Area Forecast Discussion
Issued by NWS Portland, ME

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448 FXUS61 KGYX 220113 AAB AFDGYX Area Forecast Discussion...UPDATED National Weather Service Gray ME 913 PM EDT Thu Sep 21 2017 .SYNOPSIS... Jose will wobble around well south of Cape Cod into the weekend, gradually weakening with time. It will produce some gusty winds at times along the coast into Friday. Meanwhile, a large building ridge of high pressure over the region will be the main feature through the weekend into early next week as Jose weakens, making for a very nice stretch of dry and very warm weather with temperatures running well above normal Saturday through at least Tuesday. && .NEAR TERM /THROUGH FRIDAY/...
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910 PM Update: Primary change this hour was to take temperatures down overnight based on evening trends which show decoupled sites already dropping well through the 50s. Otherwise... forecast is in good shape with considerable high cloudiness and some CT Valley fog likely developing over the next few hours. 451 PM Update: Boosted skycover a bit late this afternoon as cirrus associated with Jose/s outflow moves overhead and is creating a high overcast. Otherwise...only minor changes to hourly temperatures and dewpoints to match afternoon observational trends. Previous Discussion Below... As Jose remains stationary well south of Cape Cod, it allows a large blocking ridge of high pressure to build across the region tonight allowing for mostly clear skies. After sunset mixing will cease and most of the gusty winds will become light. This will allow radiational cooling and the normal early fall nocturnal valley fog to develop aft 06z. Temps will be near normal with lows ranging from the mid 40s in the mountains to mid 50s elsewhere.
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&& .SHORT TERM /FRIDAY NIGHT THROUGH 6 PM FRIDAY/... Jose will remain quasi-stationary well south of Cape Cod Friday and Friday night while the blocking ridge of high pressure builds from the northwest. This ridge of high pressure will bring plenty of subsidence and mostly sunny skies and mild temps reaching into the lower to mid 70s, except slightly cooler along the immediate coast. Winds along the coast may be breezy at times Friday. Friday night skies will once again be mostly clear thus some radiational cooling and the normal fall nocturnal valley fog develops in the mountains after 06z. && .LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/... Jose meanders well south of Cape Cod through the weekend. Meanwhile, the very large ridge of high pressure continues to build over the region producing a long stretch of very nice, dry, and very warm conditions that will last through Tuesday. By Wednesday, a frontal system passing northeast across southern Canada along the northern periphery of the ridge, may produce a few showers in the mountains while continued mild weather continues over southern and central areas of Maine and New Hampshire. Used superblend model for temps but realize they may be weighted down some due to climo keeping forecast max temps a little low. && .AVIATION /01Z FRIDAY THROUGH TUESDAY/... Short Term... Summary: A high pressure ridge axis will remain centered over northern New England as Tropical Storm Jose meanders south and east of Nantucket. Restrictions: VFR all sites at the moment and outside of HIE/LEB...it will continue that way through at least Friday morning. Fog may be somewhat limited given high cloud cover...northeasterly gradient and dry antecedent airmass...but there is good guidance consensus for at least a brief period of LIFR/IFR restrictions at HIE/LEB and will continue mention here. On Friday...there are indications that MVFR stratus will try to work it/s way onshore /PSM-PWM-RKD/ by late morning and during the afternoon. Confidence in this occurrence is not high and would like to see more of this low cloudiness materialize to our south and east before adding to the coastal TAFs. Still...there is some threat for MVFR restrictions at these coastal sites Fri late AM through Friday night. VFR conditions will continue elsewhere. Fog development will again be possible HIE/LEB Friday night. Winds: North-Northeast winds continue through Friday 10-20kts with some weakening to 5-10kts Friday night. LLWS: While there will remain some mixing in the low levels...1.5kft winds will remain from the northeast at 30-35kts...promoting a period of LLWS overnight at all sites except HIE/LEB. Wind fields look a bit weaker Friday night with less of a LLWS threat. Lightning: No thunderstorms are expected through Friday night. Long Term... Sat - Tue...VFR except LIFR conditions possible in valley fog at KLEB/KHIE between 08-13Z each night. && .MARINE... Short Term...Jose will remain nearly stationary well south of Cape Cod through Friday night. This will mean SCA conditions are expected tonight through Friday over the outer waters. In Penobscot bay,the SCA has been discontinued as swells were remaining outside the bay area. In Casco Bay swells of 3-6 ft continue along the outer harbor areas so a SCA due to hazardous seas is in effect and will be needed through Friday. Long Term...SCA conditions are likely through the weekend over the outer waters, mainly for seas, as Jose continues to meander south of Nantucket. && .TIDES/COASTAL FLOODING... Long period swells from Jose will continue through Friday and into the weekend. Some minor beach erosion remains possible. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...High Surf Advisory until 8 PM EDT Friday for MEZ023>027. NH...High Surf Advisory until 8 PM EDT Friday for NHZ014. MARINE...Small Craft Advisory for hazardous seas until 8 PM EDT Friday for ANZ153. Small Craft Advisory until 8 PM EDT Friday for ANZ150-152-154. && $$ SYNOPSIS... NEAR TERM...Arnott SHORT TERM... LONG TERM... AVIATION... MARINE... TIDES/COASTAL FLOODING...

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