227
FXUS63 KDTX 161945
AFDDTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
345 PM EDT TUE SEP 16 2025
KEY MESSAGES
- ABOVE NORMAL HIGH TEMPERATURES CONTINUE INTO THE WEEKEND.
- DRY WEATHER THROUGH THE FIRST HALF OF THE WEEKEND.
DISCUSSION
PSEUDO OMEGA BLOCK PATTERN MAINTAINS STAGNANT CONDITIONS AS A 590
DAM (+1.5 SIGMA) 500MB RIDGE REMAINS PARKED OVER THE GREAT LAKES
BETWEEN A COASTAL LOW IN THE MID-ATLANTIC AND A CUTOFF UPPER LOW
OVER WYOMING. SURFACE HIGH PRESSURE CENTERED ACROSS THE GREAT LAKES
INTO THE CANADIAN MARITIMES DOMINATES LOCAL CONDITIONS TONIGHT INTO
WEDNESDAY BEFORE THE COASTAL LOW WEAKENS AND RELEASES UP THE COAST.
DRY AND WARM WEATHER THIS EVENING GIVES WAY TO ANOTHER NIGHT OF
STRONG RADIATIONAL COOLING WITH LOWS DIPPING INTO THE 50S.
PREVAILING EAST TO NORTHEAST FLOW OFF THE LAKES WILL SEND THE MARINE
LAYER INLAND THIS EVENING, SETTING THE STAGE FOR ANOTHER ROUND OF
FOG DEVELOPMENT OVERNIGHT. SOME LOCATIONS MAY SEE A PERIOD OF DENSE
FOG EARLY WEDNESDAY WITH ANY FOG THEN MIXING OUT THROUGH MID MORNING.
PERSISTENCE FORECAST ON WEDNESDAY WITH THE RIDGE MAINTAINING HIGHLY
STABLE CONDITIONS ACROSS THE AREA. ANOTHER DAY OF FULL SUN SENDS
HIGHS BACK INTO THE LOWER TO MID 80S. THE RIDGE THEN BEGINS TO BREAK
DOWN WEDNESDAY NIGHT AS A NORTHERN STREAM WAVES TRACKS ACROSS
ONTARIO. THIS WAVE WILL SEND A BACKDOOR COLD FRONT ACROSS THE AREA
ON THURSDAY. LOW-LEVEL FLOW, ALBEIT WEAK, SHIFTS SOUTHWEST WEDNESDAY
NIGHT AHEAD OF THE FRONT WHICH SHOULD LOWER FOG PROSPECTS THURSDAY
MORNING. A RIDGE OF THETA-E POOLS IN AHEAD OF THE FRONT RESULTING IN
A CORRIDOR OF DESTABILIZATION THURSDAY AFTERNOON - THIS MAY BE
SUFFICIENT FOR A FEW SHOWERS. SUPPORT FOR ASCENT WILL BE WEAK AS THE
UPPER WAVE PASSES OFF TO THE EAST WITH DISPLACED UPPER JET FORCING.
ANY SHOWERS WOULD BE LIGHT AND DO NOTHING TO ALLEVIATE THE
DEVELOPING DROUGHT CONDITIONS. TEMPERATURES IN THE FAR SOUTH MAY
MAKE A RUN AT THE UPPER 80S WHILE AREAS TO THE NORTH HOLD IN THE
LOWER TO MID 80S AS THE FRONT BRINGS IN MORE CLOUDS DURING PEAK
HEATING.
THE FRONT SETTLES SOUTH OF THE AREA ON FRIDAY AS HIGH PRESSURE
SPREADS ACROSS NORTHERN ONTARIO. SLIGHTLY COOLER AIR ARRIVES BUT
HIGHS ARE STILL PROGGED TO HOLD ON THE WARM SIDE OF NORMAL IN THE
70S AND LOWER 80S. THE NEXT MID-LEVEL RIDGE CRESTS OVER THE AREA
LATE IN THE WEEK AS TROUGHING SLOWLY MEANDERS ACROSS THE NORTHERN
PLAINS. AFTER THE AXIS PASSES OVERHEAD AROUND FRIDAY, A HIGHER
DEGREE OF WARMTH SPREADS BACK INTO THE AREA WITH HIGH TEMPS BACK
INTO THE 80S LIKELY THIS WEEKEND. THE TROUGH MIGRATES INTO THE
REGION MONDAY INTO TUESDAY PROVIDING THE NEXT OPPORTUNITY FOR RAIN
SHOWERS.
MARINE
A RIDGE OF HIGH PRESSURE CONTINUES TO BRING AN EXTENDED PERIOD OF
DRY WEATHER AND LIGHTER WINDS TO THE GREAT LAKES THROUGH MOST OF THE
WEEK. WINDS CONTINUE TO FAVOR A LIGHT EASTERLY COMPONENT, WITH SOME
GRADUAL BACKING TO THE SOUTH AND THEN NORTH LATE TOMORROW INTO
WEDNESDAY. A SECONDARY HIGH PRESSURE SYSTEM IS EXPECTED TO DROP FROM
THE CENTRAL CANADIAN PROVINCES INTO ONTARIO AND QUEBEC LATE THIS
WEEK, WHICH WILL STRENGTHEN THE PRESSURE GRADIENT OVER THE GREAT
LAKES REGION. THIS WILL AGAIN REINFORCE NORTHEASTERLY TO EAST FLOW
AND WILL BRING SOME ELEVATED WIND SPEEDS FOR LAKE HURON WHERE
SUSTAINED WINDS NEARING 20 KNOTS AND GUST POTENTIAL TO 25 KNOTS WILL
BE POSSIBLE.
PREV DISCUSSION
ISSUED AT 135 PM EDT TUE SEP 16 2025
AVIATION...
STANDARD HIGH PRESSURE CONFIGURATION TODAY PROMOTES ENE WINDS AND
LIMITED CLOUDS. VFR CONDITIONS PREVAIL THROUGH THE REST OF TODAY AND
MOST OF TONIGHT WITH WINDS TRENDING TOWARD CALM. EXPECT POCKETS OF
RENEWED FOG DEVELOPMENT LATE TONIGHT INTO WEDNESDAY MORNING WHICH
COULD PRODUCE PERIODS OF MVFR TO IFR VISIBILITY REDUCTIONS. MIGHT
ALSO SEE SOME LOW STATUS DUCT IN OFF THE CENTRAL LAKES WHICH MAY
LEAD TO IFR (OR LIFR) RESTRICTIONS. OTHERWISE, THE DRY PATTERN
PERSISTS ON WEDNESDAY WITH SLIGHTLY MORE COHESIVE FLOW ORGANIZING
OUT OF THE NORTH AND FEW-SCT HIGH-BASED CUMULUS.
FOR DTW/D21 CONVECTION...NO THUNDERSTORMS EXPECTED THROUGH THE TAF
PERIOD.
THRESHOLD PROBABILITIES...
* LOW FOR CEILINGS AT OR BELOW 200 FEET BETWEEN 09Z AND 13Z
WEDNESDAY.
DTX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
DISCUSSION...TF
MARINE.......AM
AVIATION.....KGK
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