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Area Forecast Discussion (AFD)

Issued by Caribou, ME (CAR)

FXUS61 KCAR 222223

Area Forecast Discussion
National Weather Service Caribou ME
623 PM EDT Fri Mar 22 2019

Low pressure will track northeast across the Gulf of Maine this
evening and then into the Canadian Maritimes tonight through 
Saturday. A cold front will cross the region Sunday.


620 PM Update: Just a quick update to add patchy fog to SE ptns
of the Rgn this eve where winds are still SE ahead of the sfc
low advcg ENE across Cntrl Washington county.

530 PM Update: We updated to accelerate the chgovr to sn ovr NE
ptns of the Rgn a little quicker than the prev fcst with good
precip banding resulting in dynamic cooling from alf in addition
to llvl winds becoming more Nrly, neutralizing llvl warming.
Despite an earlier transition to sn, sig abv fzg sfc temps and
wet ground ovr this ptn of the FA will limit potential
accumulation with this band as it moves moves N and W of NE
ptns of the Rgn, with lesser sn rates xpctd later this eve. 

Orgnl Disc: Low pressure will continue to lift slowly northeast
along the Maine coast overnight. Rain will continue across the 
region into this evening with snow across the far northwest. As 
the low continues to move into the Canadian Maritimes, rain is 
expected to gradually transition to all snow, before tapering to
snow showers by early Saturday morning. A Winter Weather 
Advisory remains up for much of the North Maine Woods and 
portions of the Central Maine Highlands through 8 AM EDT 
Saturday, and a Winter Storm Warning is up until 8 AM for 
northern Somerset county in far northwest Maine. As the rain 
transitions to snow late tonight, expect accumulations to range 
from 2 to 4 inches by Saturday morning in the Caribou/Presque 
Isle areas. Farther south across north central areas, 
accumulations are expected to be an inch or less. Temperatures 
this evening will generally be in the low to mid 30s across the 
region and then gradually fall back into the lower 30s by 
daybreak Saturday. 

Saturday is shaping up as a mostly cloudy day with lingering
snow showers across the north early in the day, diminishing by
afternoon as the low continues to move through the Canadian
Maritimes and away from the region. As the pressure gradient
tightens between the departing low to our east and high pressure
to our southwest. Blustery northwest winds can be expected
during Saturday, with winds gusting as high as 35 mph at times 
in the afternoon, especially across the higher terrain. Mostly 
cloudy skies will give way to partial sunshine by afternoon. 
Highs on Saturday are expected to range from the mid to upper 
30s north and low to mid 40s central and Downeast.


Low pressure will exit across Labrador Saturday night, with
a cold front approaching the Saint Lawrence Valley late. Expect
partly cloudy skies across northern areas Saturday night, with 
decreasing clouds Downeast. The cold front will cross much of 
the region Sunday, approaching the Downeast coast late. Expect a
chance of snow showers with the front, across mostly the north 
and mountains. Some heavier snow showers or snow squalls are 
also possible. The front will exit the Downeast coast Sunday 
night, with a weak low possibly developing along the front. 
Expect mostly cloudy skies with a chance of evening rain/snow 
showers Downeast, with a chance of snow showers overnight. High 
pressure will build across northern areas later Sunday night in 
the wake of the cold front. Generally expect partly cloudy skies
across northern areas Sunday night, along with a chance of 
evening snow showers. The weak low will exit across the 
Maritimes early Monday drawing the cold front south, while high 
pressure builds toward the region. Expect mostly cloudy skies 
with a slight chance of snow showers early Monday Downeast with 
the exiting low, then decreasing clouds during the afternoon. 
Expect partly cloudy skies across northern areas Monday. 
Temperatures will be at near normal, to slightly above normal, 
levels Sunday in advance of the cold front. Below normal level 
temperatures will occur Monday.


High pressure builds toward the region Monday night, then
crosses the region Tuesday/Wednesday with partly cloudy to
mostly clear skies. High pressure should begin to exit eastward
Thursday through Friday, though how rapidly this occurs is still
uncertain. A warm front could approach the region later 
Thursday into Friday with the return flow around exiting high 
pressure with light overrunning precipitation. However, this 
will be dependent on how rapidly high pressure begins to exit. 
Temperatures will be at below normal levels Tuesday/Wednesday. 
Above normal level temperatures are expected Thursday/Friday.


NEAR TERM: Widespread IFR/LIFR can be expected through this 
evening in rain/snow. Rain will transition to all snow before 
tapering to snow showers by Saturday morning. IFR/MVFR 
conditions in any lingering snow showers Saturday morning will 
give way to clearing skies and VFR conditions by Saturday 
afternoon. The big story Saturday afternoon will be the 
northwest winds gusting up to 35 kt at times, especially at the 
northern TAF sites.

SHORT TERM: Expect VFR conditions across the region Saturday
night. Variable conditions will occur with snow showers across
the north and mountains Sunday with generally VFR conditions
Downeast. Occasional MVFR conditions are possible across the
entire region early Sunday night. Occasional MVFR conditions
could persist Downeast overnight, with VFR conditions across
northern areas. Occasional MVFR conditions are possible Downeast
early Monday. Otherwise, generally VFR conditions are expected 
across the region Monday into Wednesday.


NEAR TERM: Will issue the Gale Warning for Saturday in the
Northwest flow and cold advection. Have included the intra-
coastal zone as well. Visibility will be reduced to 1 to 3 NM 
in rain tonight and then improve, becoming unrestricted during 
Saturday morning. 

SHORT TERM: Small craft advisory conditions are expected
Saturday night through early Sunday night. Conditions are 
then expected to be below small craft advisory levels later 
Sunday night/Monday. Visibilities could be reduced at times in 
snow showers Sunday night through early Monday.


The combined amount of rainfall and snowmelt could be enough to
lift ice and generate ice movement and ice jam potential in the
southern half of the forecast area, particularly the 
Piscataquis and Penobscot river basins. Rainfall amounts through
tonight are generally expected to be around one inch. River 
rises are progged at 2 to 3 feet which could be sufficient to 
break up some ice. Widespread river flooding is not 
expected, just localized issues due to any ice jams as rivers 
begin flowing. 

Further north, the existing snowpack will absorb the rainfall 
without many issues, although we can't rule out localized ice 


High astronomical tides and storm surge at the time of the early
Saturday morning high tide may cause minor issues at some of 
the usual trouble spots such as the Deer Isle Causeway, Seawall 
Road, and Machias. A Coastal Flood Statement has been issued to
highlight the threat for the early morning high tide Saturday.


ME...Winter Storm Warning until 8 AM EDT Saturday for MEZ003.
     Winter Weather Advisory until 8 AM EDT Saturday for MEZ001-004-
MARINE...Gale Warning from 8 AM to 7 PM EDT Saturday for ANZ050>052.



Near Term...VJN
Short Term...Norcross
Long Term...Norcross
Tides/Coastal Flooding...