888  
FXUS63 KDTX 281041  
AFDDTX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI  
641 AM EDT SUN AUG 28 2016  
 
   
AVIATION
 
 
FOG AND LOW CLOUDS EARLY THIS MORNING WILL LIFT AND DISSIPATE,  
TRANSITIONING TO LOW VFR CU DECK THIS AFTERNOON. AN ISOLATED  
THUNDERSTORM IS POSSIBLE, BEST CHANCE ACROSS SOUTHERN TAF SITES, BUT  
COVERAGE TOO LOW TO INCLUDE IN TAFS. DRIER AIR WILL WORK INTO  
SOUTHEAST MICHIGAN LATE IN THE DAY AND THIS EVENING, WHICH WILL HELP  
LIMIT FOG POTENTIAL, BUT WOULD STILL EXPECT SOME LIGHT MVFR FOG.  
 
FOR DTW...  
 
LIGHT SOUTHWEST WINDS BECOMING WESTERLY, MAINLY BELOW 10 KNOTS  
DURING THE DAY. ISOLATED SHOWERS AND THUNDERSTORM ACTIVITY LOOKS TO  
BE PREDOMINATELY NEAR THE OHIO BORDER THIS AFTERNOON.  
 
//DTW THRESHOLD PROBABILITIES...  
 
* MEDIUM FOR CEILING AOB 5000 FEET TODAY.  
 
* LOW FOR CEILING/VISIBILITY BELOW 200 FT OR 1/2 SM LATE TONIGHT.  
 

 
   
PREV DISCUSSION
 
 
ISSUED AT 303 AM EDT SUN AUG 28 2016  
 
DISCUSSION...  
 
A CORRIDOR OF FAST LOW TO MID LEVEL WEST-SOUTHWEST FLOW HAS RESIDED  
ACROSS LOWER MI DURING THE OVERNIGHT PERIOD. MOIST ISENTROPIC ASCENT  
ALONG THE NOSE OF THE LOW LEVEL JET, TIED TO THE ENTRANCE REGION OF  
AN UPPER JET MAX WITHIN THE BASE OF THE UPPER TROUGH NOW ROTATING  
ACROSS WRN LAKE SUPERIOR, RESULTED IN THE DEVELOPMENT OF A CLUSTER  
OF THUNDERSTORMS OVER CENTRAL LOWER MI OVERNIGHT. THIS LOCALIZED  
FORCING WILL CONTINUE ON A NORTHEAST TRACK ACROSS SAGINAW BAY DURING  
THE PRE DAWN HOURS.  
 
THE UPPER TROUGH WILL CONTINUE ON AN EASTWARD TRACK ACROSS LAKE  
SUPERIOR/NRN ONTARIO TODAY. THE ENTRANCE REGION OF THE UPPER JET  
WILL LINGER OVER SRN MI THROUGHOUT THE DAY AND WILL FORCE A NARROW  
REGION OF MID LEVEL FRONTOGENESIS. THIS FRONTAL FORCING, NOW  
EXTENDING FROM SRN LAKE MI INTO CNTL LAKE HURON, WILL GRADUALLY  
SLIDE SOUTH ACROSS THE FORECAST AREA DURING THE COURSE OF THE DAY.  
MID LEVEL DRY AIR AND SUBSIDENCE WILL FOLLOW IN ITS WAKE. THIS  
FORCING WILL GENERALLY PROVIDE A SLIGHT CHANCE OF MORNING CONVECTION  
ACROSS THE NORTHERN HALF OF THE FORECAST AREA. THE CHANCES BEING  
LIMITED SUBSTANTIALLY BE WEAK AVAILABLE INSTABILITY. DAYTIME  
DESTABILIZATION WILL PROVIDE A LITTLE BETTER CHANCE FOR SOME  
AFTERNOON CONVECTION AS THE FORCING SLIDES SOUTH OF A KPHN TO KOWZ  
LINE THIS AFTERNOON. MEANWHILE, DAYTIME HEATING WILL ERODE MORNING  
FOG AND LOW CLOUDS AND WILL SUPPORT AFTERNOON HIGHS INTO THE 80S.  
THE DEEPENING DAYTIME MIXED LAYER AND LOW-MID LEVEL DRY AIR  
ADVECTION WILL RESULT IN A SLIGHT DROP IN SFC DEWPOINTS ACROSS THE  
SAGINAW VALLEY EARLY THIS AFTERNOON, SPREADING SOUTH INTO METRO  
DETROIT DURING THE EVENING.  
 
