Area Forecast Discussion
Issued by NWS Portland, ME

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021 FXUS61 KGYX 142352 CCA AFDGYX Area Forecast Discussion...CORRECTED National Weather Service Gray ME 752 PM EDT Tue May 14 2024 .SYNOPSIS... After a warm day today, a cold front drops south through the region bringing the chance for showers and thunderstorms this afternoon and evening. A stalled frontal boundary will result in unsettled, showery weather for the remainder of the week and through the weekend with temperatures remaining seasonable for mid May. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
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745 PM Update...Showers continue to wane across the region with the loss of daytime heating. An additional stray shower or thunderstorm cannot be ruled out in the western and northern zones this evening but otherwise it will remain dry with fog development late. Previously... A cold front continues to sag southward into northern areas late today and tonight, as warm air continues to spread into southern areas. Some strong gusty thunderstorms and small hail remain possible across northwestern areas into this evening, with some convection starting to show up across northern New York and Vermont. The front makes slow southward progress into northern area tonight and then stalls by morning. This serves to keep most of the scattered shower activity across northern areas overnight, while a few isolated showers make it downwind of the mountains this evening. Most of the coast and southern areas remain dry, but an area of marine fog looks poised to move onshore through the MidCoast after midnight tonight. Additionally, some valley fog is likely across northern areas that see any showers or storms this afternoon.
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&& .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/... Tomorrow`s forecast is looking drier and warmer overall across interior locations outside of the mountains and western New Hampshire. The front looks to remain stalled and gradually wash out across northern areas tomorrow. At the same, a slow moving low pressure system tracks south of New England, spreading moisture northward to where there remains weak forcing along the front. This keeps at least scattered shower activity and clouds ongoing. Meanwhile, across the coastal plain and just back from the shoreline, enough sunshine looks to make it through to allow temps to warm into the 70s. A band of showers associated with the low pressure center may push into southern New Hampshire by late in the afternoon, but most of the rain associated with this system holds off until after dark. Showers and some scattered thunderstorms continue across northern locations through the evening, before waning through the overnight hours. Elsewhere, most of the night looks dry until closer to daybreak on Thursday, at which time more moisture from the low begins to push into southern New Hampshire. Guidance on this feature continues to wobble back and forth, but by late tomorrow night chances for rain increase across southern areas as the low moves closer. Most of Maine and central NH likely stay dry through sunrise on Thursday. && .LONG TERM /THURSDAY THROUGH TUESDAY/... A largely unsettled pattern persists over the area with fuzzy day-to- day details, but a straight-forward broad picture featuring daily chances for mainly-diurnal showers and predominantly mild conditions. From a synoptic standpoint, this is due to predominantly zonal flow over the NOAM mid-latitudes featuring a conga line of northern and southern stream disturbances embedded within the westerlies. At the surface, there is good model agreement keeping high pressure centered over Maritime Canada... and extending south along the New England Coast. The combination of the two gives neither a total- washout of an extended forecast, nor a dry stretch of weather... but somewhere in between. From a hazard perspective, slow-moving/stalled fronts with disturbances running along them will promote potential for back- building and/or training showers and some thunderstorms. Looking through ensemble analysis, it appears as if deeper moisture is shunted south on Thursday with an Atlantic low east of Carolina ingesting much of it... which limits the hydrological threat to some extent. However it cannot be ruled out entirely given the uncertain specifics of the pattern, especially if certain locales near these fronts (such as across the mountains) see repeated rounds of rainfall. This flow regime also promotes periods of onshore flow. Much like the last several days however a source region from the Maritime Canada high may not be humid enough to produce classic "socked in" conditions along the coastal plain. Early looks at boundary layer lapse rates suggests as much. So ultimately it looks like we`ll enjoy nicer weather than surface wind direction may otherwise imply with temperatures generally warming into the 60s and 70s... modified by afternoon showers and storms, and by the sea breeze. Ensemble solutions suggest the greatest inroads for the marine layer comes this weekend, with the aforementioned southern stream Atlantic low potentially drifting north and bringing some of its moisture into the easterly flow across the Gulf of Maine. Although humid, PoP has actually trended down around that time given a lack of adequate phasing and forcing. On a personal note, this is my final forecast for the WFO Gray office before shipping off to my next adventure. I`ve greatly enjoyed my last 5 years in Maine, especially the skiing and living in one of the greatest foodie cities in America. Many thanks to those I`ve had the privilege to call friends and/or colleagues, you`ve made this Michigander feel at home from day one. I`ll miss the Nor`easters, but maybe not so much the marine layer! You all are in great hands with this group of dedicated meteorologists (and hydrologists, and electronics technicians, and every other cog in the NWS wheel). && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... Short Term...VFR continues into the evening, and through most of tomorrow at most terminals. The exceptions will be RKD and AUG, where a period of marine fog likely brings IFR conditions after midnight tonight through tomorrow morning, before gradually improving tomorrow morning. Showers and an isolated thunderstorm are likely at HIE and LEB this evening, bringing brief restrictions. VFR prevails most of the day tomorrow, except at HIE where MVFR may linger most of the day. Ceilings gradually lower again tomorrow night, with marine fog possible at RKD and AUG again Long Term...Low confidence in the day to day details of the forecast exists, especially along the coast. However the pattern suggests prevailing VFR with potential for periodic restrictions in overnight FG or afternoon/evening SHRA. && .MARINE... Short Term...Some brief gusts to near 25kt are likely across the southern waters into this evening, but otherwise conditions are expected to remain below SCA levels through at least tomorrow night. A cold front stalls north of the waters tonight, with low pressure slowly tracking south of the waters through tomorrow night. Areas of dense fog are likely after midnight tonight across the eastern waters. Long Term...Weak pressure gradient force keeps winds and seas below SCA thresholds through the long range forecast period. The best chance for any sort of active seas comes with a swell off a distant Atlantic storm system, which may approach 5 ft over the weekend. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ SYNOPSIS... NEAR TERM...Clair SHORT TERM...Clair LONG TERM...Casey AVIATION... MARINE...