textproduct: Caribou

WHAT HAS CHANGED

- 7:59PM UPDATE...Made changes for the 00z TAFs, see the aviation section below. The atmosphere remains very capped this evening and very little activity remains with no storms. A cold front is approach the Montreal Quebec area and that will bring the potential for some showers tonight and perhaps a Thunderstorm to the North Woods. Have made a significant overall to POPs and QPF for tonight into tomorrow. Additionally, have increased winds for tomorrow with significant boundary layer mixing up to 800mb therefore changed the Key Messages to reflect tomorrow being warm, breezy and low RHs for potential fire weather concerns.

KEY MESSAGES

1) Gusty westerly winds, combined with very warm and mostly dry conditions will lead to some fire weather concerns on Wednesday despite a few showers across the region.

2) Below average temperatures are expected Thursday through Saturday night. Near freezing temperatures are possible early Friday and Saturday mornings across the north, which may require actions to protect vulnerable plants.

DISCUSSION

KEY MESSAGE 1...Gusty westerly winds, combined with very warm and mostly dry conditions will lead to some fire weather concerns on Wednesday despite a few showers across the region.

KEY MESSAGE 1 DESCRIPTION... A cold front will approach from the northwest tomorrow and cross the region. Prior to its arrival in the late afternoon we will remain in the warm sector. Winds shift westerly tomorrow as the LLJ rapidly increases. Hi-res modeling is in fairly good agreement that the boundary layer by late morning will mix up to 825-800mb with winds increasing aloft to near 40kt which we will mix some of this down. Classic inverted "V" signature indicating how dry the surface will be despite the ongoing green up. There is some concerns for fire weather especially wherever fine fuels may still be receptive. Air temperatures will climb into the upper 70s to low 80s across the north, mid to upper 80s for Southern Aroostook County to the Downeast including Bangor Region. Only cool spots in the 60-70s will be right along the Downeast shoreline. Westerly winds 10-20mph gusting 30-35mph with the potential of gusts to 40mph especially in the higher terrain. Afternoon relative humidities will dip down into the 32-38 percent range. Cannot rule out a few isolated to scattered showers but many locations will remain dry.

KEY MESSAGE 2...Below average temperatures are expected Thursday through Saturday night. Near freezing temperatures are possible early Friday and Saturday mornings across the north, which may require actions to protect vulnerable plants.

KEY MESSAGE 2 DESCRIPTION... The frost/freeze program will expand across much of the rest of northern and eastern Maine on Thursday except across the North Woods and Saint John Valley, where it begins on June 1. Strong cold air advection is expected Thursday behind a cold front, resulting in highs only in the 50s and lower 60s, warmest along the coast. Thursday night, a modest low level jet looks to develop overhead, likely keeping unsheltered spots from decoupling, and clouds should be on the increase throughout the night as well. Drier air with dew points in the 20s and lower 30s may also prevent frost formation. Even without frost, some damage to plants is possible in these conditions with temperatures falling into the lower and mid 30s in northern areas as high pressure noses in from the Great Lakes.

By Friday night the surface ridge of high pressure extends over the area from central Quebec. This will lead to lighter winds and a better chance of decoupling over more areas, especially the lower elevations of northern Maine. Lows Friday night and Saturday morning are forecast in the 30s to mid 40s, but may end up being lower in ideal radiational cooling conditions. Dew points will also be higher in the upper 20s to mid 30s, leading to more frost formation potential across northern zones. Below average temperatures will continue for Saturday and Saturday night, but a moderation is expected as high pressure moves over and eventually east of the area. Our next chance of precipitation will be early next week.

AVIATION /00Z WEDNESDAY THROUGH SUNDAY/

00z TAF UPDATE

Tonight: An increasing W LLJ will move over the region overnight. With surface winds remaining light and primarily decoupled, widespread LLWS is expected at all terms. LLWS will generally begin between 03Z-06Z for KCAR, KPQI, KHUL, KFVE and between 06Z-09Z for KBGR, KBHB.

KFVE will hold onto IFR/LIFR cigs (OVC005-007) with BR and VCSH through the night. KCAR, KPQI, and KHUL will gradually drop from VFR to MVFR/IFR (BKN015-025) between 02Z and 06Z with cigs/BR. KBGR and KBHB will remain predominantly VFR, though a brief window of BCFG is possible at KBHB around 05Z.

Wednesday: LLWS threat will end as the stronger winds aloft mix down to the surface. Sfc winds W/NW 10-15 kt gusting 20 to 30 kt through the afternoon. All terms will return to solid VFR conditions by 12Z-15Z, lasting through the remainder of the TAF period.

Previous Discussion...

Wednesday night to Thursday: VFR. NW winds 10-15 kts with gusts to 25 kts.

Thursday night: VFR. WNW winds 5-10 kts.

Friday: VFR. NW winds NW winds 10-15 kts with gusts to 25 kts.

Friday night to Saturday: VFR with light and variable winds, increasing to around 5-10 kts during the day.

MARINE

Small Craft Advisory for outer waters in effect for tonight into Wednesday, with seas around 5ft and some wind gusts to 25kts possible. Chance for passing rain this afternoon, and chance for rain on Wednesday. SW winds today into Wednesday.

Winds and seas are likely to remain below SCA criteria Wednesday night through early next week.

CAR WATCHES/WARNINGS/ADVISORIES

ME...Air Quality Alert until 10 PM EDT this evening for MEZ029-030. MARINE...Small Craft Advisory until 8 PM EDT Wednesday for ANZ050-051.