Area Forecast Discussion
Issued by NWS Portland, ME

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KGYX 010028 AFDGYX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAY ME 728 PM EST SAT FEB 28 2015 .SYNOPSIS... HIGH PRESSURE WILL CREST OVER THE REGION THIS EVENING BEFORE SHIFTING OFFSHORE SUNDAY. WEAK LOW PRESSURE CROSSES THE REGION SUNDAY NIGHT...PRODUCING SOME ACCUMULATING SNOW...BEFORE MOVING INTO THE CANADIAN MARITIMES ON MONDAY. HIGH PRESSURE CROSSES THE AREA MONDAY NIGHT AND TUESDAY. LOW PRESSURE WILL MOVE OUT OF THE GREAT LAKES TUESDAY NIGHT AND WILL TRACK NORTHEAST THROUGH THE ST LAWRENCE VALLEY ON WEDNESDAY...BRINGING A ROUND OF MIXED PRECIPITATION TO THE AREA. A COLD FRONT FOLLOWS WEDNESDAY NIGHT. HIGH PRESSURE BUILDS IN FOR THE END OF THE WEEK. && .NEAR TERM /TONIGHT/...
-- Changed Discussion --
730PM UPDATE... HAVE UPDATED OVERNIGHT TEMPERATURE FORECAST TO LOWER FORECAST VALUES BY A FEW DEGREES PRIMARILY IN KNOWN COLD SPOTS AND ACROSS SOUTHWEST NEW HAMPSHIRE. ALTHOUGH WINDS ARE MORE CALM TONIGHT THAN LAST NIGHT... THERE ARE A FEW FACTORS WHICH GIVE REASON TO BELIEVE WE WILL GENERALLY NOT FALL AS LOW TONIGHT AS LAST NIGHT. THE FIRST IS THAT DEWPOINT VALUES ARE 5 TO 10 DEGREES WARMER THIS EVENING THAN YESTERDAY EVENING... THOUGH ADMITTEDLY THESE ARE STILL GENERALLY AROUND OR BELOW ZERO. AT THIS LEVEL OF DRYNESS IT DOES NOT TAKE MUCH TO DIG BENEATH CURRENT DEWPOINTS ONCE COOLING MAXIMIZES ESPECIALLY IN LOCAL VALLEYS. ANOTHER FACTOR IS AFTERNOON TEMPERATURES STARTED OFF WARMER TODAY... MEANING TEMPERATURES HAVE FURTHER TO FALL TONIGHT TO REACH THE SAME LEVELS. ONE FINAL FACTOR IS THE EXPECTED EVENTUAL ARRIVAL OF SOME CIRRUS CLOUDS IN ADVANCE OF THE APPROACHING SYSTEM BY MORNING. THIS COULD LIMIT COOLING JUST BEFORE DAWN BY JUST A BIT. EVEN WITH ALL THESE LIMITATIONS... STILL EXPECT A GOOD CHUNK OF THE AREA TO FALL BELOW ZERO AGAIN. SHOULD MAKE A DECENT RUN AT ZERO IN PORTLAND AS WELL. PRECIPITATION CHANCES WERE UPDATED AS WELL TO FURTHER CLARIFY WHEN PRECIPITATION SHOULD BEGIN AND END ACROSS THE AREA NOT JUST TONIGHT (NO PRECIPITATION TONIGHT) BUT ALSO TOMORROW AND SUNDAY NIGHT WHEN CONFIDENCE IS HIGH THAT COASTAL AREAS WILL SEE SOME MINOR ACCUMULATIONS. ORIGINAL DISCUSSION... THE COLDEST MONTH EVER FOR PORTLAND MAINE WILL BE IN THE BOOKS SHORTLY. LAST NIGHT WAS NEAR RECORD COLD AS WELL...WITH A LOW OF MINUS 7 IN THE FOREST CITY. THIS IS JUST SHY OF THE RECORD LOW OF MINUS 9 SET BACK IN 1950. WITH CLEAR SKIES AND LIGHT WINDS...EXPECT RADIATIONAL COOLING ONCE AGAIN TONIGHT. WILL FORECAST ON THE LOWER END OF THE 12Z MODEL SUITE WITH READINGS APPROACHING ZERO NEAR THE COASTLINE AND BELOW ZERO OVER INTERIOR LOCATIONS. HIGH CLOUDS WILL BE ARRIVING LATER TONIGHT. THIS MAY KEEP READINGS FROM TRULY BOTTOMING OUT AS WAS THE CASE LAST NIGHT.
-- End Changed Discussion --
&& .SHORT TERM /SUNDAY AND SUNDAY NIGHT/...
