textproduct: Caribou

WHAT HAS CHANGED

Update for 12z aviation discussion.

KEY MESSAGES

1) Diurnally-driven afternoon convection today will bring isolated tstms to most of the region again this afternoon.

2) Intermittent rain Saturday night into Sunday. Flooding not expected. Fog late Saturday night and Sunday morning could impact travel especially near the coast.

3) Another potential rainfall event late Monday into Tuesday with a possible Nor'easter.

DISCUSSION

KEY MESSAGE 1...Diurnally-driven afternoon convection today will bring isolated tstms to most of the region again this afternoon.

KEY MESSAGE 1 DESCRIPTION... More pop up showers this afternoon expected as upper level s/wv crosses the region. Main s/wv and upr lvl cold pool looks to track further south than yesterday and have brought isolated thunder further south for this afternoon. Setup appears similar to yesterday and cannot rule out pea size hail/graupel once again.

KEY MESSAGE 2...Intermittent rain Saturday night into Sunday. Flooding not expected. Fog late Saturday night and Sunday morning could impact travel especially near the coast.

KEY MESSAGE 2 DESCRIPTION... Wet weather returns Saturday evening and continues into Sunday. This occurs ahead of an approaching upper level shortwave trough and weak cold front. For Saturday night, the best shot at rain will be along and south/east of I-95. During the day Sunday, the most favored area shifts north to areas north of Bangor. There could be just enough instability Sunday for a few embedded storms, but not expecting anything severe. We are not looking at an all-day rain Sunday, but showers could be rather numerous in coverage. Rain totals from Saturday night into Sunday appear to be highest Downeast, where at least 0.25 inch should fall, with potentially up to 1 inch. Further north into Northern Maine, rain totals appear a bit less, with totals probably at least 0.10 inch and perhaps up to 0.75 inch. Although the ground is already very saturated, we don't anticipate any flooding from this rainfall. Fog is possible areawide Saturday night, though the best threat of denser fog is Downeast, especially the coast, from Saturday night into Sunday morning. This will be advection marine fog thanks to moist onshore flow. A bit of drying/clearing Sunday night/early Monday as the cold front attempts to slowly push south/east of the area, but there is uncertainty as to how far south/east the cold front can make it before stalling out.

KEY MESSAGE 3...Another potential rainfall event late Monday into Tuesday with a possible Nor'easter.

KEY MESSAGE 3 DESCRIPTION... There is much more uncertainty for this possible system late Monday into Tuesday, but it is worth mentioning that some models have a Nor'easter tracking northeast close enough to bring us significant precipitation from Monday afternoon into Tuesday. Some ECMWF ensemble members from the 12z and 18z runs (0z backed off a bit) are especially alarming with a rather strong Nor'easter tracking northeast across western Nova Scotia. This track has the potential to bring 1-2 inches of precipitation, and a handful of ECMWF ensemble members even are cold enough for snowfall Monday night/Tuesday. A few Canadian and GFS ensemble members have this solution, but not nearly as many as the ECMWF. The bottom line right now is that the most likely solution is a low pressure system passing far enough south/east to give perhaps a bit of rain mainly to Downeast. But there is a 40 percent chance the system passes close enough to give Downeast at least 0.50 inch of precipitation, and a 10 percent chance that somewhere in our area is cold enough for measurable snowfall.

Looking a bit further out, Wednesday looks dry, but there's a chance of even more rain Thursday/Friday. Uncertainty is very high though.

AVIATION /10Z FRIDAY THROUGH TUESDAY/

Today...VFR all terminals, though may see very brief MVFR cigs early over northern terminals. Confidence not high enough to include in Terminal Forecasts. Showers likely to be hit and miss this afternoon. NW winds 5-10kts.

Tonight...VFR. Light W winds.

Saturday...VFR Aroostook terminals. VFR early for Downeast terminals, before diminishing to MVFR/IFR late in rain. S winds 5-15kts gusting to 20-25kts in the afternoon.

Saturday Night...MVFR/IFR likely at BGR/BHB and possible from HUL north. S/SE winds 10 kts. LLWS possible at southern terminals.

Sunday-Sunday night: MVFR or lower likely Sunday. S wind 10-15 kts Sunday, becoming light Sunday night.

Monday-Tuesday: Low confidence depend on the track of low pressure to the south of the area. IFR/MVFR more likely Downeast, with VFR more likely in the north. W/NW breeze, but how strong depends on the track of the low pressure system.

MARINE

Winds and seas generally below small craft levels through the period. Winds and seas marginal this evening over the waters out to 25nm and again on Saturday evening.

Small craft conditions are likely Saturday night and Sunday, with potentially fog as well. Sub-small craft winds/seas Sunday night into Monday. Monday night/Tuesday, significant uncertainty depending on the track of a potential Nor'easter, but there is about a 60 percent chance of small craft conditions, and 25 percent chance of gales.

CAR WATCHES/WARNINGS/ADVISORIES

ME...None. MARINE...None.