Area Forecast Discussion
Issued by NWS Caribou, ME

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FXUS61 KCAR 190418

Area Forecast Discussion
National Weather Service Caribou ME
1218 AM EDT Tue Jun 19 2018

A cold front will push south across the area this evening. High
pressure will build in from the west Tuesday into Tuesday night
then move south of the area on Wednesday. A cold front will
press into the north Wednesday afternoon.


12:18 am update: Showers continue to push across the FA early
this morning with drier air just starting to filter into far
northern areas in the wake of a cold front. Still very muggy
Downeast with a 70F dew point at Bangor. The showers will come
to an end from northeast to southeast across the area overnight,
with a few showers possible along the coast until early Tuesday
morning. Made some minor adjustments based on the latest
observations and radar trends.

Previous discussion: Low pressure north of the area will track
east into the Maritimes this evening as a cold front pushes in
from the north. The cold front will produce a line of showers
and thunderstorms as it moves south through the area this
evening. The air mass in the warm sector is very moist with
precipitable water near 1.75 inches. Any thunderstorms may
produce heavy rain and gusty winds this evening. However, warm
and humid air ahead of the front has had a hard time working
into our area due to persistent low stratus and a line of
showers along the southwestern edge of the region through the
day. Most of the convection along the front will likely be
supported by elevated cape. However, given the strong winds
aloft and the saturated soundings, some gusty winds and heavy
downpours are still possible and will remain in the forecast.
The line of showers and thunderstorms will push down to the
coast around midnight and offshore after midnight. High pressure
approaching from the west will bring cooler and drier air into
the region later tonight into Tuesday. This will bring a mostly
sunny and seasonable day on Tuesday with a light northwesterly
breeze followed by a mostly clear night Tuesday night as high
pressure drops to our south.


Fast moving cold front for Wednesday and then some cooler temps
expected for Thursday.

The cold front is forecast to move across the region Wednesday
afternoon into the evening. The GFS and ECMWF match up well
w/the timing and slower it down by 3 hrs from the previous runs.
The 12Z NAM supports this scenario as well as does the Canadian
model. Showers appear to be the main wx element as deep moisture
appears limited above 750 mbs. CAPE potential is not overly
impressive w/MU CAPE maxing out around 600 joules. There is
shear available around 30 kts along w/llvl convergence along the
front. Attm, confidence is low and given the lack of deep
moisture being available, decided to stay w/the midnight crew`s
thinking of keeping the mentions of tstms out of this forecast
package. Some stronger wind gusts are possible w/the cold
frontal pass. Therefore, decided to increase the wind gusts for
Wednesday afternoon into early evening. Rainfall amounts will
generally be light averaging about 0.10" or less. The ECMWF
looked to be to wet w/its latest rainfall amounts and therefore
used a blend of the guidance minus the ECMWF for the amounts.
Daytime temps on Wednesday are expected to reach well into the
70s w/some sites across central and Downeast hitting around 80F.

The front will clear the region Wednesday night w/some clearing
taking place. High pres begins to build into the region from
Canada on Thursday. There does look like a gradient holds
through midday Thursday allowing for a winds to be up at 10-15
mph w/gust potential to 20+ mph. Winds are forecast to drop off
fairly quickly later Thursday afternoon as the high pushes
further east. Chilly day on Thursday w/daytime temps running
5-10 degrees below average.


Much colder Thursday night w/some areas seeing temps dropping
into the upper 30s. This will be mainly for low lying areas.
Friday will continue on the dry side and warmer as winds become
sw in the afternoon allowing for warmer air to be pulled
northward. Daytime temps will rebound back into the 70s and
possibly lower 80s. Continued dry for Saturday and even a bit
warmer as temps could very top 80F in the afternoon.

The long range guidance including the ECMWF, GFS and Canadian
Global show a frontal system apchg the region from the west
Saturday night w/some low clouds and pre-frontal showers
breaking out. The best chance for any showers will be across the
w and sw areas. Sunday appears to be rather mild and possibly
more humid w/some showers and the potential for some tstms.
Since it is 6-7 days out, decided to not include any mention of
tstms attm. There is still plenty of time to assess the
convective potential.


NEAR TERM: MVFR to IFR conditions in variable low clouds and
showers will improve to VFR from north to south late tonight
into early Tuesday morning following the cold frontal passage.
VFR conditions are then expected across the area Tuesday into
Tuesday night.

SHORT TERM: MVFR mainly northern sites Wednesday into Wednesday
evening. Wind gusts to 30 kts possible w/the cold front.
Otherwise, VFR expected for all terminals into Friday.


NEAR TERM: A SCA will continue through late tonight for
southwesterly winds gusting up to 25 kt over the offshore
waters. Winds should drop below SCA following the cold front
early Tuesday morning and remain below SCA through Tuesday
night. Humid air over the waters will produce fog and mist
reducing visibilities tonight ahead of the front. Seas will be
up to 8 ft tonight over the offshore waters in response to the
wind, but should decrease early Tuesday morning and drop below 5
ft by late Tuesday morning.

SHORT TERM: No headlines expected through this term. SW winds
gusting to 20 kts are possible w/the front Wednesday afternoon
into early evening. Seas are forecast to reach near 4 ft and
that should hold. WNW winds behind the front Wednesday night
into Thursday will allow for seas to be knocked down to 3 ft.
Rather quiet conditions right into the early part of the weekend
w/winds around 10 kts and seas around 3 ft.


MARINE...Small Craft Advisory until 4 AM EDT early this morning for



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