231
FXUS63 KDTX 130655
AFDDTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
255 AM EDT SAT SEP 13 2025
KEY MESSAGES
- LOWER-END CHANCE (15-20%) FOR ISOLATED TO SCATTERED SHOWERS
THIS MORNING INTO EARLY AFTERNOON.
- MUCH ABOVE NORMAL HIGHS WITH CONTINUING DRY WEATHER NEXT WEEK.
DISCUSSION
REGIONAL RADAR SHOWS THE ADVERTISED RIDGE RIDING SHORTWAVE CURRENTLY
PUSHING THROUGH WI EARLY THIS MORNING. THIS WAVE IS SET TO DROP
SOUTHEAST OVER FAR SOUTHERN LAKE MICHIGAN DUE TO THE PRESENCE OF AN
ESSENTIALLY STALLED WARM FRONTAL BOUNDARY NEAR THE MISSISSIPPI RIVER
VALLEY. NOCTURNAL LOW LEVEL JET REMAINS CONFINED ALONG THE
MISSISSIPPI LIKEWISE AS A RESULT OF STALLED BOUNDARY LEADING TO
CONVECTION CROSSING INTO LOWER MI BECOMING DETACHED FROM THEIR
PRIMARY FORCING/MOISTURE FEED THIS MORNING. AS A RESULT OF BOTH THE
LLJ POSITIONING AND WAVE TRACK WELL TO OUR SOUTHWEST, BULK OF
SHOWERS/STORMS ARE CONFINED TO THE CHICAGOLAND/NORTHERN IN AREA. ANY
RAIN LOCALLY COMES FROM ONGOING CONVECTION NEAR GREEN BAY, HOWEVER
THIS ACTIVITY WILL DECAY AS IT CROSSES LOWER MI AS IT PUSHES OFF THE
THETA-E GRADIENT THAT IS FIXED ALONG THE WESTERN SHORE OF LAKE
MICHIGAN. ADDITIONALLY FORECAST SOUNDINGS ALSO DEPICT A FAIRLY DRY
LOWEST 10KFT WITH DEWPOINT DEPRESSIONS AROUND 10C EVEN AS SHOWERS
ARRIVE MID TO LATE MORNING. END RESULT IS EXPECTED TO BE A MIX OF
SCATTERED LIGHT SHOWERS-DRIZZLE-VIRGA WITH MINIMAL (IF ANY) EMBEDDED
THUNDER. WHILE RAIN CHANCES ARE LACK LUSTER, ABUNDANT ACCOMPANYING
CLOUD COVER KEEPS HIGH TEMPS A FEW DEGREES COOLER THAN YESTERDAY,
INSTEAD TOPPING OUT IN THE UPPER 70S.
DEEPENING TROUGHING OVER THE WESTERN CONUS LEADS TO A DOWNSTREAM
AMPLIFICATION OF RIDGING ACROSS THE CENTRAL CONUS TO CLOSE OUT THE
WEEKEND. UPPER PATTERN ATTEMPTS TO DEVELOP INTO AN OMEGA BLOCK
HOWEVER TROUGHING OVER THE SOUTHEAST US IS PINCHED OFF BY THE
STRENGTHENING RIDGE INSTEAD LOOKING TO DEVELOP INTO A REX BLOCK
PATTERN BY MONDAY. SETUP GRADUALLY WEAKENS THROUGH THE WEEK THOUGH
HOLDS IN PLACE THROUGH MIDWEEK MAINTAINING AN EXTENDED PERIOD OF DRY
WEATHER AND MUCH ABOVE AVERAGE HIGH TEMPERATURES. CONFIDENCE REMAINS
HIGH IN AFTERNOON TEMPS PUSHING FIRMLY INTO THE 80S SUNDAY-THURSDAY
(OUTSIDE OF LAKESHORE AREAS). OVERNIGHT LOWS HOLD ON THE COOLER SIDE
AS CLEARER NIGHT SKIES AND LIGHT WINDS UNDER HIGH PRESSURE PROMOTE
EFFICIENT RADIATIVE COOLING.
MARINE
AN UPPER LOW DIVES FROM HUDSON BAY TOWARD NEW ENGLAND, CARVING
THROUGH THE EXISTING UPPER LEVEL RIDGE OVER THE PLAINS. ISOLATED
SHOWER POTENTIAL WILL THUS BE POSSIBLE TODAY THROUGH THIS EVENING
UNTIL A COLD FRONT SETTLES ACROSS THE NORTHERN GREAT LAKES
OVERNIGHT. LIGHT SW WINDS PERSIST TODAY UNTIL THE COLD FRONT SHIFTS
WINDS BACK TO THE EAST/NORTHEAST BY SUNDAY MORNING. THE RIDGE THEN
SLIDES EAST THROUGH EARLY NEXT WEEK, COMBINING WITH BUILDING SURFACE
HIGH PRESSURE OVER ONTARIO TO RETURN TO DRY AND QUIET MARINE
CONDITIONS.
PREV DISCUSSION
ISSUED AT 1105 PM EDT FRI SEP 12 2025
AVIATION...
SE MI CONDITIONS BECOME INCREASINGLY INFLUENCED BY A COMBINATION OF
WEATHER COMPONENTS BUT STILL RESULT IN VFR LATE TONIGHT AND
SATURDAY. SURFACE HIGH PRESSURE BUILDING TOWARD THE NEW ENGLAND
STATES REACHES BACK INTO THE GREAT LAKES TO MAINTAIN WARM AND DRY
AIR IN THE LOW LEVELS. LOW PRESSURE DEVELOPING IN THE PLAINS HAS A
WARM FRONT EXTENDING INTO THE MIDWEST BUT MAKES LITTLE EASTWARD
PROGRESS DURING THE EARLY WEEKEND PERIOD. THE SYSTEM PRODUCES
SHOWERS AND THUNDERSTORMS TO THE NORTH AND EAST OF THE WARM FRONT
BUT WHICH ONLY GRAZE NORTHERN AND SW LOWER MI. THIS LEAVES JUST LOW
PROBABILITY FOR A STRAY SHOWER ALONG THE SE MI TERMINAL CORRIDOR,
ALTHOUGH A CONSIDERABLE VIRGA SIGNAL IS EXPECTED ON RADAR.
OTHERWISE, MID AND HIGH CLOUDS INCREASE COVERAGE AND THICKEN DURING
THE DAY AND THEN BREAK UP LATE. WIND IS LIGHT AND LAKE BREEZE
AUGMENTED FROM THE SOUTH INTO SATURDAY EVENING.
FOR DTW/D21 CONVECTION... THUNDERSTORMS ARE NOT ANTICIPATED THROUGH
SATURDAY.
THRESHOLD PROBABILITIES...
* NONE.
DTX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
DISCUSSION...KDK
MARINE.......MV
AVIATION.....BT
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