Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 270323 AFDGYX Area Forecast Discussion National Weather Service Gray ME 1123 PM EDT TUE JUL 26 2016 .SYNOPSIS... Warm high pressure remains over the area through Wednesday with temperatures warming into the 80s and 90s. A weak frontal boundary will drop south out of Canada and into northern New England Wednesday night into Thursday, bringing a chance for showers and thunderstorms as it does so. The front slowly slips offshore on Friday as low pressure track easts along the front offshore of Cape Cod. This will bring another chance of rain Friday into Friday night. Cooler, more seasonable temperatures return for the weekend. && .NEAR TERM /TONIGHT/...
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1130PM UPDATE... Temperatures have been a little slow to cool in some spots, particularly over southern New Hampshire where it was in the low 90s this afternoon. Otherwise temperature forecast appears to be on track tonight with very few adjustments needed. 730PM UPDATE... Have made a few minor adjustments to hourly temperature and dewpoints and removed all precipitation chances. Afternoon cumulus clouds continue to dissipate this evening, setting the stage for a mostly clear night with good radiational cooling conditions. Expect fog in the favored valleys. ORIGINAL DISCUSSION... A short wave trough will move away from northern New England tonight. Any diurnal showers or isolated thunderstorms from Coos County NH southeastward to the Midcoast of Maine should dissipate early this evening with the loss of daytime heating. Otherwise, a mostly clear night is expected tonight with radiational cooling taking place. This will result in local valley fog, especially in areas that have received a good amount of rainfall over the last couple of days.
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&& .SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/... Another very warm to hot day expected on Wednesday with weak high pressure sinking to the southwest of the region. The opposing westerly flow in the boundary layer will likely be weaker on Wednesday and should allow an afternoon seabreeze to form. The day should be dry except perhaps near the Canadian border where there is a low prob of a very late afternoon shower or thunderstorm as a weak short wave trough approaches that area from the west. This trough will help push a weak cold front across northern zones during Wednesday night and may allow for a few showers or spot thunderstorms during the night in the far north. Elsewhere, we expected dry weather. && .LONG TERM /THURSDAY THROUGH TUESDAY/... A weak cold front accompanied by showers and thunderstorms will drop south across the region Thursday and Thursday night and then stall to the south of the area Friday as high pressure builds in from the north. High pressure should hold over the region through most of the weekend as a frontal boundary remains just to our south. Most of the models suggest this scenario, although it is a low confidence forecast for the weekend as the EURO model continues to be somewhat an outlier suggesting northern/southern stream energy phasing and thus taking a considerably further north track. With the above reasoning for the weekend, the safe play is to stick with the superblend model and see how the models play out the development of the system for the weekend. Temperatures will be comfortable late in the week and through the weekend as the heat remains to our south. && .AVIATION /23Z TUESDAY THROUGH SUNDAY/... Short Term...VFR conditions are expected tonight through Wednesday night except for perhaps a few hours of valley fog late at night tonight and Wednesday night. Long Term...MVFR conditions in scattered showers and thunderstorms Thursday into early Friday associated with a frontal passage from the north. Mainly vfr conditions expected for Friday into the weekend. Late in the weekend conditions may lower to MVFR depending on the track of low pressure to the south. && .MARINE... Short Term...Conditions are expected to remain below small craft thresholds through Wednesday night. Long Term...Conditions to remain below SCA criteria through the weekend. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ NEAR TERM UPDATE...Kimble SHORT TERM...Ekster LONG TERM...Marine is the U.S. government's official web portal to all federal, state and local government web resources and services.