textproduct: Caribou

WHAT HAS CHANGED

- Continued uncertainty in rainfall set up and totals Monday.

- Increasing confidence in strong winds Tuesday.

KEY MESSAGES

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

KEY MESSAGE 1 DESCRIPTION... High pressure makes its way into the forecast area today, with the center of the 1030mb high 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 will likely sit just south of the center of the high, with a weak but non-zero pressure gradient leading to potentially continued light winds through the night, which will ever so slightly disrupt the effectiveness of the nocturnal radiational cooling. That said, temperatures may dip low enough for a frost threat in the Bangor and Downeast regions.

The frost/freeze program has ended for the entire CWA aside for Hancock and Washington counties. That said, there is still a chance for frost, particularly in northern Hancock and central Washington, especially should the center of the high pressure shift slightly south from where global models currently put it.

KEY MESSAGE 2...

KEY MESSAGE 2 DESCRIPTION... Sunday night, a cold surface high pressure that will have brought widespread frost Sunday AM shifts to the east over the Maritimes. A potent vertically stacked low pressure system tracks into north-central Quebec with a trailing potent cold front. That front will swing across the CWA on Monday at the same time as a low pressure exits off the Mid-Atlantic coast. The interaction between the high pressure and the two lows provides significant uncertainty about rainfall. There continues to be a few different scenarios still with the models. 1. The high pressure could dominate, forcing the lows to stay to the north and south, limiting precip. 2. The Canadian low could enhance the coastal low as it rides closer to the coast northward, bringing more substantial precip to coastal areas. 3. The Canadian low could dominate, bringing enhanced precipitation along its cold front from the moisture over the southeast low. At this time, uncertainty from the models continues to be high, so forecast confidence is low, with a wide range of precipitation values.

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 increased to 70-90% with 40+ mph probabilities now 50-70% for Millinocket and areas north. For the Bangor region and interior Downeast, 35+ mph wind gusts probabilities are 50-70% with 40+ mph probabilities now 20-40%. There is ensemble guidance suggesting a potential of wind advisory headlines (31-39 mph sustained or gusts 45+ mph) but still uncertainty exists on exact expected wind speeds/gusts. 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 /06Z SATURDAY THROUGH WEDNESDAY/

Rest of tonight...Generally VFR, with brief periods of IFR possible in patchy fog rolling through various terminals, especially around KPQI/KHUL with river valley fog whenever winds become calm. Winds generally light and variable.

Today - Sunday...VFR across all terminals. NW winds 5 to 10 kts become light and variable overnight, then shift SE 5 to 10 kts on Sunday.

Sunday night-Monday...VFR Sunday night changing over to MVFR or lower possible, due to rain on Monday. Chance for overnight fog areawide, that would lift during the morning. S winds Sunday night shift to W Monday with gusts to 25 knots.

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 with gusts up to 35 to 45 knots Tuesday.

Tuesday night-Wednesday...VFR conditions. W/NW winds 10-15 knots, gusting to 25-30 knots at northern terminals and 5-10 knots with 20-25 knot gusts at the downeast terminals. Winds relax 5-10 knots area wide for Wednesday and gusts at 15-20 knots.

MARINE

NW winds and seas remain below SCA levels through Saturday night. ESE winds Sunday night will shift to W Monday, with winds increasing to 20 kts with gusts to near 30 kts and waves 3-5 ft for coastal waters and near 25 kts with gusts to 35 kts and waves 5-7 ft on outer waters, and wave heights between 2-4 ft through Tuesday afternoon before returning below SCA criteria.

CAR WATCHES/WARNINGS/ADVISORIES

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