MID LEVEL CONFLUENT FLOW AND BUILDING HEIGHTS FOLLOWING THE  
DEPARTURE OF THE MID LEVEL WAVE TO THE EAST OF LAKE SUPERIOR TONIGHT  
WILL FORCE SFC HIGH PRESSURE TO EXPAND INTO THE AREA FROM THE WEST.  
NORTH-NORTHEAST LOW LEVEL FLOW ACROSS LAKE HURON INTO SE MI WILL  
OCCUR IN ADVANCE OF THIS HIGH. THE LATEST NAM, HRRR, AND ARW ALL  
SUGGEST MARINE STRATUS WILL HAVE A DIFFICULT TIME ERODING TODAY.  
THIS MOISTURE WILL THEN ADVECT ACROSS SE MI TONIGHT WITH THE ONSHORE  
FLOW. FOG AND/OR LOW STRATUS WILL RESULT AND WILL LIKELY PERSIST  
THROUGH THE MON MORNING RUSH HOUR. ONCE THE LOW LEVEL MOISTURE MIXES  
OUT LAT MON MORNING, A WARM AND DRY AFTERNOON CAN BE EXPECTED ON AS  
THE SFC HIGH CONTINUES TO INFLUENCE THE REGION.  
 
MODEL TRENDS HAVE BEEN A LITTLE SLOWER BRINGING A SFC COLD FRONT  
INTO THE AREA FROM THE NORTH NEXT WEEK. THE LATEST MODEL SUITE DO  
NOT BRING THE SFC COLD FRONT ACROSS SE MI UNTIL TUES NIGHT. THE  
FRONT WILL BE DRIVEN SOUTH BY A MID LEVEL WAVE FORECAST TO TRACK  
FROM NRN MANITOBA INTO NRN QUEBEC. LIMITED FORCING AND INSTABILITY  
ALONG THE FRONT AS IT TRACKS ACROSS THE AREA WILL SUPPORT VERY LOW  
CHANCES FOR CONVECTION. THE PASSAGE OF THE FRONT WILL HOWEVER MARK A  
SUBSTANTIAL AIRMASS CHANGE. LONG WAVE TROUGH AMPLIFICATION ACROSS  
ERN CANADA DURING THE LATTER HALF OF THE WEEK WILL DRIVE MUCH COOLER  
AIR INTO THE GREAT LAKES (850MB TEMPS FORECAST TO DROP INTO THE  
SINGLE DIGITS BY THURSDAY). THUS COOL TEMPS (HIGHS IN THE 70S AND  
LOWS IN THE 50S) CAN BE EXPECTED THE LATTER HALF OF THE WORK WEEK.  
 
MARINE...  
WESTERLY WINDS TODAY WILL BE PREDOMINANTLY IN THE 5 TO 15 KNOT RANGE,  
EXCEPT ACROSS NORTHERN LAKE HURON WILL SUSTAINED WINDS LOOK TO BE  
CLOSER TO 20 KNOTS. WINDS WILL SHIFT TO THE NORTH TONIGHT AS HIGH  
PRESSURE CONTINUES TO BUILD IN, ALLOWING FOR LIGHT AND VARIABLE  
WINDS ON MONDAY. MODEST SOUTHWEST WINDS EXPECTED ON TUESDAY  
AHEAD OF A WEAK COLD FRONT TRACKING THROUGH.  
 

 
   
DTX WATCHES/WARNINGS/ADVISORIES
 
 
MI...NONE.  
LAKE HURON...NONE.  
LAKE ST CLAIR...NONE.  
MICHIGAN WATERS OF LAKE ERIE...NONE.  

 
 

 
 
AVIATION.....SF  
DISCUSSION...SC  
MARINE.......SF  
 
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE  
AT WWW.WEATHER.GOV/DETROIT.  
 
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