRN LOWER MI
SUGGESTS DECENT BOUNDARY LAYER CONVERGENCE, ESPECIALLY ON SATURDAY.
THIS WILL WARRANT A CHANCE OF SHOWERS. WHILE IT WILL BE RATHER COOL,
WITH TEMPS IN THE 40S, FREEZING LEVELS WILL REMAIN ABOVE 2K FEET. SO
ANY SHOWERS WILL BE ALL LIQUID. DRY CONDITIONS WILL THEN PREVAIL
SUNDAY AS THE UPPER LOW SINKS SOUTH AND WEAK SUBSIDENCE EXPANDS
ACROSS SE MI. A PROGRESSIVE MID LEVEL WAVE IS THEN FORECAST TO
ADVANCE INTO THE NORTHERN GREAT LAKES MONDAY. GIVEN THE PROJECTED
GRADIENT FLOW, THIS MAY BE SUPPORTIVE OF WINDY CONDITIONS MONDAY.
MARINE...
NORTHEAST FLOW WILL CONTINUE TO PERSIST TODAY AS THE LOW PRESSURE
SYSTEM CURRENTLY OVER THE OHIO RIVER VALLEY SLOWLY MOVES OFF TO THE
NORTHEAST. THE LOW WILL GRADUALLY MOVE TOWARDS THE NEW ENGLAND AREA
TONIGHT AND INTO FRIDAY. THIS WILL ALLOW FOR A TIGHTENING GRADIENT
AND INCREASING WINDS SPEEDS AS NORTH-NORTHEAST WINDS PERSIST. THIS
INCREASING ONSHORE FLOW WILL ALLOW WAVES TO BUILD ACROSS THE
SOUTHERN LAKE HURON BASIN AND BRING SMALL CRAFT ADVISORY CONDITIONS
TO SAGINAW BAY, NEARSHORES OF THE THUMB, AND LAKE ST CLAIR IN
ADDITION TO THE ONGOING HAZARDOUS SMALL CRAFT CONDITIONS ACROSS WEST
LAKE ERIE. TRAJECTORY OF THE LOW WILL TURN WINDS NORTH TO NORTHWEST
BY EARLY FRIDAY AS HAZARDOUS SMALL CRAFT CONDITIONS PERSIST.
DTX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
LAKE HURON...SMALL CRAFT ADVISORY UNTIL 4 AM EDT SATURDAY FOR LHZ421-441>443.
SMALL CRAFT ADVISORY UNTIL 4 PM EDT FRIDAY FOR LHZ422.
LAKE ST CLAIR...SMALL CRAFT ADVISORY UNTIL 10 PM EDT FRIDAY FOR LCZ460.
MICHIGAN WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY UNTIL 10 AM EDT FRIDAY FOR LEZ444.
AVIATION.....AA
DISCUSSION...SC
MARINE.......AA/SS
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