000 FXUS63 KDTX 032331 AFDDTX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 731 PM EDT FRI JUL 3 2009 .AVIATION... CLEARING TREND WILL CONTINUE OVER THE NEXT COUPLE HOURS WITH THE LOSS OF DIURNAL HEATING. WIND FIELD WILL WEAKEN AS WELL WITH WEAK HIGH PRESSURE BUILDING IN OVERNIGHT. VFR CONDITIONS WILL HOLD THROUGH THE REMAINDER OF THE NIGHT WITH HIGHER CLOUDS BEGINNING TO FILTER IN. CLOUDS WILL THICKEN AND LOWER INTO SATURDAY AS A LOW PRESSURE SYSTEM TRACKS THROUGH THE OHIO VALLEY AND DIURNAL HEATING ONCE AGAIN ENHANCES THE STRATO-CU DEVELOPMENT. CEILINGS WILL REMAIN AOA 5K FT DURING THIS TIME. LGT/VARIABLE WINDS EARLY WILL SHIFT TOWARD THE SOUTHWEST LATE IN THE DAY AS THE SURFACE RIDGE SLIDES EAST. && .PREV DISCUSSION...ISSUED 326 PM EDT FRI JUL 3 2009 SHORT TERM...TONIGHT LAST GASP FROM THE PERSISTENT UPPER LOW COMPLEX IS UNDERWAY WITH YET ANOTHER CLOUD FILLED AFTERNOON. SIGNS OF THE END OF THIS EPISODE ARE ON THE DISTANT WESTERN HORIZON WHERE CLOUDS ARE BECOMING MORE SCATTERED. TODAY/S CLOUD COVER HAS BEEN AIDED BY THE BRIEF INFLUX OF SUN THIS MORNING IN COMBINATION WITH THERMAL TROUGHING IN THE 925-850MB LAYER. AS THIS FEATURE EXITS STAGE RIGHT...EXPECT THE CLOUD FIELD TO THIN AND THEN NEARLY DISSIPATE POST-DUSK. HIGH CLOUDS POISED OVER THE MID/UPPER MISSISSIPPI VALLEY WILL ADVANCE EAST OVER THE AREA OVERNIGHT. OTHERWISE...TEMPERATURES WILL SLIP BACK INTO THE LOWER-MID 50S TONIGHT AS WINDS SUBSIDE IN RESPONSE TO BUILDING HIGH PRESSURE AT THE SURFACE. LONG TERM... 115+ KNOT UPPER LEVEL JET DIVING SOUTH THROUGH THE WESTERN GREAT LAKES...WITH THE UPPER LEVEL RIDGE AXIS JUST TO THE WEST QUICKLY FLATTENING...AS SHORTWAVES RIDING ALONG THE SOUTHERN CANADIAN BORDER TRACK SOUTHEAST THROUGH THE NORTHERN GREAT LAKES REGION TOMORROW AND SUNDAY. WITH THE UPPER LEVEL RIDGE FLATTENING/FOLDING OVER AND LOW LEVEL JET VEERING OVER MISSOURI TONIGHT...LOOKING AT THE WARM FRONTAL/CONVECTIVE ACTIVITY DEVELOPING OVER THE MIDWEST TONIGHT TO TRACK SOUTH OF THE CWA DURING SATURDAY...BUT WILL MAINTAIN THE LOW CHANCE POPS TOWARD THE OHIO BORDER JUST IN CASE THE SUBTLE SHORTWAVE/JET STREAK MOVING THROUGH THE CENTRAL PLAINS IS A BIT STRONGER AND 700 MB FGEN ZONE SHIFTS SLIGHTLY NORTH. WITH AT LEAST SOME MID/HIGH CLOUDS AROUND (ESPECIALLY SOUTH)...TEMPERATURES WILL PROBABLY HOLD IN THE MID 70S...AND JUST USED THE MAV GUIDANCE...AS CU RULES ALSO SUGGEST SOME LOW CLOUDS AS WELL. THE TREND FOR THE SECOND HALF OF THE WEEKEND IS FOR A BIT STRONGER UPPER WAVE/FARTHER WEST WITH THE 500 MB LOW...WHICH INCREASES THE CHANCE FOR SOME INSTABILITY SHOWERS BY SUNDAY EVENING ASSOCIATED WITH THE MID TROPOSPHERIC COLD POOL (-20 C AT 500 MB SWINGING THROUGH LAKE HURON). DO FAVOR THE SLOWER NAM/CANADIAN TIMING OVER THE GFS...AND WILL CARRY ISOLATED SHOWERS DURING THE SUNDAY EVENING/NIGHT PERIOD...AS SHOWALTER INDEX DOES DROP DOWN TO AROUND ZERO. BANKING ON THE SKINNY CAPE/SUB -20 C EQL TO KEEP THUNDERSTORM MENTION OUT. BASED ON THE EVEN SLOWER/MORE AMPLIFIED SOLUTION OF THE 12Z EUROPEAN...INCLUDED AN ISOLATED SHOWER MENTION ACROSS THE NORTH HALF OF CWA INTO MONDAY AS WELL. LOOKING AT A CONTINUED RELATIVELY COOL (70S) START TO THE WORK WEEK WITHIN THE NORTHWEST CONFLUENT FLOW OF DEPARTING UPPER LEVEL LOW/TROUGH...BUT A WARMING TREND IS THEN EXPECTED AS HEIGHTS BEGIN TO BUILD IN RESPONSE TO THE UPPER LEVEL RIDGE ANCHORED OVER THE SOUTHWEST CONUS EXTENDING NORTHEAST INTO THE SOUTHERN GREAT LAKES BY WEEKS END...PUSHING TEMPERATURES WELL INTO THE 80S. WILL LEAVE A SLIGHT CHANCE/LOW CHANCE OF SHOWERS/THUNDERSTORMS DURING THE MIDWEEK PERIOD AS THE WARM FRONT LIFTS NORTH...BUT BEST FORCING LOOKS TO BE NORTH AND WEST OF THE CWA. MARINE... NORTHWEST WINDS WILL SUBSIDE THROUGH THE EVENING AS PERSISTENT LOW PRESSURE EXITS TO THE EAST OF THE REGION. WINDS WILL BRIEFLY SWING TO SOUTHWEST ON SATURDAY IN ADVANCE OF A WEAK FRONTAL BOUNDARY ONLY TO RETURN TO NORTHWESTERLY IN IT/S WAKE. WINDS AND WAVES ARE EXPECTED TO REMAIN BELOW ADVISORY CRITERIA. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ AVIATION.....MR SHORT TERM...MANN LONG TERM....SF MARINE.......MANN YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).