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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KCAR 050459
AFDCAR

Area Forecast Discussion
National Weather Service Caribou ME
1259 AM EDT Wed Aug 5 2020

.SYNOPSIS...
Isaias will track from Vermont to near Quebec City late tonight
and the remnants of the cyclone will pass north of the area
overnight and Wednesday. An upper low will track north of the
region Thursday. High pressure will build across the area Friday
into Saturday and remain over the area Sunday.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
1 AM Update: Isaias continues to race through srn Quebec. Winds
have are picked up over the last 3 hrs w/some sites reporting
40 to 45 mph gusts. Power outages have been reported in
Hancock/Washington and srn Penobscot County. A Wind Advisory
was issued earlier for gusts to 50 mph into the early morning.
KCBW VWP showed 50 kts descending from 7k to 3k ft over the last
hr. RAP and NAMNEST soundings showed strong shear of 50+ kts
pushing n over the next few hrs. Rain shield pulling n w/some
enhanced echoes. Velocity returns showed that strong shear
w/line of enhanced echoes lifting across ern Washington County.
Kept the mention of heavy rainfall into the early morning as
this rain shield lifts through nrn areas. Also increased the
winds by 10 mph. Hrly temps adjusted to meet the latest
conditions.

Previous discussion:
Wednesday...Still breezy from the SW but strongest winds done.
Should see a fair amount of sun. Still a fair amount of moisture
around though, along with an approaching cold front in the
afternoon. Expect a line of showers and storms form just ahead
of the front mainly in Northern Maine, not too different than
what we saw Monday afternoon. CAPE not at all impressive but
enough, with values 500-1000 J/kg. Also some forcing with
approaching surface cold front and upper level shortwave
rotating around an upper low well to our NW, the same upper low
that will end up absorbing Isaias.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH 6 PM THURSDAY/...
High pressure builds in Wednesday night through Thursday with
fair weather expected. A west to southwest flow will persist
aloft around the 500 MB low centered to our north. Expect fair
weather Wednesday night along with light winds, with lows
dropping into the upper 50s to near 60. Thursday will be a
mainly sunny day with highs ranging from the mid to upper 70s
north and lower 80s Downeast. A gusty Southwest wind is expected
with a fairly deep mixed layer with gusts to around 25 mph
possible.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
Long wave upper level ridging will build over the area Friday night
as an upper trough over eastern Canada continues to lift away to the
northeast. This will bring a mostly clear night with some patchy
valley fog possible late. Upper level ridging will remain over the
region Friday into Saturday bringing sunny days and clear tranquil
nights with patchy late night and early morning fog possible in the
valleys. The ridge will remain in place on Sunday. However, a weak
shortwave sliding over the ridge and dropping down across the region
early Sunday morning may bring some patchy clouds across the north
and perhaps an isolated shower. Surface high pressure will slide to
the east on Monday allowing a return flow a humid air to set in on
southerly breezes. Clouds may begin to increase late in the day
ahead of another weak shortwave working through the ridge. The
shortwave will weaken and cross the area Tuesday bringing a chance
for some spotty showers or thunderstorms.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
NEAR TERM:
VFR conditions expected all TAF sites late this afternoon and
light winds. Conditions will deteriorate to MVFR with possible
IFR in rain and slgt chc tstm after 00z. These conditions will
persist tonight and then improve to VFR Wednesday morning,
especially KBGR/KBHB terminals. VFR all terminals Wednesday
afternoon.

LLWS will be a concern tonight at all terminals. South winds
are expected to increase to 15 to 25 kt this evening, as Isaias
passes well west of the region. A few wind gusts to 40 kt are
possible mainly 03Z to 10Z Wednesday. Southwest winds 10 to 15
kt Wednesday afternoon.

SHORT TERM:
Wed night thru Thu...VFR. Light wind Wed night, then gusty
Southwest wind Thursday.

Thursday night: VFR. Light W wind becoming calm. Chance of patchy
fog late.

Friday: VFR. Light and variable wind.

Friday night: VFR, except in patchy fog late. Calm air.

Saturday: VFR. Light SW wind.

Saturday night: VFR. Light W wind.

Sunday: VFR. Light W wind.

Sunday night: VFR. Light SW wind.

Monday: VFR. Light S wind.

&&

.MARINE...
NEAR TERM: South winds from Isaias gusting up to 30 kt tonight,
strongest from about midnight to 6am. Wave periods around 8
seconds and seas to around 7 feet. The wind will diminish
Wednesday, but the seas will likely remain elevated into Wed
night.

SHORT TERM: Winds will remain below SCA levels with seas
generally 2 to 4 ft. Winds and seas are expected to be below
SCA Friday through the weekend and into early next week.
Visibilities should generally be good over the weekend but may
lower in some fog early next week due to an increase in
humidity.

&&

.CAR WATCHES/WARNINGS/ADVISORIES...
ME...Wind Advisory until 4 AM EDT early this morning for MEZ001>006-
     010-011-015>017-029>032.
MARINE...Small Craft Advisory until 2 AM EDT Thursday for ANZ050>052.

&&

$$

Near Term...Hewitt