textproduct: Caribou

WHAT HAS CHANGED

- (8 PM Update) Minor adjustments were made to PoP, QPF, and Sky based on observations and the latest guidance. Surface observations show the cold front approaching the northern International Border and the Saint John Valley. A recent spotter observation also indicated a changeover to -SN in Madawaska. This front will continue to work into northern Maine over the next several hours, changing precipitation over to light snow with minimal accumulation expected. A second area of rain will develop across Downeast Maine in a few hours, with a few tenths of an inch expected for most locations. - Updated aviation section. - Raised precipitation totals for tonight over southern portions of the area. - Decreased precip chances for the Monday system

KEY MESSAGES

1) Colder air moving in tonight will lead to icy roads for many places north of Bangor late tonight.

2) Well below normal temperatures Friday night, Saturday, and Saturday night followed by moderating temperatures Sunday, then a light wintry mix on Monday.

DISCUSSION

KEY MESSAGE 1...Colder air moving in tonight will lead to icy roads for many places north of Bangor late tonight.

KEY MESSAGE 1 DESCRIPTION... The concern for icy roads is later tonight behind a cold front. Another area of precipitation will move in this evening, first in the north and later tonight over southern portions of the area. Most of the precipitation will be ahead of the cold front and fall as rain, though there could be a very brief changeover to snow before it ends from north to south. Any snow accumulation should be a half inch or less. What the precipitation will do is wet or re-wet the roads, and with temperatures falling fairly fast behind the cold front, think that many roads won't have time to dry before temperatures fall below freezing. The freezing line reaches Caribou/Presque Isle around midnight and Millinocket/Greenville/Danforth around 4am. The freezing line may get down to Bangor around dawn Friday, but think it will be brief enough from Bangor south that roads should not ice up.

One other issue to be aware of tonight is fog ahead of the cold front. Can't rule out locally dense fog especially over central portions of the area, and on hilltops.

The cooler, drier air and sunshine during the day Friday should allow any icy roads to dry out pretty quickly.

KEY MESSAGE 2...Well below normal temperatures Friday night, Saturday, and Saturday night followed by moderating temperatures Sunday, then a light wintry mix on Monday.

KEY MESSAGE 2 DESCRIPTION... An upper level trof will continue to pipe in an arctic airmass into the region Friday night. The 925mb temps drop to the coldest for the weekend between -18C to -20C on Friday night. Expected surface temps in the single digits below zero in the north and teens above zero in the south. By Saturday morning, the 925mb model temps show a slight warming with the partly cloud skies to -10C to -14C. Temps at the surface should remain well below normal at low 20s in the north and mid 20s in the south. Mostly clear skies on Saturday night should drop temps again into the single digits across most of the region with teens near the coast.

AVIATION /00Z FRIDAY THROUGH TUESDAY/

A band of IFR ceilings is over FVE and CAR as of 0z and is expected to move south towards the rest of the TAF sites over the next several hours. A FROPA is expected first at FVE around 0z, CAR and PQI around 2-3z, HUL around 4-5z, and BGR and BHB around 5-7z. Ahead of the front, LLWS is possible around 1kft AGL, mainly through 2z, with light S winds. Behind the front, wind shift out of the NW and increase to around 10 kts with gusts to 20-25 kts. Ceilings improve to MVFR behind the front, with clearing to VFR expected during the morning. -RA is expected with and ahead of the front, with a brief period of -SN, mainly at northern terminals just after passage.

VFR expected areawide on Friday and Friday night. NW winds around 15 kts gusting to 25 kts during the day Friday, then subsiding to 5-10 kts Friday night.

Saturday-Sunday...Mainly VFR with possible MVFR in snow showers on Sunday. NW winds 5-10 kts, then Saturday night to Sunday SW winds 5-15 kts.

Monday...Possible MVFR/IFR with uncertainty in snow. SSW winds 5-10 kts.

MARINE

Small craft conditions continue through Friday and probably Friday evening, either as seas or winds. SW winds into this evening switch to N/NW late tonight and remain from the N/NW into Friday night. Light freezing spray later Friday night.

Small Craft Advisory conditions are possible Friday night and again Sunday night and possible Gale Force conditions on Monday. Light freezing spray is possible Friday night and Saturday.

CAR WATCHES/WARNINGS/ADVISORIES

ME...None. MARINE...Small Craft Advisory until 2 AM EDT Saturday for ANZ050-051. Small Craft Advisory until 8 PM EDT Friday for ANZ052.