Area Forecast Discussion
Issued by NWS Portland, ME

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081 FXUS61 KGYX 250459 AFDGYX Area Forecast Discussion National Weather Service Gray ME 1159 PM EST Fri Feb 24 2017 .SYNOPSIS... A very warm and moist south to south to southwest flow will continue tonight through Saturday. A strong cold front accompanied by widespread showers will cross the region Saturday night followed by a drier and colder air mass for Sunday into Monday. A disturbance will approach from the west late Monday and Monday night. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... 1157 PM...minor ESTF update to reflect the current mesonet in near term grids. Prev Disc... 940 PM Update...Little change since the last update. Dense fog continues in the area of the advisory with no obvious spread since. Therefore current headlines remain in place. Other than the fog, it should be mostly dry overnight aside from some possible drizzle later on. 640 PM Update...Have issued a dense fog advisory for a portion of the forecast that has had reports of dense fog is expected to shortly. Visibilities are very low in some spots. The advisory may be expanded this evening if conditions warrant. 510 PM Update...Have updated the forecast mainly for minor adjustments to sky, temperatures, and PoP. The last substantial batch of showers will move out of our central Maine zones shortly. In their wake, it will be mainly dry overnight as area will be warm sectored (at least above the boundary layer). However, drizzle could develop late. The main concern overnight will be dense fog. Will keep an eye out for more widespread development before hoisting an advisory. Otherwise, temperatures vary from the very impressive lower 70s across southernmost NH to the 40s most other zones. Previously... A very warm moist south to southwest flow will continue tonight. The showers along and north of the warm front have moved north and will have exited to the north of the forecast area by early this evening. The warm air and increasing dewpoints will override the deep snowpack causing areas of fog to develop. Also expect fog to develop over the gulf of Maine and work into coastal areas by later tonight. Forecast min temps for tonight are well above guidance since it has consistently underperformed the southerly flow over the snowpack. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/... The warm southerly flow will continue Saturday so very mild temps are expected. H85 temps of +8 to +10C may be reached. All of the FA will be in the warm sector so expecting some partial breaks and sun if we can burn off the low level stratus and fog by late morning. Temps should once again run well above model guidance as they have the past few days. The only exceptions may be over the coastal and especially the midcoast areas the southerly flow off the cool waters will temper max temps in those locations keeping temps cool. The approaching strong upper trof and associated cold front will begin to spread showers into the region by mid afternoon from west to east and widespread showers expected by evening. The frontal passage will occur around or after midnight so any clearing will not take place until late. A strong push of much colder air will change any rain showers to snow showers over the mountains late with some light accumulations possible over the higher terrain. Stayed close to a blend of model guidance for overnight lows. && .LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/... Intense cold front moving out of the CWA early Sunday morning. Strong cold air advection and a tightly packed pressure gradient will produce gusty winds. With cyclonic northwesterly flow in place, we could see some upslope snow showers over the mountains during the day as well. A fairly progressive pattern sweeps the system quickly off to the north and east by late Sunday. A weak disturbance passes north of the area Sunday night and could bring a few showers to the mountains. However, the next significant system moves through Tuesday and Wednesday. The system is another fast moving system but will be approaching northern New England from the mid Atlantic region. It quickly moves across the Gulf of Maine early Wednesday and the best chance for precipitation will be over the very far southern sections of the CWA. However, another system is right on it`s heels coming across the Great Lakes region and will drag a robust cold front through the region late in the day on Wednesday. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... Short Term /through Saturday/...Conditions will lower to IFR/LIFR in areas of fog and low clouds tonight. Winds will be light at the surface tonight but a rather strong low level southwest flow will cause some wind shear below 2000 ft. Conditions will try to improve to VFR late Saturday morning over some areas by variable conditions from VFR to IFR can be expected Saturday. By late Sat the approaching strong cold front will spread widespread showers into the area causing widespread showers through the night and MVFR/IFR conditions. Some clearing will occur late Saturday night to VFR except in the mountains. Long Term...VFR conditions should prevail on Sunday with strong gusty northwest winds possibly generating some low level wind shear to contend with. MVFR/IFR conditions may return Sunday night as radiational cooling may produce some fog. && .MARINE... Short Term /through Saturday/...winds and seas will reach minimal SCA tonight over the outer waters and then diminish toward morning. Areas of dense fog is expected to develop tonight as the very warm moist air moves over the cool Gulf of Maine waters. Winds and seas should once again build to SCA conditions late Saturday into Saturday night ahead of an approaching strong cold front and then behind the FROPA late Sat night possible stronger Gale force winds are possible for that time frame. Long Term...Strong northwest winds behind a dynamic cold front will produce gusty winds over the waters. Expect to see at least some Gale Force winds with the best chance over the southern waters. && .HYDROLOGY... A flood watch remains posted for interior portions of Maine and new Hampshire from 00Z Saturday through 00Z Monday. Daytime temperatures will soar into the 50s and lower 60s again Saturday with mild overnight lows tonight. The cold front moves through tomorrow with 0.50 to 0.75 inch of rain possible. The warmth will continue to ripen and melt the snowpack with rivers and streams responding through Sunday. Rainfall will add to the runoff through Saturday. At the current time, the main threat is ice jam flooding. The threat is higher in New Hampshire where temperatures will be warmest and precipitation will be heaviest. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...Flood Watch through Sunday evening for MEZ007>009-012>014-020- 021. Dense Fog Advisory until 7 AM EST Saturday for MEZ007>009- 012>014-019>021. NH...Flood Watch through Sunday evening for NHZ001>009-011-012-015. Dense Fog Advisory until 7 AM EST Saturday for NHZ001>006. MARINE...Gale Watch from late Saturday night through Sunday evening for ANZ150>154. Small Craft Advisory until 7 AM EST Saturday for ANZ150-152- 154. && $$ ES is the U.S. government's official web portal to all federal, state and local government web resources and services.