000 FXUS63 KDTX 051759 AFDDTX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 159 PM EDT FRI SEP 5 2008 .AVIATION... OVERCAST STRATOCU DECK OVER THE AREA IS SLOWLY STARTING TO RECEDE ACROSS NORTHWEST LOWER MICHIGAN. THIS CLEARING LINE WILL GRADUALLY APPROACH THE NORTHERN TAF SITES BY THIS EVENING ALLOWING SKIES TO SCATTER OUT FOR TONIGHT. FURTHER SOUTH...THE CLOUD DECK IS EXPECTED TO LINGER OVERNIGHT AT THE DETROIT AIRPORTS WITH WEAK SURFACE TROUGHING EXTENDING FROM LAKE HURON TO LAKE ERIE. ADDITIONAL LOW LEVEL STRATUS WILL LIKELY DEVELOP OFF SOUTHERN LAKE HURON AND ADVECT SOUTH TOWARDS DET/DTW. HAVE INCLUDED MVFR CEILINGS AND VISIBILITIES FOR THE DETROIT AIRPORTS FROM TONIGHT INTO SATURDAY MORNING WHEN CLOUDS START TO LIFT AND SCATTER OUT. && .PREV DISCUSSION...ISSUED 331 AM EDT FRI SEP 5 2008 SHORT TERM...TODAY SFC LOW PRESSURE (REMNANTS OF GUSTAV) CONTINUING TO ACCELERATE NORTHEAST EARLY THIS MORNING...JUST NOW ENTERING SOUTHWEST LOWER MI. BROAD AREA OF RAINFALL EXTENDS NORTH-NORTHEAST OF THE CENTER OF CIRCULATION...WITH THE EASTERN EDGES WORKING THROUGH THE SAGINAW VALLEY. PRECIPITATION REMAINING MUCH MORE SCATTERED SOUTHEAST OF THIS PRIMARY MOISTURE AXIS. HEAVIER SHOWERS HAVE GENERATED A FEW GUSTS OVER 30 MPH...BUT NO EVIDENCE OF THUNDER AS INSTABILITY IS NOW VIRTUALLY NIL. LIGHT RAIN/DRIZZLE WILL LINGER INTO THE MID MORNING HOURS BEFORE THE SFC LOW AND ATTENDANT COLD FRONT LIFT THROUGH AND THE DEEPER MOISTURE BECOMES SHUNTED EAST OF THE REGION. PLENTY OF RESIDUAL POST-FRONTAL LOW LEVEL MOISTURE WILL MAINTAIN A BKN-OVC STRATUS DECK THROUGH THE DAY. THE LIMITED INSOLATION COMBINED WITH WEAK COLD AIR ADVECTION WILL HELP KEEP THE DIURNAL TEMPERATURE RECOVERY IN CHECK TODAY...DESPITE THE MILD MORNING START (TEMPERATURES STILL IN THE LOWER 70S ACROSS THE SOUTH AS OF 08Z). BASED ON PROGGED 850 MB TEMPS AND LOW LEVEL THICKNESS TRENDS...THIS LEAVES HIGHS GENERALLY IN THE 70S AREAWIDE...POSSIBLY HOLDING IN THE 60S ACROSS THE NORTHERN THUMB. LONG TERM... FEW IF ANY CHANGES MADE TO THE PREVIOUS FORECAST. ENERGETIC FLOW OVER THE GULF OF ALASKA WITH A SERIES OF SHORTWAVES DIVING SOUTHEAST THROUGH WESTERN CANADA AND INTO THE LONGWAVE TROUGH ESTABLISHED OVER THE CENTRAL CONUS. PROBLEMATIC TIMING FORECAST AS RAPID FIRE SHORTWAVES TRAVERSE THROUGH THE GREAT LAKES REGION...WITH QUESTIONS CONCERNING THE INDIVIDUAL STRENGTH OF EACH WAVE/DAMPENING EFFECTS...AS UPSTREAM STRONGER WAVES BUCKLE THE FLOW. WITH A DRYING OUT PROCESS TONIGHT INTO SATURDAY (850-700 MB THETA-E MINIMUM MOVING IN)...WILL LEAVE THE FORECAST DRY. ALTHOUGH...THERE IS SOME CONCERN WITH THE WEAKENING SHORTWAVE TRACKING THROUGH THE WESTERN GREAT LAKES. THE 00Z NAM/CANADIAN GLOBAL BOTH SHOWING A MORE SUBSTANTIAL UPPER WAVE/SHORTWAVE TROUGH MOVING THROUGH ON SUNDAY...WORTHY OF CHANCE POPS. A GOOD BAROCLINIC ZONE SHOULD BE SITUATED OVER THE SOUTHERN GREAT LAKES REGION...WHICH LOOKS TO ALLOW FOR THE RAPID SPIN-UP OF A SURFACE LOW/WAVE EARLY NEXT AS THE MAIN UPPER LEVEL TROUGH MOVES OVER THE AREA...SUPPORTING A CONTINUED CHANCE OF RAIN. LOW LEVEL COLD ADVECTION BEHIND THIS SYSTEM CERTAINLY MAY HOLD MAXES IN THE 60S ON TUESDAY WITH 850 MB TEMPS FALLING INTO THE MID SINGLE NUMBERS. OTHERWISE...LOOKING FOR NORMAL/NEAR NORMAL MAXES IN THE 70S SATURDAY-MONDAY...WITH MINS IN THE 50S. MARINE... STRONG LOW PRESSURE SYSTEM WILL QUICKLY MOVE ACROSS CENTRAL LAKE HURON THIS MORNING. THIS WILL MAINTAIN SMALL CRAFT CONDITIONS FOR WINDS AND WAVES...AS WINDS REMAIN GUSTY ON EITHER SIDE OF THE LOW THIS MORNING...THEN SHIFT TOWARD THE NORTHWEST FOR THE AFTERNOON. CONDITIONS WILL BECOME MORE FAVORABLE FOR BOATING BY TONIGHT AND INTO THE WEEKEND AS HIGH PRESSURE SETTLES ACROSS THE OHIO VALLEY. LAKES. A COLD FRONT WILL MOVE THROUGH EARLY NEXT WEEK...POTENTIALLY CREATING MORE UNSTABLE CONDITIONS AS MUCH COOLER AIR FILTERS ACROSS THE WARMER LAKE WATERS. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON... SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT HURON INCLUDING SAGINAW BAY...UNTIL 4 PM FRIDAY. LAKE ST CLAIR... SMALL CRAFT ADVISORY...UNTIL 4 PM FRIDAY. MI WATERS OF LAKE ERIE... SMALL CRAFT ADVISORY...UNTIL 4 PM FRIDAY. && $$ AVIATION.....KEC SHORT TERM...MR LONG TERM....SF MARINE.......MR YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).