-- Changed Discussion --
A BROAD AND WEAK AREA OF WARM AIR ADVECTION WILL ALLOW CLOUDS TO THICKEN ON SUNDAY ACROSS THE FORECAST AREA. LIGHT SNOW WILL BREAK OUT SUNDAY NIGHT AS THIS DEVELOPING MOISTURE INTERACTS WITH AN APPROACHING UPPER LEVEL TROUGH. SURFACE LOW PRESSURE WILL FORM IN THE GULF OF MAINE LATE SUNDAY NIGHT...BUT LIKELY TOO LATE TO BRING APPRECIABLE MOISTURE AND SNOWFALL TO THE REGION. NEVERTHELESS...THERE WILL BE TWO TO AS MUCH AS FOUR INCHES OF SNOW OVER SOUTHERNMOST PORTIONS OF THE FORECAST AREA. FURTHER TO THE NORTH...AS HAS BEEN THE CASE MUCH OF THIS WINTER...LESS SNOW WILL FALL. TEMPERATURES WILL BE MODERATING BUT STILL BELOW NORMAL FOR THIS TIME OF THE YEAR.
-- End Changed Discussion --
&& .LONG TERM /MONDAY THROUGH SATURDAY/...
-- Changed Discussion --
A SURFACE LOW EXITS RAPIDLY EAST INTO THE MARITIMES MONDAY WHILE THE UPPER TROF MOVES THROUGH NORTHERN NEW ENGLAND. THE PRECIPITATION WILL QUICKLY COME TO AN END EARLY MONDAY AS DOWNSLOPING NORTHWEST WINDS KICK IN. HIGH PRESSURE BUILDS INTO THE AREA MONDAY NIGHT AND TUESDAY. A FAST MOVING SHORT WAVE WITH ASSOCIATED WARM AIR ADVECTION OVERRUNNING PRECIPITATION WILL MOVE INTO THE AREA TUESDAY NIGHT IN THE FORM OF SNOW. SEVERAL INCHES OF SNOW IS EXPECTED THROUGHOUT THE AREA. BY WEDNESDAY MORNING A BRIEF CHANGEOVER TO A MIX OF RAIN OR SNOW SHOWERS OVER SOUTHERN AREAS IS POSSIBLE BEFORE THE PRECIPITATION ENDS AS LOW AND MID LEVEL TEMPERATURES MAY WARM ABOVE CRITICAL LEVELS. BY LATE WEDNESDAY MORNING A COLD FRONT MOVES ACROSS THE AREA AND THEN OFFSHORE WITH CLEARING BEHIND THE FRONT. HIGH PRESSURE BUILDS INTO THE REGION FOR THURSDAY AND FRIDAY WITH FAIR CONDITIONS. TEMPERATURES WILL GENERALLY REMAIN BELOW NORMAL FOR THE WEEK. USED A BLEND OF THE MODELS FOR TEMPERATURES AND POPS.
-- End Changed Discussion --
&& .AVIATION /00Z SUNDAY THROUGH THURSDAY/...
-- Changed Discussion --
SHORT TERM...VFR CONDITIONS DETERIORATING TO MVFR AND IFR SUNDAY NIGHT IN LIGHT SNOW. LONG TERM... MVFR TO IFR CONDITIONS EARLY MONDAY WILL IMPROVE TO VFR BY LATE MORNING MONDAY AND CONTINUE THROUGH TUESDAY. TUESDAY NIGHT MVFR TO IFR CONDITIONS WILL DEVELOP AND CONTINUE INTO WEDNESDAY MORNING. CONDITIONS WILL RETURN TO VFR BY WEDNESDAY AFTERNOON AND CONTINUE THROUGH FRIDAY.
-- End Changed Discussion --
&& .MARINE...
-- Changed Discussion --
SHORT TERM...NO FLAGS. WINDS BELOW SCA THRESHOLDS AS WELL AS SEAS IN THE SHORT TERM PORTION OF THE FORECAST. LONG TERM...EXPECT TO NEED A STRONG SCA MONDAY AFTERNOON INTO MONDAY NIGHT IN AN INCREASING WEST FLOW...WINDS DIMINISH LATE MONDAY NIGHT. SCA MAY BE NEEDED AGAIN IN A SOUTH TO SOUTHWEST FLOW LATE TUESDAY NIGHT AND WEDNESDAY.
-- End Changed Discussion --
&& .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...NONE. && $$ NEAR TERM UPDATE...KIMBLE SHORT TERM...CANNON LONG TERM...MARINE AVIATION...CANNON/MARINE MARINE...CANNON/MARINE

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.