NWS Caribou, Maine Area Forecast Discussion

FXUS61 KCAR 161028

Area Forecast Discussion
National Weather Service Caribou ME
628 AM EDT Thu Aug 16 2018

High pressure will build today and crest over the region
tonight. Low pressure will cross the region later Friday
through Saturday.

630am update...No changes. The upper trough is currently moving
through with mid and upper lvl clds. Cu will develop in the next
few hours and have maintained partly sunny for most zones.

Previous discussion...
An upper trough that is responsible for showers and
thunderstorms currently exiting southeastern Washington County
will move east this morning. As temperatures hit 80F along the
Washington County coast by midday, a few light showers could
redevelop with the cooler air aloft still in place. Otherwise,
it will be dry across the forecast area through tonight. There
will be ample H850 moisture for widespread cu and sc fields
today. Highs will still reach the lower 80s for Bangor and the
coast with an offshore flow, but humidity will be much lower.
Dew points across the area will be 10 to 15 degrees lower than
yesterday. Upper level ridging this afternoon will create
subsidence above the cu/sc fields and eventually dry out that
moisture layer as clear skies are expected tonight. The surface
high will strengthen as it moves over the area tonight. Lows
tonight will drop to 40s in the northern half of the area while
lower 50s are expected for Bangor and the Down East region.
These temperatures will cause some patchy shallow fog by late
tonight in valleys and over relatively warmer lakes and rivers.

High pressure will exit across the Maritimes early Friday, with
low pressure approaching from the west late. Cloud cover will
increase early Friday. Rain chances will then increase, from
west to east, during the afternoon. The low crosses the region
Friday night into Saturday, with high pressure starting to build
toward northern areas later Saturday. Rain, with a chance of
thunderstorms, will occur across the forecast area Friday night.
Precipitable water values increase to between 1.50 and 2.00
inches Friday night which will also help support heavy rain. The
primary low will exit across the Maritimes early Saturday, while
a secondary low tracks southward across the Gulf of Maine and
high pressure begins to build across northern areas. The most
extensive showers early Saturday will occur across Downeast
areas, with lesser shower chances northward across the remainder
of the forecast area. Showers will end across northern areas
Saturday afternoon along with decreasing clouds, while skies
remain mostly cloudy with decreasing shower chances Downeast.
High pressure builds south across the forecast area Saturday
night with mostly clear skies north and decreasing clouds
Downeast. Temperatures will be at near normal levels Friday.
Near normal, to slightly below normal, level temperatures are
expected Saturday.

High pressure should remain across the region Sunday into
Tuesday with mostly clear skies. A cold front will begin to
approach later Tuesday, which could bring a slight chance of
showers/thunderstorms to western areas late. The cold front and
low pressure should cross the region Tuesday night into
Wednesday with more extensive showers or rain. Near normal level
temperatures are expected Sunday through Wednesday.

NEAR TERM: Patchy shallow fog is possible near sunrise today,
but will quickly disappear. Patchy shallow fog will again be a
threat towards sunrise Friday morning for a brief time.
Otherwise, expect excellent vis and cigs around 5K feet or

SHORT TERM: VFR conditions are expected across the region
early Friday. MVFR/IFR conditions will then develop later
Friday. MVFR to LIFR conditions are expected Friday night
through early Saturday. Rain could be heavy at times Friday
night along with a chance of thunderstorms. Conditions will
improve to VFR levels across northern areas Saturday afternoon,
with MVFR/IFR conditions Downeast. VFR conditions are expected
across northern areas Saturday night, with conditions improving
to VFR levels Downeast. VFR conditions are expected across the
entire region Sunday into Monday.

NEAR TERM: Thunderstorms and fog will exit the waters early this
morning. Otherwise, no significant weather is expected through

SHORT TERM: Winds/seas are expected to remain below small craft
advisory levels Friday through Saturday night. Visibilities
will be reduced in rain and fog Friday afternoon into Saturday,
along with a chance of thunderstorms Friday night.


Near Term...MCW
Short Term...Norcross
Long Term...Norcross

NWS CAR Office Area Forecast Discussion