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Area Forecast Discussion (AFD)

Issued by Caribou, ME (CAR)

FXUS61 KCAR 161406

Area Forecast Discussion
National Weather Service Caribou ME
1006 AM EDT Tue Jul 16 2019

High pressure will move east of the region today. A cold front 
will cross the region Wednesday into Wednesday evening. High 
pressure follows for Thursday into Friday and will be followed 
by a weak trough Saturday.

950 am update...Adjusted thunderstorm forecast for tonight.
Elevated instability arrives in northern zones late evening and
spreads to all areas after midnight. Will use isolated coverage.
Raised lows for tonight as much warmer and humid air overspreads
the area. Added areas of fog over the coastal waters and along
the coast in response to the higher dew points...which will
reach over 70F ahead of the cold front tomorrow afternoon. The
case for locally heavy rainfall was compelling and added mention
of it in southern zones Wednesday afternoon. Not as concerned
with winds at this point.

Prev discussion blo...
Sfc ridge axis leading to moclr skies and lgt winds ovr the FA
tonight. Upr lvl ridge wl be cresting acrs the state this aftn.
At the same time H5 system wl be mvg twd Hudson's Bay. Lead s/wv
located nr the UP of MI wl translate east and help begin to
break ridge down after 21z. 

As the ridge begins to break down clds wl be on the increase in
the aftn. All areas wl be in the 80s except along the coast 
where a sea breeze wl dvlp. 

A wmfnt wl lift into the region tonight with showers
overspreading the north and west aft 00z. With area in the
wmsector and elevated instability present isold thunder can't be
ruled out aft 06z, especially with a cdfnt appchg the state from
Canada. Temps tonight wl be warm and muggy with lows in the 60s.

A cold front across the Saint Lawrence River Valley at 12Z Wed 
morning will cross northern and central portions of the FA Wed, 
and should be across the Down East Region by Wed evening. The 
front is expected to interact with some moisture associated  
with the remains of Barry. The air mass will be very humid to 
the south of the front with dew points likely to get close to 
70F Down East where the PWATs will approach 2 inches. Although 
the threat of severe storms looks low, some of the showers and 
thunderstorms may contain torrential downpours. Drier air will 
begin to filter in northern Aroostook County during the 
afternoon with dew points dropping into the more comfortable 
50s. High pressure builds into eastern Quebec and northern Maine
Wed night with dry and cool weather. Lows will likely drop well
down into the 40s in the normally cooler northwest valleys 
(upper 30s can't be ruled out in spots like Estcourt Station and
Big Black River) with upper 40s to low 50s for most northern 
areas, and mid to upper 50s Down East. Temperatures were lowered
several degrees in the normal cold spots. Thursday looks real 
nice as high pressure slowly drifts east of the area with a 
return flow to set up by evening. It will be m/sunny north and 
p/sunny along the coast, and seasonable with comfortably low 
humidity levels.

A major mid-summer heat wave is expected to take shape to the 
south of our region late this week into the weekend. A strong 
sub-tropical ridge will build north and is expected to stretch 
from the Central Plains to the Middle Atlantic coast. Thu night
will be dry, and with return flow into the region will become 
more muggy and not as cool with perhaps a bit of patchy fog 
along the coast. Friday will be warmer and much more humid and 
with a disturbance to track along the northern periphery of the 
ridge it may touch off a few showers and thunderstorms. Warm and
muggy Fri night, and given the pattern have sided with the 
warmer raw model temp data that usually does better in such 
patterns. The showers and thunderstorms will just add to the 
humidity, and Saturday looks mainly dry and will likely be the 
warmest day of the week with highs well into the 80s and 
potentially into the low 90s for parts of the Bangor Region and 
interior Down East. There is the potential for 3 to 6 hours with
heat index values in the m/u 90s around Bangor and interior 
Down East, but with it still being 4 days off this is 
something to continue to monitor at this point, but will mention
in the HWO. Sunday looks to be another very warm and humid day 
with a better chance of showers and thunderstorms during the 
afternoon and evening as a disturbance and cold front work 
across the region. The guidance diverges quite a bit by early 
the following week with the GFS bringing a cooler and drier air 
mass in the wake of the front with the ECMWF and Canadian faster
with the initial cold front over the weekend and return flow 
into the region early next week. Given the low forecast 
confidence have gone with a blended solution which would still 
keep some lower chance Pops across the area on Monday.

NEAR TERM: VFR next 24 hours at terminals, outside of brief MVFR
restrictions twd end of TAF valid time. Light sw winds tonight 
will back twd the south during the course of the day but will 
remain below 10kts.

SHORT TERM: Outlook Wed-Sat

Wed night & Thu...VFR.

Thu night: VFR, except local IFR Possible in patchy late night 
fog at KBHB. 

Fri & Sat...Mostly VFR with locally MVFR in showers and 
thunderstorms Fri afternoon and evening. Local MVFR possible in 
any fog patches Fri night, mainly in areas that receive showers 
Fri pm.

NEAR TERM: Winds and seas will remain well below SCA levels
through tonight.

SHORT TERM: The wind and seas are expected to remain below small craft 
advisory levels Wed-Sat.  A warmer and humid air mass Thu night into 
Sat could result in some fog patches, especially late night/early 
morning hours.


Near Term...Farrar
Short Term...CB
Long Term...CB