textproduct: Caribou

WHAT HAS CHANGED

- Heat advisory remains in effect until 6 PM this evening over much of the Downeast region. A few thunderstorms are possible into the early evening hours.

KEY MESSAGES

1) Scattered showers and thunderstorms through the weekend. A few severe storms are possible, with the best chance being Sunday. Very heavy downpours with any storms could lead to localized flooding.

2) Scattered rain showers and thunderstorms early next week.

DISCUSSION

KEY MESSAGE 1...Scattered showers and thunderstorms through the weekend. A few severe storms are possible, with the best chance being Sunday. Very heavy downpours with any storms could lead to localized flooding.

KEY MESSAGE 1 DESCRIPTION... Shortwave swinging through Saturday, bringing a potential for showers. The best chance for storms on Saturday will be Downeast along the sea breeze boundary through the afternoon, with the threat for storms shifting northwards Saturday evening as the next low pressure system to the northwest pushes eastward, with a cold front approaching on Sunday. There is some instability ahead of the cold front, as moisture and instability funnels into the region this weekend. Models continue to align with 1,500 - 2,000 J/kg of CAPE and and plenty of precipitation. Soundings are very moist, with classic long and skinny CAPE throughout most of northern and eastern Maine. PWAT values around 1.5-1.75, which is roughly in the 90th percentile for PWATs based on sounding archives. Storm motions could be slow with these storms, and if any slow moving storms do develop with heavier showers, there could be localized flooding. Three hour flash flood guidance is roughly 1.5 - 2 in the north, and 2-3 Downeast. Currently, looking at maybe an inch of rain, but areas with convection could so higher totals. Shear is weak, however, and cold front does not seem to be very strong.

KEY MESSAGE 2...Scattered rain showers and thunderstorms early next week.

KEY MESSAGE 2 DESCRIPTION... Rounds of shortwaves move through the north early next week, bringing a chance for rain showers and some thunderstorms. Thunder possible in the north on Monday, and areawide Tuesday. Environment does not look too impressive for strong thunderstorms, so could just be some brief isolated storms below severe criteria.

AVIATION /18Z FRIDAY THROUGH WEDNESDAY/

Tonight: Mainly VFR. Slight chance for MVFR/IFR at KBHB/coastal terminals should marine low stratus and fog push onshore overnight. Winds light and variable.

Saturday: Cigs trending down towards MVFR through the day from south to north. IFR possible in any showers and possible thunderstorms through the afternoon and evening. Light S winds.

Saturday night: MVFR/IFR possible in showers and thunderstorms early, improving to VFR late outside of any patchy fog. Winds light and variable.

Sunday: MVFR/IFR possible in showers and thunderstorms Sunday afternoon. MVFR or lower possible in fog early Sunday morning. Winds W/SW at 5-10kts.

Sunday night: VFR. MVFR or lower in possible fog. Winds from the W at 5kts.

Monday: MVFR possible in any storms, otherwise VFR. SW/W winds, gusting to 15-20kts possible.

Monday night-Tuesday: MVFR possible in any showers Monday night and any storms Tuesday afternoon, otherwise VFR. Light winds overnight, becoming W Tuesday afternoon.

Tuesday night-Wednesday: VFR overnight. MVFR possible in any showers Wednesday afternoon. Winds W at 5-10kts.

MARINE

Seas below SCA criteria this weekend into early next week. Seas around 2-4 ft. Potential for some showers on Monday into Tuesday. Winds shift S Sunday, and SW Monday.

CAR WATCHES/WARNINGS/ADVISORIES

ME...Heat Advisory until 6 PM EDT this evening for MEZ011-015>017- 029>031. MARINE...None.