089
FXUS63 KDTX 311621
AFDDTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1221 PM EDT FRI OCT 31 2025
KEY MESSAGES
- SEASONALLY COOL CONDITIONS WILL PREVAIL THROUGH THE WEEKEND.
BREEZY CONDITIONS TODAY WILL ADD A SLIGHT WIND CHILL TO THE COOL
TEMPERATURES. THERE IS A CHANCE OF SCATTERED 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. CHANCES FOR RAIN
FAVORED TOWARDS NORTHERN HALF OF THE REGION.
AVIATION
WNW WINDS WILL REMAIN GUSTY (20 TO 25 KNOTS) THROUGH THE AFTERNOON
GIVEN THE STEEP LOW LEVEL LAPSE RATES. THE ONSET OF NIGHT TIME
COOLING WILL ALLOW A DROP IN THE GUSTINESS OF THE WINDS THIS
EVENING. WINDS WILL FURTHER DIMINISH OVERNIGHT AS THE GRADIENT
DECREASES AND WEAK SURFACE TROUGHING MOVES INTO SE MI. THE AIRMASS
IS COLD ENOUGH TO GENERATE AMPLE CLOUDS OFF THE LAKES. ALTHOUGH SOME
MVFR BASED CLOUDS HAVE DEVELOPED THIS MORNING, DAYTIME BOUNDARY
LAYER GROWTH WILL SUPPORT PREDOMINATELY VFR BASED CLOUDS THROUGH THE
REST OF THE DAY. THE LOW LEVEL INVERSION IS FORECAST TO LIFT TONIGHT
DUE TO SOME MID LEVEL COLD AIR ADVECTION, WHICH WILL AT LEAST ALLOW
MORE VARIABILITY IN CEILING HEIGHTS IF NOT SIGNIFICANTLY ERODING THE
LOWER (4K) FOOT DECK. THE PERSISTENCE OF A HIGHER BASED INVERSION
(AROUND 7K FEET) SUGGESTS SOME DEGREE OF A MID CLOUD DECK HOLDING
THROUGH THE NIGHT.
FOR DTW/D21 CONVECTION...NO THUNDERSTORM ACTIVITY EXPECTED THROUGH
THE TAF PERIOD.
DTW THRESHOLD PROBABILITIES...
* MODERATE IN CEILINGS AOB 5000 FEET THIS AFTERNOON AND TONIGHT.
HIGH ON SATURDAY.
PREV DISCUSSION
ISSUED AT 321 AM EDT FRI OCT 31 2025
DISCUSSION...
SE MI RESIDES BETWEEN THE DEPARTING MID-UPPER TROUGH NOW OVER THE ST
LAWRENCE RIVER AND ANOTHER MID-UPPER TROUGH DIGGING SOUTH OUT OF THE
CANADIAN PRAIRIE OVER THE UPPER MIDWEST. POSITIONING OF THESE WAVES
RESULTS IN INDUCED LOW AMPLITUDE MID-LEVEL RIDGING PIVOTING OVER
SOUTHERN LOWER MI THROUGH THE DAY. WHILE THE COOLER TRAILING AIRMASS
(850MB TEMPS -1 TO -2C) SUPPORTS A SUFFICIENT DELTA T FOR LAKE
EFFECT DEVELOPMENT, ACTIVE SUBSIDENCE UNDER THE RIDGE LEADS TO
INVERSION HEIGHTS BEING CAPPED AROUND 5KFT GREATLY LIMITING THE
DEGREE SHOWERS OFF LAKE MICHIGAN ARE ABLE TO PENETRATE THIS FAR
EAST. A FEW ISOLATED SHOWERS OR POCKETS OF DRIZZLE CAN'T BE RULED
OUT, HOWEVER THE VAST MAJORITY OF THE AREA REMAINS DRY TODAY.
