FXUS63 KAPX 190116 AFDAPN AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 910 PM EDT MON AUG 18 2003 .SHORT TERM...RIDGE AT SURFACE AND ALOFT WILL PROVIDE MAINLY CLEAR CONDITIONS OVERNIGHT...WITH DEWPOINTS RANGING FROM THE MID 50S TO LOWER 60S SUPPORTING PATCHY FOG. CONVECTION WAS NOTED NORTH OF LAKE SUPERIOR...ON PERIPHERY OF UPPER RIDGE...BUT 23Z ANJ GOES SOUNDING AND 0Z APX SOUNDING DEPICTED A DRY/STABLE/CAPPED ENVIRONMENT OVER THE FORECAST AREA. EXPECT AXIS OF MOISTURE/FORCING/INSTABILITY... FAVORED REGION FOR ADDITIONAL CONVECTION...TO REMAIN N/W OF THE FORECAST AREA THROUGH AT LEAST 6 AM...SO ANY CONVECTION THAT ATTEMPTS TO PUSH SE OVERNIGHT WILL WEAKEN AND WILL ONLY SPREAD SOME MID/HIGH CLOUDS INTO THE EASTERN UP TOWARD DAYBREAK. && .PREV DISCUSSION...ISSUED 356 PM AUG 18 LONG TERM...MAIN FORECAST CHALLENGE INVOLVES PRECIP CHANCES ACROSS UPPER MI TUESDAY INTO WED. OTHERWISE...HIGH PRESSURE/UPPER RIDGING AND WARM TEMPS WILL CONTINUE TO DOMINATE WEATHER PATTERN OVER THE STATE THROUGH MID WEEK WITH THE BEST CHANCES FOR SHOWERS/STORMS COMING ON THURSDAY WITH UPPER TROUGH/SFC FRONTAL PASSAGE. TUESDAY AND TUESDAY NIGHT...UPPER RIDGE AXIS NOW EXTENDING INTO WESTERN LAKE SUPERIOR SLIPS EASTWARD ACROSS THE STATE ALONG WITH 591-593 DM HEIGHTS BUILDING OVER THE CWA. WARM FRONT FORECAST TO SET UP FROM NORTHERN MN ACROSS LK SUPERIOR WITH GOOD WARM ADVECTION PATTERN DEVELOPING ACROSS THE STATE AND LOW LEVEL MOISTURE AXIS NOSING INTO UPPER MI AND FAR NORTHERN LOWER MI BY AFTERNOON. 850 MB TEMPS WARM TO +18-20C BY LATE AFTERNOON AND WITH QUITE A BIT OF SUN ANTICIPATED OVER NORTHERN LOWER TEMPS SHOULD EASILY WARM INTO THE UPPER 80S IN MANY AREAS...PARTICULARLY IN THE DOWNSLOPE AREAS OF NW LOWER MI (WITH 10-20 MPH SW WINDS). HOWEVER...BIGGER FORECAST ISSUE INVOLVES PRECIP CHANCES ACROSS UPPER MI VERY LATE TONIGHT AND AGAIN TUESDAY JUST ALONG STRENGTHENING BOUNDARY AND LOW LEVEL MOISTURE AXIS. ETA/MESOETA HAVE BEEN SUGGESTION OVER THE LAST FEW RUNS AT SOME CONVECTION ALONG THE BOUNDARY SLIPPING INTO UPPER MI WHILE GFS KEEPS BULK OF PRECIP FURTHER NORTH INTO ONTARIO. HOWEVER...ATMOSPHERE FAIRLY WELL CAPPED OFF BY MID LEVEL ISOTHERMAL LAYER THAT THE ETA SOLUTIONS WANT TO RAPIDLY COOL LATE TONIGHT AND ON TUESDAY ULTIMATELY ALLOWING CONVECTION TO DEVELOP FURTHER SOUTH INTO UPPER MICHIGAN. GFS SHOWS A MORE GRADUAL COOLING AND FALLING HEIGHTS TUESDAY NIGHT WHICH MAKES MORES SENSE WITH THE UPPER RIDGE FIRMLY IN PLACE. THUS...WILL KEEP FORECAST DRY ACROSS THE ENTIRE CWA TUESDAY AND FINALLY BRING CHANCE OF SHOWERS/STORMS INTO UPPER MI LATE TUESDAY NIGHT. WEDNESDAY