552 FXUS61 KCAR 312301 AFDCAR Area Forecast Discussion National Weather Service Caribou ME 701 PM EDT Tue Oct 31 2017 .SYNOPSIS... A trough of low pressure will move to the east of the region tonight. High pressure builds Wednesday. A warm front will move northward across the region Thursday, followed by a cold front on Friday. && .NEAR TERM /THROUGH WEDNESDAY/... 655 PM Update... Adjustments were made on the hrly temps/dewpoints to show readings cooling down. Basically mostly clear attm per the IR satl imagery w/some clouds to the east. A batch of clouds back to the west apchg the Maine border. A sfc trough is moving toward the east from Quebec. Some showers were showing up on radar. The latest RAP and HRRR showing some of the showers moving across western and northwestern areas before drying up as the activity moves east. Daycrew had things set pretty well. Previous Discussion... Lgt echoes currently showing up on radar ahd of upr lvl wv rotating thru the northeast in cyclonic flow. Mocldy skies acrs the CWA wl clr acrs Downeast with sunset, diminishing acrs the north aft midnight but still rmng pcldy. H9 temps wl drop blo 0C this evng acrs the north as cold air filters in fm Canada and appch 0C acrs Downeast zones twd daybreak. Sfc hipres wl be building south of the state in the morning, likely resulting in calm winds acrs srn areas. This wl be impactful on mins expected tonight with m/u 20s acrs the north and temps dropping nr frzg acrs Downeast, slightly wrmr along the coast. Unfortunately tens of thousands of customers rmn without power in our CWA alone with a fairly cold night on tap. Winds back around to the south in the aftn as high builds east twd Nova Scotia. Temps wl rise to just slightly blo normal for highs on Wed with clds increasing fm the west in the aftn. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/... High clouds increase ahead of a warm front during Wednesday night, but Wednesday night's temperatures will still fall into the upper 20s to lower 30s before midnight. After midnight, warm advection is strong with the southerly flow on the backside of the high. Precip will probably break out in the far NW before dawn, but will back off on any mention of snow as the boundary layer looks too warm based on today's 12Z guidance. The warm front gradually crosses Thursday with rain and temperatures climbing back into the lower 50s...except towards the Saint John Valley where 40s will remain as the cold air stays entrenched. Warm frontal rainfall amounts look fairly light with no more than a few tenths of an inch. Rain and drizzle looks like it'll occur much of the day towards northern Aroostook County, but may not affect the coast until late day. The coast and the Bangor area will get some strong south winds with some gusts to around 25 to 30 mph...and it could be higher if there's mixing to a greater depth. On Thursday night, a cold front will gradually approach from the northwest. Expect clouds to persist in the warm sector...which combined with continuing warm advection...will make for a relatively mild night in the upper 40s to lower 50s. Temperatures will probably remain steady or rise overnight. A low level jet emerges over the area later in the night into Friday morning ahead of the cold front. As a result, maintained fairly strong winds through Thursday night and have some concerns about a few gusts towards 40 mph on Friday morning ahead of the front and with the front. These gusts would be most likely towards the eastern border of the state. The cold front will slowly move through the area on Friday with showers and mild temperatures in the upper 50s to lower 60s. The front should be through the state by evening. In terms of precipitation, the cold front could bring some moderately heavy rainfall with some surface-based instability and the help of a strong upper jet. Amounts up to a half-inch are possible north of Houlton. Overall precipitation amounts from Thursday and Friday will be nearly an inch in the Saint John Valley, but just around a tenth of an inch on the coast. The air behind the front will be markedly colder. Winds will remain gusty through the night. A big Canadian high will start to build and it will dominate area weather for the entire weekend. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... The 1037mb Canadian high will generate mostly clear skies for the weekend until Sunday. Winds will still be gusty on Saturday, but decrease Saturday night. It will be sharply cooler. For Saturday, that means highs close to 40F towards the Crown of Maine and upper 40s to near 50F for Bangor and Ellsworth. The high crosses over the state Saturday night and will likely cause the first morning with widespread lows in the teens...at least in Aroostook County. Highs on Sunday will be cooler than Saturday as H925 temperatures will also be some 3-4C cooler than Saturday and clouds will thicken. The high will push off to the east Sunday and a slow-moving warm front will gradually approach the area Sunday into Monday evening. The big question will be how fast precipitation arrives Sunday while the cold air remains in place. It will be cold enough for snow. There is a fast- moving and ill-defined shortwave that will be racing into the area Sunday. If this shortwave materializes as the GFS advertises, many areas could see their first snowfall. However, the GFS is an outlier at this point and have blended the warmer ECMWF and GFS to generate some snow in the Allagash...mainly in high terrain...but not elsewhere. By Sunday evening, thermal profiles have warmed such that light rain and drizzle will be the p-type for all locations into Monday. Highs on Monday will recover to the mid to upper 50s. A cold front will cross Monday evening. While there may be some briefly heavier showers with the cold front, the primary concern will be gusty winds. Another LLJ is expected ahead of the front. Behind the front, a cold Canadian high builds later Tuesday into Wednesday with seasonable temperatures for November. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... NEAR TERM: VFR expected next 24 hours. Sw winds will be gusty through 00z tonight with gusts upwards of 30kts across northern sites. SHORT TERM: Wednesday night will begin VFR for all sites, but MVFR cigs will likely arrive in northern zones later in the night and spread across the area Thursday. Occasional IFR cigs are possible north of HUL in the afternoon. For Thursday night into Friday morning, IFR cigs will become the primary condition with some fog possible along the coast. IFR conditions will likely linger all of Friday near the coast, but elsewhere, cigs will increase to MVFR. Some LLWS will be possible ahead of a cold front crossing the area Friday afternoon. VFR conditions return across the area Friday night and continue into early Sunday morning. On Sunday, snow is possible for sites north of MLT and HUL with some reductions in vis at times. && .MARINE... NEAR TERM: SCA has been extended through 12z Wed with winds gusting above 25kts this evening before dropping off after midnight. Waves will likely drop below SCA levels in the intra- coastal zones after midnight with seas remaining high on the outer waters thru Wed aftn. SHORT TERM: An SCA will be likely be needed Sunday night into Tuesday. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...None. MARINE...Small Craft Advisory until 8 AM EDT Wednesday for ANZ050>052. && $$ Near Term...Farrar/Hewitt Short Term...MCW Long Term...MCW Aviation...Farrar/Hewitt/MCW Marine...Farrar/Hewitt/MCW