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Area Forecast Discussion (AFD)

Issued by Caribou, ME (CAR)

FXUS61 KCAR 191745

Area Forecast Discussion
National Weather Service Caribou ME
1245 PM EST Tue Feb 19 2019

Canadian high pressure will build across the region today and
crest over the area Wednesday then move east Wednesday night. 
Low pressure from the Great Lakes will approach late Wednesday 
night then cross the area Thursday.


1220 pM Update: SC cld cvr has remained sct E of the mtns even
as far N as Nern ME, so we trimmed back cld cvr ovr NE and
Cntrl ptns of the FA. Isold sn flurries was kept for the far 
NW, closest to the St Lawrence vly where streamer moisture could
enhance SC cld streets. Otherwise, we updated fcst hrly 
temps/dwpts into the late aftn hrs with hi temps raised only
1 deg F across the Rgn based on midday sfc obs trends. 

Orgnl Disc: The high will bring generally clear skies as 
there's very little low level moisture for cu and stratocu. The 
only exception could be the Saint John Valley where moisture 
advection from the St Lawrence and upslope could generate some 
clouds and even a flurry. While ingredients such as strong cold 
air advection, trajectory and upslope favor a flurry in the 
Saint John Valley. Wind chills are really the primary issue 
today with the Wind Chill Advisory in place for northern zones 
until 10 am. Subzero wind chills are expected for the entire 
area through much of the day. Highs today will again be far 
below normal with readings in the low teens north and upper 
teens to lower 20s in the southern half of the area. Winds are 
the challenge for tonight's forecast. If the winds went calm 
with the building ridge and cold air mass, readings less than 
minus 20F would be possible in Aroostook County. However, the 
ridge axis will stay west all night and maintain steady 
northwest winds. A deep low northwest of Newfoundland will help 
maintain a decent pressure gradient over the forecast area much 
of the night. Do not expect another round of Wind Chill 
Advisories for tonight, but it'll still be cold. Subzero 
readings are anticipated in northern zones and low single digits
further south.


High pressure will cross the region Wednesday with 
mostly/partly sunny skies. Low pressure tracking east from the 
Great Lakes will approach New England Wednesday night with a
secondary low possibly starting to develop along the New England
coast. Clouds will increase early Wednesday night, with snow 
developing overnight. The remnants of the primary low will 
cross the region Thursday, while the potential secondary low 
crosses the Gulf of Maine. Generally expect precipitation in the
form of snow Thursday. However, dependent on the strength of 
the secondary low, enough warmer air could reach the Downeast 
coast to allow the snow to mix with rain there. However, a 
stronger secondary low across the Gulf of Maine would limit the 
amount of warm air and allow precipitation to remain mostly in 
the form of snow even along the Downeast coast. Generally expect
total snow accumulations of 4 to 5 inches across much of the 
region through Thursday, though amounts along the Downeast coast
will be dependent on the potential mix with rain. The low will 
exit across the Maritimes Thursday night with snow tapering to 
snow showers across the north and mountains with decreasing 
clouds Downeast. Temperatures will be at below normal levels 
Wednesday. Near normal level temperatures are expected Thursday.


High pressure should cross the region Friday into Saturday, 
with generally partly cloudy/mostly clear skies. Could also have
a slight chance of snow showers across the north and mountains 
Saturday. Low pressure will approach from the Great Lakes 
Sunday, with a secondary low again possibly developing across 
the Gulf of Maine. The lows should cross the region Sunday
night through early Monday, then exit across the Maritimes later
Monday. Expect accumulating snow to develop across the region
Sunday then persist through early Monday. Dependent on the 
strength and track of the potential secondary low, the snow 
could transition to a wintry mix Downeast later Sunday. The 
snow will taper to snow showers later Monday in the wake of the 
exiting low. Near normal, to slightly above normal, level 
temperatures are expected Friday through Monday.


NEAR TERM: VFR conditions with gusty NW winds are forecast. 
Some gusts to 25 kts can be expected north of HUL and 
GNR, especially at sites such as MLT, GNR and FVE. LLWS is 
forecast north of HUL early this morning with over 35 kts at 
2000ft. A few afternoon snowshowers with tempo IFR vis cannot be
ruled out at FVE, and possibly HUL. 

SHORT TERM: VFR conditions are expected Wednesday. Conditions 
will lower to MVFR/IFR levels Wednesday night. IFR/LIFR 
conditions are expected Thursday. Conditions will then improve 
to VFR/MVFR levels later Thursday night. Occasional MVFR 
conditions are possible across the north and mountains Friday, 
with VFR conditions Downeast. VFR conditions are expected across
the entire region Saturday.


NEAR TERM: The Small Craft Advisory will remain in place through
the forecast period. Mdt frzg spray with another adv will occur
again later tngt ovr the waters.

SHORT TERM: A Small Craft Advisory is in effect through 
Wednesday morning. Conditions should briefly fall below small 
craft advisory levels later Wednesday through early Wednesday 
night. Small craft advisory conditions are then expected later 
Wednesday night through Thursday night. Light freezing spray is 
expected Wednesday morning. Visibilities will lower in 
developing snow Wednesday night, with a snow/rain mix expected 


MARINE...Small Craft Advisory until noon EST Wednesday for ANZ050>052.



Near Term...VJN
Short Term...Norcross
Long Term...Norcross