Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 170536 AAC AFDGYX Area Forecast Discussion...UPDATED National Weather Service Gray ME 136 AM EDT Mon Oct 17 2016 .SYNOPSIS... A weak cold front will sweep across the region tonight preceded by a few rain showers. The front will stall to our south on Monday. Monday should turn out mild and dry before the stalled front returns north with another round of showers for Monday night. Even warmer air will move into southern sections Tuesday, and then all areas Wednesday with an isolated shower possible. Unsettled weather is expected for the end of the week with somewhat cooler temperatures. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... 950 PM Update...Just some minor timing adjustments on PoPs for the next few hours based on latest reflectivity trends, otherwise very little change to the going forecast. Band of showers should move through by 06z for the most part, with mainly western zones seeing light measurable rain. 630 PM Update...Just a few minor changes to the forecast for the rest of the evening based on latest trends in observational data and latest mesoscale model data. Highest PoPs continue to be in the mountains overnight where forcing for ascent will be the greatest. They will tend to weaken as they head to the coast, with only a few hundreths expected on the coastal plain at best. Have also added patchy fog late. Previously... At 18z...a 994 millibar low was centered east of Hudson Bay with a trailing cold front through the eastern Great Lakes. NWS doppler radar mosaic showed a band of scattered to broken convection along and ahead of this boundary. For tonight...shortwave impulse noted on GOES water vapor imagery over north Great Lakes will race eastward across Ontario and Quebec Provinces tonight. This is impulse will serve to drive the surface cold front southward across the forecast area along accompanied by clouds and showers. With the exception of upslope areas in the mountains...clearing will occur from northwest to southeast across the area late tonight with patchy stratus and fog developing. It`ll be notably milder then the past few nights with lows in the upper 40s to mid 50s. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TUESDAY/... On Monday...the cold front will run out of gas and stall just to our south. Lingering clouds across the mountains will scatter out as surface high pressure builds by to our north across Quebec province. Highs will range from the 60s to the lower and mid 70s elsewhere in initially light offshore flow. By Monday evening...clouds will once again be on the increase as the stalled surface front begins to return north as a warm front in response to an approaching shortwave over the Great Lakes. Shower activity will gradually increase for the overnight period in response to best forcing. Lows will be mainly in the lower and mid 50s...with upper 40s along the international border area. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... Chance of high impact weather: Minimal. The broad ridging at 500 mb over the ern half of the CONUS holds through most of the week, and despite some smaller scale waves in the flow, it will continue to being in some very warm air aloft. More persistent and deeper troughing moves in for next weekend, as blocking sets up to our NE. Models differ on the extent of the blocking and subsequent deeping of the trough and intrusion of the cold air, but the trend will be cooler, and perhaps wetter, over the weekend into early next week. Tuesday will start off fairly cloudy with a threat showers across most of the CWA in the morning as WAA moves across the region. The sfc warm front will lag behind the upper front as initially E-SE will promote the cooler more stable air thru much of the day in the eastern zones. Where the front does push through, and the sun breaks out in the warm sector, it will be quite warm with highs in the 70s. At this point this looks to be the the srn third of NH, the CT valley and perhaps into far SW ME. North of the front highs will be stuck in the mid 50s to mid 60s, with clouds lingering thru most of the day. Should see enough of a push to the sfc front that it eventually breaks the inversion across all but far NE zone late Tue and Tue night with overnight on the balmy side for mid October, in the mid 50s to low 60s. Cold front will push through late Tue night into early Wed, and the htreat of another round of showers is possible Tue night. As is often the case, especially in cases like this where air above the surface doesn`t change all that much, it will be warmer across all those areas that stayed N of the warm from on Tuesday and Wed highs will range from the mid-upper 60s in the mtns to midto upper 70s in srn NH and SW ME. Sfc high builds in beneath ridging aloft Wed night and Thu, with milder temps, but a little cooler with more clouds and flow turning from to south. By Friday models deepen trough to our west and move it through New England FRiday and Saturday before stalling just to our NE. Best chance for precip will be centered around Fri and Fri night when good southerly flow ahead of the front and potential offshore low come together and good produce a period of rain, Otherwise any precip just looks showery at this point, and unlikely to occur in all periods that have chc pops, but just to uncertain to narrow down at this point. && .AVIATION /06Z MONDAY THROUGH FRIDAY/...
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Short Term /through Tuesday/... Summary: A cold front will settle south of the region today with improving flying conditions after showers and some fog through daybreak. This front will return Monday night and Tuesday bringing additional chances for showers and deteriorating flying conditions. Restrictions: Showers now departing the terminals...with perhaps a few vicinity RKD over the next couple of hours. Expect MVFR cigs to hold through daybreak HIE...with patchy fog south of this bringing LIFR/IFR conditions CON/AUG/LEB...and possibly MHT. VFR takes over early Monday morning and continues through the evening. Monday night...showers work back in from the west /for northern areas/ ...with likely a new round of restrictions HIE/LEB...with fog again possible south of this. Low clouds may cause restrictions to persist over our Maine terminals through much of Tuesday as surface warm front will likely get stuck to the south and west of this. Winds: Light west/southwesterly through daybreak will become 5- 10kts from the northwest today /outside of afternoon sea breezes/. Monday night and Tuesday...a shift to more easterly flow is expected...but wind speeds remaining below 10kts. LLWS: None through Monday night. LLWS possible over Maine terminals Tuesday atop stout llevel inversion associated with northeastward lifting warm front. Thunder: Very slight chance of an embedded thunderstorm northern areas Monday night as an area of showers pushes from west to east across the area. Long Term...Could see another brief round of flight restrictions Tue night as a cold front moves through. VFR expected Wed into Thu, with possible flight restrictions Thu night and Friday.
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&& .MARINE... Short Term /through Monday night/...Winds and seas will be near small craft for much of tonight as a cold front crosses the waters. Thereafter...winds and seas are expected to remain below sca threshold the remainder of the period. Long Term...Winds/seas approach SCA late Tuesday and Tuesday night in SW flow ahead of cold front, and could see borderline conds for a few hours in this timeframe. Otherwise winds/seas below SCA through the end of the week. && .TIDES/COASTAL FLOODING... We`re currently in the period of high astronomical tides. High tides of note are referenced to the Portland Harbor tide gage where flood stage is 12 ft mllw. It won`t take much onshore wind or wave action to cause issues along the coast and the situation will be watched closely through late this week. 1217 PM Mon 11.7 ft mllw 1251 AM Tue 11.0 ft mllw 108 PM Tue 11.7 ft mllw 200 PM Wed 11.5 ft mllw 256 PM Thu 11.1 ft mllw && .GYX WATCHES/WARNINGS/ADVISORIES...
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ME...None. NH...None. MARINE...Small Craft Advisory until 6 AM EDT early this morning for ANZ150-152-154.
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&& $$ SYNOPSIS... NEAR TERM...Ekster SHORT TERM... LONG TERM... AVIATION...Arnott MARINE... TIDES/COASTAL FLOODING... is the U.S. government's official web portal to all federal, state and local government web resources and services.