557 FXUS61 KGYX 262355 AAA AFDGYX Area Forecast Discussion...UPDATED National Weather Service Gray ME 755 PM EDT Sat Jul 26 2025 .SYNOPSIS... Smoke and haze from Canadian wildfires continue through this evening, but otherwise the rest of today remains warm with lower humidity. High pressure shuffles east as the next system moves in Sunday with chances of showers and storms, especially across southern NH. Heat and humidity begin to build again early next week. && .NEAR TERM /THROUGH SUNDAY/... 8pm Update: Quick update to drop the beach hazards statement for the Midcoast region and also to extend the haze mention through the remainder of the evening per visible satellite... webcams...and latest smoke forecasts from the HRRR. Otherwise no changes to the forecast as temperatures slowly settle back from afternoon highs with a dry profile overhead as per 26.00Z GYX RAOB. Previous Discussion Below... High pressure that is currently overhead will provide a warm and dry rest of the day today with humidity levels remaining comfortable as we mix down dry air aloft to keep dewpoints in the 40s and 50s. We`re starting to get some high clouds across western areas, and it may also remain hazy into early this evening as northwest flow aloft brings in Canadian wildfire smoke. The high will steadily shift to the east through tonight and give way to an approaching shortwave trough. Clouds will increase through tonight, which is expected to both keep temps a little milder than this morning and also largely prevent fog from developing. Forecast lows are mostly in the 60s, but far northern and eastern areas still could cool into the 50s with lesser/thinner cloud cover. A vort max associated with the incoming shortwave may start bringing showers into SW NH as we approach daybreak, but I think most of these will hold off until after. && .SHORT TERM /SUNDAY NIGHT/... Chances for showers and a few thunderstorms will increase through the morning and afternoon on Sunday as the 500mb shortwave crosses. Guidance continues to favor the southern half of NH and into far southwest ME for the higher of the precip chance with even better chances for SW NH. Increasing PWATS and a deep warm cloud layer suggest some of the showers and storms could contain heavy downpours with the latest HREF suggesting localized amounts of 1-1.5" rain possible across SW NH. Storms are not expected to be strong or severe with limited instability and it being mostly remaining elevated. These areas should see a decrease in chances later in the afternoon once the wave passes, but some degree of redevelopment is possible. Farther to the north and east, chances for precip decrease as the air will be drier and more subsident, but a secondary shortwave dropping to the south and east in Canada still may bring a few showers and storms in the afternoon and evening. Clouds and more precip will likely keep southern areas cooler and in the 70s, but less clouds to the north and east will probably still allow temps to reach the lower 80s. Mostly dry conditions are expected Sunday night, but a moist boundary layer and little to no low-level flow will allow for fog development in some areas, especially those that see rain on Sunday. Lows will be in the upper 50s to low 60s. && .LONG TERM /MONDAY THROUGH SATURDAY/... Overview: Warm and humid conditions will prevail early next week with scattered showers and thunderstorms, especially during the afternoon hours. Cooler weather will then arrive by the middle to end of the week through the upcoming weekend with mainly dry conditions. Impacts: Afternoon heat index values could reach the 95-100F range across portions of south-central NH and southwestern ME Monday and Tuesday. Otherwise, confidence is low for any hazardous weather at this time. Forecast Details: Monday will feature warm and humid conditions as H5 ridging builds overhead with sfc high pressure to our southwest. High temperatures will range from the upper 80s/lower 90s for interior locations with upper 70s/lower 80s along the coast due to onshore flow. A few afternoon showers and thunderstorms are possible as a weak stationary boundary remains in the region. A weak wave of energy may cross Monday night, allowing for a continued chance for scattered showers with the greatest potential of rain across the far north and mountains. Lows will be primarily into the 60s. Warm and humid conditions will persist on Tuesday ahead of a sfc cold front that will be approaching from the north. Ahead of this front, highs will soar into the lower to middle 90s south of the mountains with heat indices approaching 95-100F. Scattered showers and thunderstorms are possible, some of which may contain gusty winds. Lows will once again be mainly into the 60s. A secondary cold front will likely cross on Wednesday with scattered showers and rumbles of thunder under partly cloudy skies. A large temperature range is likely with readings ranging from the 70s across the north to near 90 in southern NH. Cooler air will begin to filter in on Wednesday night with lows into the 50s/60s. The rest of the week and the upcoming weekend will feature cooler temperatures as troughing develops over the Northeast. Other than a few scattered showers at times, much of the period will be dry. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... Short Term /through Monday/... Summary: A trough will push through the region on Sunday bringing deteriorating conditions and a chance of showers and an embedded thunderstorm. High pressure and improving conditions arrive for Monday. Restrictions: VFR conditions through tonight...with deterioration to MVFR south of HIE from west to east on Sunday as clouds lower with showers and embedded thunderstorms possible. Any shower/storm activity will end by mid/late afternoon. Skies clear Sunday night...with overnight fog possible throughout the region. Winds: Winds currently diminishing to 5kts or less for the overnight before shifting southerly 10g15kts for the day Sunday. Winds again diminish to 5kts or less Sunday night before shifting northwest 5- 10kts for the day Monday with afternoon seabreezes PSM/PWM/RKD. LLWS: 1-1.5kft southwesterlies increase to 20kts overnight...a bit short of LLWS criteria. This llevel shear will end quickly Sunday morning as mixing commences with no LLWS expected through Monday. Lightning: There is some potential for thunder for LEB/CON/MHT/PSM by late Sunday morning through mid afternoon. No thunder is expected beyond this through Monday. Long Term...Mainly VFR conditions are expected through the period outside of any scattered SHRA/TSRA. Some valley FG and marine FG may develop mid-late week as well, possibly bringing localized restrictions. && .MARINE... Short Term...SCA conditions are not expected through Sunday night. High pressure will shift east of the waters tonight with south to southwest flow prevailing ahead of a weak low pressure and front that will bring showers and few storms to the waters Sunday morning and afternoon, primarily south of Casco Bay. The weak front crosses sometime Sunday night, and winds may shift briefly to more westerly. Long Term...Winds and seas to remain below SCA criteria through the period as a series of weak fronts move near or across the waters. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...Air Quality Alert until 11 PM EDT this evening for MEZ007>009- 012>014-018>028-033. NH...Air Quality Alert until 11 PM EDT this evening for NHZ001>015. MARINE...None. && $$ NEAR TERM UPDATE...Arnott AVIATION UPDATE...Arnott