Area Forecast Discussion
Issued by NWS Portland, ME-- Highlight Changed Discussion --
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FXUS61 KGYX 131350
Area Forecast Discussion
National Weather Service Gray ME
850 AM EST Fri Jan 13 2017
A cold front will exit the region this morning with much colder
air arriving on gusty northwest winds behind it. High pressure
will build in from the west through Saturday. A weak cold front
will cross the area the area early Sunday, although will not
produce more than some clouds and a few flurries in the
moutnains. High pressure will build in behind the front Sunday
afternoon through Monday. The high pressure shifts east on Tuesday
and will allow a southwest flow of warmer air into the region.
Weak low pressure crosses the region mid-week with a threat of
.NEAR TERM /THROUGH TONIGHT/...
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Temperatures this morning cooling a little quicker than
expected...especially over the mountains. Will update the package
to adjust things down a little bit and account for current trends.
Winds will begin to increase over the next few hours. Expect
southern waters to remain at Small Craft Advisory but it will be
close enough that we will need to watch things closely.
Otherwise...no significant changes expected.
Have added the latest observations to the forecast to help pull
the hourly temperature trends in the right direction. Cold
advection ongoing across the area now, so daily high temperatures
are essentially the current temperatures. Cooling has been delayed
just a bit in the north where clouds have piled up against the
mountains. These should dissipate soon as dry air moves in.
A cold front is pushing through the area at this hour (3AM). Ahead
of the front, temperatures are in the 40s and 50s, but behind the
front the temperature drops quickly through the 30s. By sunrise
expect the colder temperatures to have arrived all the way to the
coast. Even after the sun comes up it is unlikely that
temperatures will rebound. Temperatures will instead be on a
managed decline through the day as cold advection continues. There
may be a couple of separate boundaries with stronger cold
advection behind them which move through today, the first early
this morning and the second during the late morning hours. Expect
gusty northwest winds as cold advection causes strong mixing to
occur. Winds aloft are expected to be on the order of 40 KT, so
generally we are expecting wind gusts to about 30 MPH. However, a
few gusts up to 40 MPH are possible as cold advection and
downslope winds on the coastal plain will aid in transporting some
of those stronger wind gusts toward the surface. By afternoon the
entire area should fall below freezing.
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.SHORT TERM /SATURDAY/...
Winds gradually diminish tonight as high pressure moves in from
the west. Cold advection continues into the evening with
temperatures falling below zero in the north and into the single
digits above zero for most other areas. Due to the cold advection
and pressure gradient, winds may prevent good radiational cooling
conditions from occurring for much of the area. However, a clear
sky and very dry air will allow the possibility of low
temperatures falling to zero or below for any areas where winds
are able to go calm. This will be most likely across western New
Hampshire by early Saturday morning. Across the north, the
combination of cold temperatures and moderate winds will lead to
wind chill values of 20 below zero or colder. As a result, a Wind
Chill Advisory has been issued for the areas most likely to see
the combination of cold temperatures and persistent winds.
Cold high pressure crosses the area on Saturday with temperatures
about 10 degrees below normal, generally in the teens and 20s for
an afternoon high in spite of a good amount of sunshine.
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Chance of high impact weather: Low.
500 mb pattern in the extended will be dominated by split flow
over the eastern Pacific and western CONUS, which will basically
flood the CONUS and southern Canada with Pacific air and allow
above normal conditions well into next week. The tendency over the
eastern CONUS will be for ridging as the split flow to the west
breaks down and slowly carves out a trough there, but models have
been consitent moving a trough through the northeast around mid-
week providing a chance for some precip.
Saturday night will not be as cold as Friday night with weak 500
mb trough passing to our N and W, but should allow for some
clouds and warmer air ahead of another weak cold front which will
cross the area early Sunday. Dry air ahead of the front will
likely limit its sensible weather effects to some clouds and few
flurries or SHSN in the mountains. Also, the shot of cold air
behind this system will be brief and similar to airmass ahead of
it, so highs Sunday will likely be warmer than Saturday and close
to normal, ranging from around 20 in the N, to the low to mid 30s
in the S.
Behind this trough zonal flow at 500 mb persists into Monday
eventually transitioning to ridging by mid-week, so the trend
will be for gradual warming through the early part of the week
and generally dry conditions. By Wednesday, we will start to see
effects of several weak waves in SW flow in advance of the next
500mb trough, although models differ on timing, but 00Z Euro focus
best chance for precip in the Wednesday to Wednesday night
timeframe. P-type will likely be mainly rain, as unseasonably warm
air moves in, but could start as a short period of snow or FZRA
inland areas. System should clear by Thursday morning, with weak
ridging moving through for the end of the week. Temps may drop off
a bit behind this system, but will still be above normal.
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
Short Term...Expect VFR conditions today with the exception of
Whitefield early where MVFR ceilings will linger. Northwest winds
will gust to 20 or 30 KT at times during the day today, but will
eventually diminish tonight.
Long Term...VFR through Tuesday.
Short Term...Strong northwest winds are expected behind the cold
front today. At this point gale force wind gusts are most likely
across the eastern waters where a Gale Warning has been issued.
Further to the southwest, wind gusts should top off around 30 KT
and a Small Craft Advisory will cover this. As high pressure
builds in early Saturday, winds should fall below advisory levels
areawide by Saturday morning.
Long Term...NW winds may approach SCA levels briefly Sunday
afternoon, but otherwise will remain below criteria through
-- Changed Discussion --ME...Wind Chill Advisory from 10 PM this evening to 10 AM EST
Saturday for MEZ007>009.
NH...Wind Chill Advisory from 10 PM this evening to 10 AM EST
Saturday for NHZ001.
MARINE...Small Craft Advisory until 6 AM EST Saturday for ANZ152>154.
Gale Warning until 8 PM EST this evening for ANZ150-151.
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