DESPITE RAIN CHANCES BEING MINIMAL, LAKE MOISTURE TRAPPED BELOW THE
INVERSION LEADS TO A ROBUST STRATOCU DECK FOR MOST OF THE DAY WHICH
IN COMBINATION WITH WEAK CAA, LIKELY KEEPS HIGHS CONFINED TO THE LOW
50S. DEEPENING SURFACE LOW OVER NORTHEASTERN US LARGELY MAINTAINS A
STEADY STATE GRADIENT OVER SE MI TODAY ALLOWING FOR ANOTHER BREEZY
DAY WITH PEAK GUSTS NEAR 20-25MPH.
AFOREMENTIONED UPPER MIDWEST TROUGH EVENTUALLY DIVES SOUTH ROUGHLY
FOLLOWING THE MISSISSIPPI RIVER SATURDAY SHUNTING THE LOCAL MID-
LEVEL RIDGE TO THE EASTERN GREAT LAKES. 00Z MODEL RUNS CONTINUE TO
FOLLOW EARLIER TRENDS IN TRACKING THE ASSOCIATED SURFACE CIRCULATION
OVER FAR SOUTHERN LOWER MI DAYTIME SATURDAY. OVERALL SYNOPTIC
FORCING IS QUITE WEAK AS THE MAIN PV RESERVOIR PASSES OVER NORTHERN
IL WITH A POSITIVELY TILTED TROUGH AXIS OVERHEAD. THIS SHOULD BE
ENOUGH FOR AT LEAST WIDELY SCATTERED SHOWERS, FOCUSED LATE MORNING
THRU EARLY EVENING, HOWEVER WILL BE HARD PRESSED TO SEE COVERAGE
MUCH MORE THAN SCATTERED GIVEN THIS FORCING FIELD. P-TYPE STILL
EXPECTED TO BE ALL RAIN AS FREEZING LEVELS HOLD 2-3KFT AGL.
ACCOMPANYING CAA ONLY DROPS 850MB TEMPS BY A DEGREE OR SO LEADING TO
SIMILAR SEASONABLY COOL HIGHS THOUGH WITH A FEW MORE AREAS FAILING
TO BREAK OUT OF THE UPPER 40S INSTEAD.
ACTIVE PATTERN CONTINUES FOR EARLY NEXT WEEK AS AN ENERGETIC (160+
KT) JET DRIVES A PACIFIC NORTHWEST SHORTWAVE ACROSS THE NORTHERN
CONUS/CENTRAL CANADA. CURRENTLY, BULK OF THIS WAVE IS PROGGED TO
PASS WELL NORTH OF THE CENTRAL GREAT LAKES WITH THE LOCAL AREA
RESIDING UNDER ITS SOUTHERNMOST FRINGE. ATTENDANT SURFACE COLD FRONT
IS DRIVEN ACROSS THE REGION DAYTIME MONDAY OFFERING THE NEXT RAIN
CHANCES (GREATER POTENTIAL FURTHER NORTH YOU ARE). STRONG
GRADIENT/COLUMN WIND FIELD LOOKS TO SUPPORT A WINDY DAY MONDAY WITH
LOCAL PROBABILISTIC GUIDANCE ADVERTISING ~50-60% CHANCES TO SEE
GUSTS REACH 35-40MPH.
MARINE...
THE LOW PRESSURE SYSTEM THE IS BRINGING INCREASED WINDS TO THE GREAT
LAKES WILL CONTINUE TO GRADUALLY MOVE TOWARDS THE NEW ENGLAND
REGION. AS THE LOW SHIFTS OFF TO THE EAST, NORTH TO NORTHWEST FLOW
WILL PERSIST THROUGH THE DAY ON FRIDAY. THIS INCREASING ONSHORE FLOW
WILL ALLOW WAVES TO BUILD ACROSS THE SOUTHERN LAKE HURON BASIN AND
BRINGS A CONTINUATION TO 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. THE
PRESSURE GRADIENT BEGINS TO SLACKEN OVERNIGHT FRIDAY AND INTO
SATURDAY, ALLOWING NORTHWESTERLY WINDS TO DIMINISH.
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 THIS AFTERNOON FOR LHZ422.
LAKE ST CLAIR...SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR LCZ460.
MICHIGAN WATERS OF LAKE ERIE...NONE.
AVIATION.....SC
DISCUSSION...KDK
MARINE.......SS/AA
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