textproduct: Caribou

WHAT HAS CHANGED

- Increased sky cover today through Monday.

KEY MESSAGES

1) Warmer, seasonable temperatures this weekend through early next week with no precipitation. The next chance for precipitation is towards the end of next week.

DISCUSSION

KEY MESSAGE 1...Warmer, seasonable temperatures this weekend through early next week with no precipitation. The next chance for precipitation is towards the end of next week.

KEY MESSAGE 1 DESCRIPTION... High pressure builds in through the weekend with the airmass gradually warming. No precipitation this weekend. One little hiccup is the potential for stubborn clouds 3-6K AGL stuck just underneath the subsidence inversion aloft. Feel that NBM is underdoing these clouds and went cloudier than NBM, especially in north/east portions of the area for today through Sunday. A bit of a north breeze today, then light winds Sunday.

Most models develop a closed low off the mid-Atlantic coast Sunday night/Monday, then have it slowly slide east starting Monday night. This feature does two things Sunday night-Monday night. 1) It maintains a low level NE-N flow over the region and 2) It slows the eastward progression of the deep layered ridge from the Great Lakes into the Appalachians during this time frame.

The former advects in low level moisture from the maritimes. The latter allows for a gradually thickening subsidence inversion to trap this low level moisture over the region - promoting partly to mostly cloudy sky cover during this time frame, which is more clouds than indicated by the NBM. Based on the increased cloud cover, blended in the NBM 50 to raise low temperatures and lower high temperatures. The CMC-Reg typically handles patterns like this better than most other models, so leaned towards it Sunday night-Monday night - especially for cloud cover. For now, did not introduce the drizzle it implies over Northern Aroostook, but if confidence in this occurring increases over the next couple of days could see it being added to the forecast.

Deep layered ridging builds in Tuesday-Wednesday, with increasing subsidence inversion drying the low levels. The GFS likely is too progressive in building the deep layered ridging across the region and too the east, as this is a known bias to the model. In addition the closed low off the mid-Atlanctic coast will continue to impede the eastward progression of the ridge as well.

Because of the differences in handling of the deep layered ridge, the models differ on the timing of rainfall, and the corresponding build in of a trough of low pressure aloft. For now not fully buying into the GFS/CMC idea of tapping moisture from the closed low off the mid-Atlantic Coast and bringing in rainfall on Wednesday, with pops limited to slight chance to chance. For now believe that any widespread rainfall holds off until Thursday and tapers off on Friday. Models differ on the amount of rainfall into the end of next week frm a few tenths of an inch (ECMWF) to 1-3"+ (CMC), and hence on any impacts for late next week.

AVIATION /06Z SATURDAY THROUGH WEDNESDAY/

Today: Generally mostly cloudy skies today with cigs mainly at low VFR levels, though MVFR ceilings are likely (60 percent probability) at FVE after about 13z. Can't rule out MVFR cigs from time to time CAR/PQI/HUL from 14z onward, but probability of any MVFR cigs at these sites is around 30 percent. Winds today from the north 10 kt gusting 20 kt in the north, and sustained 5-10 kt BGR/BHB with minimal gusts.

Tonight and Sunday: Generally VFR, but can't rule out intermittent MVFR cigs mainly at FVE/CAR/PQI/HUL. Confidence is low. Variable wind around 5 kts.

Sunday Night-Monday: MVFR possible with best chance at northern terminals.

Monday night: MVFR or lower possible at northern terminals with MVFR possible elsewhere.

Tuesday: Becoming VFR throughout. SE winds G15KT possible in the afternoon.

Tuesday night-Wednesday: VFR. SE winds G15KT possible Wednesday afternoon.

MARINE

Winds and seas below small craft levels through Sunday.

A relaxed pressure gradient over the waters Sunday night-Tuesday should limit winds to 10 kt or less and seas to 4 ft or less.

A persistent easterly swell builds seas: on the open ocean waters build to 5-8 ft Tuesday-Wednesday night; on the coastal ocean waters to 5-7 ft and on the intra-coastal waters to 3-5 ft Wednesday-Wednesday night. Sustained winds should increase to 15-20 kt by Wednesday as well on all waters.

CAR WATCHES/WARNINGS/ADVISORIES

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