865 FXUS61 KCAR 010451 AFDCAR Area Forecast Discussion National Weather Service Caribou ME 1251 AM EDT Fri Jun 1 2018 .SYNOPSIS... A warm ridge of high pressure will slide east of the region late tonight and Friday morning. A cold front will cross the area Friday evening. High pressure will build Saturday into Sunday. && .NEAR TERM /THROUGH TODAY/... 1245 AM Update: Just minor chgs to fcst hrly temps/dwpts across the Rgn based on trends seen from latest obs. Also, we delayed the onset of ST cld cvr across Downeast areas by a few hrs late tngt given that little has yet to be obsvd even at lctns alg the immediate Downeast coast. Orgnl Disc: Still expecting tstms to dvlp late mrng/erly aftn along pre- frontal trof with the biggest threat being locally hvy rainfall with vry slow mvmnt expected and PW values appchg 2.0 inches. Another round of storms appears lkly ahd of cdfnt as it mvs thru late aftn/evng hrs. Prev discussion blo... Onshore winds will affect the coast where lows will drop into the lower 50s. Further inland, temperatures will fall very slowly as warm advection continues with a powerful upper ridge cresting over the state tonight. Humidity will continue to increase this evening into Friday ahead of the front until dew points reach the mid to upper 60s Friday afternoon...a 35 to 40 degree jump from Wednesday for many locations. This increasing humidity leads to several effects. First, an area of fog and stratus lurking off the Mass. coast will creep onto the Maine coast after midnight and spread northward towards Bangor and interior Down East later in the night. Fog may persist along the coast most of Friday due to the moisture advection, but further inland, the low level moisture will quickly retreat back to the coastal zones...with most locations likely to measure highs in the low to mid 80s accompanied by higher humidity. The higher dew points also will fuel some heavier thunderstorms on Friday afternoon. With PWATS moving towards 2 inches, very slow storm motions and a deep warm cloud layer, locally heavy rainfall is a threat along both a pre-frontal trough (along the thermal ridge) and the frontal boundary Friday afternoon/evening. It's conceivable that some storms could dump a quick inch or two of rain within a hour. Shear continues to look weak as well as upper level dynamics. However, a few subtle differences in the thermodynamic profile could produce enough CAPE for some stronger pulse-type storms that could produce locally strong winds and hail. Will just go with heavy rain in the forecast for now and see how 00Z data and guidance looks for any further upgrades. Freezing levels are on the high side, so it'll take quite a strong storm to get hail on the ground. Towards the coast, the stabilizing action of fog and stratus will weaken the storms that occur inland. && .SHORT TERM /TONIGHT THROUGH SUNDAY/... Cold front drops south to the coast Friday night. Some storms may linger into the evening, but dissipate overnight as we lose the daytime heating and as the front moves offshore. Much drier air Saturday, with the dry airmass persisting into Sunday. Looking like a beautiful weekend for getting outside. Saturday will be rather breezy though, with winds generally 10 to 20 mph from the north. Lighter winds on Sunday. Potentially some frost in the far north Saturday night, but that will depend on if the high pressure can build in enough by dawn Sunday to allow for full decoupling. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... Tough forecast for the extended. Most models have a potent upper level low pressure system diving southeast out of Canada into somewhere over the Northeast, and setting up camp. Question is who gets the nasty weather...is it us or areas to our south? Went with a chance of showers Monday night to Wednesday and cooler than average daytime temperatures. However, there is a very real shot that we will stay totally dry during this period if the upper low passes to our south. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... NEAR TERM: VFR expected across northern terminals until showers and thunderstorms dvlp in the afternoon. May see locally heavy rainfall in storms toward end of TAF valid time, mainly to the north of HUL. Further south VFR conditions give way to IFR in the morning, after 05z at BHB and after 09z at BGR. BGR will improve to VFR after 12z with potential for MVFR in showers after 20z. BHB will likely remain IFR through 16z before briefly scattering to low MVFR between 16z and 22z, before back to IFR. SHORT TERM: Mostly VFR Friday night except lower conditions in the evening with any remaining storms, and IFR right along the coast from low ceilings. Cold front moving offshore late Friday night allows for VFR conditions all weekend and into Monday. Next potential weather system with lower conditions Monday night into Tuesday. && .MARINE... NEAR TERM: Fog will materialize after midnight and persist all day Friday as very humid air moves over the cold waters. Winds will pick up towards 15kts tonight and maintain that level much of Friday, but no gustiness is expected due to the very high stability. SHORT TERM: Conditions remaining below small craft levels over the weekend into Monday. Potential for higher seas above 5 feet Tuesday into Wednesday. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...None. MARINE...None. && $$ Near Term...VJN Short Term...Foisy Long Term...Foisy Aviation...VJN/Foisy Marine...VJN/Foisy