Area Forecast Discussion
Issued by NWS Portland, ME
FXUS61 KGYX 212343
Area Forecast Discussion
National Weather Service Gray ME
643 PM EST Tue Feb 21 2017
A weakening frontal system will cross the area tonight. Low
pressure moving east through southern Canada will push a cold
front toward the region late Thursday. The front will be
followed by high pressure through early Friday. A warm front
will approach from the southwest late Friday and will lift north
of the area Friday night. A coastal system may bring more
widespread precipitation over the weekend.
.NEAR TERM /TONIGHT/...
Have updated the forecast based on latest observations and to
reflect current forecast thinking. Area of rain noted on
regional radar over far western New York state. Some radar
echoes have shown up further east moving into Vermont, but these
are falling from a very high cloud deck with significant low
level dry air resulting in little if anything reaching the
ground. Do not expect anything to be noted out of this as it
moves into the area. The better chance of any precipitation
would be with the heavier band of rain over eastern Lake Ontario
at the moment, though this is forecast to break up and dissipate
as it arrives. Even as it is, it is only producing very light
rain with a mid level cloud base and no visibility restrictions
noted. This supports the idea that this may not make it to our
area tonight. Meanwhile, temperatures are cooler over Maine than
they are over New Hampshire, but both areas have noted some
minor cooling in the last few hours in spite of abundant high
level clouds. Expect only minor cooling overnight due to the
extensive cloud cover. Biggest change to overnight temperatures
was to warm things up in northern areas where MOS forecasts tend
to be well too cold on nights like this. Temperatures will
ultimately be borderline, right around the freezing mark, as any
remnant precipitation arrives. Expect precipitation type to be
light rain or freezing rain depending on temperatures, but
again, there is still not a lot of confidence that this will
occur and if it does so amounts will be very light.
We have had a moderately warm day today with slightly above
normal temperatures for most spots in NH and western Maine. High
pressure currently straddling the coast will continue to move
offshore tonight with increasing moisture moving northward and
clouds thickening ahead of a cold front. Models have backed off
on QPF for the frontal passage overnight with only a few
hundredths in mainly elevated locations. Any precipitation that
reaches the ground will be in the form of sleet or freezing
rain...however it will be so sparse will not be issuing any
headlines and will instead handle the situation with Special
Weather Statement(s) when the time comes. Lows overnight will
generally range through the 20s to lower 30 degrees along the
.SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/...
Cold front weakens and essentially washes out on Wednesday
leaving the region in a warm southwesterly flow. High
temperatures will push well above normal with most of the region
topping out in the 40s to near 50 over southern New Hampshire
and SW Maine. A warmer night will be on tap for Wednesday night
with moisture still in place and a warm front lifting into the
region overnight. Here we will likely see some light
rain/freezing rain along the international border around
daybreak, but again it looks very spotty.
.LONG TERM /THURSDAY THROUGH TUESDAY/...
Low pressure will move across southeast Canada Thursday and will
drag a warm front northeast across the region. A few scattered
showers are possible in the mountains with the warm frontal
passage Thursday. As the low moves rapidly east into the
maritimes Thursday night it will then drag a trailing weak and
shallow cold front south across the region with weak high
pressure building into the area behind the front late at night
into early Friday with dry conditions. By late in the day the
front moves north once again as a warm front with a very broad
southerly flow developing late Friday and continuing through
Saturday. Warmer daytime and nighttime lows are expected and
reflected rather well in superblend guidance. By late Saturday a
progressive upper trof moving through the Great Lakes will have
a strong surface cold front associated with it and will allow
showers to develop by late Saturday and become widespread
Saturday night as the front and upper trof moves rapidly east
across the area.
On Sunday into Monday a return to a more zonal flow aloft with
high pressure, colder temperatures, and dry conditions
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
Short Term...VFR likely through tonight, but MVFR ceilings
possible early Wednesday morning mainly at Lebanon and
Whitefield perhaps persisting into the day on Wednesday. Very
slight chance of freezing rain in these areas tonight.
Long Term...VFR conditions Thu into Thu night. MVFR conditions
may develop Fri in a developing moist southerly flow with some
scattered rain showers. Variable conditions expected early
Saturday but with the approaching cold front late Sat and Sat
night expected conditions to become MVFR to IFR in showers.
Short Term...A couple gusts to 25 kts will be possible over the
outer waters tonight, but confidence is in the occurrence for
more than a stray observation is too low for an advisory.
Long Term...Winds and seas will remain below SCA thresholds
thru the end of the week. A strong cold front will cross the
waters over the weekend...and bring an extended period of SCA
conditions to all waters.
NEAR TERM UPDATE...Kimble