000 FXUS63 KDTX 240855 AFDDTX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 355 AM EST TUE NOV 24 2009 .SHORT TERM...TODAY NOT TOO MUCH TO SAY IN THE SHORT TERM FORECAST AGAIN AS CONDITIONS REMAIN LARGELY UNCHANGED. LOW STRATUS/PATCHY FOG WILL ERODE SOMEWHAT TODAY...BUT STILL EXPECT MOSTLY CLOUDY SKIES THROUGHOUT THE DAY. ANY SIGNIFICANT BREAKS IN THE LOWER CLOUDS WILL BE MASKED BY THICKENING CIRRUS IF NOTHING ELSE. HIGH TEMPERATURES WILL ONCE AGAIN CLIMB TO AROUND 50 DEGREES ACROSS THE AREA WITH LIGHT SOUTH/SOUTHEAST WINDS. && .LONG TERM...TONIGHT THROUGH NEXT MONDAY THE UPPER LEVEL LOW OVER THE CENTRAL PLAINS SHOULD BEGIN TO OPEN AS IT REJOINS THE MAIN NORTHERN STREAM OF THE JET AND EJECTS TOWARD MI. THIS LOW WILL BRING THE START TO AN EXTENDED PERIOD OF UNSETTLED WEATHER TONIGHT. AS THIS UPPER LOW TRACKS ACROSS SE MI THE ASSOCIATED SURFACE LOW WILL TRACK A BIT MORE NORTH ACROSS NORTHERN LOWER MI. MOISTURE ADVECTION BEHIND THE WARM FRONT WILL ENHANCE A NARROW BUT RICH THETA-E RIDGE THAT WILL PUSH THROUGH THE AREA BETWEEN 00Z-12Z WEDNESDAY AND SHOULD BE SUFFICIENT TO PRODUCE RAIN. MODEL SOUNDINGS ARE SHOWING SOME FAIRLY DECENT INSTABILITY AND MID LEVEL LAPSE RATES ON WEDNESDAY AFTERNOON WITH THE PASSING COLD FRONT WHICH MAY BE ENOUGH TO ALLOW SOME RAIN SHOWERS TO DEVELOP. ON THE HEALS OF THE CENTRAL PLAINS WAVE IS A FAST MOVING SHORTWAVE DIVING SOUTHEAST OUT OF CANADA. MODELS ARE IN GOOD AGREEMENT THAT THIS WAVE WILL DIG DOWN INTO THE OHIO VALLEY ON THURSDAY. THIS WAVE WILL REINFORCE THE LONGWAVE TROUGH AND BRING DOWN A VERY COLD CANADIAN AIRMASS WITH IT...ECMWF -6C/GFS -7C/NAM -5C...FOR THE LATTER HALF OF THE WEEK. SE MI WILL MOST LIKELY STRUGGLE TO REACH 40F ON FRIDAY AND WILL ONLY INCREASE SLIGHTLY FOR THE WEEKEND INTO THE LOW 40S. THIS WAVE WILL ALSO ACT TO STALL/BACK BUILD THE SURFACE LOW KEEPING IT OVER MI TIL FRIDAY EVENING. THIS COLD AIRMASS WILL LEAD TO A POSSIBLE CHANGE OVER FROM ALL RAIN TO A RAIN/SNOW MIX MIDDAY THURSDAY AND THROUGH FRIDAY AS THE DEFORMATION AXIS SWEEPS THROUGH THE AREA. THE LAKES WILL ACT TO ENHANCE ANY PRECIP ON THE BACK SIDE OF THIS LOW. THERE LOOKS TO BE A POSSIBLE BREAK IN THE ACTION EARLY ON THURSDAY AS THE SECOND WAVE CATCHES AND BEGINS TO MERGE WITH THE INITIAL WAVE AND BEFORE THE DEFORMATION AXIS SWEEPS THROUGH THE AREA. CONTINUED CHANCE POPS FOR THAT TIME PERIOD ALTHOUGH MAY NEED TO BE ADJUSTED DOWN THE ROAD AS MERGER DRAWS NEARER AND BECOMES BETTER HANDLED BY MODELS. WEAK UPPER LEVEL RIDGING MOVES INTO THE AREA TO START THE WEEKEND BEHIND THE EXITING LOWS...BRINGING US A BREAK FROM THE PRECIP BUT NOT MUCH IN THE WAY OF TEMPERATURE RECOVERY. HIGHS WILL ONLY TOP OUT IN THE LOW/MID 40S FOR SATURDAY/SUNDAY. THE RIDGE LOOKS TO BE SHORT LIVED AS THE NEXT STORM SYSTEM WILL BRING A COLD FRONT THROUGH THE AREA ON SUNDAY. && .MARINE... SOUTHEASTERLY WINDS WILL CONTINUE AS HIGH PRESSURE EXITS TO THE EAST COAST AND A LOW PRESSURE SYSTEM SLOWLY APPROACHES FROM THE PLAINS. WINDS WILL INCREASE TO 15 TO 20 KNOTS ON THE OPEN WATERS OF LAKE HURON BY WEDNESDAY AS THIS AREA OF LOW PRESSURE APPROACHES...WITH THE POSSIBILITY FOR SMALL CRAFT ADVISORIES ON WEDNESDAY NIGHT AS WINDS VEER AROUND TO THE WEST. WAVES SHOULD INCREASE TO 3 TO 5 FEET ON THE SAGINAW BAY ON WEDNESDAY NIGHT BUT WILL HOPEFULLY BE ABLE TO HOLD OFF ON ANY SMALL CRAFT ADVISORIES ELSEWHERE UNTIL THE PASSAGE OF A STRONGER COLD FRONT ON FRIDAY. THIS SYSTEM WILL BRING COOLER TEMPERATURES WITH THE POSSIBILITY FOR A MIX OF RAIN AND SNOW SHOWERS BY THURSDAY. && .PREV DISCUSSION...ISSUED 1159 PM EST MON NOV 23 2009 AVIATION... ABUNDANT LOW LEVEL MOISTURE WILL REMAIN FIRMLY ENTRENCHED ACROSS SOUTHEAST LOWER MI AGAIN TONIGHT. THIS IS TRANSLATING PRIMARILY INTO A STRATUS DECK AND LOOKS TO BE THE DOMINANT CONDITION FOR AT LEAST THE EARLY PART OF THE NIGHT /IFR TO BRIEF LIFR PTK SOUTH... MVFR-IFR TO THE NORTH/. POCKETS OF CLEARING AND THE PERSISTENT MOIST SOUTHEAST FLOW OFF LAKES HURON/ERIE MAY YET ALLOW FOR BETTER FOG FORMATION...ALBEIT LESS WIDESPREAD/DENSE. THE POTENTIAL REMAINS FOR A PERIOD OF LIFR VISIBILITY BETWEEN 10-14Z WITH THE BEST OPPORTUNITY AT MBS. OTHERWISE MAINLY IFR CONDITIONS AT ALL TERMINALS INTO THE MID MORNING HOURS. GRADUAL IMPROVEMENT THROUGH LATE MORNING/EARLY AFTERNOON...ALTHOUGH MVFR CLOUD COVER WILL PERSIST INTO THE EVENING. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...DG LONG TERM....DRK MARINE.......DG AVIATION.....MR YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).