Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 160218 AAC AFDGYX Area Forecast Discussion...UPDATED National Weather Service Gray ME 1018 PM EDT Sun Oct 15 2017 .SYNOPSIS... A warm southwest flow will continue through this evening. Low pressure will track east through southern Canada tonight driving a trailing cold front through the region. Canadian high pressure with cooler and dry weather follows for Monday into Tuesday. A large ridge of high pressure builds across the eastern U.S. allowing a warm dry southwest flow to return for the last half of the week and into the weekend. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
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1014 PM Update: Primary changes this hour are to continue to raise temperatures for the next couple of hours before frontal passage. Otherwise...matched near term cloud cover... temperatures and dewpoints to evening observational trends. Wind gusts reaching 30-35 mph in spots...that should about do it given weakening trend in arriving convective showers. 740 PM Update: Continue to boost near term temperatures as they only slowly fall this evening with good mixing ahead of approaching surface cold front. Otherwise...have seen some blossoming stratus in SW NH and have increased cloud cover through the evening hours as a result. Showers are still about 1-2 hours upstream. Have seen very impressive wind gusts through parts of upstate New York...but KENX/Albany 88D shows convective line beginning to decay as downstream instability wanes. Will have a look at the 00Z RAOB which is in process...but see gust potential of no more than 30-35 mph over exposed hilltops in parts of western NH as line continues to decay. Unfortunately...not looking like much in the way of QPF either. Will continue to monitor as line moves through Albany and western Vermont...but see no significant impacts at this time. 430 PM Update: Boosted near term temperatures as they reach their highs this afternoon...and have kept the forecast completely dry through 7-8 pm with precipitation still well upstream associated with approaching cold front. No other changes needed at this time. Previous discussion below... A warm front pushed northwards through the region today. Strong south to southwesterly flow will continue through evening as southern Maine and New Hampshire remains in the warm sector. Winds are currently gusting to around 20kts. Temperatures have climbed to near 70F and will hold fairly warm ahead of the fropa later tonight. A strong low level jet is present with this line, however the relatively low mixing heights and late timing of the front will prevent the core of the jet from mixing to the surface. The highest wind gusts will be just before sunset as the pressure gradient and low level jet approaches before we begin to see the surface layer stabilize. A few gusts to around 30kts are possible particularly along the eastern portion of the coastline such as the Camden hills and Penobscot bay islands.
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&& .SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/... A fine line is easily visible on both radar and satellite demarcating the cold front just entering western New York at 3pm. This line of showers with some embedded thunder will push east at a good clip expected to arrive into the Ct River valley around 9pm. This timing has been well handled by short term models and has been quite consistent all day thus PoPs remain low through sunset. With the strength of the front a rumble of thunder especially along our southwest border as the front moves in can`t be ruled out but the late timing both seasonally and time of day will prevent widespread thunder from being a concern. The front will cross the region over night with scattered showers. Behind it is a shift to west to northwesterly flow. Winds will subside overnight but persistent flow will prevent any fog from forming and keep temperatures into the 50s overnight. Monday will be colder than today as the northwesterly post-frontal flow gradually subsides through the day. && .LONG TERM /TUESDAY THROUGH SUNDAY/... A westerly zonal flow aloft will exist through midweek. By late in the week and into the weekend a high amplitude broad upper long wave ridge axis builds across the eastern US. This all means a dry weather pattern through the outlook period. After a cool day/night Tuesday, the rest of the outlook period looks to return to above normal temperatures. Accepted the superblend guidance for temps and POPs. && .AVIATION /02Z MONDAY THROUGH FRIDAY/... Short Term... Summary: A cold front will cross the region tonight with high pressure building into the region during the day Monday into Monday night. Restrictions: 920pm update...MVFR stratocumulus has expanded ahead of the approaching cold front...and will likely impact PSM/PWM/MHT/CON for the next few hours until the front brings improving conditions. Relevant previous discussion: A decaying line of showers will bring the threat of restrictions /and a possible wind gust to 30kts/ in the 1-4Z timeframe at LEB/HIE...but confidence is not yet high enough to include restrictions in the current TAF package. The showers will continue to weaken to the east with less threat of any impacts to the other terminals. SCT-BKN VFR cloudiness is expected on Monday with clearing skies Monday night with fog potential at LEB/HIE. Winds: Southwest winds 10g20kts will shift westerly tonight and then northwesterly 10g18kts for the day on Monday before diminishing to less than 5kts Monday night. Lightning: No thunderstorms are expected through Monday night. LLWS: 2kft winds have increased to 45-50kts and will continue through the evening before diminishing after cold frontal passage later tonight. This will promote a period of LLWS despite some winds remaining at the surface. No LLWS expected Monday and Monday night. Long Term...VFR. && .MARINE... Short Term... Strong south to southwesterly flow ahead of a cold front will impact the coastal waters through evening. Forecast soundings show 50kts low level jet around 2000ft parallel to and just ahead of the front this evening. With the waters over the Gulf of Maine still relatively warm /in the upper 50s to 60F/ expect the surface to remain well enough mixed for some of these gusts to reach the ocean. Thus a Gale warning has been issued for the easternmost ocean zones where there is the greatest southwesterly fetch. Elsewhere a Small craft advisory remains in place. Long Term... Wed and Thu...Small craft conditions are possible outside the bays. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...Small Craft Advisory until 11 AM EDT Monday for ANZ151-153-154. Gale Warning until 2 AM EDT Monday for ANZ150-152. && $$ SYNOPSIS... NEAR TERM...Arnott/Curtis SHORT TERM...Curtis LONG TERM...Marine AVIATION...Arnott/Marine MARINE...

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