Area Forecast Discussion
Issued by NWS Caribou, ME

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000 FXUS61 KCAR 222253 AFDCAR Area Forecast Discussion National Weather Service Caribou ME 653 PM EDT Sat Apr 22 2017 .SYNOPSIS... A trough of low pressure will cross the area this evening. High pressure builds from the southwest late tonight into Sunday. A weak cold front will move through the region Sunday night. High pressure returns Monday into Tuesday. && .NEAR TERM /THROUGH SUNDAY/... 640 PM Update: Not much in chgs with going fcst with radar ref imagery still showing bands of sn shwrs N and rn/sn shwrs Cntrl and Downeast. Only slow improvement is xpctd thru mid eve, with shwrs then xpctd to move E into NB prov and dissipate into the ovrngt hrs. Only very minor chgs were made to fcst hrly temps/ dwpts and ovrngt lows, with not much of any temp falls xpctd with cld cvr and little to no thermal advcn. Orgnl Disc: Low pressure is moving south of the Gulf of Maine and well south of Nova Scotia. As it moves eastward, an inverted trough extends to the northwest towards a decaying low in Quebec. As this inverted trough and associated upper level trough cross this afternoon and evening, it will cause continued light rain, drizzle and snow. The snow will be mostly in higher terrain and is not expected to accumulate...especially since most of the precip will have fallen by nightfall. With lower levels saturated, drizzle continuing, and light winds, fog will tend to thicken and become more widespread later in the evening. Temperatures will only fall a degree or two overnight from this afternoon`s readings. The fog and low level moisture will slowly erode during the course of Sunday. A southwest wind will commence later in the morning towards midday and accelerate clearing. With a warming air mass ahead of the cold front, temperatures will quickly shoot into the 50s and a few 60F readings are possible towards southern Penobscot County on Sunday afternoon. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... A cold front pushing into the CWA Sun night will bring some rain showers to the Crown of Maine, but precip is expected to fizzle before it moves south of the Katahdin region. The surface boundary will push south to Bangor by sunrise, and to the coast by around 8am, if not a bit earlier. However, that`s about as far as the front gets before it stalls near the coast during the day Mon, then weakens and dissipates Mon night. The next system will approach from the Southeastern US, with precip spreading into the CWA from south to north Tues afternoon and evening. Given that this system is associated with a 500mb cut-off low, it`s not surprising that there are some timing differences between the models. The CMC was the fastest, while the ECMWF was on the slower side. The GFS was in the middle, but somewhat skewed toward the ECMWF solution. The forecast for northward advance of the POPs was weighted more toward those two solutions. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... The Low will continue to advance northeast Tue night through Wed, and is likely to cross Cape Cod Wed eve or night, then move across the CWA Wed night or early Thu AM. The heaviest, most widespread rain appears likely between 00z Wed and 00z Thu. As the sfc low approaches Maine, the upper-level feature will begin to weaken and get absorbed into the broader flow, and upper- level ridging following right on the heels of the sfc low may lead to a fairly quick end to precip as the sfc low passes. S`ly winds on Thu may push temps above normal, though mostly cloudy skies appear likely to persist as the next system approaches from the west. This system, a weakening front, may bring some rain to the area, but there are disagreements on timing. The GFS would bring rain in Thu eve and night, but the ECMWF and CMC both hold off toward sunrise Fri. Regardless, POPs were kept under 50 pct at this point, and as the front weakens, precip may dissipate during the day Fri. There are hints of another system impacting us Fri night into Sat, but as of now there is significant model discrepancy regarding the timing and form of both the upper-level flow and sfc features. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... NEAR TERM: IFR to LIFR is expected for all sites until Sunday morning due to snow, low cigs, drizzle and fog. Conditions will lift to MVFR towards mid-morning Sunday and become VFR Sunday afternoon. SHORT TERM: Some MVFR to psbl IFR CIGs are likely with the front for KPQI to KFVE between 00z and 09z Mon. Areas of IFR vsby and CIGs are likely to develop with fog for KBHB and KBGR between 06z and 12z Mon, and could linger a little longer for KBHB depending on the timing of frontal passage. Otherwise, a return to VFR conditions expected Mon afternoon and night. Mid-level clouds spread south to north during the day Tue, with MVFR conditions developing Tue eve as rain spreads north. MVFR to IFR conditions are expected Wed into Wed evening with areas of heavy rain. Expect clearing late Wed night into Thu. && .MARINE... NEAR TERM: Rain, drizzle and reduced visibility can be expected through this evening. Seas will slowly decrease from 4 to 5 feet towards around 2 feet by later Sunday. Winds will also tend to decrease through the period as high pressure builds. SHORT TERM: Gusty SW winds expected Sun night and may approach SCA criteria, then drop off sharply Mon AM. Some areas of dense fog are also possible overnight into the morning hours. Moderate E-NE`ly breezes with freshening gusts are on order Mon night and Tue, approaching SCA levels. Seas will build toward SCA levels later Tuesday, as well. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...None. MARINE...None. && $$ Near Term...VJN Short Term...Kredensor Long Term...Kredensor Aviation...VJN/Kredensor Marine...VJN/Kredensor is the U.S. government's official web portal to all federal, state and local government web resources and services.