textproduct: Caribou

WHAT HAS CHANGED

- Have extended the Small Craft Advisory for the Coastal Waters out to 25nm until 2PM EDT Saturday.

- Have reduced thunderstorm chances through the weekend with the significant cloud cover reducing instability development.

- Have increased POP chances Saturday using hi-res CAMs.

KEY MESSAGES

1) Showers into the weekend along with a slight chance of afternoon thunderstorms.

2) A low pressure system passes through the region Monday night into Tuesday, though track and timing are uncertain.

3) Prolonged troughing in the Northeast will lead to multiple rounds of showers and storms this week.

DISCUSSION

KEY MESSAGE 1...Showers into the weekend along with a slight chance of afternoon thunderstorms.

KEY MESSAGE 1 DESCRIPTION... A broad upper level trough continues to sit over the state into this weekend, persisting an unsettled pattern with scattered rain showers every day. The greatest chance for rain showers will be across the north, closer to the center of the source of broad instability, though showers down through Bangor and the Interior Downeast region are possible as well. Weak CAPE with the instability from this synoptic pattern could support isolated afternoon thunderstorms each day through this weekend.

Temperatures will be cool, especially across the north where persistent cloud cover will limit surface heating, and temperatures are expected to remain below average through the weekend. For Bangor and the Downeast region, increased breaks in the cloud cover will allow temperatures into the 70s.

KEY MESSAGE 2...A low pressure system passes through the region Monday night into Tuesday, though track and timing are uncertain.

KEY MESSAGE 2 DESCRIPTION... An upper level low moves into the region from the Great Lakes Monday evening. Models differ on the track of the low. The GFS has the track off the coast with the majority of the precip over the Gulf of Maine but some rain along the shore. The ECMWF has the low along the coast and producing a significant rainfall across large portion of the CWA and the Canadian has a broad open wave. The model trends operational and ensembles have been all over the place, with differing trends in strength, timing, and track. This system will need to continue to be monitored but with the long wave trof expect chances of rain to remain elevated and below to near normal temperatures.

KEY MESSAGE 3...Prolonged troughing in the Northeast will lead to multiple rounds of showers and storms this week.

KEY MESSAGE 3 DESCRIPTION... Global ensembles continue the positive Pacific North American Pattern across the CONUS. This will result in large ridging over the Western US with long wave trofing in the east impacting the Northeast. This will keep the pattern progressive but allow for multiple shortwaves to produce frontal systems and precipitation chances. This will keep temperatures generally in the 70s during the day with a couple days potentially seeing 80s. However, this will keep the chances of showers and thunderstorms possible. It will not be a complete washout but will need to monitor the trends to see when synoptic/mesoscale features impact the region. Significant model differences in timing/strengths of systems exist for mid to late week. This continues with the theme from CPC of near to below normal temps and above normal precipitation.

AVIATION /18Z FRIDAY THROUGH WEDNESDAY/

Rest of Today...BKN VFR south with mainly VFR north but brief SCT-BKN MVFR possible. Lingering -SHRA continues, particularly north of KBGR. Gusty, with WSW winds 10 to 15 kts gusting 20 to 30 kts.

Tonight...BKN-OVC IFR/LIFR conditions return over northern terminals, while KBGR/KBHB and Downeast terminals remain VFR overnight. W winds 5 to 10 kts.

Saturday...Slow improvement back to VFR across all terminals. There will be -SHRA possible at all terminals, though most likely north of KBGR. Low confidence in potential MVFR cigs at BGR and BHB. NW winds 10 to 15 kts with gusts 20 to 25 kts.

Saturday night...VFR. A slight chance of showers, mostly north, which could result in some MVFR conditions. Some patchy fog is possible. NW winds 10 to 15 knots, becoming N/NW 5 to 10 knots.

Sunday...VFR/MVFR with showers. Chance of an afternoon thunderstorm. W/NW winds 5 to 10 knots, becoming variable.

Sunday night...VFR. Patchy fog possible. Winds light and variable.

Monday - Monday night...MVFR/IFR in heavier showers, with a chance of thunderstorms. S winds 5-10 knots, becoming NE 5-10 knots. Uncertainty in track of low pressure system, which could shift precip more offshore and shift forecasted wind direction.

Tuesday... MVFR/IFR in heavier showers, with a chance of thunderstorms. Improving to VFR late afternoon. NE winds 5-10 knots gusts to 20 knots, shifting to NW 5-10 knots.

Wednesday...Mainly VFR. Possible MVFR northern terms in the afternoon with showers and chance of thunderstorms. N-NW winds 5-10kt.

MARINE

Intra-Coastal Waters...Winds/seas below SCA through Tuesday AM. A storm system crossing the waters Tuesday may bring SCA wind gusts to the waters. Chances of rain and fog Saturday through Tuesday may reduce vsby at times especially at night.

Coastal Waters out to 25nm...Small Craft Advisory in effect until 2PM EDT Saturday. SW winds 10-20kt with gusts up to 30kt this afternoon but relaxing this evening below SCA. The seas remain elevated into Saturday afternoon generally 4-7ft. Winds/seas below SCA Saturday night through Tuesday AM. A storm system crossing the waters Tuesday may bring SCA wind gusts to the waters. Chances of rain and fog Saturday through Tuesday may reduce vsby at times especially at night.

Outer Waters 25-60nm...Gusty winds up to 30kt through Saturday evening. Winds relax less than 15kt Sunday into Tuesday AM. Will need to watch that storm system for Tuesday PM which poses a low end risk of brief Gales. Seas 4-6ft into Sunday then subsiding to less than 3ft into Tuesday AM. Chances of rain and fog Saturday through Tuesday may reduce vsby at times especially at night.

CAR WATCHES/WARNINGS/ADVISORIES

ME...None. MARINE...Small Craft Advisory until 2 PM EDT Saturday for ANZ050-051.