Area Forecast Discussion
Issued by NWS Portland, ME

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527 FXUS61 KGYX 170954 AFDGYX Area Forecast Discussion National Weather Service Gray ME 554 AM EDT Tue Sep 17 2019 .SYNOPSIS... A weak trough will drop south across the area today and tonight with a few clouds and widely scattered sprinkles. High pressure will build across the region Wednesday and remain through Friday. This will result in some chilly nights, with the potential for a frost or freeze Wednesday night in several areas. Warmer than normal weather is expected late week through at least Monday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 553 AM...Minor ESTF update to reflect the current mesonet and low cloud trends in near term grids. Prev Disc... At 06z...an east-west surface boundary was over northern Maine. A 1024 millibar ridge extended from the Great Lakes through northern Quebec. GOES infrared imagery showed an area of broken clouds across northern and eastern areas with the trough. Elsewhere...clear skies and light winds were allowing valley fog and stratus to form. For today...fog and stratus should quickly burn off with clouds gradually spreading further south and west with the trough and daytime heating. The most sunshine will be found across southern and western sections of New Hampshire today where highs will be in the upper 60s to around 70. Elsewhere highs will be in the lower and mid 60s with a few upper 50s along the international border. It should be a dry day..although a brief sprinkle can`t be ruled out over our far eastern Maine zones this afternoon. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... Tonight the surface boundary/weak backdoor front continues to settle to the south and west along with a band of broken cloud cover and the chance for a few sprinkles or patchy drizzle over southern and coastal sections. Where we keep the clouds for the balance of the night lows should be in the 40s. Where we do clear it`ll be a chilly night with lows in the mid and upper 30s with the chance for spotty frost before fog and stratus forms. On Wednesday...the boundary should dissipate with rising heights and building high pressure making for a sunny but cool day with highs in the 60s. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... High pressure is expected to settle over the region Wednesday night. Clear and calm conditions are expected which should allow for strong radiation cooling. The result will be quite a bit of valley fog as well as a frost and perhaps a freeze in some areas. The fog will burn off Thursday morning revealing a sunny day with high temperatures right around normal. Another radiational cooling night is expected Thursday night with high pressure remaining overhead. Deep layer ridging builds in Friday through the weekend allowing for high temperatures to rise to above 10 degrees above normal with little in the way of clouds expected. A cold front looks to approach on Monday on several guidance sources, but it may gradually wash out as it approaches which should only allow for a few SCT showers and thunderstorms and may not bring much of a change to our warm air mass. && .AVIATION /10Z TUESDAY THROUGH SATURDAY/... Short Term /through Wednesday/...VFR. Lcl IFR/LIFR 08 - 12z this morning and Wed morning in valley stratus and fog. Long Term...VFR conditions are expected Wednesday night through the weekend. However, nighttime and early morning valley fog is expected. && .MARINE... Short Term /through Wednesday/...Winds and seas remain below SCA threshold as high pressure gradually builds in. Long Term...Winds and seas are expected to remain below SCA thresholds Wednesday night into the weekend. However, some long period swells may begin to arrive from the east later in the weekend into early next week. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ ES

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