Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 211349 AFDGYX Area Forecast Discussion National Weather Service Gray ME 949 AM EDT SUN AUG 21 2016 .SYNOPSIS... High pressure anchored well offshore will circulate warm and increasingly humid air into the region today. A strong cold front will move through the region tonight with a period of rain expected across the region. Behind this...much cooler and drier air will arrive for Monday and Tuesday as high pressure builds into the region. As this high shifts offshore by midweek...expect temperatures and humidity to gradually increase. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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950 am update: Only minor tweaks to reflect current sky cover conditions and temps otherwise no changes at this time. 8am update: Quick update for the morning sky cover forecast based on using latest visible satellite imagery. Stratus and areas of fog only along midcoast Maine and sunny elsewhere over far southern and coastal areas of Maine and southeast New Hampshire. Rest of forecast looks good so no other changes needed at this time. 627 AM...minor ESTF update to reflect current satellite trends and to ingest the 10z mesonet into near term grids. Prev disc... Due to onshore winds and building seas, there is a moderate risk of rip currents along the coast of Maine and New Hampshire today. At 06z...a 1024 millibar high was centered south of Newfoundland. A 991 millibar low was centered over northern Ontario Province with a trailing cold front through the eastern Great Lakes. GOES infrared imagery showed broken clouds and patchy fog developing across the region in the persistent onshore flow courtesy of the Newfoundland surface high. For today...clouds along with coastal stratus and fog should lift and breakup for at least several hours this morning before the more significant cloud shield with the approaching cold front arrives this afternoon. Highs today should be mainly in the 70s...with a few 80 degree readings mainly over southern New Hampshire and the Connecticut valley. A band of showers...and possibly some embedded thunder...arrive in the Connecticut valley towards dusk ahead of the cold front with scattered showers possible further east.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/... The cold front will sweep east across the forecast area tonight accompanied by a band of showers with locally heavy downpours. By morning...its cleared the coast with any lingering morning showers confined to our far eastern Maine zones as well as the mountains. QPF will range from as much as one and a quarter inches in the mountains to between one-half and three quarters of an inch elsewhere. Lows tonight will range from the 50s in the mountains to the lower and mid 60s elsewhere. On Monday...lingering morning clouds and widely scattered showers for the mountains...otherwise a mostly sunny day in the downslope flow. Highs will range from the 60s in the mountains to the 70s elsewhere. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... High Impact Weather Potential in the Extended Forecast: Minimal. High pressure settled over the Appalachians Monday night will continue to allow for cold air advection over Northern New England Monday night. Much drier air settles into the region with dew points dropping into the 40s across the majority of Maine and New Hampshire. Despite gradient, winds may decouple in sheltered inland valleys by late at night. This will lead to the chillest readings in quite some time with overnight lows in the 40s inland with lower 50s along the coast as H8 temperatures drop to about +7C. This sets the stage for a September like day on Tuesday with partly sunny conditions and dry 70s over the region for highs. Still plenty of cold air aloft and cyclonic curvature along with relatively steep lapse rates to allow for CU to develop during the day. Warm air advection aloft will allow for an inversion Tuesday night. This will likely lead to more patchy fog. This developing west to southwesterly flow will lead to a rebound in temperatures by Wednesday as a surface ridge of high pressure exits off the New England coastline. Daily highs in the 80s will become more widespread. By Thursday, warm conditions will persist with a slow, gradual increase in dew points and humidity values continuing. This will continue on Friday, however a developing trough of low pressure associated with a cold front near the coast may allow for cooling conditions right along the waters edge during the day. With the heat and humidity in place, scattered showers and a few thunderstorms are possible during the day. However, there is not a well established moisture connection from the Atlantic or the Gulf of Mexico so rainfall amounts are not expected to overly heavy. In essence, the dry trend continues in the most part for the extended. There will be more dry conditions behind this front. Although readings will cool down below this front, a southwest flow aloft will still keep temperatures near or above normal for this time of the year. && .AVIATION /14Z SUNDAY THROUGH THURSDAY/... Short Term /through Monday/...VFR conditions will be variable to IFR/LIFR in developing areas of coastal stratus and fog as well as some interior late night valley fog. Valley fog burns off by 14z today...but coastal low clouds may remain. By tonight showers associated with a cold front will produce widespread MVFR/IFR conditions. Conditions improve to vfr Monday morning with a NW surface wind gusting up to 20 kt. Long Term...VFR conditions look to dominate flying conditions through Thursday...with restrictions limited to overnight fog potential each night HIE/LEB and possibly CON. && .MARINE... Short Term /through Monday/...light south to southeast flow will increase later today and early tonight ahead of a strong cold front any may briefly approach small craft in gusts outside of the bays. Seas will also build but should remain just below 5 ft. Northwest winds follow the cold front for late tonight and Monday with winds and seas expected to remain below small craft threshold. The increasingly southerly flow and building seas will result in a MODERATE RISK of RIP CURRENTS along area beaches today. Long Term...Winds and waves to remain below sca levels with northwesterly winds turning southwesterly for Wednesday and Thursday. Southwesterly winds may reach SCA levels on Thursday night and Friday. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ NEAR TERM...Marine SHORT TERM...Marine is the U.S. government's official web portal to all federal, state and local government web resources and services.