Area Forecast Discussion
Issued by NWS Caribou, ME

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684 FXUS61 KCAR 171750 AFDCAR Area Forecast Discussion National Weather Service Caribou ME 1250 PM EST Mon Dec 17 2018 .SYNOPSIS... Low pressure from the mid Atlantic states is expected to move northeast toward the eastern Canadian Maritimes today and tonight, then remain stationary over the eastern Maritimes on Tuesday as high pressure from the upper Great Lakes begins to move east. && .NEAR TERM /THROUGH TONIGHT/... 1250 PM Update... Low pressure will continue to move northeast toward eastern Nova Scotia this afternoon. Snow will continue across the region into tonight. Across downeast areas, especially the coast, precipitation has changed to rain as warmer air is wrapping westward around the low. The precipitation is expected to change back to all snow downeast later this afternoon as colder air works back into region behind the departing low. No major changes to current forecast at this time. previous discussion Intensifying low pressure is expected to move across the out portion of the Gulf of Maine Today then across Eastern Nova Scotia Tonight. Also an upper level trough will approach from the west today and move across the Gulf of Maine Tonight. This system is expected to produce snow across much of the region with some mixed precipitation expected along along the coast. Greatest amounts of snow are expected in the eastern portion of the region. Have used the Top Down Tool for precipitation type with snow amounts generated using the snow ratio grids. Expect winds to increase later tonight as the low pressure system continues to intensify over the Maritimes. This may result in blowing and drifting snow across much of the region late Tonight. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... Last gasp of snow wl be mvg out of far ern zones by 12z Tue. Strong H9 wind wl impact the entire area twd daybreak on Tue with 35-40kt speed max under increasing pressure gradient. Strong cold advection aloft wl low-lvl steepen lapse rates, lkly allowing full mixing to occur. Cannot rule out 35kt gusts, especially ovr the higher terrain and agricultural areas Tue morning into the aftn. Expect this to result in blowing snow around daybreak Tue into the evng hrs. Skies wl be clearing fm south to north drg the aftn but at the same a trof crossing Hudson Bay wl spill high clds into nrn areas drg the ovrngt hrs. Winds wl begin to back arnd twd the sw on Wed aftn. Sfc ridge axis then bisects CWA Wed night. && .LONG TERM /THURSDAY THROUGH SUNDAY/... Next appchg system wl be digging into the southeast U.S. Thu night. Sfc low wl be in the vicinity of the cntrl Appalachians by 12z Fri with sfc ridge shifting off to the south and east. May see light pcpn mv into the area aft midnight Thu night but this wl depend on how strong sfc high ends up being. Based on model soundings most of the moisture may evaporate btwn 00-12z Fri but wl run with just isold pops for Thur night. Warm nose wl mv north on Fri with light snow in the mrng bcmg freezing rain and eventually ovr to all rain as temps rise into the u30s/l40s drg the day. 36-hr QPF amnts look to range fm 1-2 inches acrs the south to 0.75-1 inch ovr nrn areas. Given the ever-thickening river ice acrs the area, may need to be alert for ice jam flooding and wl continue to monitor as the event comes closer. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... NEAR TERM: Expect IFR conditions today and tonight. SHORT TERM: IFR conditions will rise to MVFR by mid-morning Tue as light snow winds down. Downeast terminals will see VFR on Tue with MVFR remaining at northern terminals due to low cigs and blsn. VFR for all terminals thru Wed night with possible low cigs moving into nrn terminals by Thu morning. && .MARINE... NEAR TERM: Will use the Nam to initialize winds. For Waves: Currently the primary wave system is a longer period southerly swell accompanied by an east southeasterly wind wave. The southerly long period wave system will be the primary wave group today and tonight building to around 7-8 feet/10 seconds with the northeasterly wind wave building to around 4 feet resulting in a combined sea of 8-9 feet later today into this evening. Total Water Level: Surge guidance indicates around half a foot of storm surge. This appears a little low so will keep the Base Tide Anomaly at round +0.50 feet to compensate for this. Later tonight the surge models indicate a reverse surge of -1.0 feet or greater as off-shore winds increase. A reverse surge of closer to -0.50 appears to be more reasonable so will use a Base Tide Anomaly of +0.50 to compensate for this into Wednesday then slowly reduce the anomaly. SHORT TERM: Gale force winds Tue morning wl continue through late Tue night. SCA level winds look to be present into Wed afternoon. Seas remain above 5 feet into Tue evening before diminishing. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...Winter Weather Advisory until 1 AM EST Tuesday for MEZ001>006- 010-011-015>017-029>032. MARINE...Gale Warning from 1 AM Tuesday to 1 AM EST Wednesday for ANZ050>052. && $$ Near Term...Duda/Mignone Short Term...Farrar Long Term...Farrar Aviation...Duda/Mignone/Farrar Marine...Duda/Mignone/Farrar

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