000 FXUS63 KAPX 231642 AFDAPX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 1142 AM EST MON NOV 23 2009 .SYNOPSIS.../ISSUED AT 429 AM/ HIGH PRESSURE TO OUR EAST WILL MAINTAIN MILD AND QUIET WEATHER THROUGH TUESDAY. LOW PRESSURE WILL START TO ORGANIZE IN THE CENTRAL PLAINS TONIGHT...AND THEN SLOWLY MOVE TOWARD NORTHERN MICHIGAN THRU THANKSGIVING DAY. THIS SYSTEM WILL BRING COOLER AND WETTER WEATHER BY WEDNESDAY AND THURSDAY...THOUGH LITTLE IN THE WAY OF SNOW IS EXPECTED. JZ && .SHORT TERM.../ISSUED AT 1035 AM/...TODAY DEPARTING HIGH PRESSURE WILL REMAIN IN CONTROL OF NRN MICHIGAN/S WEATHER THROUGH TODAY BEFORE GIVING WAY TO MORE UNSETTLE WEATHER OVER THE NEXT FEW DAYS. PERSISTENT WITH THE LAST FEW MORNINGS...LOW STRATUS/PATCHY FOG ONCE AGAIN WIDESPREAD ACROSS NRN MICHIGAN. SHALLOW TO BE SURE...LESS THAN 1000 FEET IN DEPTH PER 12Z APX SOUNDING. DIFFERENCE TODAY VERSUS THE LAST FEW DAYS RESTS IN WARM ADVECTION HIGH CLOUD COVER WHICH HAS INCHED INTO THE STATE ON THE BACKSIDE OF THE SLOWLY DEPARTING HIGH PRESSURE SYSTEM...AS WELL AS A SLIGHTLY STRONGER INVERSION SITTING AT 900 MB. COMBINED...WILL BE A BIT MORE DIFFICULT TO THIN/ERODE THE LOW STRATUS LAYER TODAY VERSUS THE PREVIOUS FEW DAYS. HEATING/MIXING MAY ULTIMATELY THIN OUT THE LOW LAYER TO SOME EXTENT. BUT HAVING SERIOUS DOUBTS ABOUT THAT AND PLAN FOR NOW IS TO NUDGE THE FORECAST TOWARD THE CLOUDIER SIDE OF THINGS...TODAY AS WELL AS THROUGH TONIGHT. THIS WILL OF COURSE HAVE OBVIOUS IMPLICATIONS ON TODAY/S MAX TEMPS AND WILL TWEAK EXPECTED HIGHS DOWNWARD ACCORDINGLY. ADAM && .LONG TERM.../ISSUED AT 429 AM/...TONIGHT AND BEYOND HIGH PRESSURE AND DRY AIR OVER THE ERN LAKES TO REMAIN IN CONTROL MONDAY NIGHT THROUGH TUESDAY AFTERNOON...WHILE A SRN PLAINS STORM SYSTEM LIFTS INTO THE CENTRAL PLAINS AND AN UPPER TROUGH DIGS INTO THE CENTRAL PLAINS. MODEL SOUNDINGS AND MSTR PROGS SHOW 850/500MB RH LINGERING AROUND 40 PCT THRU 00Z WED. WILL CONTINUE A DRY FCST OVER THE NRN LAKES MONDAY NIGHT AND TUESDAY. LOW TEMPS TUESDAY IN THE MID 30S AS AIRMASS REMAINS UNCHANGED...AFTN TEMPS IN THE 45 TO 50 DEGREE RANGE AS SOME UPPER CLOUDS INCREASE OVER THE STATE IN ADVANCE OF APPROACHING SFC AND UPPER LEVELS FEATURES. TUESDAY NIGHT AND WEDNESDAY...CENTRAL PLAINS STORM SYSTEM LIFTS NORTH INTO THE UPPER MIDWEST TUESDAY NIGHT BEFORE LIFTING NORTH INTO THE STRAITS AND ERN UPPER MICHIGAN WEDNESDAY. MODEL SOUNDINGS AND MSTR PROGS SHOWING MSTR INCREASE OVER THE NRN LAKES THROUGH THE PD AS THE STORM SYSTEM LIFTS INTO NRN MI. 850/500MB RH WILL INCREASE TO