Expires:No;;291372 FXUS63 KDTX 271118 AFDDTX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 618 AM EST FRI NOV 27 2009 .AVIATION... NORTHWEST WINDS WILL REMAIN GUSTY TODAY AS COLDER AIR CONTINUES TO FUNNEL IN. GUSTS WILL REACH 20 TO 25 KNOTS AT TIMES. RESIDUAL POST-FRONTAL MOISTURE WILL REMAIN IN PLACE IN THE FORM OF HIGH MVFR/LOW VFR STRATUS INTO THIS EVENING. STRATUS GRADUALLY CLEARS OVERNIGHT AS SUBSIDENCE INCREASES WITH BUILDING HIGH PRESSURE. THE GUSTINESS WILL ALSO SUBSIDE OVERNIGHT AS MIXING CEASES AND THE PRESSURE GRADIENT SLACKENS. && .PREV DISCUSSION...ISSUED 354 AM EST FRI NOV 27 2009 SHORT TERM...TODAY MAIN SYNOPTIC FORCING LIFTING EAST EARLY THIS MORNING AS THE UPPER LOW TRANSLATES NORTHEAST AND THE ATTENDANT COLD FRONT SWEEPS ACROSS LAKE ERIE. GIVEN THE LACK OF STRONGER UPPER SUPPORT...SEEING PRECIPITATION RAPIDLY DIMINISH IN COVERAGE. MODERATE POST-FRONTAL COLD AIR ADVECTION CREATING SUFFICIENT OVERLAKE INSTABILITY /850 MB TEMPS OF -8C/ TO GENERATE SOME LAKE EFFECT SNOW SHOWER ACTIVITY ACROSS SOUTHWEST LOWER MI. LATEST RADAR IMAGERY/OBSERVATIONS SUGGEST THIS ACTIVITY WILL SHIFT ACROSS AREAS SOUTH OF I-96 THIS MORNING. MINIMAL ACCUMULATION GIVEN THE WARM GROUND AND LIMITED SNOWFALL INTENSITY/COVERAGE...BUT ISOLATED LOCALES COULD SEE A COUPLE HEAVIER BURSTS OVER THE NEXT SEVERAL HOURS. FALLING EQUILIBRIUM LEVELS ACCOMPANYING A GENERAL SHIFT TOWARD THE NORTHWEST IN THE LOW LEVEL WIND FIELD /925-700MB/ WILL CONFINE ANY ADDITIONAL LAKE EFFECT ACTIVITY TO THE WEST BY MIDDAY. ANY LINGERING ISOLATED LIGHT SNOW SHOWERS/FLURRIES GENERATED WITHIN THE RESIDUAL CYCLONIC FLOW WILL END AT THIS POINT. ONLY EXCEPTION MAY BE RIGHT ALONG THE THUMB AS SOME ENHANCED CONVERGENCE ACCOMPANYING THE PASSAGE OF A SECONDARY SURFACE TROUGH MAY PROVE SUFFICIENT IN SUSTAINING SOME SCATTERED SNOW SHOWERS THROUGH THE AFTERNOON. THE DEGREE OF COLD AIR ADVECTION TODAY WILL KEEP THE DIURNAL TEMPERATURE RECOVERY LIMITED. HIGHS WILL STRUGGLE INTO THE 35-40F RANGE. LONG TERM... A MODEST WARMUP IS ON TAP FOR THE WEEKEND AS AN UPPER LEVEL RIDGE BUILDS INTO THE CENTRAL GREAT LAKES. THE WARMUP WILL BE SHORT-LIVED HOWEVER...AS UPPER WAVE OVER BRITISH COLUMBIA AND ENERGY OVER THE GULF OF ALASKA COMBINE AND ARRIVE BY SUNDAY NIGHT WITH THE SURFACE COLD FRONT MOVING THROUGH SOUTHEAST MICHIGAN SUNDAY AFTERNOON/EVENING. SATURDAY MORNING SHOULD START OUT RATHER COLD (MOSTLY UPPER 20S) AS SURFACE RIDGE AXIS WILL BE IN PLACE WITH SKIES AT LEAST PARTLY CLOUDY FOR A PERIOD. LOW LEVEL WARM ADVECTION ON SATURDAY...AS BOTH NAM/GFS SHOWING 925 MB TEMPS WARMING TO AROUND +3 C (ON AVERAGE)...WHICH SUPPORTS MAX TEMPS IN THE MID TO UPPER 40S...AS A DRY WARM FRONT LIFTS NORTH INTO THE AREA. THE COLD FRONT COMING THROUGH DURING SUNDAY IS WORTHY OF CHANCE POPS WITH THE INCREASING LOW LEVEL CONVERGENCE/LIFT...BUT TOUGH CALL ON WHETHER OR NOT THE DEEPER PACIFIC MOISTURE HANGING OUT OVER MEXICO ARRIVES IN TIME. BETTER UPPER LEVEL SUPPORT COMES THROUGH SUNDAY NIGHT...BUT LOW LEVEL MOISTURE AXIS IS PUSHING EAST BY THIS TIME. NONE-THE-LESS...MID LEVEL FGEN COULD PROVE SUFFICIENT FOR PRECIPITATION (RAIN TURNING TO SNOW). POSITIVELY TILTED TROUGH AXIS SWINGING THROUGH THE CENTRAL GREAT LAKES ON MONDAY...COUPLED WITH LAKE ENHANCEMENT AND DIURNAL INSTABILITY (STEEPENING LOW LEVEL LAPSE RATES) WILL BRING WITH IT A CHANCE OF SNOW SHOWERS...AS 850 MB TEMPS PROGGED TO DROP DOWN TO AROUND -9 C (PER 00Z GFS). WITH THIS AMOUNT OF LOW LEVEL COLD AIR...MAXES SHOULD BE STUCK IN THE MID TO UPPER 30S. MARINE... NORTHWEST WINDS WILL GUST UP TO 30 KNOTS AT TIMES TODAY AS COLDER AIR MOVES ACROSS THE WARMER LAKE WATERS. GUSTS WILL DIMINISH THROUGH THE EVENING AS A RIDGE OF HIGH PRESSURE BUILDS INTO THE REGION. IN ADDITION TO THE GUSTY WINDS...A LONG FETCH OVER THE WATER WILL ALLOW WAVES TO BUILD AS HIGH AS 7 FEET OVER THE NEARSHORE WATERS OF LAKE HURON TODAY. WAVES WILL DECREASE INTO SATURDAY AS WAVES SHIFT TOWARD THE WEST AND DECREASE. HIGH PRESSURE RIDGE SLIDES EAST SATURDAY NIGHT AS A LOW PRESSURE SYSTEM LIFTS INTO THE GREAT LAKES. A WEAKER WIND FIELD WILL EXIST IN ADVANCE OF THIS SYSTEM...BUT MAY STRENGTHEN OUT OF THE NORTHWEST AS IT SHIFTS EAST SUNDAY NIGHT INTO MONDAY. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON... SMALL CRAFT ADVISORY...INNER SAGINAW BAY...UNTIL 6 PM FRIDAY. SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT HURON INCLUDING OUTER SAGINAW BAY...UNTIL 10 AM SATURDAY. LAKE ST CLAIR... SMALL CRAFT ADVISORY...UNTIL 6 PM FRIDAY. MI WATERS OF LAKE ERIE... SMALL CRAFT ADVISORY...UNTIL 6 PM FRIDAY. && $$ AVIATION.....MR 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).