Area Forecast Discussion
Issued by NWS Portland, ME

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167 FXUS61 KGYX 260753 AFDGYX Area Forecast Discussion National Weather Service Gray ME 353 AM EDT Sat May 26 2018 .SYNOPSIS...
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A cold front will slowly drop south through the region today and will stall south of New England tonight. High pressure will build in from the northeast on Sunday and will hold over the region Sunday night. High pressure will shift east on Monday as a weak warm front approaches from the west. A cold front will drop south through the region Monday night. High pressure will build over the region Tuesday and will push offshore south of New England Wednesday.
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&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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Today will be all about the timing of the back door cold front as it shifts from the NE to the SW. For the most part interior srn NH, should generally be partly sunny and warm as the front won;t make it there until late in the day or this evening, however, could see showers or t-storms develop mid-late afternoon there. Think the front begins to move SW thru the CWA about midday in the NE zones and moves along the coast during the mid afternoon. The showers will continue to run from the NW- SE along the front thru the day, although likely to remain sct. There are a couple times today where the showers could become more numerous, the first is during the first part of the morning across the northern zones, and then maybe again late this afternoon across srn and central NH as well as SW ME. Could see some thunder with this batch as well. As the front moves thru look for any sun to disappear as skies become OVC, and temps to drop quickly. This is especially true along the coast where the flow will become quickly onshore and could be gusty for an hour or so, so temps may drop 10-15 F in an hour or two here. This looks to be the classic spring back door front on the coast. Points S of a line from Sebago Lake thru the NH lakes region and toward KLEB should see a fairly decent and warm day with highs in the 80s. Highs across the rest of the CWA will range from the mid to upper 70s from the White Mtns SE toward Casco Bay and around 70 in the ME mtns, SE across the Capital region and onto the mid-coast. Of course should the timing change, even by an hour or two and the forecast max temps could be more than a few degrees off.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
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Temps will turn colder this evening across any place the front has not passed in the afternoon, and this should be mainly srn NH. Lows will drop down to the mid 40 to around 50 in all but srn NH, where the lows will be in the lower 50s. Some lingering showers and perhaps a few t-storms are expected in srn into this evening, but mostly showers should become far and few between after midnight. Direr and clearing will begin to work in N and E zones, but clouds linger to the S and W, and some fog is possible. here as well. On Sunday will see a weak sfc wave develop to our south, so the E-NE flow will increase, and this will keep temps down, especially ion the coast where highs will like be in the low to mid 50s /matching offshore water temps pretty well/, with winds of 10-15 mph. The one bit of good news, is that, although the mixed layer is only 1-2 ft deep, the easterly flow is deeper, to 5K or 6K ft, and there is marked during above the mixed lyr. Thus, the top of the boundary layer should be diffuse and see a lot of motion, so not anticipating DZ or FG during the day, however, there will be a lot of clouds. Cannot rule out a shower on Sunday either, especially in the south, but any that do develop would be isolated. Also some good news if you`re in the ME mtns or the Penobscot Vly Sunday, some sun is possible on Sunday as well, as the high noses in from the east. This also likely where temps will be warmer, in the low to possible mid 60s.
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&& .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
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High pres centered over the maritimes will continue to provide a cool, moist onshore flow Sun night into Mon. A few light showers are possible in this flow, mainly southern areas. By Mon night an upper trof moves southeast across the region allowing a much drier northwest flow to develop as a large Canadian ridge of high pres builds southeast into the region through midweek. A return to sunny and warmer conditions can be expected Tue through Thu with fairly low dewpoints. By Fri the ridge moves well off the eastern seaboard allowing a return southerly flow to develop. The remnants of Alberto will become entrained with the lower/upper level southerly flow and may reach the region Fri with some much needed rainfall.
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&& .AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...
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Short Term...VFR expected through this morning. BAckdoor cold front will shift through the area form NE-SW this afternoon, and will see conds quickly become VFR mid-late afternoon, and then IFR this evening. IFR could linger at the coast thru Sunday, but should see some improvement, to VFR anyway, at inland terminals. Long Term...MVFR to local IFR cigs on the coast and perhaps across southern NH Sunday night into Monday with onshore flow. VFR conditions return later Monday night through Wednesday.
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&& .MARINE...
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Short Term.., Winds seas stay below SCA into tonight. although could see a few gusts approach SCA levels briefly mid-late afternoon, as backdoor cold front shifts thru and winds switch from west to NE. May need SCA on Sunday as weak low passes S of the waters and easterly flow picks up. Long Term...SCA due to seas over the outer waters possible Sunday night into Mon.
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&& .FIRE WEATHER...
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For the most light winds expected today with moderate RH values. srn NH will be the only place that could see RH dip down to 35-40 percent this afternoon. Otherwise, flow switches onshore this after into this evening and stays that way into Monday, so expect higher RH and only light to moderate winds, with scattered showers.
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&& .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$

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