Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 201404 AFDGYX Area Forecast Discussion National Weather Service Gray ME 1004 AM EDT Tue Mar 20 2018 .SYNOPSIS... High pressure will continue to settle over northern New England today bringing continued colder than normal temperatures. A storm system will pass to our south late Wednesday and Thursday likely bringing accumulating snow to much of the forecast area. An upper level low will cross over New England this weekend. A storm may form well out to sea early next week. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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10 AM Update...Little change to the going forecast. Sunny skies are expected today with perhaps an increase in clouds in the far south late. Winds will be lighter than yesterday even though temperatures will still be a bit chilly. 625 am Update: Clear skies and light winds early this morning. Another very cold start to the morning with minor tweaks to the early morning temps based on latest obs. Previous Discussion: Another sunny day today as high pres settles over the region. Temps will continue to be below normal. The good news is the winds will be much lighter to near calm conditions.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... Low pres develops off of DELMARVA tonight and Wed and spreads thickening clouds northward into southern areas later tonight and further north Wed morning. Some light snow or mixed rain/snow should begin to develop into southern areas by later in the day. Boundary layer temps at the onset of any precipitation will be marginal for all snow so a mix expected at the onset, but by evening evaporational cooling and increased UVV should wipe out any warm layers. Used a blend of models for timing. Temps will once again be below normal. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... A complex area of low pressure will move northeast off the New England coastline Wednesday night into Thursday. Initial surface low will track just east of the Gulf of Maine, before a secondary system, coupled with the upper low follows a similar track during this period. Models continue to diverge somewhat with this system. As the confidence levels increase that some accumulating snow will fall over southern New Hampshire and southern Maine, the range of possible scenarios still exists. At this time, will use a blend of most available guidance within the 00Z suite, however will lean slightly towards the middle of the road GFS in terms of snowfall amounts. At this time, it appears that a stripe of 3 to 6 inch snow totals will be possible over southern areas. This forecast lines up well with our neighbors as well as WPC. Temperatures Wednesday night should be cool enough in the boundary layer to have any mix with rain restricted to the over the offshore islands. A period of light snow is possible over eastern portions of our forecast area on Thursday as the system lifts off to the northeast. Some upslope snow showers possibly in the mountains as well, especially the western mountains of Maine. Plenty of clouds will remain in place for Friday as an upper level low pressure system crosses over the Northeast. Scattered snow showers are a possibility, especially over the higher terrain. This weekend will feature yet another upper level low pressure system to cross the region. More scattered snow showers are possible, especially in the mountains. Below normal temperatures will continue as well. Finally, the European model and previous runs for other models continue to suggest the formation of a storm well out to sea early to mid week next week. This storm will be too far out to sea to affect the region with changing sensible weather conditions. However, this has the potential to bring large, long period swells to the coast and has been noted in the coastal flood discussion below. && .AVIATION /14Z TUESDAY THROUGH SATURDAY/... Short Term /through Wednesday/...VFR conditions today into early Wed. By late Wed some MVFR conditions may develop over southern areas in developing areas of light rain or snow. Long Term...Ceilings and visibilities will lower Wednesday into Wednesday night and early Thursday over southern New Hampshire and southern Maine. Initially, there may be a snow, rain mix before the precipitation changes to all snow. Mainly VFR or MVFR over northern areas. Occasionally MVFR conditions are possible in any scattered snow showers Friday into Saturday. && .MARINE... Short Term /through Wednesday/...Winds and seas to remain light into tonight. Small craft conditions will likely develop late tonight and likely increase to Gales Wed as the intensifying storm system develops off the mid Atlantic coast. Long Term...Gale force winds will continue into Thursday as winds continue to back with time. Winds and waves will then slowly diminish with time Friday and into the weekend. An intensifying offshore storm may produce large swells next week. && .TIDES/COASTAL FLOODING... The highest tides of the month will combine with an increasing storm surge and building waves Wednesday night to allow for beach erosion, splash-over and possibly minor coastal flooding. Total water level tables have been adjusted for this tide due to the increasing northeasterly winds. Models are suggesting the possibility of a large and intense storm to develop well out to sea next week. The forecast suggests this storm may form a small loop and retrograde Monday night into Tuesday. This may produce large, long period swells next week which may lead to some beach erosion. Note, astronomical tides are relatively low next week. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...Gale Watch from Wednesday morning through Thursday afternoon for ANZ150>154. && $$ NEAR TERM...Ekster is the U.S. government's official web portal to all federal, state and local government web resources and services.