Area Forecast Discussion
Issued by NWS Portland, ME-- Highlight Changed Discussion --
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FXUS61 KGYX 141142
Area Forecast Discussion
National Weather Service Gray ME
642 AM EST Tue Feb 14 2017
Weak high pressure builds south of the area Tuesday with mainly
sunny skies and highs in the mid 20s to low 30s. Another strong
upper trof of low pressure will move east to southeast from the
upper Great Lakes Wednesday allowing a coastal low to rapidly
intensify off the Maine coast by Wednesday night bringing
potentially heavy snows across a good portion of Maine and New
Hampshire. The system slowly exits into the Canadian maritimes
Thursday but with lingering snow in the morning tapering to
scattered snow showers. A more quiet pattern develops toward the
weekend with high pressure accompanied by a warming trend.
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
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Have updated the grids based on current conditions. Clouds have
become trapped in the Connecticut River Valley and the northern
mountains of Maine and New Hampshire. Also adjusted temperatures
were vary greatly from location to location. Otherwise, little
change to the current package.
A weak ridge of high pressure will quickly pass
over the forecast area today. This will bring dry conditions to
the region and relatively light winds compared to the last
couple days. With some sunshine, temperatures will recover
through the 20s during the day.
This break in the active weather pattern ends as we head into
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.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
A large upper level low pressure system will continue to be
quick on the heels of the departing storm from yesterday. This
energy is digging southeastward from northern Canada, a data
sparse area. However, the 00Z model suite is relatively
consistent from model to model in regards to the overall
development of the next weather system.
Cyclogenesis will occur south of the New England coastline
Wednesday night in response to the digging trough and strong
warm air advection well out over the open Atlantic. Low pressure
will quickly deepend Wednesday night just east of the Gulf of
Maine. In the meantime, a reflection of the upper trough in the
form of an inverted trough will effect western Maine as well as
Central and Northern New Hampshire.
Snow will break out across the region, especially along and near
the inverted trough axis. Northeasterly winds will funnel
moisture in off the Gulf of Maine along with milder
temperatures. There is a possibility that the snow will mix with
rain for a period along coastal communities. Any rain/snow mix
in coastal areas will transition to wet snow by Wednesday
evening. The heavy wet snow may lead to isolated power outages.
Also, the snow from a series of recent storms may lead to
problems of weight on rooftops.
The upper level low pressure system will cross the region
Wednesday night. It appears that the H850 and H700 mb low will
cross over central New Hampshire and southern Maine. Areas south
of the track of the upper level features will have less in the
way of precipitation.
Due to the track of the system arriving out of central/northern
Canada, the exact timing and path of the system is uncertain.
Confidence level in the exact track and therefore potential
snowfall amounts is not high at this time.
.LONG TERM /THURSDAY THROUGH MONDAY/...
Low pressure in the Gulf of Maine early Thursday will slowly
exit into the Canadian maritimes. In its wake the wraparound
snows during the morning will gradually taper to snow showers
Thursday followed by some partial clearing in the afternoon,
especially over southern downsloping areas while the mountains
may have afternoon scattered snow showers continuing.
A broad surface/upper ridge of high pressure builds into the
region Friday through early next week providing a quiet period
of weather with a general warming trend. Used the superblend
model for overall forecast of temps and trend.
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
Short Term...Expect mainly VFR conditions today and tonight with
the exception of an isolated snow shower over the mountains
early this morning. Conditions lowering to MVFR and IFR on
Wednesday in developing snow. Some rain may mix in at PWM, RKD
and PSM. IFR conditions expected in snow Wednesday night.
Long Term...IFR conditions early Thursday will gradually improve
to VFR from south to north. Generally VFR conditions expected
Friday and through the weekend.
Short Term...SCAs will continue for the outer waters today,
first for winds then continuing the rest of the day for seas.
Long Term...SCA conditions are expected Thursday on a northwest
flow as the low departs into the Canadian maritimes. Quiet
conditions are expected Friday and through the weekend.
ME...Winter Storm Watch from Wednesday morning through Thursday
morning for MEZ007>009-012>014-018>028.
NH...Winter Storm Watch from Wednesday morning through Thursday
morning for NHZ001>006-009-010.
MARINE...Small Craft Advisory until 6 PM EST this evening for ANZ150-