Area Forecast Discussion
Issued by NWS Portland, ME

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945 FXUS61 KGYX 261312 AFDGYX Area Forecast Discussion National Weather Service Gray ME 912 AM EDT Tue Sep 26 2017 .SYNOPSIS... Warm, humid weather continues today and Wednesday, though it will be cooler for areas closer to the coast. A cold front will move into the area Wednesday night, bringing an end to this warm and humid air mass, replacing it with a cooler and drier one. This cooler, drier weather will last through the weekend. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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900 AM Update... Quick update to drop dense fog advisories. Vsby in most areas on the way up and any remaining fog will burn off over the next hour. Aside from a few temp/td other changes planned attm. Prev Disc... 715 AM Update... Plenty of fog will remain early this morning and dense fog advisories have been modified per current observations. Visibilities are down to a quarter mile in many areas. If LEB or CON were to reach 90 degrees today, they would have an official heat wave with three consecutive days in a row with readings at or above 90. With fog this morning and high clouds crossing the region today, have forecasted slightly cooler readings than yesterday. Nevertheless, most areas will top out between 80 and 90 degrees today with the warmest readings once again in southwest New Hampshire. Coolest readings will be along the coast, particularly the Midcoast region where ocean temperatures are the coolest with the onshore breeze. Otherwise, a large ridge of high pressure will continue to dominate the region today.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... Plenty of fog redevelops tonight through early Wednesday morning. By Wednesday afternoon, the long awaited cold front will be approaching the region. There will be a chance of a late day shower over northern areas. CAPE values increase and there may be sufficient instability for thunderstorms as well. One or two of these storms could produce gusty winds. There may be a shower along the Midcoast as well as moisture converges along a prefrontal trough. Readings will continue to be above normal with temperatures still between 75 and 85 degrees for afternoon highs. This will be due to an increased southerly flow off the Gulf of Maine, so the warmest readings once again will be over southern and western New Hampshire away from the marine layer. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... Cold front crosses the area Wednesday night with a chance of showers or a thunderstorm as it does so. The best forcing for precipitation will be sliding to the northeast, so precipitation in our area will not be very widespread, with the northwest portion of the area most likely to see any rainfall. This front will be an air mass changer, with a cool, dry air mass moving in behind it and lasting through the weekend. An upper trough slides by on Saturday, possibly triggering a few showers, but mainly just serving to reinforce the cooler air. High pressure builds out of the Great Lakes and into the Northeast Sunday and Monday, bringing light winds and good nighttime cooling conditions. && .AVIATION /13Z TUESDAY THROUGH SATURDAY/... Short Term...Areas of LIFR conditions early this morning in fog, improving today. Areas if IFR and LIFR conditions redeveloping tonight with this very humid airmass. Long Term...There could be areas of IFR especially along the coast Wednesday night ahead of the cold front. The front should clear this out, though, with VFR conditions expected through the weekend outside of valley fog at night. && .MARINE... Short Term...Have placed areas of dense fog in the marine layer for much of the day. Visibilities will frequently be near a quarter mile in fog. Long period swells have arrived along the Midcoast region from Maria. Periods on 4 to 6 foot swells are up to as long as 6 seconds. Have issued SCAs for seas for the eastern outer waters based on this trend. Long Term...Long period swell may reach 5 to 6 FT through Thursday. A cold front Thursday morning will shift winds to the north, though wind speeds are expected to remain just below 25 KT. && .TIDES/COASTAL FLOODING... High surf advisories have been issued for much of the Midcoast region except for coastal Waldo County which is protected by islands in Penobscot Bay. The swells are being produced by Maria. Expect long period 4-6 foot waves to reach the shoreline today, mainly northeast of Portland. There will be a high risk for strong rip currents in this areas. && .GYX WATCHES/WARNINGS/ADVISORIES...
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ME...High Surf Advisory until 6 PM EDT this evening for MEZ025>027. NH...None. MARINE...Small Craft Advisory for hazardous seas until 6 PM EDT Wednesday for ANZ150-152-154.
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