


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
42
43
44
45
46
47
449 FXUS61 KGYX 241911 AFDGYX Area Forecast Discussion National Weather Service Gray ME 311 PM EDT Sat May 24 2025 .SYNOPSIS... Scattered showers will persist into early this evening as low pressure moves towards New Brunswick, Canada. It will take until Sunday before we get some slow improvement to the weather and temperatures with drier and warmer temperatures going into Monday. A warming and drying trend will continue into the middle of next week, but another period of unsettled weather is then likely once again by the end of next week. && .NEAR TERM /THROUGH TONIGHT/... Satellite imagery and latest RAP depicts the center of the upper low now over New Brunswick with the surface low nearly over the same area, per latest observations. Vort maxes associated with a couple of shortwave troughs stemming from the upper low will cross the area through early this evening and capitalize on the low-level instability generated from the steepening lapse rates to provide fairly high coverage of showers. For the next couple of hours, I have 50-60% PoPs across much of western ME and then 30-40% farther to the south and west across central and southern NH. These showers are capable of producing brief heavy downpours and maybe even graupel in a couple of them. Once this initial wave passes, we should start seeing a downward trend in showers toward early evening and then even moreso toward and after sunset with the loss of the diurnal instability. For tonight, the upper low continues to slowly move eastward and expect lingering showers to stay mostly in the mountains (and snow showers in the highest elevations) with partly to mostly cloudy skies to the south. Winds will again be light, and given the recent rains, patchy fog will again be possible. Lows will be mostly in the 40s. && .SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/... The stacked low pressure will be centered in the Nova Scotia vicinity on Sunday, setting up a northwest flow across New England. Upsloping will keep skies mostly cloudy from the mountains northward along with scattered showers, possibly still mixed with snow in the highest elevations. For areas to the south, forecast soundings depict steep low-level lapse rates resulting in a small amount of instability during the day. So even if there is some clearing tonight or early in the morning, sufficient moisture and the LL instability will probably bring periods of mostly cloudy skies during the day and perhaps a few showers, but chances are much lower than today with PoPs limited to about 20%. Temperatures will tack on a few degrees from today`s highs with most expected to reach the upper 50s to lower 60s, except a bit cooler still in the mountains. Shower chances mostly end around sunset, except could last a little longer in the mountains. Otherwise, expect partly cloudy skies overnight with low mostly in the 40s. MOS guidance is suggesting mid 30s possible across the north and may result in patchy frost. && .LONG TERM /MONDAY THROUGH SATURDAY/... Overview: High pressure expected for the first half of next week, though a diurnal shower or two can`t be ruled out across western NH. Towards the end of the week, two upper-level lows merge over New England. The upper-level lows could bring more unsettled and cooler weather next weekend. Details: The work week starts off mostly clear, as high pressure moves in from the Great Lakes. Diurnal heating should allow for warmer high temperatures approaching 70F most places, and a little instability could develop through the day as well. Northerly flow over the mountains may provide enough forcing for a couple pop-up showers to form Monday afternoon. Showers will be weak, and shouldn`t produce much rainfall. Any showers will fizzle out quickly after sunset. A mid-level ridge starts to build in Tuesday, with a warming trend expected in the first half of the week. High temperatures look to be in the mid-70s across most of the area, with cooler temperatures in the mountains and along the immediate coast. Ridging and warmer temperatures continue through Wednesday, with Wednesday looking like the warmest day of the week, but not much warmer than Tuesday. Towards the end of the week, two upper-level lows could barrel down on the northeast - one from the west and one from the north. The combination of these UL lows likely suggests that unsettled weather and showery conditions are likely starting Thursday and possibly continuing through the weekend. && .AVIATION /19Z SATURDAY THROUGH THURSDAY/... Short Term...Currently expecting a mix of MVFR and VFR ceilings through tonight and early Sunday. Sites mostly likely to see periods of MVFR through Sunday will be LEB and HIE, but AUG and RKD could see some too. Otherwise scattered showers persist this afternoon/early evening then gradually fade beyond 00Z through tonight. These showers may produce brief MVFR vsby, but then will have to watch for fog development tonight. Mostly VFR Sunday into Sunday night with a few showers developing Sunday afternoon, but HIE may continue to see MVFR ceilings. Long Term...A few showers may lower restrictions briefly on Monday, with VFR expected otherwise. High pressure and clear skies should allow for fair weather through the first half of next week, with no other opportunities for restrictions expected. && .MARINE... Short Term...Conditions are expected to remain below SCA levels through Sunday night. Low pressure to the northeast of the waters will keep winds out of the northwest, but these may become more west to southwesterly Sunday afternoon as a seabreeze tries to develop. Long Term...Fair marine conditions are expected through the first half of next week, with variable winds at 4-10kts and 1-2ft seas expected Monday through Wednesday. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ NEAR TERM...Combs SHORT TERM...Combs LONG TERM...Palmer