Area Forecast Discussion
Issued by NWS Portland, ME
Issued by NWS Portland, ME
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678 FXUS61 KGYX 201715 AAB AFDGYX Area Forecast Discussion...UPDATED National Weather Service Gray ME 115 PM EDT Sat Jul 20 2024 .SYNOPSIS... High pressure provides fair weather today. A cold front drops south tonight through Sunday that will bring the chance for isolated showers. Otherwise, mostly dry conditions continue into Monday. Moisture increases Tuesday with daily chances for showers and afternoon thunderstorms into Friday. High pressure looks to return for next weekend. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 945 AM Update: Only very minor changes to the forecast this morning to align near term temperatures and dewpoints with mid morning observations. 12Z GYX RAOB shows robust subsidence inversion around 790 MB which...with a relatively dry boundary beneath suggesting some scattered clouds with some high clouds also streaming overhead from shower activity across the Mid Atlantic. A warm/dry afternoon is expected with highs south of the mountains reaching well into the 80s. 630 AM Update...Minor changes were made to sky cover and temperatures to reflect observational trends. Previously... High pressure centered south of New England will allow for another day of fair weather today. Skies will start off mostly clear outside of some patchy valley fog early this morning. Waves of low pressure moving through the Mid-Atlantic will spread some cirrus into southern areas this afternoon. A cold front dropping south through Quebec will lead to steady WSW winds through the afternoon. These steady WSW winds will limit the inland penetration of a sea breeze with highs generally in the mid to upper 80s with comfortable humidity levels as dewpoints will be in the 50s. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/... The cold front in Quebec will start to weaken as it approaches northern zones tonight. This front will bring scattered showers across the north tonight. Winds also look to remain steady overnight limiting radiational cooling. Lows will not drop as low as last night and will range from the 50s north to the 60s across the south. The cold front continues to weaken as sinks into southern zones Sunday. Mesoscale models generally keep the forecast area dry as the front drops south of the mountains while an isolated shower cannot be ruled out. Highs on Sunday will range from the 70s across the north to mid 80s across the south with winds shifting more northwesterly. && .LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/... Overview... A stalled front lingers over New England into the middle of week as a ridge builds in from the southeast, bringing increasing moisture and chances for showers and storms. It takes until late in the week for the next front to push through to bringing any meaningful clearing as high pressure gradually builds in from the west. Details... The front wobbles back and forth for a few days, with scattered showers and storms developing in the afternoon. Monday looks like the best chance for a dry day, with the front most likely south of our forecast area. By Tuesday, the front begins to drift northward with increasing moisture as the ridge builds along the Northeast coast. This threat increases into Wednesday as the front remains nearby while moisture continues to increase. Wednesday looks to feature the most widespread threat for showers and storms. There is the threat for some areas of heavier rainfall, but we`ll have to wait until we`re closer in time to try to pin down these locations and see where the stalled front has drifted to by that timeframe. By Thursday, a weak wave of low pressure may try to develop and drift along the front as a stronger cold front approaches from the west. Showers and storms are likely again on Thursday with these features, but then chances drop by Friday as high pressure begins to build in from the west behind the front. In terms of temperatures, temps look to remain warm for Sunday and into the first part of the week as the humidity increases. Wednesday and Thursday look like the only chances for highs to get close to or just a hair below normal with the rain and clouds. Then by Friday and into next weekend temps warm again as the sunshine returns. && .AVIATION /18Z SATURDAY THROUGH WEDNESDAY/... Short Term... Summary: A cold front crosses the region from north to south late tonight and Sunday with clouds and a few showers before much drier air moves into the region with clearing skies late Sunday and Sunday night. Restrictions: VFR conditions are expected to dominate the period through Sunday night. Increased cloud cover tonight will likely limit fog development except at LEB where there is potential for fog just before daybreak. Any shower activity is expected to be light and...while some localized restrictions are possible... confidence is not high enough to include mention of them in this afternoon/s TAF package. Winds: Outside of a robust seabreeze for coastal locations... southwest winds around 10kts will gradually diminish with all sites 5kts or less for the overnight. Winds become northwesterly and increase to 8g15kts for the day on Sunday with some potential for a seabreeze again at PSM. Winds go calm/light-variable Sunday night. LLWS: LLWS is not expected through Sunday night. Lightning: There is a very low /20%/ potential for thunder at CON-PWM-AUG Sunday afternoon. Long Term...Mainly VFR prevails during the daytime Monday through Tuesday, with nighttime valley fog likely each night. A stray afternoon shower or storm may bring brief restrictions at any terminal each day. On Wednesday and Thursday, showers and storms look more frequent with restrictions at times. VFR likely prevails from Friday into next weekend. && .MARINE... Short Term...Winds and seas remain below SCA thresholds today through Sunday with high pressure centered south of New England today. A weak cold front approaches the waters tonight shifting winds out of the SW and then briefly out of the NW Sunday morning before winds turn back onshore Sunday afternoon. Long Term...A front stalls and lingers across the waters on through early next week. Areas of locally dense fog are possible starting on Tuesday. These conditions continue through the middle of the week as a weak wave of low pressure moves along the front Wednesday and Thursday. Pressure gradients remain weak through next week, so conditions mostly look to stay below SCA levels. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ AVIATION...Arnott