Area Forecast Discussion
Issued by NWS Portland, ME-- Highlight Changed Discussion --
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FXUS61 KGYX 111334
Area Forecast Discussion
National Weather Service Gray ME
834 AM EST Wed Jan 11 2017
A front will move through the area this morning with
precipitation coming to an end and warm air spilling in from the
west. The warmth continues into Thursday before a cold front
arriving Thursday night brings colder temperatures back into the
area on brisk northwest winds Friday. Saturday will be the coldest
day of the week before temperatures begin to moderate back toward
normal levels Sunday and Monday. Another warm up is expected
through the middle of next week as low pressure in the center of
the country pumps warm air northward ahead of it and into New
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
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Quick update to adjust temp/td/sky/pop/wx grids. Rain has push
east of the forecast area this morning and aside from a few
sprinkles in the mountains the remainder of the day should be dry.
With the exception of the mountains...skies will be quickly
clearing from west to east through late morning. Temps already in
the lower to mid 40s should push into the upper 40s to lower 50s.
Winds have settled down in mid coast areas so will be dropping
wind advisories for those areas. No other changes planned attm.
645 AM Update... Precipitation is quickly moving away and have
cancelled the winter weather advisory for central Somerset County.
Winds are still coming up along the Mid Coast where the wind
advisory is in effect through 9 AM...so will leave it alone for
Precipitation now moving through the forecast area is mostly in
the form of rain but some snow is falling in the higher terrain
and especially towards the Canadian border where cold air is being
more stubborn. Gusty SSW winds accompanying a warm front are
translating warmer air northward however and expect all
precipitation to either change over to rain or simply be outrun by
forcing for ascent later this morning. Have kept the winter
weather advisory going for central Somerset County which will have
the most time with colder air in place to produce a few inches of
Skies will clear out from SW to NE during the day with gusty SW
winds developing for the entire area behind the frontal passage.
In particular, the Mid Coast of Maine remains under a wind
advisory as the LLJ impinges on this area with around 50-70 kts.
Temperatures will respond to the warming downslope component and
readings will reach the 40s and 50s for all but the far north.
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.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
Clouds increase tonight as another fast moving, sheared out
system ejects from the Great Lakes region. Overnight lows will
occur early in the night due to this...bottoming out in the 20s
and 30s with coastal locations around 40. We will most likely see
some light freezing rain as the precipitation arrives late tonight
into Thursday. As warmer air nudges northward freezing rain will
change to plain rain by Thursday morning. Since we currently have
a winter weather advisory out, will hold off on issuing anything
for this event to avoid confusion...but will mention in the HWO.
Once again strong SW winds will drive temperatures up with the
frontal fracture straddling northern New England. Readings in the
mid 40s to lower 50s will be common and are of course well above
normal for this time of year.
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
Expect a sharp cold front to move through from northwest to
southeast rather quickly Thursday night. Some rain showers are
expected along and ahead of the front, with the best forcing for
ascent riding northward along the front as it moves through,
bringing the best rain chances to western and northern parts of
the area. By Friday morning temperatures will be falling by cold
advection more so than by radiational cooling.
A pocket of cold air from Canada pours into the region during the
day on Friday. Temperatures aloft at 850MB drop about 23C from 00Z
Friday to 00Z Saturday, with about 14C of that occurring from 12Z
to 00Z. Such strong cold advection does not always lead to falling
temperatures during the day, but it is indicative of superb low
level mixing. Cold air pouring in aloft will aid in transporting
stronger winds to the surface. Models are showing about 40 to 50KT
of northwesterly winds at 850MB as the peak of cold advection
crosses the area around midday which will likely translate into a
period of gusty winds. Will keep wind gusts below advisory levels
for now, but this is worth keeping an eye on due to the excellent
mixing potential especially downwind of the mountains where
downslope conditions will aid in the process.
High pressure builds into the area Friday night into Saturday with
winds diminishing. Saturday will be the coldest day of the
forecast with highs in the north only in the low to mid teens and
in the mid 20s in southern areas. The coldest night should be
Saturday night into Sunday morning as the elongating high pressure
becomes best situated over the region setting the stage for good
radiational cooling conditions. Have blended the SuperBlend with
the MEX and undercut the typical cold spots in order to introduce
some better low temperature numbers into the forecast Sunday
morning. Models often like to show warmer low temperatures the
second night after a cold front as temperatures aloft begin to
moderate, but this is rarely the case. There is still some room to
go lower with forecast lows Sunday morning as dewpoints should be
near zero. One factor working against excessive cooling is the
lack of a fresh snow cover. In fact, a good portion of the
populated corridors may have little to no snow left on the ground
at this point. This should not prevent radiational cooling in
these areas, but a fresh snow pack would allow for even colder
Elongated area of high pressure stretching from the Great Lakes to
New England remains in control of the weather Sunday and Monday.
This will spell gradually moderating temperatures with pretty good
radiational cooling possible each night, depending on any cloud
cover which passes through.
On Tuesday, surface high pressure shifts offshore. A large trough
of low pressure in the southern jet stream over the central United
States will force ridging over the East Coast for the middle of
next week. This will pump warm air northward again into New
England ahead of the slow moving trough. Models are now in fairly
good agreement than any precipitation associated with this trough
will not arrive until Wednesday, with the warm air favoring rain
as the precipitation type.
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
Short Term...IFR/LIFR/MVFR ceilings/vsby continue tonight in rain
showers and will improve to VFR later this morning. A strong LLJ
will contribute to cause wind shear of 50 kts at FL015 today
despite gusty SSW surface winds. Areas of MVFR conditions possible
on Thursday, especially in the west.
Long Term...Conditions improve to VFR Friday morning as a cold
front pushes through and much drier air arrives. Cold advection
leads to strong northwest winds on Friday, but these should begin
to diminish Friday evening. Light winds and VFR conditions
expected for the weekend.
Short Term...Strong south winds ahead of a front this morning will
shift to the west and diminish this afternoon. Could see winds
strengthening out of the southwest again on Thursday in advance of
a cold front.
Long Term...A strong cold front crosses the waters from the
northwest Friday morning. Expect a stiff northwest wind on Friday
with small craft conditions likely and borderline gale force gusts
possible. Winds diminish Friday night into Saturday as high
pressure moves over the area and remains nearby through early next
Strong south to southeast flow overnight will create a storm surge
of 0.5 to 1 foot. This may create some splashover or beach erosion
at the time of high tide around 930 AM Wednesday. A Coastal Flood
Statement has been issued to highlight the threat.
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MARINE...Gale Warning until 10 AM EST this morning for ANZ151>154.
Storm Warning until 10 AM EST this morning for ANZ150.
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