AROUND 80 PCT WHILE 850MB DEW PTS INCREASE FROM -8C TUESDAY TO 0C BY 12Z WEDNESDAY. MODEL SOUNDINGS SHOWING ABV FREEZING LAYER FROM THE SFC TO ARND 4000 FT TUESDAY NIGHT...EXTENDING TO 5500 FEET WEDNESDAY. THEREFORE PCPN ALL IN THE FORM OF RAIN THROUGH THIS PERIOD. LOW TEMPS IN THE 30S TUESDAY NIGHT WITH HIGHS IN THE MID 40S WEDNESDAY. WEDNESDAY NIGHT AND THURSDAY...STORM SYSTEM OVER THE NRN LAKES LINGERS BUT BECOMES STRETCHED OUT ACROSS THE STATE...AS THE LOW TRIES TO LIFT NORTH TWD HUDSON BAY. THE DIGGING 500MB TROUGH DROPS SOUTH OF THE STATE AND MOVES EAST OVER THE OHIO VALLEY. MODEL SOUNDINGS SHOWING COLDEST 850MB AIR TO LINGER WEST OF THE REGION AND SWEEP SOUTH ACROSS THE OHIO VALLEY. OVR NRN MI...850MB TEMPS DROP FROM AROUND 0C/+1C WEDNESDAY NIGHT TO -3C THURSDAY. MODEL SOUNDINGS SHOWING ABOVE FREEZING LAYER EXTENDING FROM THE SFC THRU 4K FT WEDNESDAY NIGHT DROPPING TO AROUND 2500 FEET BY 00Z FRIDAY. WILL TREND TWD ALL RAIN EVENT WEDNESDAY NIGHT AND MUCH OF THURSDAY AFTERNOON. WILL MENTION A MIX RAIN/SNOW TO ALL SNOW THURSDAY NIGHT...WHEN VERTICAL TEMP PROFILE ON SOUNDINGS SHOW ABV FREEZING LAYER DROPPING UNDER 1500 FEET. HIGHS THURSDAY GENERALLY AROUND 40 MOST LOCATIONS. SWR && .MARINE.../ISSUED AT 429 AM/ WINDS AND WAVES EXPECTED TO REMAIN BELOW SCA CRITERIA TODAY THROUGH TUESDAY...WITH WINDS PRIMARILY FROM THE SOUTHEAST. STRONGEST WINDS AND HIGHEST WAVES TODAY EXPECTED IN THE STRAITS AND BTWN THE BRIDGE AND DETOUR...HOWEVER EXPECTED TO REMAIN BELOW SCA. FOG THIS MORNING TO DIMINISH AS SFC HIGH PRESSURE AND DRY AIR LINGER ACROSS THE ERN LAKES. CLEARING SLOWEST OVER THE ERN LAKES ONCE AGAIN TODAY WITH OVERALL SE FLOW ACROSS THE REGION AND LATE NOV SUN ANGLE. NEXT CHANCE OF RAIN OVER THE NRN LAKES NEARSHORE WATERS...WILL BE TUESDAY NIGHT AND WEDNESDAY AS A PLAINS STORM SYSTEM LIFTS NORTH INTO NRN MI. SWR && .AVIATION.../ISSUED AT 1142 AM/...VALID FOR 18Z TAFS WILL TREND CONSIDERABLY MORE PESSIMISTIC WITH THE FORECASTS... PARTICULARLY IN REGARD TO CLOUD COVER. LOW STRATUS (IFR) ONCE AGAIN DEVELOPED OVERNIGHT AND PERSISTS THIS MORNING. BUT UNLIKE PREVIOUS DAYS...INCREASING WARM ADVECTION/STRENGTHENING INVERSION AND INCREASING HIGH CLOUD COVER LIMITING HEATING...WILL CONSPIRE TO KEEP STRATUS LAYER INTACT THROUGH TODAY AND POSSIBLY THROUGH TONIGHT. THINNING/LIFTING OF THE LOW CLOUDS NOT COMPLETELY OUT OF THE QUESTION...BUT NOT BANKING ON IT. THUS HIGH IFR/LOW MVFR ANTICIPATED THROUGH THE PERIOD. ADAM && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. LH...NONE. LS...NONE. && $$