NWS Forecast Discussion
For Fremont, NH
220 FXUS61 KGYX 140128 AFDGYX Area Forecast Discussion National Weather Service Gray ME 928 PM EDT Sun Jun 13 2021 .SYNOPSIS... A trough of low pressure will bring a few showers and possibly a thunderstorm for the beginning of the work week. Clouds and showers exit to the east by Wednesday with fair weather and comfortable temperatures expected through Friday. A warm trend precedes the next chance for precipitation, which will be over the weekend as a frontal system approaches from the west. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... 925 PM Update... Made some adjustments to temperatures, winds, and sky cover based on surface observations and satellite imagery. High cirrus continues to stream in from the southwest, especially across northern locations. PoPs were also adjusted through tomorrow based on the latest near term forecast guidance. Expecting rain showers to first approach southwestern NH towards dawn on Monday before gradually advancing to the north and east through the day. This rain will likely struggle to reach the surface initially, especially across Maine as the 00Z KGYX sounding shows a dry layer extending up to around 700 mb. As a result, rain onset times were delayed some across eastern areas. The rest of the forecast remains on track. Previously... 730 PM...A quick update, mostly to sky and temps based on current obs. I think going forecast POPs are good for arrival of showers later tonight across N and E zones. Lows should bottom midnight or shortly there after in most spots and remain steady there through the night generally in the mid 50s to 60. Previously...An advancing trough of low pressure will allow for an increase in cloud cover later tonight over western portions of the forecast area. Sufficient diffluent flow aloft and increasing moisture will allow for scattered late night showers over western portions of the forecast area. Prior to the increase in cloud cover and scattered showers, some patchy fog is possible, mainly over the Connecticut River Valley. Temperatures will drop into the 50s for overnight lows in most areas. A few locations in southernmost New Hampshire will remain at or above 60 degrees. && .SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/... The trough will continue to approach the region from the west Monday. Showers will gradually spread east during the day, reaching the Penobscot River Valley by late in the day. CAPE values increase as the atmosphere destabilizes and heights fall aloft, leading to a few thunderstorms during the day. A southerly flow will increase off the Gulf of Maine. This will keep temperatures a little cooler along the immediate coastline and unfortunately lead to a dampening effect of the well needed precipitation. A few showers and thunderstorms will continue into Monday night. A few of the storms Monday evening may contain pea sized hail as heights continue to fall across the region. By late Monday night, both the surface and upper level trough will remain west of our forecast area. && .LONG TERM /TUESDAY THROUGH SUNDAY/... A long wave trough will be positioned over the eastern CONUS Tuesday with the trough axis just to our west. A vort maxima or two will rotate through the base of this trough along with a surface trough setting up over New England Tuesday into Tuesday night. This will bring periods of showers and a chance for thunderstorms centered on Tuesday afternoon with a drying trend expected into Wednesday. The long wave trough will be stubborn to migrate eastward Wednesday into Thursday keeping temperatures near their seasonal norms with highs in the 60s north to 70s south. Ridging aloft builds in Thursday night into Friday for a warming trend Friday into Saturday. Another trough approaches from the west Saturday with a frontal system crossing the area Saturday into Sunday. Tuesday will start off with mostly cloudy skies with pockets of showers and fog. CAMs and global models indicate that cloud cover will thin with some breaks of sun late Tuesday morning allowing for the atmosphere to destabilize as lapse rates steepen from the approaching trough axis. This will lead to SBCAPE to climb into the 500 to 1000 J/kg range early Tuesday afternoon. As CAPE increases the best shear will be shifting offshore placing the best overlap over the foothills and Lakes Region of New Hampshire through the coastal plain. Chances for thunderstorms will increase late Tuesday morning into the afternoon as a surface trough sets up ahead of a cold front in Canada. Chances for widespread severe convection look to remain low as parameters don`t quite overlap well. However, there remains uncertainty with timing differences of vort maxes translating through the long wave trough and can`t rule out the chance for a few strong storms. Areal coverage looks widely scattered with chances that some towns remain dry Tuesday. The long wave trough does not move much Wednesday into Thursday as an upper low closes off to our north. Drier air will filter in Wednesday on northwest winds, although cyclonic flow aloft will lead to some afternoon clouds with a slight chance for a shower in the mountains. Thursday will be similar to Wednesday as the upper trough slowly shifts off the East Coast. Ridging aloft builds in Thursday night into Friday allowing for highs to climb into the mid 70s to low 80s Friday into Saturday. The next upper trough looks to swing through the Great Lakes Saturday with the potential for a frontal system to cross the area Saturday afternoon into Sunday. && .AVIATION /01Z MONDAY THROUGH FRIDAY/... Short Term...VFR conditions expected in most areas tonight. There may be some late night patchy fog in the Connecticut River Valley briefly lower restrictions to IFR. Showers late tonight gradually spread east on Monday with generally MVFR conditions. A thunderstorm in possible. Areas of IFR and LIFR conditions develop Monday night in showers, thunderstorms and patchy fog. Long Term...Areas of IFR/LIFR Tuesday morning in showers and fog with some improvement to MVFR/IFR late Tuesday morning into early afternoon. Scattered showers and -TSRA late Tuesday afternoon will bring pockets of restrictions with a drying trend expect Wednesday for IFR through the end of the work week. && .MARINE... Short Term...An approaching trough will allow for a southerly wind to increase overnight. There may be a couple gusts near 25 kt during the midday hours on Monday as the southerly gradient briefly increases. Fog will lower visibilities Monday night as moisture increases over the Gulf of Maine. Long Term...There will be some reduced visibility Tuesday morning in scattered showers and fog with southerly winds. Southerly winds will shift out of the northwest Tuesday night into Wednesday for a drying trend. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ NEAR TERM...Cempa/Tubbs