Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 222343 AAB AFDGYX Area Forecast Discussion...UPDATED National Weather Service Gray ME 643 PM EST Wed Feb 22 2017 .SYNOPSIS... Low pressure moving east through southern Canada will allow a mild southwesterly flow to continue tonight through Thursday. Highs will climb into the 50s to near 60 across New Hampshire...with 40s to lower 50s over western Maine. A weak cold front will try and push south across the area Thursday night with a few rain showers before returning north as a warm front by late Friday. A strong cold front and more widespread showers will move across the region Saturday night followed by a drier and colder air mass for Sunday. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... 513PM Update: Minor changes to match late afternoon temperatures and reduce cloud cover based on the last few visible images of the late afternoon. Previous discussion below... The evening will start out mostly clear as per satellite imagery. By later tonight patchy valley fog is expected to develop due to the residual low level moisture from the snowmelt this afternoon combined with calm winds. Tonights overnight lows will be mild with temperatures in the upper 20s to lower 30s. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/... Thursday models show a mild southwest flow to develop with h85 temps aloft to reach +6 to +8C. This flow should allow temps to reach near 50 in the mountains and southern Maine and could reach near 60 over southern NH. A weak cold front tries to push south across the area but weakens and then washes out as it moves through the area by Thu evening. A few showers are possible in the mountains with its passage Thursday afternoon and evening but it should remain dry elsewhere. Patchy fog may once again form overnight due to the snowmelt. Temps will once again be mild with overnight lows ranging from near 30 in the mountains and mid 30s to lower 40s elsewhere. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... Models are in fairly good agreement in the long term. A frontal boundary will stall just south of the region Friday...then start to push back through the area as a warm front Friday night as low pressure moves northeast through southern Quebec. This will lead to a rather warm day Saturday. As the low continues northeast Saturday night the trailing cold front will cross the region with rain showers which will change to snow showers in the mountains overnight Saturday night as colder air pushes into the region. At this time it appears that the moist system moving northeast in Atlantic will not phase with the northern frontal system until after it passes through the region. The models continue to show the heaviest showers with the frontal passage in the mountains...and combined with the snowmelt caused by the warm temperatures may produce some ice movement on the rivers. Drier air moves into the area Sunday but with a northwest flow there will be a persistent threat of snow showers in the mountains through Monday. Weak systems pass north and south of the region late Monday and Tuesday with the next threat of significant precipitation for the area on Wednesday. && .AVIATION /00Z THURSDAY THROUGH MONDAY/... Short Term... Summary: Southwesterly flow continues through Thursday as low pressure passes north of the region with a few showers arriving as an attendant cold front pushes through the area Thursday night. High pressure then noses into the region from the north on Friday before stalled frontal boundary to our south returns north as a warm front. Restrictions: VFR attm and this will continue through the evening. Lots of ground moisture out there from recent melting and there are some signs given good radiational cooling that this will result in some fog development...particularly with continued good moisture advection in the southwest flow aloft. NARRE-TL points to low ceiling potential over southern NH/coastal ME as well...with good agreement from the LAV/MAV/MET. Thus...expect IFR fog and some coastal low stratus to develop after midnight with conditions a bit better /MVFR/ at HIE/LEB. For the day on Thursday...expect gradual improvement to VFR outside of LEB/HIE where nearby approaching front will help MVFR cloudiness linger longer...potentially through the day. MVFR restrictions possible in a few light rain showers Thursday night before a return to VFR conditions on Friday morning. Front to our south returns north Friday afternoon...with restrictions in rain showers again possible towards evening. Winds: Calm/light-variable winds overnight will become southwest 5 to 10kts for the day on Thursday before diminishing to 5kts or less Thursday night and shifting northwest overnight. Light northwesterly winds /less than 10kts/ expected Friday. LLWS: LLWS possible Thursday evening in southwesterly flow ahead of approaching surface cold front. Frontal passage will end the threat from north to south overnight. Long Term...MVFR to IFR conditions possible in showers and fog Friday night into Saturday night. MVFR to IFR conditions will persist in the mountains in scattered snow showers through Monday. && .MARINE... Short Term...A warm front moves north across the waters tonight. A developing southwest flow Thu will begin to build seas to near 5 ft by evening and continue Thu night. SCA`s may be needed for Thu night due to seas over the outer waters. Long Term...SCAs likely outer waters late Saturday through Monday and again on Wednesday. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ SYNOPSIS...Arnott NEAR TERM...Arnott/Marine SHORT TERM...Marine LONG TERM...Jensenius AVIATION...Arnott/Jensenius MARINE...Marine/Jensenius

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