textproduct: Caribou

WHAT HAS CHANGED

-Fog has developed and is lingering in the St. John Valley, and along the Downeast coast, reducing visibility. Expected to dissipate as the sun rises.

KEY MESSAGES

1) Gusty winds, along with very warm and dry conditions, leads to fire weather concerns today, despite a few rain showers Downeast.

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 winds, along with very warm and dry conditions, leads to fire weather concerns today, despite a few rain showers Downeast.

KEY MESSAGE 1 DESCRIPTION... Low pressure and warm front moves northeast further into Canada, as associated cold front moves through Maine this evening. Since front moves through later in the day, northern and eastern Maine remain in the warm sector of the system throughout most of the day, warming the region up pretty well. Daytime highs in the upper-70s to low-80s in the north, mid-80s in Central Highlands to Southern Aroostook, and mid-to-upper 80s Downeast. Relatively decent pressure gradient behind this low pressure system, alongside decent mixing, which allows for gusty winds tomorrow, peaking in the afternoon around 30-35 mph in the north and 25-30mph Downeast. Minimum relative humidity values generally in the 30s today, resulting in some fire weather concerns. There is some instability, primarily in the Downeast region, that could support some developing rain showers during the afternoon. These showers are not anticipated to be severe, or long lived. But there could be a quick burst of rain and maybe a rumble of thunder before sunset, primarily in Hancock and/or Washington counties.

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 most of the Saint John Valley, where it begins on June 1. Strong cold air advection is expected Thursday behind a cold front, with 1000-500mb thicknesses dropping below 540dam for much of the forecast area by Thursday night. With a strong jet streak overhead and moderate surface pressure gradient, decoupling is less likely except across the most sheltered valley locations. Drier air with dew points in the mid 20s may also prevent frost formation. Even without frost and full decoupling, some damage to sensitive plants is possible in these conditions as 2 meter temperatures fall into the mid 30s north of Baxter State Park and some of the cooler valleys of the North Woods fall to around freezing.

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 of the area, especially the lower elevations of northern Maine. Low temperatures into early Saturday morning may be a few to several degrees lower than blended guidance as a result. Dew points will also be higher in the upper 20s and lower 30s, leading to more frost formation potential across northern zones. A warm front across southern New England will lead to a shield of cirrus clouds approaching southern parts of the area late, which may cut down on cooling potential closer to the coast. 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.

AVIATION /06Z WEDNESDAY THROUGH SUNDAY/

Today: Generally VFR, except for MVFR/IFR at KFVE and KBHB in fog. Fog is expected to dissipate by morning. During the day, VFR conditions. SW winds around 10-15 kts, with gusts 25-30 kts possible. LLWS until daybreak.

Tonight: VFR. N/NW winds Gusts 20-25 kts possible.

Thursday: VFR. NW winds at 10-15 kts. Gusts 20-25 kts possible.

Thursday night to Saturday: VFR. NW winds 10-15 kts with gusts to 25 kts during the day Friday, otherwise NW at 5-10 kts.

Saturday night to Sunday: VFR with light and variable winds, shifting SE at 5-10 kts Sunday.

MARINE

Small Craft Advisory for outer waters in effect until this evening, with seas around 5ft and a few gusts to 25kts possible. Marine fog has already developed, and should burn off when sun rises. Chance for passing rain today. SW winds today, shifting WNW by Thursday.

Winds and seas will remain below advisory criteria Thursday night through early next week. The lightest winds and seas are expected this weekend, with winds around 5 kts and seas 1 to 2 feet or less.

CAR WATCHES/WARNINGS/ADVISORIES

ME...None. MARINE...Small Craft Advisory until 8 PM EDT this evening for ANZ050- 051.