Area Forecast Discussion
Issued by NWS Caribou, ME

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS61 KCAR 181030
AFDCAR

Area Forecast Discussion
National Weather Service Caribou ME
630 AM EDT Fri Aug 18 2017

.SYNOPSIS...
A warm front will approach the region from the west today and
will move across the area tonight. An occluded front will slowly
cross the area Saturday and Saturday night. High pressure builds
to the south of Maine Sunday into Monday.

&&

.NEAR TERM /THROUGH TONIGHT/...
625 AM update...Band of showers associated with an area of warm
advection and lift aloft currently stretches from eastern NY
down into southern New England. This precipitation will continue
to shift to the east through the morning hours. The latest hi-
res model guidance shows this line crossing our area this
afternoon, then a second batch to move through this evening and
overnight. Model trends have shifted further south with the
heaviest QPF with this second round this evening, so have
adjusted PoPs, weather, and QPF a bit with this update, but will
let subsequent shifts make any significant changes as new
guidance comes in later today.

Previous discussion...Showers to spread across the region today
and tonight, especially Downeast, where locally heavy rainfall
is possible.

Low pressure currently spinning over the Michigan UP will slowly
move eastward today and tonight. Moisture is already lifting
northward out ahead of the system, as evidenced by showers on seen
on radar. This activity will slowly push eastward through the day;
expect eastern areas will remain dry much of the day as the showers
will need to overcome the dry airmass that is in place. Highs will
be in the mid 60s to around 70 in most locations.

Showers will become more numerous this evening - particularly
Downeast - as the warm front lifts onshore, ushering in deep
moisture. The warm front will quickly be followed by an occluded
front which will march from west to east late tonight into Saturday.
Out ahead of this second front, PWATs of 1.75-2.0 inches will spread
across Downeast, especially along the coast. This combined with warm
cloud depths of 12-14 kft will allow for locally heavy rainfall,
particularly along the coast. Note that much of Downeast Maine is
currently included in WPC`s Excessive Rainfall Outlook. Elevated
instability will exist out ahead of the occluded front as well, so
expect we`ll have some rumbles of thunder in southern portions of
the forecast area. It`ll be a muggy night with lows in the upper 50s
to lower 60s.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY/...
The weekend will not be a wash-out, but will have some shower
activity, more so Saturday.  Saturday will start with a warm front
across central Maine with an occluded front to the west of the area.
The best chance of steadier rain will likely be saturday morning
across the Downeast Region.  As the occluded front moves closer to
the area more showers will likely develop across western
portions of the forecast area in the afternoon. The day will
feature a lot of low clouds and some fog in the morning, and
it is doubtful that much of the area sees any sunshine,
but clouds may thin for a few breaks in the afternoon across
central and western portions of the area. The occlusion comes
through Sat night with a few more showers and is followed by an
upper trough Sunday. Sunday will feature more clouds than sun in
the north and mountains along with a few showers, although most
of the day will be dry. Further south, the Downeast Region and
along the coast will start with clouds than will give way to a
partly sunny sky. Temperatures Saturday will be near average
for the second half of August, and and Sunday will be a few
degrees above average.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
A surface ridge crests to the south of the area Sun night and moves
east Monday.  It looks dry with above average temperatures.  The GFS
does have a weak disturbance and attempts to generate a late day
shower in a few spots across the north woods, but chances look slim
and will keep it dry for now. The air mass is quite warm Monday
with 925H temps around +22C Downeast, and with a decent amount
of sunshine and a downslope wind m/u 80s are expected. Highs
will likely top 80F all the way north to the Saint John Valley.
Attention turns to a sharp upper trough digging into the Great
Lakes Region Tue night and Wednesday with a lot of energy and a
deep surface low for this time of year that is expected to be to
the west of the area by 12Z Wed. The models differ on the depth
and position of the low that will have important implications
on the sensible weather across northern and eastern Maine. Some
initial overrunning rain is possible Tuesday, mainly across
northern areas. Most of the area stands to pick up some rainfall
Tue night and Wednesday, but the details on where the heaviest
rain will fall still remain uncertain. Somewhat drier by Thu,
but with an upper trough in the vicinity a couple of showers
still can`t be ruled out.

&&

.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
NEAR TERM: VFR conditions will prevail at all sites through at
least 22z Friday, though showers will be spreading from west to
east through the day. Expect ceilings will lower to MVFR to IFR
at the southern terminals shortly thereafter; the northern sites
will see ceilings lower to around 1500 ft around 00z Sat and
then remain there much of the night. Visibilities will be
reduced to 3-5SM at times in rain and patchy fog after 00z Sat.

SHORT TERM: IFR conditions likely to start the day Sat with LIFR
possible, especially at KBHB.  Conditions will likely improve to
MVFR, at least at the northern terminals from KHUL to KFVE by Sat
afternoon.  Predominately MVFR Sat night into early Sun, with
conditions to improve to VFR by afternoon, except for some patches
of MVFR ceilings across northern areas.  VFR expected Sun night
through Tue, with the possible exception of any patches of late
night fog or in any showers later in the day Tue.

&&

.MARINE...
NEAR TERM: A Small Craft Advisory is in effect for tonight into
Saturday. Winds and seas will increase today and especially
tonight as low pressure lifts to the north and west of the
waters today, bringing an occluded front across the waters late
tonight. Gusts of 25 kt and seas of 4-6 feet are expected after
8 pm tonight, continuing through daybreak Saturday.

SHORT TERM: Small craft advisory level seas are expected through
Saturday evening. Areas of fog will produce poor visibility at
times through Sun morning.

&&

.CAR WATCHES/WARNINGS/ADVISORIES...
ME...None.
MARINE...Small Craft Advisory from 8 PM this evening to 8 PM EDT
     Saturday for ANZ050>052.

&&

$$

Near Term...Hastings
Short Term...CB
Long Term...CB
Aviation...Hastings/CB
Marine...Hastings/CB



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.