textproduct: Caribou

WHAT HAS CHANGED

-Wind probabilities for 40 mph gusts have decreased due to uncertainty of cloud cover Tuesday. Continue to monitor forecast for updates.

KEY MESSAGES

1) Widespread frost is expected for northern areas on Saturday night, with patchy frost elsewhere in interior Downeast.

2) Another round of rain is possible Monday.

3) Strong westerly winds on Tuesday could lead to some isolated power outages.

DISCUSSION

KEY MESSAGE 1...Widespread frost is expected for northern areas on Saturday night, with patchy frost elsewhere in interior Downeast.

KEY MESSAGE 1 DESCRIPTION... 1030mb high centered over southern Ontario will continue building, crossing the northern half of the CWA overnight tonight. This will lead to clear skies and calm winds, especially directly under the high, which will be prime conditions for efficient radiational cooling and temperatures dropping below freezing, especially in the north directly under the high.

Downeast may be able to maintain a gradient but interior Downeast may be able to decouple briefly for an hour or two. Thus have min forecasts around 37 over central Washington and interior Hancock which may be enough for frost to develop and have issued a Frost Advisory from 07-12z tonight. Coastal Downeast will remain in the u30s to lwr 40s.

The frost/freeze program has ended for the entire CWA aside for Hancock and Washington counties.

KEY MESSAGE 2...Another round of rain is possible Monday.

KEY MESSAGE 2 DESCRIPTION... A vertically stacked system will swing over James Bay Sunday night. Weak lopres will be moving south of Cape Cod with possible showers spreading over the waters and possibly into Downeast though will likely see dry air hold on long enuf with ridge axis along the coast to prevent much measurable precip from falling.

The bigger story will be the cold front sweeping through the area on Monday afternoon. The weak low over the waters should move fast enough to prevent interaction with the approaching system from the northwest. 300mb speed max should provide enuf lift in the left front exit region to enhance rainfall totals over the north, generally between 0.30-0.50 inches. This will likely have little impact on the ongoing drought. Coastal low deepens as it heads into Nova Scotia and as it does so northwest winds increase just above the surface with gusts approaching 30 mph late in the afternoon and evening.

KEY MESSAGE 3...Strong westerly winds on Tuesday could lead to some isolated power outages.

KEY MESSAGE 3 DESCRIPTION... Increasing confidence on Tuesday that, as the low pressure system deepens in the Northern Maritimes, we can expect strong surface high pressure to dive over the eastern Great Lakes. This will lead to a strong pressure gradient between the low and high, resulting in gusty west winds developing during the afternoon and evening hours on Monday. Tuesday probabilities for 35+ mph wind gusts have stayed consistent to 70-90%, with 40+ mph probabilities now 40-70% for Millinocket and areas north. For the Bangor region and interior Downeast, 35+ mph wind gusts probabilities are 20-50%. 40+ mph probabilities have decreased to 0-20%. There is ensemble guidance suggesting a potential of wind advisory headlines (31-39 mph sustained or gusts 45+ mph). Uncertainty remains in wind speeds due to uncertainty with cloud cover throughout the day on Tuesday. However, it is likely that significant leaf loss may be possible in areas of Northern Maine where peak foliage has been reached. Additional leaf loss is possible in the Central Highlands to Downeast Maine where the foliage is moderate to high. Gusty winds could also lead to some isolated power outages. Continue to monitor the forecast for updates, as models get a better handle on the atmospheric set up.

AVIATION /18Z SATURDAY THROUGH THURSDAY/

Through 00z...VFR. NW winds 5-10kts gusting 15-20kts.

Tonight-Sunday...Mainly VFR, outside of patchy IFR valley fog at PQI and HUL between 03-12z. Light and variable winds becoming S 5-15kts.

Sunday night-Monday...VFR early becoming MVFR/IFR late in rain and fog. S 5-15kts becoming SSW 5-15kts gusting to 25kts. LLWS possible.

Monday night-Tuesday...VFR/MVFR north. VFR Downeast. Westerly winds 15 to 25 knots with gusts up to around 30 knots Monday night. West winds 20 to 30 knots, then gusts at northern terminals up to 35-40 knots, at southern terminals 20-30 knots.

Tuesday night-Wednesday...VFR conditions. W/NW winds 10-15 knots, gusting to 20-25 knots at all terminals. Winds relax 5-10 knots area wide for Wednesday and gusts at 15-20 knots.

Wednesday night-Thursday...VFR conditions. S winds 5-10 knots, gusting 15-20 knots at all terminals. Thursday winds S at 10-15 knots with gusts 20-25 knots.

MARINE

Winds and seas remain below small craft levels through Sunday night. Wind gusts increase above 25kts over the outer waters Monday afternoon and approach gale force in the evening remaining around these levels through Tuesday. Waves build to 5ft Monday evening with 2 to 5 feet over remaining waters through Tuesday. Tuesday night winds W 10-15 knots for coastal waters with gusts 15-25 knots. Outer waters W 15-25 knots, 25-35 knots gusts. Wednesday W winds 5-10 knots, gusts 10-15 knots on coastal waters, outer waters winds at 10-15 knots, gusts 20-25 knots. Wave heights Wednesday 2-4 coastal, outer-waters 3-5 ft then going 1-3 ft during the evening both waters.

CAR WATCHES/WARNINGS/ADVISORIES

ME...Frost Advisory from 3 AM to 8 AM EDT Sunday for MEZ016-017. MARINE...None.