864 FXUS61 KCAR 171925 AFDCAR AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CARIBOU ME 220 PM EST TUE FEB 17 2004 .SYNOPSIS...HIGH PRESSURE WILL MOVE TO THE EAST OF THE REGION TONIGHT BUT IT WILL MAINTAIN CONTROL OF THE WEATHER THROUGH WEDNESDAY. LOW PRESSURE DEVELOPING OFF THE SOUTHEAST COAST IS FORECAST TO INTENSIFY AS IT MOVES NORTHEAST AND THEN TO THE SOUTH OF NOVA SCOTIA ON THURSDAY. SOME SNOW FROM THIS SYSTEM IS LIKELY TO CLIP THE EASTERN PORTION OF THE DOWNEAST COAST LATE WEDNESDAY NIGHT AND THURSDAY. HIGH PRESSURE WILL RETURN BRIEFLY FOR FRIDAY BUT ANOTHER LOW WILL MOVE EAST FROM THE MIDWEST AND THROUGH THE GULF OF MAINE ON SUNDAY. DISCUSSION... SHORT RANGE: (TONIGHT-FRI ) MODELS IN GOOD AGREEMENT IN SYNOPTIC EVOLUTION THROUGH THE SHORT RANGE, BUT THERE ARE IMPORTANT DIFFERENCES IN THE EXACT TRACK OF A MAJOR STORM THURSDAY. TONIGHT...HIGH PRESSURE WILL RETREAT EAST OF MAINE WITH WEAK SFC RIDGING REMAINING. ALOFT A WEAK TROUGH OF LOW PRESSURE WILL APPROACH THE REGION LATE. SATELLITE IMAGES INDICATE MID AND UPPER LEVEL CLOUDS WITH THIS FEATURE. EXPECT THESE CLOUDS TO OVERSPREAD THE CWA TONIGHT. THESE CLOUDS ALONG WITH A SW WIND WILL PREVENT TEMPERATURES FROM FALLING TOO MUCH. WED-THU...ATTENTION WILL FOCUS ON LOW PRESSURE DEVELOPING ALONG THE MID ATLANTIC COAST. MODELS MOVE THIS SYSTEM NE...THE BIG QUESTION IS HOW CLOSE TO THE COAST. THE ETA IS FURTHEST WEST AND HITS EXTREME EASTERN WASHINGTON COUNTY WITH OVER AN INCH OF QPF. THE GFS AND GEM ARE FURTHER EAST BUT STILL BRING 3 TO 5 TENTHS OF QPF TO EASTERN WASHINGTON COUNTY. FOR NOW WILL LEAN TOWARDS THE GFS/GEM SOLUTION...BUT WILL UP THE QPF A BIT. THIS STORM WILL NEED TO BE WATCHED CLOSELY AS A SLIGHT DEVIATION FURTHER WEST COULD RESULT IN SIGNIFICANT SNOW. HAVE ISSUED AN SPS TO DRAW ATTENTION TO THIS STORM AND ITS POSSIBLE IMPACTS. THE STORM MOVES EAST OF THE REGION THURSDAY NIGHT WITH WEAK RIDGING EXPECTED FRIDAY. LONG RANGE: (FRI NIGHT-TUE) MEDIUM RANGE MODELS IN DECENT AGREEMENT FOR NEXT STORM SYSTEM SAT/SUN WITH DETAILS BECOMING MORE COMPLICATED. 12Z GFS HAS TRENDED MUCH WARMER WITH THIS SYSTEM WHICH SEEMS REASONABLE WITH A RATHER PROLONGED PERIOD OF WARM ADVECTION AHEAD OF THE SYSTEM. WARM ADVECTION CLOUDS WILL SPREAD ACROSS THE REGION FRI NIGHT AND THEN SNOW INITIALLY ON SAT WITH THE HIGHEST POPS OVER THE DOWNEAST. GFS THICKNESS FIELDS/VERTICAL TEMPERATURE PROFILES INDICATE THAT ENOUGH WARM AIR WILL WORK NORTHWARD SAT NIGHT TO CHANGE THE SNOW TO RAIN OVER THE COASTAL WATERS AND LEAST PRODUCE A MIXTURE OF RAIN/SNOW INLAND DOWNEAST. PRECIPITATION LIKELY TO CHANGE BACK TO SNOW DOWNEAST BEFORE ENDING LATE SUN. FOR MON/TUE TIME-FRAME PREFER TO USE A MODEL ENSEMBLE APPROACH WITH GFS SOMEWHAT OF AN OUTLIER DEVELOPING A LONG WAVE TROUGH EASTERN CANADA. 12Z GFS TRENDING MORE TOWARD GEM/ECWMF WITH UPPER RIDGE BEGINNING TO BUILD E TOWARD NEW ENGLAND, SO WILL TRY TO END PRECIPITATION SUN NIGHT WITH DRY CONDITIONS RETURNING FOR MON/TUE. NO LARGE DEVIATIONS FROM GFS MOS...EXCEPT FOR SAT NIGHT SUN. EXPECT TEMPERATURE MAY SLOWLY RISE SAT NIGHT ESPECIALLY DOWNEAST SO WILL INDICATE THAT IN GRIDS. WENT WITH HIGHER TEMPERATURES FOR SUN BASED ON 12Z GFS RUN. MARINE...WINDS AND SEAS WILL BEGIN TO INCREASE WEDNESDAY NIGHT. BOTH ETA/GEM BRING THE OCEAN STORM CLOSER TO THE COASTAL WATERS THAN GFS.HAVE INCREASED WINDS TO 30 TO 35 KT FOR THURSDAY AND THURSDAY NIGHT. WILL STAY CLOSE TO WNA WAVE WATCH III FOR SEAS BUT THIS MIGHT HAVE TO BE INCREASED ALONG WITH WINDS IF THE SYSTEM MOVES CLOSER. AVIATION...VFR CONDITIONS EXPECTED AT ALL TAF SITES NEXT 24 HOURS. .CAR...NONE. SHORT TERM: LULOFS LONG TERM: GABRIC AVIATION: NORTON