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Area Forecast Discussion (AFD)

Issued by Caribou, ME (CAR)

FXUS61 KCAR 181016

Area Forecast Discussion
National Weather Service Caribou ME
616 AM EDT Thu Apr 18 2019

High pressure will move east of the region today. A warm front
will lift north across the area tonight. The region will remain
in a moist south to southwest flow Friday through Sunday with
rain at times.


6:16 am update: High pressure is now beginning to retreat to 
the east of the FA. Some high clouds are starting to drift 
across the area and they will thicken this morning with mid 
level clouds to follow later this morning from the west. Made 
some minor adjustments to the sky grids and also backed the 
timing of the rain by a couple of hours based on the latest 
upstream radars and near term model trends. 

Previous discussion:
High pressure across eastern Maine early this morning will retreat 
into the northwest Atlantic through tonight.  Low pressure across 
the western Great Lakes will lift up to near Quebec City late 
tonight.  As a deep upper low digs into the central U.S. tonight 
with a deep sfc low to develop in the diffluent flow aloft and lift 
into the Ohio Valley late tonight.  

Clouds will increase today with showers to develop this afternoon, 
mainly to the north and west of the Katahdin Region.  Highs this 
afternoon will be near 50F in most areas, but with 40s along the 
immediate coast owing to the onshore flow and cold ocean waters.

A warm front will lift north across the FA tonight with showers and 
areas of drizzle and fog.  Rainfall amounts will likely range from 
1/3 to 1/2 of an inch with local amounts of up to 3/4 of an inch. 
Lows tonight will mostly range from the upper 30s to low 40s across 
the FA, but temps will likely slowly rise after midnight.


Moist southerly flow will be in place on Friday between a strong
area of high pressure across the western Atlantic and a complex
frontal system to our northwest. The moist southerly flow will
result in abundant low level moisture in the form of marine
stratus and patchy fog early Friday. A cold front along the St.
Lawrence River Valley Friday morning will slowly push into far 
northern Maine by Friday afternoon. As it does so, expect a band
of showers to accompany the frontal boundary, mainly north of 
the Katahdin region. Rainfall amounts through Friday afternoon 
generally look to be around one-quarter inch or less. Elsewhere,
across central and downeast areas, expect mainly cloudy skies 
with a few showers. High temperatures on Friday will be well 
above normal for this time of year, with highs away from the 
coast ranging from the upper 50s to lower 60s. The front will 
stall out across central areas Friday night into Saturday. 
Expect a steady rainfall to develop Friday night and Saturday 
across northern and central areas in the vicinity of the 
baroclinic zone associated with the nearly stationary frontal 
boundary. Precipitable water values increase to 1.0-1.5 inches 
Friday night and Saturday. The rain could be heavy at times. The
combination of run off from melting snow and rainfall will 
result in continued rises and area rivers and streams through 
Saturday. Highs on Saturday will range from the upper 40s to 
lower 50s across the far north and upper 50s to lower 60s across
central and interior downeast areas. It will be much cooler 
along the downeast coast.


Expect continued chances for occasional rain or showers Saturday
night into Sunday. Showers should begin to diminish by late
Sunday as the upper trof kicks east of the region. Another
weaker system may bring more showers to the region on Monday. 

The main concern late weekend into early next week will be with
regard to the flood potential. The combination of the expected 
rainfall and snowmelt is expected to cause significant rises on 
area rivers and streams into next week. (See hydrology section 
below for more details).

Canadian high pressure will build into the region Tuesday and
then move east on Wednesday. Expect fair weather both days with
high temperatures close to seasonable levels for this time of


NEAR TERM: VFR into early this afternoon with conditions to 
lower to MVFR by mid-late afternoon at the Aroostook County 
terminals. Conditions will lower to IFR this evening at all of
the northern and eastern Maine terminals, and will continue 
tonight in showers and fog, with local LIFR possible late 
evening and overnight. LLWS is expected tonight with a strong 
south wind approaching 50 knots at 2k ft agl. 

SHORT TERM: Widespread IFR conditions expected in low clouds 
and patchy fog early Friday. Conditions should improve to MVFR 
Friday afternoon. Widespread IFR/LIFR conditions expected 
Friday night through Sunday in rain and patchy fog. MVFR 
expected Sunday night into Monday in scattered showers.


NEAR TERM: A small craft advisory has been issued starting at 6
pm this evening. A south flow will increase today into tonight,
and a few gusts may approach 35 knots tonight, but widespread
gale conditions are not expected. 

SHORT TERM: Small Craft Advisory level conditions are expected
to persist Friday through Saturday. Visibilities will be 
reduced to 1 NM or less at times in rain and areas of fog.


A flood warning remains in effect along the Aroostook River in 
the vicinity of Washburn and Wade. The gauge at Washburn is just
over 18 feet early this morning with reports of water coming up
over the Gardiner Creek Road as of late last evening. A report
as of 6:15 am that Castle Hill Road in south Wade is flooded and
the road is closed. Will update and continue the flood warning 
through today, and it will likely need to remain in effect until
the ice gets flushed downriver. 

There is also a flood warning in effect for the Mattawamkeag
River at Mattawamkeag for very minor flooding. The river is now
forecast to drop below flood stage later today.  

Concerns turn to open water flooding over the weekend and into
next week. Rainfall amounts may exceed 2 inches in spots from
tonight through the weekend, with the highest totals across the
northern half of the HSA. The combination of rain and
snowfall is expected to cause significant river rises beginning
Saturday night and likely continuing into early next week. There
is the potential for moderate to major flooding, but the details
on just how much rain falls and how much snow melts makes
predictions of the magnitude of the flooding uncertain, although
there is a high likelihood that there will be some areas that
experience significant flooding. Please continue to closely
monitor the latest forecasts from the National Weather Service
for possible flood watches and warnings this weekend and into
next week.


MARINE...Small Craft Advisory from 6 PM this evening to 6 PM EDT Friday 
     for ANZ050>052.



Near Term...CB
Short Term...Duda
Long Term...Duda