AND WEDNESDAY NIGHT...ONE MORE DAY OF WARM WEATHER AS UPPER RIDGE AXIS REMAINS OVER THE OHIO VALLEY. WARM FRONT FORECAST TO LIFT FURTHER N INTO ONTARIO DURING THE DAY LEAVING MUCH OF THE CWA IN THE WARM SECTOR AND STILL FAIRLY CAPPED OFF. ONCE AGAIN ETA SOLUTIONS CONTINUE TO BE VERY AGGRESSIVE WITH CONVECTIVE DEVELOPMENT ACROSS UPPER MI THROUGH THE PERIOD AND EVEN INTO PORTIONS OF FAR NORTHERN LOWER MI. STILL PREFER GFS IDEA OF AGAIN KEEPING MOST (ACTUALLY ALL) PRECIP OUT OF THE CWA UNTIL AT LEAST WED NIGHT. HOWEVER...GIVEN THE UNCERTAINTY INVOLVED WILL NOT HASTILY PULL ALL POPS OUT OF CURRENT FORECAST. INSTEAD WILL TRIM POPS FURTHER AND REMOVE FROM NORTHERN LOWER MI ON WED BUT STILL KEEP CHANCE POPS GOING IN E UPPER MI. THEN...WITH LOWERING HEIGHTS AND APPROACHING SHORT WAVE AND ASSOCIATED SFC SYSTEM MOVING INTO THE WESTERN GREAT LAKES WED NIGHT WILL KEEP CHANCE FOR SHOWERS/THUNDERSTORMS IN E UPPER AND FAR NW LOWER MI WED NIGHT. THURSDAY THROUGH MONDAY...EUROPEAN SOLUTION HAS COME INTO BETTER AGREEMENT WITH GFS/NCEP ENSEMBLE MEAN. SOLUTIONS STILL SUGGEST BETTER PHASING WITH THE NORTHERN STREAM AND A DEEPER/SLOWER/STRONGER SHORTWAVE TROUGH AND ATTENDANT SFC SYSTEM PASSING THROUGH THE GREAT LAKES ON THURSDAY THEN CLEARING THE STATE BY FRIDAY MORNING. EXTENDED ETA ALSO SUPPORTS THIS IDEA ALTHOUGH A FEW HOURS SLOWER WITH THE MAIN TROUGH/FRONTAL PASSAGE. WILL MAINTAIN SCATTERED SHOWERS/THUNDERSTORMS FOR THE ENTIRE CWA THURSDAY AS THIS SYSTEM COMES THROUGH. MAY EVENTUALLY HAVE TO INCLUDE POPS IN THE FORECAST FOR THURSDAY NIGHT/EARLY FRIDAY MORNING...BUT AT THIS POINT MAJORITY OF THE DAY FRIDAY APPEARS DRY. HIGH PRESSURE THEN FORECAST TO BUILD INTO THE GREAT LAKES FRI/SAT WITH DRY CONDITIONS STILL ON TRACK. THEN...OPERATIONAL GFS/EUROPEAN SOLUTIONS STILL DISAGREE SOMEWHAT FOR THE REMAINDER OF THE FORECAST PERIOD. GFS STILL RETAINING TROUGH PATTERN OVER THE NE CONUS AND EASTERN CANADA WHILE UPPER RIDGING/SFC HIGH PRESSURE REMAINS DOMINANT OVER THE MIDWEST AND GREAT LAKES. EUROPEAN SOLUTION STILL REMAINS A LITTLE MORE PROGRESSIVE (BUT AGAIN HAS TRENDED TOWARD GFS) BRINGING ANOTHER SYSTEM THROUGH THE NORTHERN GREAT LAKES SUN/MON. ECMWF CONTINUES TO BE LEAST CONSISTENT AND AN OUTLIER COMPARED REST OF OPERATIONAL MEDIUM RANGE MODELS AND NCEP ENSEMBLE MEAN. STILL INCLINED TO LEAN MORE TOWARD THE OPERATIONAL GFS AND ENSEMBLE MEAN SOLUTIONS BUT NOT AS COOL AS THE GFS/MEX NUMBERS SUGGEST. THUS...WILL KEEP DRY FORECAST GOING RIGHT THROUGH MONDAY AND TEMPS RUNNING HIGHER THAN MEX GUIDANCE. && .APX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ ADAM/ROWLEY