FXUS61 KGYX 191923 AFDGYX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAY ME 323 PM EDT FRI MAR 19 2010 .SYNOPSIS... LOW PRESSURE OVER QUEBEC WILL TRACK EAST AND PULL A TRAILING COLD FRONT ACROSS THE AREA LATE SATURDAY. AN UNSEASONABLY MILD SOUTHERLY FLOW WILL PRECEDE THE FRONT. THE COLD FRONT WILL STALL SOUTH OF THE AREA SUNDAY AND SUNDAY NIGHT...AS LIGHT RAIN AND SNOW DEVELOPS. MUCH COOLER TEMPERATURES AND STEADY PRECIPITATION IS EXPECTED MONDAY INTO TUESDAY AS LOW PRESSURE PASSES SOUTH OF THE AREA. HIGH PRESSURE WILL BUILD IN BEHIND THE SYSTEM FOR THE MIDDLE AND END OF NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... GOES IMAGERY INDICATED A FEW CLOUDS ACROSS NORTHERN SECTIONS AS OF 18Z... WITH CLEAR SKIES FOR THE REMAINDER OF THE AREA. A 1003 MILLIBAR LOW WAS OVER QUEBEC WITH WARM FRONT EXTENDING SOUTHEAST INTO NORTHERN SECTIONS OF THE AREA. WHILE MANY INTERIOR SECTIONS HAD WARMED INTO THE 60S...MUCH OF THE COAST WAS LIMITED TO 50S IN THE ONSHORE FLOW. I CONFINED CLOUDS AND SLIGHT CHANCE POPS TO FAR NORTHERN AREAS OVERNIGHT...WHERE A FEW RAIN SHOWERS UPSTREAM ALONG THE QUEBEC/ONTARIO BORDER AT PRESENT COULD BRUSH THE AREA THROUGH 12Z. A BLEND OF MET/MAV TEMPERATURES WERE USED TO INITIALIZE OVERNIGHT MIN TEMPERATURES. && .SHORT TERM /SATURDAY/... ON SATURDAY...THE FRONT SINKS INTO MOUNTAIN SECTIONS BY MIDDAY AND SHOULD EXIT THE COAST AROUND DUSK. MUCH OF THE CLOUDS ARE ALONG AND BEHIND THE FRONT AND THERE SHOULD BE A GOOD DEAL OF SUNSHINE AHEAD OF THE FRONT TO BOOST TEMPERATURES WELL INTO THE 60S...WITH A FEW LOWER 70S POSSIBLE OVER SOUTHEAST NEW HAMPSHIRE AND SOUTHWEST INTERIOR MAINE. EVEN THE SOUTHWEST MAINE COAST AND SEACOAST NEW HAMPSHIRE SHOULD SEE THE WARMTH...AS SOUTHERLY FLOW INTI ALLY ALONG THE COAST BECOMES SOUTHWEST WITH APPROACH OF FRONT AND SEABREEZE BECOMES A LAND BREEZE...ALLOWING THE COAST TO WARM WELL INTO THE 60S. GIVEN THE LACK OF MOISTURE WITH THE FRONT...I CONFINED SLIGHT CHANCE POPS TO MOUNTAINS SECTIONS ON SATURDAY. A MET/MAV BLEND WERE USED FOR MAX TEMPERATURES THEN ADJUSTED FROM THERE. && .LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/... CONDITIONS DETERIORATE THROUGH THE EARLY PORTION OF THE PERIOD... GET BETTER FOR A WHILE THE MIDDLE OF NEXT WEEK...AND POSSIBLY A RETURN TO A MORE WINTRY PATTERN LATE NEXT WEEK. THE SURFACE COLD FRONT SHOULD CROSS THE REGION WITH LITTLE SENSIBLE WEATHER SATURDAY EVENING. THE MID LEVEL SHORT WAVE THAT PUSHES THE FRONT ALONG SHEARS OUT TO THE NORTHEAST...AND THE FRONT WILL SLOW AS IT SAGS SOUTH LATE SATURDAY NIGHT. WITH THE AIRMASS IN TRANSITIONS... FAVORED THE SLIGHTLY WARMER GFS MOS NUMBERS FOR LOWS. THE CLOSED MID LEVEL SYSTEM OVER THE LOWER MISSISSIPPI VALLEY THIS AFTERNOON WILL MOVE EAST THROUGH SUNDAY NIGHT. AHEAD OF THE CLOSED SYSTEM...WARM AIR ADVECTION BEGINS SUNDAY MORNING. THE AIRMASS SHOULD BE DRY ENOUGH TO HOLD PRECIPITATION OFF AT FIRST...AS THE WARM AIR ADVECTION MOISTENS THE COLUMN. AS THE BEST WARM AIR ADVECTION GETS GOING BETWEEN 1800 UTC AND 0600 UTC MONDAY...PRECIPITATION WILL OVERSPREAD THE TERRAIN. THE HIGHEST CHANCE OF PRECIPITATION WILL BE IN THESE AREAS. THE COLUMN SHOULD ALSO BE COLD ENOUGH TO SUPPORT SNOW IN THE HIGHER TERRAIN. EVEN PORTIONS OF