Area Forecast Discussion
Issued by NWS Portland, ME
Issued by NWS Portland, ME
426 FXUS61 KGYX 011855 AFDGYX Area Forecast Discussion National Weather Service Gray ME 255 PM EDT Thu Oct 1 2026 .WHAT HAS CHANGED... No significant changes with this forecast update. && .KEY MESSAGES... 1. Very warm temperatures continue through Friday before a cold front returns the region to more seasonable weather. 2. A polar air mass brings the coldest overnight temperatures so far this season early next week. Many locations south of the mountains may see their first hard freeze. && .DISCUSSION... KEY MESSAGE 1 DESCRIPTION... Increasing cloud cover and warm advection overnight will keep low temps very mild for this time of year. Temps Fri morning may actually be closer to average highs this time of year. That will lead to another well above normal day for most of the area Fri. The one exception will be across the mtns, where clouds and showers will arrive early enough to cap daytime heating. Here I blended in hi-res guidance to the NBM to knock those readings back into the 60s. Otherwise the high floor start to the day will allow temps to run well into the 70s again with some 80s possible. The rain showers will not be much to write home about as the front moves thru the region. Most areas should remain less than a tenth of an inch. Otherwise any rain will make valley/radiation fog more likely Fri night as we clear out. KEY MESSAGE 2 DESCRIPTION... A polar air mass brings the coldest overnight temperatures so far this season early next week. Many locations south of the mountains may see their first hard freeze. DISCUSSION: Strong high pressure slides through the area this weekend bringing dry and cooler weather. The front slides through during the day Saturday so temperatures in areas north of the mountains top out in the upper 50s and low 60s. From the foothills south, there should be enough time to warm into the mid to upper 60s. The front should be through Saturday night so just about everyone likely wakes up to temperatures in the 30s Sunday morning. Clouds then build across the region early on Sunday ahead of an approaching trough so after a chilly morning temperatures aren`t expected to rebound much and likely only climb into the low to mid- 60s areawide. On the other hand, clouds stay abundant Sunday night only allowing temperatures to fall into the upper 30s and 40s. Vertically stacked low pressure moves through Quebec on Monday and dragging a front through our region. Ensembles are not currently very excited about this being a worthwhile precipitation event as probabilities of greater than a tenth of an inch decrease to 10 to 30 percent outside of the mountains. The bigger weather story is going to be the cold dry airmass that fills in behind this front. In fact, any showers that linger in the mountains Monday night may transition to light snow. High temperatures Tuesday look to only reach the upper 40s to mid-50s from north to south, and with a tightening pressure gradient, breezy winds may make it feel even colder. Long range ensembles suggest dewpoints drop into the upper 20s and low 30s behind the front, and with 850 mb temperatures also -5 to 0 C this seems like a reasonable floor for surface temperatures Tuesday and Wednesday morning. The current NBM is capturing this reasonably well with upper 20s and low 30s across the mountains and foothills, and mid to upper 30s for the coastal plain. I wouldn`t be surprised to see those temperatures on the coastal plain come down as we get into the hi-res window as it looks like a favorable setup for radiational cooling. These zones are also still eligible for Frost/Freeze products, so this will have to be watched closely. Temperatures become more seasonable again Wednesday and Thursday night as high pressure exits to the east and we see southwesterly winds through the column. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... VFR conditions are expected to continue thru the first half of Fri. Southwest winds are expected to stir the air enough tonight to avoid both valley fog and marine fog/stratus. The best chance for IFR or lower CIGs will be RKD in the near term as the fog continues drift east. Then the front sags into the area and showers start to settle into the forecast area. Local MVFR or lower conditions will be possible in any steady/heavier rain rates. Clearing skies Fri night will promote valley fog, especially around HIE and LEB. Outlook... Saturday-Sunday: Generally VFR conditions are expected as high pressure moves through the region. Monday: Generally VFR with some brief MVFR restrictions possible in light rain and/or snow. Tuesday: VFR prevails once again as high pressure once again builds into the region. && .MARINE... Southwest winds will freshen tonight and continue thru Fri as a cold front sags into the region. This should be enough wind to keep marine fog/stratus confined to Downeast Maine or Nova Scotia. Otherwise winds and seas are expected to remain below SCA thresholds even after the wind shift to westerly. Generally sub-SCA conditions are expected as much of the forecast period is dominated by high pressure settling over the waters. However, a strong cold front crosses the waters Monday night and may elevate seas and wind gusts to SCA criteria. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ DISCUSSION...Baron/Legro