FXUS61 KCAR 171634

Area Forecast Discussion
National Weather Service Caribou ME
1234 PM EDT Tue Jul 17 2018

A cold front will approach from the west today and cross the
region this evening. High pressure will build over the area
Wednesday into Thursday.

1230 PM Update...
Elevated convection continues to move across the area with
locally heavy showers producing a quick half inch of rain. The
more explosive convection will continue well to the south of the
forecast area. The Moosehead Lake region is still expected to
receive the most rainfall in the forecast area...up to 1.5
inches. The best elevated CAPE should be east of the area by
late afternoon. A second round of instability follows with the
cold front. The front will cross the area tonight...bringing
much cooler and less humid air for Wednesday.

Previous discussion...

The main focus today continues to be with regard to the potential
for locally heavy rainfall and thunderstorm chances in advance
of an approaching cold front from the west. The cold front was
currently entering western Quebec province and will move east
today. Very moist air mass will be in place ahead of the front
with dew points expected to surge into the mid 60s to around 70
degrees. Precipitable water values will be nearing 2.0 inches.
This would lend to the possibility of some locally heavy
rainfall rates in any showers and thunderstorms in advance of
the approaching front. Despite the potential for locally heavy
rainfall today, considering the dry antecedent conditions and
current FFG guidance values, not expecting flash flooding at
this time. However, will continue to mention the chance for
locally heavy rainfall today in any shower and thunderstorms.
We did note that SPC Day one outlook did have much of the
region in a marginal risk today. Limiting factor for stronger
storms today will likely be the lack of much in the way of
surface based instabilty with extensive cloud cover that is
expected. The front will begin to cross the region tonight and
then be off the coast by daybreak Wednesday. Any showers and
thunderstorms this evening will gradually diminish from west to
east with the passage of the front late tonight.

High pressure will build in from the west on Wednesday bringing a
return of dry air to the region. A weak upper level trough and some
cooler air at the mid levels will result in some cumulus clouds on
Wednesday. Any clouds will dissipate late in the day giving way to a
clear sky Wednesday night. High pressure continuing to build in on
Thursday will then bring a mostly sunny and seasonably warm day with
very light winds Thursday.

High pressure will shift east of the region at the end of the week
as warmer and more humid air returns behind the high. This will
bring mostly sunny and very warm weather Friday into Saturday. Our
focus late in the weekend will be on a deepening trough of low
pressure over the Great Lakes which is something we haven't seen
much of yet this summer. This has the potential to bring a
significant rain event with low pressure developing east of the
trough along the Mid-Atlantic coast Saturday night and then tracking
north to bring rain on Sunday. The upper trough lifting into eastern
Canada combined with strong high pressure well off the east coast
will continue to funnel moisture north across the region Monday into
Tuesday. This will bring a continued chance for rain. Wet weather
may continue through mid-week with the trough remaining to our
northwest and the strong high staying positioned well to our east in
the open Atlantic.

NEAR TERM: 610 AM Update...
LIFR/VLIFR conditions can be expected early this morning at
KBGR/KBHB in areas of dense fog and low clouds. Low clouds will
begin to advance northward across the Aroostook county terminals
with MVFR/IFR conditions developing toward daybreak. Expect
conditions at all terminals, except KBHB, to improve to MVFR by
late morning or early afternoon. KBHB is expected to remain IFR
today in low clouds and areas of fog. Showers and scattered
thunderstorms will affect the terminals this afternoon and into
this evening. Low confidence on timing and the scattered nature
of any storms led to omitting from 06z TAF package but will re-
evaluate with next issuance.

SHORT TERM: VFR conditions are expected to persist Wednesday
through Saturday as high pressure builds over the area.
Conditions will then likely drop to IFR from south to north
Saturday night and be IFR in low clouds and rain on Sunday.

NEAR TERM: Winds/seas will generally remain below small craft
advisory levels through tonight. Areas of fog will reduce
visibility to 1 to 3 nm at times through tonight. Showers and
scattered thunderstorms will be possible across the waters this
afternoon and tonight.

SHORT TERM: Winds and seas are expected to be below SCA
Wednesday through Saturday. A long southerly fetch, clouds and
rain will likely result in a SCA, high seas and fog late in the


Near Term...Duda
Short Term...Bloomer
Long Term...Bloomer
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