SOUTHEAST NEW HAMPSHIRE AND SOUTHWEST MAINE COULD SEE A MIX AT THE START AS THE COLUMN IS DRY (WHICH EQUALS COLD THIS TIME OF YEAR). HIGHS SUNDAY WERE BASED ON A BLEND OF MOS NUMBERS...AS THE GFS MOS APPEARED TO BE TOO COLD. THE INITIAL WARM AIR ADVECTION PEAKS SUNDAY NIGHT INTO MONDAY MORNING. AGAIN...THE COLUMN SHOOULD BE COLD ENOUGH ACROSS THE MOUNTAINS FOR MOST OF THE PRECIPITATION TO FALL AS SNOW. HOWEVER... AS TIME WEARS ON SUNDAY NIGHT AND MONDAY MORNING...THE EVENT MAY BECOME MORE OF AN ELEVATION DEPENDENT EVENT WITH REGARD TO PRECIPITATION TYPE. RIGHT NOW...IT APPEARS AS THOUGH A FEW INCHES OF SNOW IS POSSIBLE IN THE HIGHER TERRAIN. AS THE AIRMASS SATURATES...NOT EXPECTING MUCH TEMPERATURE CHANGE SUNDAY NIGHT...AND LOWS WERE BASED MORE ON THE WARMER GFS MOS NUMBERS. THE FORECAST FOR MONDAY NIGHT AND TUESDAY WILL HINGE TO A LARGE DEGREE ON THE POSITION OF THE MID LEVEL CLOSED LOW AND ITS SURFACE SYSTEM. THE TREND THE PAST FEW MODEL CYCLES HAS BEEN TO BRING BOTH SYSTEM FURTHER SOUTH. WHILE THERE WILL STILL BE A FRONTAL BOUNDARY TO OVERRUN DURING THIS PERIOD...IT APPEARS AS THOUGH THE BEST FRONTOGENETIC FORCING WOULD REMAIN SOUTH OF THE REGION. SO FOR NOW NOW EXPECTING HEAVY PRECIPITATION DURING THIS PERIOD... THOUGH THERE ARE A FEW MEMBERS OF THE MID RANGE ENSEMBLE THAT SUPPORT THE POSSIBILITY. AS THE MID LEVEL SYSTEM LIFTS OUT...THE FLOW BECOMES ZONAL FOR THE MIDDLE OF NEXT WEEK. AFTER THIS...THERE ARE STRONG INDICATIONS THAT THE NORTHERN STREAM WILL BECOME ACTIVE AGAIN LATE NEXT WEEK. THIS COULD MEAN A RETURN TO COLDER TEMPERATURES FOR NEXT WEEKEND. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... SHORT TERM...VFR CONDITIONS THROUGH SATURDAY. LONG TERM...VFR CONDITIONS ARE EXPECTED THROUGH THE COLD FRONTAL PASSAGE SATURDAY NIGHT...AS THE LOW LEVELS REMAINS DRY. COULD BE A FEW GUSTS TO NEAR 25 KNOTS AT KPWM AND KPSM WITH THE PASSAGE SATURDAY EVENING. AFTER THIS...THE COLD FRONT WILL COME TO REST SOUTH OF THE AREA SUNDAY INTO MONDAY. OVERRUNNING OF THE BOUNDARY WILL RESULT IN LOWERING CEILINGS SUNDAY...BUT CONDITIONS SHOULD REMAIN VFR. A BROAD OVERRUNNING PATTERN CONTINUES SUNDAY NIGHT AND MONDAY...AND A PROLONGED PERIOD OF IFR CONDITIONS ARE EXPECTED SUNDAY NIGHT INTO TUESDAY MORNING. HIGH PRESSURE BUILDING IN TUESDAY AND WEDNESDAY SHOULD BRING A RETURN TO VFR CONDITIONS. && .MARINE... SHORT TERM...NO FLAGS THROUGH SATURDAY. LONG TERM...THE COLD FRONT CROSSES THE WATERS SATURDAY EVENING. WHILE THE LOW LEVEL PUSH BEHIND THE FRONT IS PROBABLY NOT STRONG ENOUGH IN THE 1200 UTC MODEL SUITE...THE NORTHEAST FLOW SHOULD REMAIN BELOW 25 KNOTS. AFTER THE PUSH IN FINISHED...THE FLOW SHOULD VEER TO THE SOUTHEAST AS THE FRONT COMES TO REST SOUTH OF THE WATERS. WILL HAVE TO WATCH THE TREND OF THE SURFACE LOW ASSOCIATED WITH THE CLOSED LOW IN THE MID LEVEL FLOW ACROSS THE MID ATLANTIC. RIGHT NOW...IT APPEARS AS THOUGH THE CLOSEST APPROACH WILL BE MONDAY NIGHT AND TUESDAY. DURING THAT TIME...WINDS SHOULD REACH SMALL CRAFT LEVELS. THERE IS A LOW PROBABILITY THAT THE SOUTHERN OCEAN WATERS COULD REACH GALE...BUT THIS WOULD REQUIRE A SLIGHTLY CLOSER SURFACE LOW APPROACH TO TIGHTEN THE GRADIENT ENOUGH. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...NONE. && $$