Area Forecast Discussion
Issued by NWS Portland, ME
Issued by NWS Portland, ME
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401 FXUS61 KGYX 141946 AFDGYX Area Forecast Discussion National Weather Service Gray ME 346 PM EDT Sun Jul 14 2024 .SYNOPSIS... Humidity will increase on Monday and Tuesday before a stronger cold front arrives late Wednesday with the potential for some showers and thunderstorms. It won`t be as hot with lower humidity behind the front at the end of the week into next weekend. && .NEAR TERM /THROUGH MONDAY/... Visible satellite imagery this afternoon shows some diurnally driven cumulus across the region but otherwise skies are mainly sunny. These sunny skies have allowed temperatures to warm into the upper 80s across much of the region with a few lower 90s in southern locations. Afternoon mixing has allowed sfc dew points to fall into the lower to middle 60s in most locations though, which is keeping heat indices near the actual air temperature. A sea breeze is slowly advancing inland over western ME but the westerly flow is slowing its forward progression. It will continue to be a warm and dry afternoon and evening with temperatures cooling towards sunset. Mainly clear skies tonight combined with light winds and relatively low dew points will allow for one more cool night with lows falling into the upper 50s across the north to the lower and middle 60s south. Valley fog is once again likely after midnight with perhaps some patchy fog across the Mid-Coast and islands. Mainly sunny skies on Monday morning will become partly cloudy by the afternoon as daytime instability combines with some weak forcing from a passing sfc trough. This will result in a building cumulus field with a few widely scattered showers and thunderstorms. A stronger storm or two cannot be ruled out with the primary threat being locally strong winds. H8 temperatures will be around 3-5 degrees warmer than today and this will allow highs to reach the lower to middle 90s south of the mountains. Dew points will also be on the increase with readings into the upper 60s/low 70s and this will help to push afternoon heat indices to the 95-100 degree range. A Heat Advisory has been issued to account for this across portions of the area. && .SHORT TERM /MONDAY NIGHT/... Scattered showers and storms will dissipate Monday evening with lows into the 60s. Nighttime fog is once again likely and it could be more widespread due to rainfall. && .LONG TERM /TUESDAY THROUGH SUNDAY/... %00 Mb pattern cross NOAM moves from a zonal to become more amplified by late in the week, with ridging over the inter- mountain west and troughing in the east. But before things become less warm, we still have several days of heat to go, as the ridge over the east gets a poleward push from the digging trough over the Great Lakes and Midwest. The trough will linger into next weekend, and while it will be cooler, temps will still be running on the warm edge of the normal envelope. On Tuesday it looks sunny enough with decent SW flow to mix the hot air aloft down to the sfc, and this will allow for highs of 90-95 everywhere but the mtns and the mid coast, with mostly mid 90s in S NH and interior SW ME. The SW flow and mixing should keep Tds limited to around 70 F, so while it will be hot and humid Heat indices are expected to top at out a little over 100, and not reach the 105 warning criteria. Still it will be a day where staying cool and hydrated will be important. It will be unstable enough to pop a few isolated convective cells almost anywhere, and with a weak passing well to the N, there will be a better chance in the mtns. But more areas will stay dry than see any SHRA/TSRA. Tuesday night mins will mostly be 70-75, but upper 60s in the mtns and the mid-coast, perhaps warmer in the more populated areas of S NH. SCT showers and convection could linger in the mtns through the evening as well. Given the highs Tds some fog is possible ins sheltered areas, but the SW flow should remain strong enough, that it will only be patchy. Wed will be another hot day, but probably not quite as bead as Tuesday, as we see more in the way of clouds through the day, and the chance of SHRA/TSRA ahead oi the cold front to our NW. Could also see some turning of the flow onshore, with a better sea breeze in the afternoon, as the storms develop further inland. However, will probably need a heat advisory for one more day, although maybe with less coverage than Tuesday. The sfc front pushes offshore in the evening, but is expected to stall S of the CWA, so while the mtns and foothills may see the benefit of cooler temps and lowers Tds Wed night, it is unlike closer to the coast and in S NH, although it will be cooler than previous night with lows ranging from around 60 in the N to the mid to upper 60s in the S. 12Z Euro has stalled that front further S than some previous runs, but could still see a lot of clouds around in the S on Thu, with a chance of showers, and a chance of showers in the N Thu afternoon as the upper level trough approaches. Highs will be in upper 70s to mid 80s. The trough stays well to our N Friday and Saturday, and will usher in more seasonable mid level air, and highs both days look to be 75-80 in the mtns and in the low to mid 80s S of there, with over night lows ranging from the mid 50s N to the low to mid 60s in the S. && .AVIATION /20Z SUNDAY THROUGH FRIDAY/... Short Term...VFR conditions dominate tonight through Monday night. The exception will be at KLEB and KHIE where valley fog and IFR to LIFR restrictions are likely each night. Some fog is also possible at KRKD and KAUG, although of lower confidence. Winds will be primarily out of the west-southwest at 10-15 kts. No LLWS is expected. Long Term...Tuesday and Wednesday will be hot days with high humidity and warm lows Tue night. A few SCT TSRA are possible on Tue afternoon as well. Fog will likely be limited to the KHIE/KLEB Tue night as SW flow does keep it a bit overnight. A better chance for TSRA is expected Wed aft/eve, as if overnight fog Wed night. A few isol TSRA remain possible on Thu, but Friday looks dry attm, with VFR. and the threat of fog each night. Also SCT TSRA are possible both afternoons. The next chance of more widespread flight restrictions will be Wed night into Thu morning as the cold front pushes through and may stall just off shore. && .MARINE... Short Term...South-southwesterly winds will mainly remain below 25 kts through the period but a few gusts to near 25 kts are possible Monday across the outer waters. Seas will be at 2-4 ft, highest outside the bays. Long Term...Generally winds/seas stay below SCA levels through the coming week, but could approach SCA gusts late Wed or Wed night in advance of a cold front. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...Heat Advisory from noon to 8 PM EDT Monday for MEZ012-018>020- 033. NH...Heat Advisory from noon to 8 PM EDT Monday for NHZ004-006- 008>010-012>015. MARINE...None. && $$ NEAR TERM...Tubbs SHORT TERM...Tubbs LONG TERM...Cempa