Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 281605 AFDGYX Area Forecast Discussion National Weather Service Gray ME 1205 PM EDT Fri Apr 28 2017 .SYNOPSIS... A warm front will work northward across the region today followed by a trailing cold front this afternoon. Another cold front will push across New England on Saturday. High pressure will build in from the northwest Saturday night and will shift offshore on Sunday as the stalled frontal boundary lifts north as a warm front. The warm front will stall over the region Sunday night and Monday. Low pressure lifting northeast out of the Great Lakes will drive an occluded front toward the region Monday night and will across the region on Tuesday. Low pressure will slowly move east through southern Canada Tuesday night through Wednesday. && .NEAR TERM /UNTIL 7 PM THIS EVENING/... 1202 PM...Surface cold front was over western New England at 15z. GOES water vapor imagery showed a weak impulse over eastern New York state that will ride northeast across the forecast area this afternoon. Expect some isolated convection to develop this afternoon associated with this feature, combined with daytime heating and proximity of weak surface boundary. For this ESTF update...only minor adjustments to reflect current mesonet. 905 AM...At 13z a warm front extended through eastern New England with a trailing cold front through eastern New York State. NWS Doppler Radar mosaic showed a band of convection from the Penobscot Valley southward through coastal New England. For today...low clouds and fog will gradually lift ahead of the surface cold front with additional scattered convection developing by afternoon with daytime heating and passage of weak impulse. For this ESTF update...I made adjustments to near term grids to reflect current satellite and radar trends as well as the mesonet. Prev Disc... 6 AM Update...Not much change to the previous forecast. Locally dense fog across mainly ME should gradually improve as the morning progresses. Otherwise, a short wave trough moving through the region this morning may bring a few showers and possibly a rumble of thunder before quickly moving out. Previously... A warm front situated over southern NH at 3 AM early this Friday morning will gradually work northward this morning and finally reach eastern zones this afternoon. Showers and isolated thunderstorms over Upstate NY in association with a short wave trough will continue to work northeastward early this morning, with the bulk of that activity missing our CWA to the northwest. However, we cannot rule out a shower or two this morning across the region as that weak forcing for ascent moves through. Locally dense fog and patchy drizzle will be around this morning as well, especially on the coast. It`s possible that a relatively small dense fog advisory may be needed for a few hours early this morning, but at this time visibilities are generally a half mile or more. Otherwise, a much warmer air mass moves in from sw to ne today in the wake of the warm front. Highs should reach 80 across southern NH with 70s in many other areas. The exception will be the immediate coast as well as the mid coast zones where fog may persist much of the day. Another short wave trough approaches from the west early this afternoon. This short wave will be accompanied by a SFC trough as well. This may be enough to spark a few convective showers this afternoon - perhaps even a thunderstorm or two as weak SFC-based instability develops. In fact, the HRRR and a few other convection allowing models do develop a storm or two today, particularly affecting central Maine. Have therefore inserted low PoPs this afternoon - mainly north of Cumberland County. && .SHORT TERM /7 PM THIS EVENING THROUGH 6 PM SATURDAY/... Quiet and dry weather is expected tonight, with perhaps some patchy fog. A short wave trough and associated cold front quickly approaches from the west late tonight and crosses the region Saturday. This will come through will little fanfare - just an increase in clouds and a couple of showers. Temperatures will once again be warm Saturday, with highs mainly in the 70s. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... High pressure will build in from the northwest Saturday night bringing clearing skies and diminishing winds. Lows overnight will range from the mid 30s north to the mid to upper 40s south. Stalled frontal boundary south of New England will begin to lift north to the west of the region on Sunday as high pressure shifts offshore. Looking for variable cloudiness during the day with a chance of showers....mainly in northwest zones. Highs will range from the mid 50s north to the mid 60s south. Warm frontal boundary will continue to lift into the region Sunday night with shower activity focused mainly across northern zones overnight. Increasing onshore flow will bring ocean stratus and patchy fog into the region overnight. Lows will range from the upper 30s north to the mid 40s south. Warm front will remain draped across the region on Monday as a moist onshore flow continues ahead of of a slow moving area of low pressure over the western Great lakes. Looking for occasional drizzle or scattered showers under cloudy skies. Surface low trapped under a broad upper low over the great lakes will drive an occlusion toward the area Monday night. Looking for showers and possibly a few thunderstorms as this boundary pushes into the region from the west by Tuesday morning. Expect this boundary to push east of the region on Tuesday with an increasing southwesterly flow behind the front clearing low level moisture. Highs on Tuesday will generally range through the 60s to near 70. Slow moving closed upper low will shift into the northeast Tuesday night and Wednesday. Will see increasing clouds Tuesday night with scattered showers shifting into the region from the west. Wednesday will remain cloudy...cool and unsettled as upper low remains in place over the region. Highs will range through the 50s to near 60. Another deep shortwave digging into the Ohio Valley will bring more wet weather for the end of the week after a brief respite on Thursday. Low pressure is forecast to spin up along the east coast and will bring another round of rain to the area Thurday night and Friday. System will likely slow as the upper low closes off over the northeast producing a prolonged rainfall across the area with several inches possible. && .AVIATION /16Z FRIDAY THROUGH TUESDAY/... Short Term...Low conditions early this morning will give way to VFR conditions by late morning, except the mid coast of Maine where fog may linger even into this evening. Otherwise, mainly VFR tonight and Saturday. Long Term...VFR Saturday night and Sunday. MVFR/IFR ceilings developing Sunday night with IFR/LIFR ceilings Monday through Monday night. Areas of MVFR ceilings on Tuesday. && .MARINE... Short Term...SCA for seas remains in effect for today on the ocean waters as swells of 4-6 ft continue to affect the waters. These will diminish tonight. Gusty winds will be possible Saturday in association with a cold front. Long Term...SCA`s likely Monday night and Tuesday. && .FIRE WEATHER... Warmer and drier conditions are expected today as a warm front moves to the north. A cold front will move across the region Saturday allowing for continued dry weather into Sunday. && .TIDES/COASTAL FLOODING... 11.7 ft tide at Portland once again tonight (1:32 AM Saturday). However, swells are expected to be lower tonight and winds offshore. Therefore we are not expecting any flooding at this time and will forgo any sort of coastal flood advisory at this this time. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...Small Craft Advisory for hazardous seas until 8 PM EDT this evening for ANZ150-152-154. && $$ ES

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