Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 151113 AFDGYX Area Forecast Discussion National Weather Service Gray ME 713 AM EDT Thu Mar 15 2018 .SYNOPSIS... Broad low pressure will move toward the Canadian maritimes today and Friday, with snow showers continuing in the mountains. Temperatures will be a little cooler than normal with abundant cloud cover. The next trough will drop down out of the Canadian Arctic and arrive in New England on Saturday with colder conditions expected for the weekend. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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7am update... minor adjustment to Pop as the shower coverage has decreased a bit. prev disc... Scattered snow showers are ongoing across the area early this morning as northwesterly flow remains in the wake of yesterday`s storm moving into the Maritimes. The combination of NWly flow and cold air aloft will allow for snow showers to continue through the mountains this afternoon. Expect a few inches of additional accumulation along the Canadian border with just a few tenths into the coastal plain. With additional accumulations below 4 inches will go ahead and allow the existing Winter Weather Advisory to end with this forecast update. For the high temperature have leaned a bit cold compared to the MOS, which are a bit too aggressive given the cloud cover and snow cover. Still expect the southern portion of the area to reach 40F and near freezing north.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/... Showers will finally decrease in coverage this evening as the moisture decreases. Cloud cover will still be in place however and temperatures will remain in the mid 20s south to upper teens north. Friday will see some clearing in the coastal plain as the upper level low lifts off into the Maritimes. Snow showers will erode to just the far northern mountains as the drier northwesterly flow takes hold. Temperatures will be slightly colder than Thursday as the core of the cold air aloft comes over. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... Upper air pattern continues to be dominated by a persistent trough over eastern Canada and New England. A ridge of high pressure over western Canada keeps the northwesterly feed into the back side of this trough helping to keep this downstream trough in place. Another ridge over the western Atlantic and far northeast Canada has prevented the trough from moving east while also locking the coldest air far north over the North Pole and Asia. Within the broader eastern North America trough, smaller sub-vortices rotate around. The most recent of these brought our last snowstorm with its remnants over the Canadian maritimes gradually moving north toward Labrador. While this vortex moves north, it will open the door for another vortex to drop southward out of the Canadian Arctic this weekend, this time bringing us just a piece of the colder air that has been locked over the North Pole for the last several weeks. Upslope snow showers should gradually be diminishing by Friday night as low level flow becomes more westerly ahead of the Arctic front which should arrive on Saturday. With this front having its origins over the Canadian Arctic, it will not have enough moisture with it to bring precipitation, but it will bring noticeably colder weather. Temperatures this weekend will be more typical of mid winter rather than early spring. Highs on Sunday will likely only be in the 20s while lows drop to near zero up north and in the single digits and teens in the south. We see some moderation of the temperature by Monday when it should warm to near freezing again. Our next potential storm gets its origins in a southern stream trough over the western US. A piece of this trough breaks off and squirts eastward across the southern half of the US Sunday into Monday, emerging off the Virginia coastline on Tuesday. Biggest forecast question will be how this trough interacts with the northern stream trough over eastern North America. Some models are now pushing this wave out to sea south of New England with minimal impacts, while others pull it a little more northward and close enough to bring snowfall which could last into Wednesday. Still too early to have a lot of confidence in what will happen in this period, but we cannot rule out an accumulating snowfall during the middle of next week. && .AVIATION /11Z THURSDAY THROUGH MONDAY/... Short Term... Widespread MVFR in SHSN through much of the area. Brief reductions to IFR in SHSN are possible through the mountains today. Overnight expect the coastal plain to come around to VFR and remain VFR in NWly flow through the weekend. In the mountains MVFR will remain through the next few days as NWly flow is upslope for HIE and across the mountains into Jackman. Long Term...VFR conditions expect for all areas Friday and Saturday. A cold front moves in early Saturday and could bring some MVFR conditions to the mountains, but there is not a lot of moisture to work with so there should not be much precipitation. && .MARINE... Short Term... Have extended the SCA through tomorrow as persistent cold advection and NWly flow is expected to result in gusts to around 30kts over the waters. Currently in a bit of a lull with only IOSN3 above 25kts, but feel this will be short lived and thus have opted to just extend the existing headline rather than drop and then reissue. Long Term...Northwest flow strengthens a bit Friday night and could reach into the gale force range for the outer waters. A cold front drops down from the north on Saturday and brings colder temperatures as well as advisory level wind speeds which could last into Sunday. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...Small Craft Advisory until 8 AM EDT Friday for ANZ150>154. && $$ SYNOPSIS... NEAR TERM...Curtis SHORT TERM...Curtis LONG TERM...Kimble AVIATION... MARINE... is the U.S. government's official web portal to all federal, state and local government web resources and services.