Area Forecast Discussion
Issued by NWS Portland, ME

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
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
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KGYX 280131 AFDGYX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAY ME 931 PM EDT FRI MAR 27 2015 .SYNOPSIS... THE INTERACTION BETWEEN A WEAK SURFACE TROUGH...AND LOW PRESSURE PASSING OFFSHORE...WILL PRODUCE CLOUDS AND A FEW SNOW SHOWERS ACROSS THE AREA TONIGHT INTO SATURDAY. SHOWERS WIND DOWN SUNDAY AS HIGH PRESSURE BUILDS IN FROM THE WEST. A PRE FRONTAL TROUGH CROSSES THE REGION MONDAY FOLLOWED QUICKLY BY A COLD FRONT. LOW PRESSURE CROSSES OVER SOUTHERN NEW ENGLAND LATE TUESDAY INTO WEDNESDAY. MORE SIGNIFICANT PRECIPITATION IS POSSIBLE LATE NEXT WEEK. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
-- Changed Discussion --
UPDATE... HAVE UPDATED GRIDS BASED ON CURRENT CONDITIONS AND NEW SET OF MESOSCALE MODELS. VERY INTERESTING CASE TONIGHT AS A BAND OF SNOW SHOWERS WILL LIKELY SET UP LATE AT NIGHT AND SATURDAY OVER EASTERN NEW HAMPSHIRE AND ADJACENT AREAS OF WESTERN MAINE AS H850 WINDS SWITCH TO THE EAST AT OR SHORTLY AFTER 06Z. GROUND TEMPERATURES WILL REMAIN WARM FROM TODAYS HIGH TEMPERATURES...SO ANY POTENTIAL SNOWFALL ACCUMULATIONS SHOULD BE LIGHT. NEVERTHELESS...WILL BE MONITORING ANY PERSISTENT BANDS...SHOULD THEY DEVELOP DURING THE LATE NIGHT HOURS FOR ANY POCKETS OF HIGHER ACCUMULATIONS. FOR THE MOST PART...SOME AREAS MAY RECEIVE A COATING TO UP TO 2 INCHES OF SNOW THROUGH SATURDAY AFTERNOON. THERE MAY BE POCKETS OF HIGHER ACCUMULATIONS...MOST LIKELY OVER SOUTHEAST NEW HAMPSHIRE...BUT THE CONFIDENCE LEVEL ON THE LOCATION AND THE AMOUNTS REMAINS LOW. PREV DISC... VERY SLOW BUT PROGRESSIVE UPPER TROF WILL SLOWLY DRIFT EAST FROM THE EASTERN GREAT LAKES TONIGHT. ENOUGH CYCLONIC FLOW AND RESIDUAL MOISTURE SHOULD SUFFICE IN DEVELOPING SCATTERED SNOW SHOWERS TONIGHT AND BOUNDARY LAYER AND TEMPERATURES ALOFT WILL BE COLD ENOUGH FOR PTYPE AS SNOW SHOWERS AFTER 00Z. AT THE SURFACE... MODELS HINTING AT AN INVERTED TROUGH EXTENDING NORTHWEST INTO COASTAL MAINE FROM SURFACE LOW WELL OUT TO SEA TO THE SOUTHEAST. THIS MAY HELP ENHANCE ANY SNOW SHOWER ACTIVITY LATER TONIGHT INTO SATURDAY BUT QPF OFF MODELS SUGGESTS MINIMAL AMOUNTS. USED A BLEND OF MODELS FOR OVERNIGHT LOWS WHICH SHOULD RANGE FROM NEAR 20 IN THE MOUNTAINS TO NEAR 30 ALONG THE COAST.
