Area Forecast Discussion
Issued by NWS Portland, ME-- Highlight Changed Discussion --
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FXUS61 KGYX 191623
Area Forecast Discussion
National Weather Service Gray ME
1223 PM EDT Wed Apr 19 2017
Cool onshore flow will persist today. Weak low pressure tracks
across Quebec this afternoon and tonight and drags a cold front
across the region tonight. Weak high pressure builds in
Thursday, and brings slightly warmer temperatures. Low pressure
will move out of southern Ontario on Thursday night and spread
precipitation across the region on Friday. Weak high pressure
will build in for late Saturday into Sunday before another
disturbance arrives on Monday.
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --1222 PM...Minor ESTF update to reflect current satellite trend
and the 16z mesonet in near term grids.
935 AM...GOES imagery shows clouds arriving from
the west with low clouds beginning to move onshore in the
onshore flow. We`ll see a mix of clouds today with showers
currently on NWS Doppler Radar Mosaic over upstate New York
arriving in the Connecticut Valley and International border area
by late today. For this ESTF update...I adjusted near term
grids to reflect the current mesonet as well as satellite
705 AM...Forecast in good shape. Update reflects a few changes
to forecast based on current conditions. Coastal stratus seems
to be holding so far, but cirrus and mid-lvl clouds thick enough
to still call things mostly cloudy in many spots.
Onshore flow increases today in advance of sfc cold front
approaching from the west. This will keep the wx on the cloudy
and cool side today. Exceptions will be areas west and north of
the mtns where some sun will be possible this morning, and
perhaps parts of interior srn NH which could see flow shift more
SW than SE later today and cold see a little sun this
afternoon. Highs will be in the mid-upper 40s, except in the CT
valley and srn NH where they will reach into the low to mid 50s.
Showers could move into wrn zones late this afternoon.
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.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
The cold front will move the region tonight, and will produce a
period of showers, especially this evening. QPF continues to
trend downward in the 00Z model runs, and will range from a
tenth of an inch to a third of inch, higher amounts in the
north. Higher elevations will see the SHRA change to SHSN. Lows
will drop to the mid-upper 30s in the north to the low 40s in
the south. AS usual, it remains questionable as to whether the
front mixes to the surface before sunrise on the coastal plain,
in which case some fog may develop.
The 00z models also continue to trend to weak sfc ridging
building in for Thursday, and the forecast trends a little
warmer and little brighter, especially in the morning. Inland
areas should get some breaks of sun, but the weak NW flow flow
will be short lived and onshore flow will develop along the
coast in the afternoon, with low clouds and fog working back in
late. Any precip from the next system should hold off until Thu
night. Highs will rise to around normal, generally from around
50 in the north, to around 60 in inland srn NH and SW ME. It
will be cooler near the coast.
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
The week will come to an end with some wet weather as a series
of short waves move along the US Canadian border. The core of
the cold air is locked up in Nunavut with a more zonal flow in
place across southern Canada and the Northern United States.
A wave just starting to move through British Columbia tonight
will move eastwards and begin to cut off over southern Ontario
early Friday morning. This will move through Southern Quebec
Friday into Saturday morning bringing rain to the region. Rain
will move into western NH by daybreak on Friday and spread
across the entire forecast area by midday. Overall expect 0.5-1"
of total precipitation with the highest amounts along the
coast. Elevations above 4000ft may see some of this fall as
snow but overall the warm lower layers should prevent any
significant accumulation with just a few tenths expected.
The rain will move out on Saturday morning allowing for weak
high pressure to build in. By Sunday temperatures will climb
back up with highs in the mid 50s ahead of another front moving
through Sunday night into Monday. Monday morning features a tug
of war between a weak cold front moving through Quebec and a
elongated surface low tracking up the eastern seaboard.
Currently the low is the out to sea looser with the northern
portion of the forecast area feeling the effects of the Quebec
front in the form of showers. Either way the week will start off
cloudy with some unsettled weather.
.AVIATION /16Z WEDNESDAY THROUGH SUNDAY/...
Short Term...Cigs will drop to MVFR this morning, and will
persist there through the day. Should see lowering to IFR
tonight in SHRA and some fog. Some improvement to MVFR or VFR
possible Thu, especially inland.
A storm system will move in THursday night resulting in MVFR
conditions deteriorating to IFR rain from west to east by
daybreak. Rain will continue on and off through the day on
Friday. Conditions will improve Saturday morning to overcast but
VFR in the south and MVFR in showers in the north and
Short Term...S-SE flow increases today with SCA gusts developing
this afternoon into tonight. Winds will veer to the SW this
evening, and then weaken below SCA levels by early Thursday as
they shift briefly N-NW Thu morning, before beginning to turn
onshore again in the afternoon.
Long Term... Easterly flow ahead of the low
pressure will reach small craft criteria on Thursday night and
remain through the day on Friday. Winds and seas will subside on
Saturday returning to generally calm by Saturday night.
Cool and moist onshore flow will persist through the end of the
week. There will be showers late today and tonight and night
more widespread rain expected Thursday night into Friday.
Flood warning continues for the Connecticut River at Dalton
which has crested as is once again beginning to recede. THe
Androscoggin and Kennebec have also crested and dropped back
below flood stage.
With snow water equivalent almost completely gone from all but
the highest elevations expect the river flooding threat due to
snow melt to be over in the next day or so.
-- Changed Discussion --ME...None.
MARINE...Small Craft Advisory until 6 AM EDT Thursday for ANZ150>154.
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