Area Forecast Discussion
Issued by NWS Caribou, ME-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KCAR 271650
Area Forecast Discussion
National Weather Service Caribou ME
1250 PM EDT WED JUL 27 2016
A cold front will approach from the northwest this afternoon and
stall across the region tonight into Thursday. The front will push
further south Thursday night and stall near the coast on Friday.
.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --1245 PM Update...16Z meso analysis showed the northern and western
areas destabilizing w/lis dropping to -1 to -2. Nose of mid to
upper 60 dewpoints residing back across Quebec sliding down the
Maine-Quebec border. LAPS soundings were close to the NAM12
soundings showing MU CAPE of 1000 joules across the n an w. There
was some shear noted esp in the 0-3km layer of 30 kts. So, wind
threat for any storms still a concern. Freezing levels started out
at 13k ft but since then have dropped back to around 12k ft.
Projection is that freezing levels will drop some more this
afternoon down to around 11.5k ft which would allow for any
stronger updrafts to support hail. Biggest offsetting parameters
are alot of dry air residing from 700-500mbs and weak mid level
lapse rates(below 6.0c/km). This would squelch any organized
convection. SPC updated the DAY1 Convective Outlook to remove the
Marginal Risk and now have the entire state in a General Category.
For now, wil keep the enhanced wording for gusty winds and hail
but pushed back the timing until late afternoon.
Adjusted the afternoon maxed up a few degrees across central and
downeast including the coast as readings are already hitting mid
to upper 80s and still a good deal of sunshine. Could see around
90 or so in the Bangor region and mid 80s for Bar Harbor and
Machias until sea breeze penetrates this afternoon.
Previous discussion below...
Current sfc analysis places high pressure up the spine of the
Appalachians with ridge axis nosing into CWA as of 06z. Cdfnt is
dropping into Quebec fm James Bay with regional Canadian radars
showing showers and an isold tstorm approx 150 miles north of
Ottawa. Timing of cdfnt is much slower than previously thought
with projected arrival time to international border well aft 00z
tonight and even closer to 06z.
Tda wl be the warmest day of the week with sw flow drawing in H9
temps on the order of +21C acrs nrn zones. Dwpts wl rmn in the lwr
60s with projected highs in the l/m 80s this aftn. Convective temps
progged to be in the lwr 80s and expect that storms wl begin to
fire acrs the Crown of Maine after about 18z as diurnal htg
maximizes. Hv dropped pops down to just isold until aft 21z where
tstorms could become more sctd in cvrg. Frzg levels of around 10kft
combined with 35-40 kts of 0-6km bulk shear may lead to small hail
along with gusty winds, mainly for northern Aroostook this aftn
Expect a dry and sunny day for Downeast as temps appch the 90-
degree mark. Capping inversion arnd 600mb wl prevent storms fm
As the evng wears on expect pcpn to dwindle to just isold showers
due to loss of htg. Patchy fog wl be a possibility once again
tonight as front wl take it`s sweet time mvg into the CWA and
eventually stalling out as guidance indicates sfc low wl ride up
along the bndry sometime in the mrng.
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.SHORT TERM /THURSDAY THROUGH FRIDAY/...
A trough of low pressure will be over Eastern Canada on Thursday
as a ridge of high pressure remains along the coast. A weak cold
front will be stalling across the central part of our region on
Thursday bringing a mostly cloudy sky and showers. Soundings are
showing capes over 1000 J/KG, so a chance of thunderstorms,
supported by some weak surface convergence and cooling aloft, will
be included during the afternoon. A very weak upper level
shortwave may also enhance cooling aloft a bit and support
thunderstorm development on Thursday. As the shortwave pushes east
Thursday night, it will push the front a bit further south. The
front will reach the coast overnight Thursday night and stall
along the coast on Friday. this will bring a chance of showers and
some thunderstorms to Downeast areas Friday while northern areas
have partial clearing.
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
The front along the coast will push offshore Friday night into
Saturday as high pressure builds in from the west. Saturday will
turn out a bit cooler and drier across the area with sunshine mixed
with fair weather cumulus clouds. Sunday will be sunny to partly
cloudy and comfortable with high pressure over the region. Dry and
seasonably warm weather should prevail Monday and Tuesday as surface
high pressure takes residence just to our south. A frontal boundary
across eastern Canada will be nearby to the north and may allow a
thundershower to stray into far northern areas either afternoon.
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
NEAR TERM: Mainly VFR expected today outside of localized low
MVFR/IFR restrictions in fog this morning. Northern terminals may
see -shra/-tsra this afternoon into evening but confidence is too
low to include in terminal forecasts, with the exception of FVE,
at this time.
SHORT TERM: MVFR conditions can be expected on Thursday in
variable low clouds and some showers. MVFR conditions may persist
Downeast Thursday night into Friday with an improvement to VFR
across the north. VFR conditions are likely in high pressure over
NEAR TERM: Winds and seas will be below SCA criteria through
tonight. Fog will reduce visibilities once again late tonight over
SHORT TERM: Winds and Seas are expected to remain below SCA
Thursday through the weekend. Fog will likely reduce visibilities
over the waters Thursday through Friday morning as a result of
warm humid air over the colder waters.