


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
38
39
40
41
586 FXUS61 KGYX 030613 AFDGYX Area Forecast Discussion National Weather Service Gray ME 213 AM EDT Thu Jul 3 2025 .SYNOPSIS... A cold front will approach from the west this afternoon with more showers and thunderstorms, a few of which could be strong to severe. That front will usher in a much drier air mass for Independence Day, with temperatures in the 70s and 80s and comfortable relative humidities. The weekend will gradually get warmer and more humid with shower chances mainly confined to the mountains on Sunday. && .NEAR TERM /THROUGH TODAY/... A short wave trough and attendant SFC cold front will approach from the west today providing the necessary forcing for ascent for thunderstorm development. By late morning and afternoon MLCAPE, deep shear, and low/mid level lapse rates will be supportive of scattered severe thunderstorms with damaging winds being the main threat, especially with low to mid level theta-e differences approaching 30 K. This will support wet microbursts. With the air mass generally uncapped, we will probably see the onset of storm development between noon and 2 PM. The most likely modes will be line segments and organized multicell clusters, but deep shear values increasing to around 35 kt by late morning may foster the development of isold supercells with the attendant risk for large hail this afternoon. Have added damaging wind wording to the forecast for nearly all zones as even the coast will not be completely out of the woods. This is in agreement with the SPC`s upgrade to slight risk. && .SHORT TERM /TONIGHT/... Any thunderstorm activity should end early this evening with the passage of the short wave trough. Clearing is then expected except for some fog on the Midcoast. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... A more comfortable airmass settles in Friday featuring highs mainly in the mid 70s to lower 80s with lower dewpoints/humidity. As the upper low crosses into the eastern part of Maine, it may set off a few showers and a storm or two across northern areas, but the vast majority of the area will stay mostly to partly sunny and dry. Friday night temps will be mostly in the 50s, but northern valleys may see the upper 40s. Mostly dry conditions are expected over the weekend as a 500mb ridge steadily builds in, although models are hinting at a weak wave moving in on the northwest flow aloft, which may bring a few showers across the north Saturday night. Otherwise, the building ridge will bring a warming trend with highs in the low to mid 80s Saturday, and by Sunday, lower 90s are possible across portions the area as 850mb temps are progged to get to around +19C with humidity also creeping back upward as a front approaches from the north. Speaking of the front, there`s been a slowing trend in its approach, so chances for precip have continued to decline for Sunday with most expected to stay dry at this point, except maybe far northern areas where PoPs remain at 20-30%. The front begins pushing southward early next week with the higher chances for showers and thunderstorms coming Monday into Tuesday. It looks to remain hot Monday, and then temperatures may come down Tuesday into Wednesday depending on how far south the front progresses. && .AVIATION /17Z WEDNESDAY THROUGH SUNDAY/... Short Term...Scattered showers and thunderstorms are expected this afternoon ahead of a cold front. Some may produce SFC wind gusts in excess of 45 kt. In between storms, VFR conditions are expected, except perhaps at RKD where fog may be in and out. Main VFR conditions tonight except for the possibility of low vsbys in fog at RKD. Long Term...Mainly VFR Friday with a couple of showers possible, mainly north of an AUG-HIE line. Over the weekend, prevailing VFR during the day, but there may be valley fog at night. A front approaching from the north may bring a chance of showers and storms as early as Sunday, but it`s more likely showers and storm hold off until Monday. && .MARINE... Short Term...Conditions are generally expected to remain below SCA levels today. However, locally dense fog may be present at times off the Midcoast today through tonight. Long Term...SCA conditions not expected Friday with offshore flow behind a frontal boundary...but may become more variable in the afternoon as a seabreeze tries to develop. High pressure becomes centered southeast of the waters over the weekend into early next week as a frontal boundary approaches. The pressure gradient may become tight enough to bring SCA conditions as south to southwest winds increase in the late Saturday through Monday timeframe. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ NEAR TERM...Ekster SHORT TERM...Ekster LONG TERM...Combs/Cornwell