Area Forecast Discussion
Issued by NWS Caribou, ME
FXUS61 KCAR 300445
Area Forecast Discussion
National Weather Service Caribou ME
1245 AM EDT Sun Apr 30 2017
A cold front will move offshore tonight followed by high pressure
on Sunday. Low pressure tracking to our west will lift a warm
front across our region on Monday. An occluded front will push
into the area Monday night and Tuesday.
.NEAR TERM /THROUGH TODAY/...
1230 AM Update: SC cld cvr is hanging arnd Nrn ptns of the
region late tngt, so we had to bump up cld cvr ovr this ptn
of the Rgn til about 09z, after which, stronger llvl subsidence
should lead to the break-up of this cld cvr. Otherwise...fcst
hrly temps/dwpts into the erly morn hrs were updated based on
trends seen from latest obs, with ovrngt lows across NW rvr vly
lctns lowered about 2 to 3 deg F thinking that winds may briefly
decouple ovr these areas arnd daybreak to allow shallow
radiational vly cooling/sfc invsn.
Orgnl Disc: The cold front will bring sharply cooler
temperatures for tonight and Sunday. There could be a brief
shower in northeast Aroostook this afternoon with the cold
front, but otherwise, it should not generate any precipitation.
It will produce a lot of post-frontal wind with a tight pressure
gradient, steep lapse rates and strong winds at H925. With the
cold air advection, winds are expected to continue strong much
of the night and temperatures will fall to the upper 20s and
lower 30s north. Bangor and the Down East region will record
overnight lows mostly in the upper 30s. Drier air will continue
advecting into the region overnight into early Sunday. Dew
points will be in the 20s after reaching the low 60s last
Thursday. Winds will die off in the morning as high pressure
builds over the area. Highs will only reach the low to mid 50s
in this cooler air mass. While Sunday will start with sunshine,
mid and high overrunning clouds will increase during the day in
the southern half of the forecast area. Northern zones should
maintain sunshine much of the day.
.SHORT TERM /TONIGHT THROUGH TUESDAY/...
As a low pressure system moves into the Midwest, a warm front
will lift across the Mid-Atlantic and into New England. As it
does so, precip is expected to spread in from the west, mainly
impacting central and Downeast areas Sun night. There remains
some discrepancy on the northward extent of precip Mon AM and
early aftn, but the NAM stands alone in not having precip
reaching the Saint John Valley by 18z Mon. Thus, definite POPs
were extended north to the valley in the early afternoon hours.
Some upper ridging may lead to some diminished or clearing
precip later Mon aftn and early eve. Another round of increased
POPs appears likely between 00z and 12z Tue as the warm front
lifts across the CWA, while the cold front and upper low
approach from the west. As the cold front pushes through during
the day Tue, precip will diminish, but some isolated showers may
linger to the end of the short term as the upper low remains
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
Some spotty rain may linger Tue night into Wed AM as the upper
trough slides across the CWA. As the base of the trough moves
off to the east, precip will clear up Wed PM into Thu. A new
upper trough approaching from the west Thu night and Fri will
push a low pressure system across the Mid-Atlantic and toward
Cape Cod and Nova Scotia Fri into Fri night. Widespread precip
across the CWA is possible with this system, but differences in
timing and track between models limit POPs to likely at this
point. Depending on temps and storm track, snow may be possible
up north, but for now have it almost all rain.
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
NEAR TERM: VFR next 24 hours. Northwest winds will continue to
gust tonight following cold front passage. Expect winds will
diminish Sat afternoon as high pressure builds in.
SHORT TERM: VFR conditions will deteriorate to MVFR and IFR CIGs
and eventually vsby Sun night into Mon AM as precip spreads
across the area. MVFR to IFR conditions are expected to persist
Mon aftn and night as the precip persists, and fog may develop
in moist S-SE`ly flow Mon night. Some improvement is likely Tue
night into Wed, but some spotty MVFR to IFR conditions are still
possible in any lingering rain showers.
NEAR TERM: Hv issued SCA thru 12z Sun for winds gusting to
25kts overnight. As cold front moves through winds will be
gusting 25-30kts for svrl hrs and believe this is enuf to
SHORT TERM: Offshore conditions will be good Sun night into Mon
as seas remain low and gentle to moderate S`ly winds turn E`ly.
Winds will shift back SE-S`ly and increase Mon night into Tue,
with a few gusts possibly getting close to SCA levels during the
day Tue. Persistent onshore flow will lead to seas exceeding SCA
criteria during the day Tue.
MARINE...Small Craft Advisory until 8 AM EDT this morning for