-- End Changed Discussion --
&& .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... UPPER CYCLONIC FLOW CONTINUES AND WILL ALLOW SCATTERED SNOW SHOWERS TO CONTINUE AS THE UPPER TROUGH CONTINUES TO SLOWLY DRIFT ACROSS NEW ENGLAND SATURDAY. TEMPERATURES ALOFT ON SATURDAY AND SATURDAY NIGHT COMBINED WITH COOLER BOUNDARY LAYER TEMPERATURES WILL SUPPORT ANY PRECIPITATION TO BE IN THE FORM OF SNOW. NO ACCUMULATIONS ARE EXPECTED WITH THIS SYSTEM AT THIS TIME ALTHOUGH WOULD NOT BE SURPRISED TO SEE A FEW BURSTS OF STEADIER SNOW ALONG PARTS OF SOUTHERN COASTAL AREAS. QPF AMOUNTS OFF MODELS ARE MINIMAL AND ACCEPTED. SURFACE TEMPERATURES WILL BE IN THE 30S. BY LATER SATURDAY NIGHT THE SYSTEM FINALLY EXITS TO THE EAST AND CLEARING SHOULD BE NOTED FROM NORTHWEST TO SOUTHEAST. && .LONG TERM /SUNDAY THROUGH FRIDAY/... BY SUNDAY MORNING A LONGWAVE TROUGH AXIS WILL BE MOVING OFFSHORE. SURFACE HIGH PRESSURE WILL HAVE ALREADY PUSHED INTO THE REGION OVERNIGHT WITH W/NW SURFACE WINDS DAMMING THE COOLER AIR ALONG THE MOUNTAINS AND ALLOWING DOWNSLOPING TO WARM THE COASTAL PLAIN MORE DURING THE DAY. HIGHS SHOULD PEAK INTO THE LOWER TO MID 30S NORTH TO UPPER 30S TO LOWER 40S ELSEWHERE. THE HIGH PRESSURE CENTER WILL BE PUSHED TOWARDS THE DEEP SOUTH AS A STRONG SURFACE CYCLONE DEEPENS AND APPROACHES THE GREAT LAKES LATE IN THE DAY. SOUTH WINDS WILL DEVELOP AND PULL MOISTURE NORTHWARD BUT THIS SYSTEM WILL BE SOMEWHAT MOISTURE-STARVED. PRE FRONTAL TROUGH WILL CROSS THE REGION MONDAY NIGHT FOLLOWED QUICKLY BY A COLD FRONT. THIS BRINGS SCATTERED LIGHT RAIN AND SNOW TO THE REGION WITH THE RAIN/SNOW LINE LIKELY SETTING UP SOMEWHERE IN THE FOOTHILLS. OROGRAPHIC LIFT SEEMS TO BE A KEY PLAYER IN THIS SETUP WITH THE COASTAL PLAIN GETTING VERY LITTLE QPF. SOME LINGERING SHOWERS ARE POSSIBLE INTO TUESDAY MORNING ALONG THE INTERNATIONAL BORDER. A WARM FRONT NEARS FROM THE WEST TUESDAY AFTERNOON WITH THE STEERING FLOW KEEPING THE SYSTEM ON A EASTERLY TRACK. MODELS VARY FROM JUST SKIRTING OUR AREA TO BRINGING AROUND A THIRD OF AN INCH OF LIQUID PRECIPITATION TO SOUTHERN SECTIONS OF NH AND SW MAINE THROUGH MIDDAY WEDNESDAY. A MORE SIGNIFICANT PRECIPITATION EVENT IS POSSIBLE THURSDAY INTO FRIDAY WHICH COULD POSE A TRAVEL THREAT FOR EASTER WEEKEND. HOWEVER CURRENTLY HAVE LOW CONFIDENCE IN LONG TERM SOLUTIONS SO HAVE REMAINED WITH CHANCE POPS. AS FAR AS TEMPERATURES... WAVES OF MESOSCALE AS WELL AS SYNOPTIC WARMING KEEP DAYTIME HIGHS HOVERING WITHIN A COUPLE DEGREES OF NORMAL VALUES FOR PORTLAND AND CONCORD. OVERNIGHT MINIMUMS ALSO SEEM TO BE NEAR THE MARK. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/... SHORT TERM...VARIABLE MVFR CONDITIONS TONIGHT AND SATURDAY IN SCATTERED SNOW SHOWERS. VFR SATURDAY NIGHT. LONG TERM...VFR CONDITIONS EXPECTED SUNDAY AS HIGH PRESSURE BUILDS IN. A COLD FRONT WILL CROSS THE AREA MONDAY... WITH SCATTERED MVFR CONDITIONS IN RAIN OR SNOW SHOWERS. SNOW SHOWERS CONTINUE TO BE POSSIBLE FOR KHIE AND KLEB TUESDAY MORNING. TUESDAY EVENING INTO EARLY WEDNESDAY MORNING LOW PRESSURE WILL IMPACT SOUTHERN NH AND SW MAINE... BRINGING SCATTERED SNOW SHOWERS TO THE REGION. KPSM MAY SEE RAIN INSTEAD. && .MARINE... SHORT TERM... AN SCA FOR HAZARDOUS SEAS OVER THE OUTER WATERS HAS BEEN ISSUED FOR LATER TONIGHT AND THROUGH SATURDAY NIGHT. SWAN WAVE MODELS SHOWS SEAS BUILDING OVER THE OUTER WATERS THROUGH THAT TIME FRAME. LONG TERM...WAVES DECREASE BELOW SCA CONDITIONS EARLY SUNDAY MORNING. WINDS AND SEAS LOOK TO INCREASE ABOVE SCA THRESHOLDS AGAIN EARLY MONDAY AHEAD OF NEXT COLD FRONT AND LAST JUST THROUGH THE DAY. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 2 AM SATURDAY TO 8 AM EDT SUNDAY FOR ANZ150-152-154. && $$ JC

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