Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 221250 AFDGYX Area Forecast Discussion National Weather Service Gray ME 850 AM EDT Sat Oct 22 2016 .SYNOPSIS... A slow moving low pressure system will move across central and northern New England today allowing scattered showers. Later today and tonight the low will gradually lift north into Canada. On the backside of this system...colder air will arrive on gusty northwest winds for the latter part of the weekend and early next week. Some accumulating snow will be possible in the mountains Saturday night into Sunday night. A large Canadian high pressure system will then dominate the region through midweek next week. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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Update... Very heavy rainfall last night led to many locations receiving 2-4 inches of rain with locally higher amounts in the 5-6 inch range. Showers will be limited this morning thanks to the presence of the dry slot associated with an area of low pressure developing in the Gulf of Maine. However, patchy drizzle and fog will continue, especially over southern areas. Band of showers over upstate New York will rotate back into the forecast area this afternoon and this evening. Mesoscale models suggest this precip will reach southern New Hampshire between 15Z and 18Z before spreading into Maine. Prev Disc... Models show the developing surface and upper low to move north across the region today creating instability showers. The heavy rains that were in excess of 3 inches over some areas from the system overnight, has moved off to the east so only additional light amounts of showers are expected today. There is plenty of low level moisture that will linger through the day due to a lack of ventilation due to the center of the system passing overhead today. This will mean, aside from any showers, a cloudy day can be expected. Used a blend of models for max temp forecast today and RFC qpf forecast.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/... The center of the deep surface/upper low moves north into Quebec tonight and in its wake a strong westerly pressure gradient will develop. Strong cold air advection can be expected with this system later tonight and Sunday. The combination of the strong cyclonic pressure gradient and cold air advection will allow winds winds to become strong and gusty Sunday. Temperatures will be cold enough across the mountains to allow the instability showers in the mountains to turn to snow showers with some light snow accumulations possible. Elsewhere in the downsloping areas conditions should remain dry. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... The 500mb pattern in the extended features some flexible omega blocking across NOAM and adjacent oceans to the east and west. Over the the long range period the pattern will tend toward troughing, but will see some ridges moving through. Overall, the mean troughing should keeps temps below normal to normal through the period. We`ll start off with the closed low in the vicinity of the Canadian maritimes Monday and Tuesday and this should provide breezy conditions, showers in the mountains, and a a secondary surge of cold air as a wave moves through Mon night. Highs Sunday night through Tue will be in the 40s to around 50 /perhaps a little warmer on Monday/. Lows will range form 30 to 40 both nights. The upslope showers in the mountains will likely falls as snow at times, but any accums should be limited to areas above 2000 feet, and these will be light. Sfc high builds in on Wed, so we`ll finally see a break in the breezy conditions, but this will limit any mixing effects, and highs will once again be in the 40s to near 50. Models begin to differ significantly by late Thursday with Euro bringing a weak low and trailing cold front and the GFS remains dry. Either way should see temps warm a some at the end of the week. && .AVIATION /13Z SATURDAY THROUGH WEDNESDAY/... Short Term...IFR/LIFR conditions early this morning in areas of fog and stratus and also showers across the Maine portions. Conditions through the rest of the day will remain primarily IFR over most areas. Tonight conditions will improve to mvfr and then vfr as winds shift to the west as the system exits. Vfr conditions are expected Sunday although MVFR in the mountains. Gusty west winds are expected to develop later tonight and especially Sunday. Long Term...Mainly VFR Sun night through Wed, except at KHIE which could see tempo flight restrictions in low cigs and SHRASN Sun night into Mon night. && .MARINE... Short Term...SCA conditions will continue today mostly in the form of higher seas since will slack off as the center of low pressure passes over the waters this afternoon. Eventually CAA developing on the backside will increase winds to gale force on the outer waters tonight through Sunday so a Gale warning had been issued for the outer waters. In the bays a SCA will continue tonight and Sunday. Long Term...Persistent W to NW flow will keep an extended period of SCA winds going right into Tuesday at least. Gales may persist into Sun night, and could briefly return Mon night into early Tue. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...Small Craft Advisory until 7 PM EDT Sunday for ANZ151-153. Small Craft Advisory until 8 PM EDT this evening for ANZ150- 152-154. Gale Warning from 8 PM this evening to 7 PM EDT Sunday for ANZ150-152-154. && $$ JC is the U.S. government's official web portal to all federal, state and local government web resources and services.