Area Forecast Discussion
Issued by NWS Caribou, ME
FXUS61 KCAR 301040
Area Forecast Discussion
National Weather Service Caribou ME
640 AM EDT TUE AUG 30 2016
High pressure will slide east today while a warm front lifts
toward the region this afternoon. The warm front will lift north
of the area overnight while a cold front approaches for
Wednesday. Unsettled weather expected into Thursday.
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
640 AM Update...
Adjusted the hrly temps/dewpoints to match the latest obs w/temps in
the 50s except for lyings areas and out w. Houlton(KHUL) dropped down
to 49F as of 6 AM. Sky conditions were adjusted to match w/the latest
IR satellite imagery showing high cloudiness moving through the CWA.
Used the NAM12 for the sky setup. Rest of the fcst on track attm.
Challenge this term will be areal coverage of showers and convection
High pres will continue to slide to the east today. Mid and high
clouds, seen on the IR satellite imagery were streaming across
the region from Quebec. These clouds will halt a further drop in
temperatures this morning as some sites back across the wnw were
in the mid 40s such as Estcourt Station(45F). Temperatures will
rebound and warm later this morning but the warming will be slowed
due to thickening clouds this afternoon as a warm front lifts
toward the region. Some showers can be expected, mainly across
the north and west. Forcing looks weak, but llvl convergence is
there to support some activity. The HRRR and Hi Res WRF support
this w/some shower activity by the afternoon into the evening.
Convective potential not overly impressive but some CAPE is there
w/values of 400-600 joules. Mid level lapse rates are weak, but
llvl lapse rates(0-3km) are forecast to be around 7.0+ c/km.
0-6km shear around 20 kts. So, the potential is there. SPC has the
region in a General Risk through tonight. Decided to include
isolated tstms for this afternoon into tonight mainly north and
west. The best potential for convection looks to be tonight w/a
mid level jet streak of 30 kts forecast to slide across the
region. The NAM soundings show 300-500 joules of elevated CAPE and
mid level lapse rates steepening to around 6.5c/km. Therefore,
convection potential looks better tonight as the warm front lifts
through northern areas.
As for temperatures, highs will be in the lower to mid 70s north
and along the immediate coast, while central and interior Downeast
will top out in the mid to upper 70s. Overnight lows will be in
the upper 50s to lower 60s.
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
Most models continue to support the idea of an initial surge
of moisture moving into mainly northern portions of the forecast
area early Wednesday, well in advance of a 500 mb trof
approaching from western Quebec. Another round of moisture is
then expected during Wednesday afternoon in association with an
approaching cold front from the west. Will have a chance of
showers Wednesday afternoon. Will continue to mention the chance
of thunderstorms Wednesday afternoon, although the threat of
strong convection is looking less likely at this point. Surface
based Cape generally ranges from 500J upwards to around 1000J
based on various models. There also appears to be a cap near 700
mb that may inhibit the ability of any storms to grow. That being
said, enough 0-6 km shear will exist to support gusty winds with
any storms that would develop. Any diurnally driven thunderstorms
Wednesday afternoon will give way to lingering showers Wednesday
night, especially across downeast areas. Thursday will see partly
sunny skies along with a few lingering showers, mainly across
eastern portions of the forecast area. Temperatures both Wednesday
and Thursday will not be all that far from normal for this time of
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
An upper trof will axis will cross the region Thursday night. Expect
partly to mostly cloudy skies across the region with the chance
of showers, mainly across eastern areas. Friday and Saturday will
feature mostly sunny days and mainly clear nights, as a large
ridge of high pressure builds across the region. The high will
move east Saturday night through Sunday with continued fair
weather expected. Mainly dry weather is expected to continue
through early next week. Temperatures through the period will be
below normal and then moderate to above levels next weekend
through early next week.
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
NEAR TERM: VFR through tonight. A period of MVFR cigs could occur
from KCAR to KFVE later tonight as the warm front lifts north.
SHORT TERM: VFR conditions are expected Wednesday through Thursday
with the potential for brief MVFR conditions in any shower
activity. VFR conditions are then expected Thursday night through
NEAR TERM: No headlines expected. Swells from Hurricane Gaston
have been running 2-3 ft. There was a brief period where swells
came up to around 4 ft as was shown by the buoy 44034, but the
swell has since subsided. Stayed close to the daycrew will brings
swells up gradually into tonight to a range of 3-5 ft w/the
highest heights over the outer zones. Sustained winds are
forecast be 10 kts w/up to 15 kts over the outer zones.
SHORT TERM: Winds/seas should generally remain below small craft
advisory levels through the period.