Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 082353 AFDGYX Area Forecast Discussion National Weather Service Gray ME 653 PM EST Fri Dec 8 2017 .SYNOPSIS... a weakening ridge of high pressure will remain across the area tonight. Low pressure will develop offshore and intensify as it tracks across the Gulf of Maine late Saturday and Saturday night. This system will spread snow into much of the forecast area late Saturday through early Sunday. Beyond the weekend we will have to watch for another coastal low developing offshore in the mid week period, that could deliver some snow to the region. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
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650 pm Update: Northern fringe of mid/high clouds from the developing system to the south extends across southern and coastal areas. Added more cloud cover into these areas for the night. Oherwise imported mesonet data with only very minor tweaks needed. Previous Discussion: Quiet weather under a weakening surface ridge tonight. We`ll see a mix of high mid and low cloud across the area overnight and I expect we`ll stay dry. The only exception may be a few flurries across the mountains in residual moisture from Lake Ontario Plume.
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&& .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... The shortwave impulse over the west gulf states this afternoon on GOES water vapor imagery will phase with northern stream energy by Saturday morning. In response...the baroclinic zone currently stalled offshore of New England will see a rapidly intensifying surface low form along it. This low will track across the Gulf of Maine late Saturday and Saturday night. The trend over the past day has been to nudge the storm track and axis of heavier precipitation further west with each model run. Given the sharp west to east gradient in QPF we`ll see a quick drop off in amounts as we head inland from the coast. The most likely area for a 6 inch plus snowfall will be the coast and inland to the Interstate 95 corridor with amounts dropping off quickly as you head towards the mountains and Connecticut Valley. The winter storm watch is for the area with the greatest potential of seeing warning or advisory level snows with this event. Snow gradually tapers from west to east Saturday night as the surface low exits into the maritimes. && .LONG TERM /SUNDAY THROUGH FRIDAY/... Synoptic scale pattern shows a deep and wide closed low over Canada with ridging over the west coast. Several spokes of mid and upper level energy will rotate around this feature through the coming week. This will essentially bring additional snow to New England with reinforcing cold temperatures. Overall temperatures will be about 10-15 degrees F below normal for highs. Sunday will be variably cloudy with a secondary shot of cold air arriving along with scattered snow showers for the mountains. Sunday will also be gusty with CAA moving in on NW winds behind the frontal zone. Transient high pressure passing by quickly on Monday with increasing moisture ahead of the next system. Confidence in a widespread measurable snow on the heels of the weekend system is increasing with time with the long term deterministic models in much better agreement for the mid week system. The baroclinic zone will shift just to our south as the next weather maker dips into the northern Plains before taking a more ENE trajectory across the Great Lakes. A warm front lifts into the region early Tuesday spreading precipitation north and east. The current path of the Nor`easter has it bisecting the Gray CWA and bringing 2-4 inches of snow to the region. This fast moving system rotates into northern Maine by Tuesday night with a dry slot pushing in from the SW. Additional snow is likely for upslope regions Wednesday. Weak ridging builds in with another system on tap for next Friday. At this time it is pointless to put much detail into this later storm which will doubtlessly change in timing and path. For now have gone close to consensus and kept chance PoPs going. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... Short Term /through Saturday Night/...VFR through Saturday morning. Conditions lower to MVFR in SN with areas of IFR along the coastal plain and southeast NH by Sat afternoon. Conditions gradually improve to MVFR throughout aft 06z Sunday as SN tapers to -SHSN. Long Term...MVFR conditions will be possible for the mtns on Sunday into Sunday night as a boundary crosses the region. Gusty NW winds will reach 25-30 kts at times. Monday will see improvement everywhere and mostly VFR. Tuesday expect LIFR to MVFR ceilings and vsbys at all terminals as a low pressure system crosses the region. LLWS will likely be an issue at times with the center of the low so close. Improvement early Wednesday morning with additional -SHSN in the mtns throughout the day. && .MARINE... Short Term /through Saturday Night/...Winds and seas remain below small craft through Saturday afternoon. Strengthening northerly flow around intensifying Gulf of Maine low should bring Small Craft conditions to all waters Saturday night. Long Term...Northwesterly cold advection will keep SCA conditions in the waters through the day on Sunday before seas and winds subside Sunday night. Calm conditions hold through the start of the week before the next low approaches for Tuesday. This storm may bring gales to the waters. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...Winter Storm Watch from Saturday afternoon through Sunday morning for MEZ012>014-018>028. NH...Winter Storm Watch from Saturday afternoon through Sunday morning for NHZ006-008>010-012>015. MARINE...None. && $$ NEAR TERM...Marine is the U.S. government's official web portal to all federal, state and local government web resources and services.