


Area Forecast Discussion
Issued by NWS Portland, ME
Issued by NWS Portland, ME
Versions:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
820 FXUS61 KGYX 251941 AFDGYX Area Forecast Discussion National Weather Service Gray ME 341 PM EDT Wed Jun 25 2025 .SYNOPSIS... Drier air will work into the region tonight bringing relief from the humidity into Thursday. Mostly dry conditions will prevail Thursday into Friday, although a front southwest of New England could lead to some showers at times across New Hampshire. Chances for showers increase late Friday with a soaking rain Friday night into Saturday as low pressure crosses New England. Weak high pressure will bring a drying trend Sunday into Monday with temperatures and humidity increasing ahead of a cold front Tuesday. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... Another hot day today, but relief is in sight as a cold front drops through the forecast area. Cumulus has been present much of the day throughout the forecast area, but growth has been limited by warm air aloft. The cold front bringing some of this lift will push south this evening. Consolidated shower chances a bit further south for this evening as window will be closing on enough instability and forcing. Main focus will be across southern NH and far southern ME. Can`t rule out a rumble of thunder or two in stronger cells, but deeper CAPE will be fleeting. Considering the dry air and inverted V model soundings this afternoon, good mixing is underway this afternoon. Thus stronger cells could also bring some gusty winds. Tonight, conditions will be more pleasant as overnight temps fall into the lower 60s and 50s and a light breeze. Temps may be slow to decrease in southern NH given the slow moving front and low level mixing. Temperatures may still be in the 70s here shortly after midnight. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/... A very pleasant start to Thursday, but clouds will be thickening and lowering into early afternoon. This cloud will eventually bring the chance of showers, but there is uncertainty on coverage and timing. Upper levels saturate quickly as moisture pushes through Upstate NY and Quebec, but broad dry layer in the mid and low levels. Believe this holds off measurable precipitation until Thursday evening for the mountains and foothills. Further to the south, low level moisture that has been positioned just to the south of the forecast area mid week will push north and showers across southern NH look to onset earlier in Thursday afternoon. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... High pressure will retreat to the northeast Friday as a low amplitude wave sends an area of low pressure across the eastern Great Lakes. This system will bring increasing chances for showers Friday afternoon followed by periods of rain Friday night into Saturday morning. Precipitation chances will gradually diminish Saturday night through Sunday as the low pressure system exits into the Atlantic. Weak high pressure builds in Monday for mostly dry conditions with increasing temperatures. A deeper trough will approach Tuesday with temperatures continuing an upward trend with increasing humidity ahead of a cold front. Latest guidance is in decent agreement that this cold front will cross the region near or just after peak heating favoring the development of thunderstorms. A period of cooler and cloudier weather is looking likely from Friday into Sunday. A warm front is forecast to impinge upon the area Friday bringing increasing clouds and chances for showers Friday afternoon. Highs will mainly be in the 60s with the warmest spots across eastern zones where there will be more sunshine Friday morning. The 12Z model suite brings a surface low WSW to ESE across New England Friday night into Saturday morning. This will likely bring a widespread soaking rain to much of the area. PWATs will be on the increase Friday night approaching 1.75 inches by Saturday morning along with warm clouds depths greater than 12KFT. The track of the low will keep the best instability well to the south of the area that should preclude rainfall rates from reaching their full potential given the high PWATs and deep warm cloud depths. Current QPF forecast from Friday through Saturday is around 0.75 to 1.25 inches south of the mountains with 1.5 to 2.25 inches across the mountains and north. WPC has the forecast area in a Marginal Risk for excessive rainfall through the duration of the event, which seems reasonable given the high PWATs but lack of instability. Steady rain will transition showers late Saturday into Saturday night with highs on Saturday mainly in the 60s. Low pressure will be offshore by Sunday while subtle waves aloft will keeps low chances for showers in the forecast. Highs on Sunday will range from the upper 60s north to mid 70s across the south. Weak high pressure will build in for mostly dry conditions Monday with highs climbing into the 80s. Temperatures and dewpoints will continue to rise into Tuesday that will foster an unstable airmass ahead of an approaching cold front. Models are in good agreement at this time range that a front will cross sometime Tuesday afternoon through Tuesday night that will bring chances for thunderstorms. && .AVIATION /19Z WEDNESDAY THROUGH MONDAY/... Short Term...Afternoon cumulus will dissipate later this evening with VFR conditions expected to continue. Still a few -SHRA possible in southern NH this afternoon and evening, but dry trend expected overnight and much of Thursday. Long Term...Mainly VFR Friday. Clouds thicken and lower Friday night with RA likely bringing at least periods of MVFR into Saturday morning. Conditions will improve some late Saturday into Sunday morning with a return to prevailing VFR Monday. && .MARINE... Short Term...Below SCA conditions expected to continue as a cold front passes the waters today. Gusty NE to N winds continue tonight, but will tend to slacken Thursday morning as high pressure nears from the NW. Long Term...A warm front approaches the waters Friday followed by an area of low pressure crossing Saturday. This system will bring increasing easterly flow with winds generally below 25 kts. The persistent easterly flow will bring seas to 5 feet Saturday into Monday. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...Heat Advisory until 7 PM EDT this evening for NHZ012-013. MARINE...None. && $$ NEAR TERM...Cornwell SHORT TERM...Cornwell LONG TERM...Schroeter