884 FXUS61 KGYX 302305 AFDGYX Area Forecast Discussion National Weather Service Gray ME 705 PM EDT Fri Jun 30 2023 .SYNOPSIS... Ridging aloft will allow for mostly dry conditions through Saturday. A series of upper waves will start to impact the region Sunday through Tuesday bringing chances for showers and storms with potential for locally heavy rain centered on late Sunday into Monday. Ridging then looks to build in for the middle to second half of the week for mostly dry conditions and temperatures trending upwards while the humidity will remain. A cold front then approaches late in the week into the weekend. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... 7 PM Update...Little going on the way of precipitation at this hour and this trend is expected to continue overnight with mainly dry weather expected except for perhaps a isolated shower two. Low clouds and fog will continue to advect westward on the coastal plain this evening, with the potential need for a dense fog advisory a little later this evening. Previously... S/WV ridging is providing us a small respite from rainfall as weak forcing and dry air aloft has limited afternoon convection to isolated small showers along the higher terrain. With the loss of daytime heating these showers will start to dissipate as they continue to drift north. Of greater concern will be marine fog and stratus. Onshore flow continues overnight...much like last night. I expect that around sunset the low clouds and fog will begin streaming back into coastal zones. It is already streaming inland at the Seacoast...and never cleared the Casco Bay area. I have areas of dense fog in the forecast tonight...but guidance is a little higher on visibility especially for the Midcoast so I did not issue a dense fog advisory at this time. It may be more locally dense than widespread. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... Sat the strongest forcing remains to our west during the day...so convection is expected to stay west of the CT River Valley for most of if not all of the daylight hours. Outside of the fog...temps should be able to climb into the 80s. Where fog takes longer to scatter out temps will be slightly cooler...much like today around PWM. Sat night decaying convection will start to spill into the western portion of the forecast area. Given all the rainfall and moist conditions lately the top concern is flooding. At this time storm motion does not look to be fast...around 15 kt...but fast enough that significant training is not anticipated. If storm motion vectors start to become oriented more along the boundary that would be more cause for concern. && .LONG TERM /SUNDAY THROUGH FRIDAY/... One short wave will pass north of the area Sunday while a second wave moves into the Great Lakes. This second wave will sharpen going into Monday giving rise to an area of low pressure that will slowly cross New England through Tuesday. This will bring yet another period of unsettled weather with potential for widespread showers with embedded heavy rain. Low pressure will pull away from the area Tuesday night with potential for a few mostly dry days the second half of next week as ridging builds in. A cold front then looks to approach the region late Friday into the weekend for renewed chances of showers. Temperatures will start the period near normal and will trend upwards through the end of next week while the humidity will remain with dewpoints approaching oppressive levels around 70 degrees. A weak front associated with the short wave passing to the north will sag into the forecast area Sunday providing a focus for showers with PoPs increasing from north to south. Temperatures will range from near 70 degrees near the Canadian border to near 80 degrees across southern NH. Low pressure developing to our southwest will start to shift this front northward late Sunday into Monday as a warm front. This will allow for temperatures to creep upwards Monday along with dewpoints climbing into the upper 60s to low 70s. The 12Z model suite suggests that southern portions of the area will reside within the warm sector, although how far north this warm sector gets varies amongst model solutions. Within the warm sector instability is projected to build in excess of 1000 J/kg, which will be sufficient for thunderstorms. PWATs will be very high Sunday night into Monday with values approaching two inches. Thus, the combination of high PWATs and convective processes will bring the threat of heavy rain and WPC places much of the area in a Marginal Risk for excessive rainfall Sunday into Monday. Low pressure and the short wave aloft will take their time traversing the area through Tuesday maintaining chances for showers and storms through the holiday. PWATs will trend downwards going into Wednesday as short wave ridging builds in from the west while surface dew points will remain elevated in the upper 60s. The incoming short wave ridge will lead to more in the way of sunshine and unfavorable conditions for ascent. However, with elevated dewpoints and strong surface heating, CAPE should be plentiful and therefore there will be chances for showers and storms. Short wave ridging then crests over the area Wednesday night and Thursday providing mostly dry conditions with temperatures climbing well into the 80s. Ridging looks to hold into Friday for another mostly dry day before a cold front approaches from the west. && .AVIATION /23Z FRIDAY THROUGH WEDNESDAY/... Short Term...Widespread LIFR in marine stratus barely scattered out for near coastal areas today...and is already sucking back into coastal zones behind a weak sea breeze. More LIFR is expected in low CIGs tonight...with some locally dense fog possible near the coast as well. Much like today that will tend to gradually scatter out midday Sat. And once again fog/stratus is expected to move back into the same areas Sat night. In addition to the marine influence...clear skies and recent wet weather will be a recipe for valley fog inland too. So in generally all TAF sites have an LIFR...VFR...LIFR trend to them thru Sat night. Long Term...Chances for SHRA and TSRA will increase north to south Sunday with these likely bringing flight restrictions. SHRA and fog will be prevalent Sunday night with likely IFR to LIFR conditions. Chances for SHRA and TSRA continue during the day Monday and Tuesday with fog and low cigs likely at night bringing periods of restrictions. A drying trend is anticipated into Wednesday for improving conditions. && .MARINE... Short Term...Little progression of the frontal boundary to the west means that onshore flow will continue thru at least another couple of nights. That means areas of fog and stratus will remain over coastal waters for the time being. Locally dense fog will be possible overnight...lingering thru midday before lifting briefly during the afternoon. Long Term...Winds and seas look to remain below SCA thresholds Sunday into Wednesday. A period of active weather is expected Sunday into Tuesday with low pressure passing over New England. This will bring seas close to 4 feet with southerly winds approaching 20 kts Monday. There will also likely be periods of marine fog through the period. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ NEAR TERM...Ekster/Legro SHORT TERM...Legro LONG TERM...Schroeter