Area Forecast Discussion
Issued by NWS Caribou, ME

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000 FXUS61 KCAR 131121 AFDCAR Area Forecast Discussion National Weather Service Caribou ME 721 AM EDT Tue Mar 13 2018 .SYNOPSIS... Low pressure will intensify as it moves northeast toward Nova Scotia today. It then moves slowly north through the northern Canadian Maritimes Wednesday night and Thursday. && .NEAR TERM /THROUGH WEDNESDAY/... 720 am update... Hv added in patchy freezing drizzle acrs the far north for a few hrs this morning. Lgt snow has mvd into far southwest Maine as of 11z with dry air continuing to hold acrs CWA but expect airmass wl saturate down by mid-morning. No major chgs needed with this update. Prev discussion blo... Coastal low is located approx 300 miles east of the Delmarva and heading northeast. WV imagery shows compact upr low rotating north and east well south of Cape Cod while upr trof digs into Appalachians. Svrl lightning strikes hv been noted nr the center of the storm with precipitation slowly working its way north and is currently mvg into Mass and NH as of 08z. Due to the slow mvmnt of pcpn and dry air to overcome hv delayed pops by svrl hrs this mrng with Winter Storm Warning for Downeast not going into effect until 15z. As the system mvs northeast it wl lkly spread a band of hvy snow into Downeast areas drg the aftn and evng hrs. This wl lkly disrupt the evng commute with 1-2 inch per hr snowfall rates. Steep mid-lvl lapse rates may produce convective snow which wl lkly increase the snowfall rates. In addition to the snowfall rate expected northeast winds will be very gusty thru the aftn hrs. Considered issuing a blizzard warning for coastal Hancock and Washington counties for this afternoon but am not confident that we will be able to see blizzard criteria for 3 hrs based off of latest hires bufkit sndgs for BHB as compared with sites further to the west in Maine. However, near-blizzard conditions are certainly possible along the coast. Expect that similar to last noreaster nrn Aroostook cnty will see the least amnt of snow with only arnd 10 inches expected. Central and Downeast zones will likely top out between 1-2 feet as it rmns all snow with the possible exception of the Eastport area. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/... The model guidance is in good agreement through the short term period of the forecast. A surface low will track north and stack stationary Upper low over the Gulf of ST Lawrence. Wrap around precipitation extending back across Maine. The upper low will be the dominant weather feature at the through the period. A secondary low southwest of Nova Scotia at the start of the period will track across the eastern portions of Nova Scotia then north into the Gulf of ST Lawrence keeping Maine under wrap around precipitation through the period. A high pressure ridge builds south from Hudson Bay to Southern Indiana will slowly ridge toward western Maine. Loaded a blend of the GFS/NAM/ECMWF to smooth out the minor differences in the models. Used NAWAVE4 for seas in the coastal waters. Loaded windgust by factor tool add to winds 20% over land, 26% for the coastal waters. Used GFS Guidance for QPF. && .LONG TERM /SATURDAY THROUGH MONDAY/... The extended models are in good agreement at the start of the period. A broad area of low pressure over the Gulf of ST Lawrence with a co-located surface and upper low will continue to produce scattered snowshowers across northern Maine. Higher pressure from the Hudson Bay extending south into Northern Tennessee will slowly build into Maine. By Saturday morning the ridge will have built across the state. A new low over Hudson Bay Saturday afternoon will move southeast and cross Maine early Sunday morning. By Sunday afternoon the ridge will build back across the area. The ridge will dominate the weather through the end of the period. Tuesday afternoon to Tuesday evening the guidance is indicating another low pressure system developing along the coast of NC/VA by the end of the period the GFS shows it south of SW Nova Scotia, EC shows it east of NJ, and the GEM shows two lows one over Long Island the other well east of NJ. The development of this system will need to be watched could potentially become another N`easter beyond this period. Loaded a blend to smooth out the differences in the models. Used NAWAVE4 for seas in the coastal waters. Loaded windgust by factor tool add to winds 20% over land, 26% for the coastal waters. Used HPC Guidance for QPF. && .AVIATION /11Z TUESDAY THROUGH SATURDAY/... NEAR TERM: MVFR at BGR and BHB this morning will give way to IFR -sn with LIFR through most of the day. Further north MVFR gives way to IFR after 21z as -sn finally moves into terminals. Northeast winds will gust to around 30kts at southern terminals and 25-30 across the north. SHORT TERM: MVFR with periods of IFR in snowshowers through the period. Snowshower activity will be more frequent across northern and eastern Maine. Higher pressure will build into Maine Friday night clearing out the snowshowers and cloud cover. VFR conditions Friday evening for BHB and BGR, extending to all other sites by Saturday morning. && .MARINE... NEAR TERM: A storm warning is in effect for the outer waters this morning into this evening, while a gale warning is in effect for intracoastal waters through midnight. As low pressure departs over Nova Scotia the winds will lessen but still remain above SCA levels in the bays and above gale force for outer waters. SHORT TERM: A Small Craft Advisory will likely be needed through the period. Winds and or Seas will be above SCA criteria through the period. && .TIDES/COASTAL FLOODING... Tide cycles of greatest concern are Tuesday 8:50 AM and 9:25 PM. Due to the Lunar Cycle these astronomical tides will be 2-3 feet below the highest tides of the month. Expect the greatest storm surge and largest waves to occur mid afternoon Tuesday. Due to the lower astronomical tide and timing of surge and waves, coastal flooding appears unlikely at this time. Runup, splash over, and beach erosion are expected to be minimal. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...Winter Storm Warning from 6 PM this evening to 2 AM EDT Thursday for MEZ001-002. Winter Storm Warning from noon today to 8 PM EDT Wednesday for MEZ003>006-010. Winter Storm Warning from 11 AM this morning to 2 PM EDT Wednesday for MEZ011-015>017-029>032. MARINE...Gale Warning until midnight EDT tonight for ANZ052. Storm Warning from 11 AM this morning to 8 PM EDT this evening for ANZ050-051. && $$ Near Term...Farrar Short Term...Norton Long Term...Norton Aviation...Farrar/Norton Marine...Farrar/Norton Tides/Coastal Flooding...Farrar is the U.S. government's official web portal to all federal, state and local government web resources and services.