Area Forecast Discussion
Issued by NWS Portland, ME-- Highlight Changed Discussion --
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FXUS61 KGYX 181413
Area Forecast Discussion
National Weather Service Gray ME
913 AM EST Wed Jan 18 2017
Low pressure will redevelop off the mid Atlantic coast early
today. Another weak front will pass through the area early
Thursday. This will be mainly dry with just clouds across the
region and a few upslope snow showers along the Canadian border.
High pressure will build in for the remainder of the week, with
above normal temperatures expected into Monday. A storm system may
affect the region beginning Sunday night and continuing into early
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --910 AM Update...Have updated the forecast...mainly for
pops/wx/snow amounts for the next several hours based on trends in
radar data as well as mesoscale model data. Most locations are
experiencing light snow...with some light rain mixing in across
southernmost zones mainly near the MA border. There is actually a
decent surge of colder air emanating from the northeast that is
dropping temps at this hour...even in places like KPSM. Have
adjusted for a colder scenario today. In addition, an ocean
enhancement component is occurring on the coast...especially the
southern ME coastal zones. Have actually boosted snow accums an
inch or two in these areas because of that. Otherwise, light
freezing drizzle may mix in from time to time today, but impacts
are expected to be minimal.
Low pressure south of Long Island will move east and out to sea
today. This will bring snow to an end. One band of more intense
snowfall on radar extends from portland into southern Oxford
county as of 3am, this will continue to move east and dissipate
over the next few hours. In New Hampshire surface observations
show light snow persisting below the radar beam. This low level
moisture will become freezing drizzle during the morning as the
upper level dry slot moves in and cuts off the heavier
precipitation. Light icing south of the Lakes region is possible
until temperatures rise above freezing mid morning. All the
precipitation will come to an end by early afternoon.
Changes have been made to warnings and advisories to better
reflect the lower snowfall totals. In Maine the precipitation was
slow to move in last night as the dry air remained at the surface
and as a result lower totals are expected. The winter storm
warnings have been converted to winter weather advisories to
reflect the lower amounts and chance for some brief ice early this
morning. In New Hampshire Strafford and northern Carroll have been
converted to winter weather advisories based on low precipitation
amounts. The warnings remain in place for Belknap, Merrimack and
Central and Western Hillsborough county. This area had the highest
snow totals as of midnight and some elevated terrain which may
enhance the snowfall amounts. All the hazard end times have been
cut back to noon when precipitation should be done.
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.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
A weak front will move through on Thursday from the north bringing
widespread clouds and mountain snow showers. Minimal accumulation
of 1-2inches is possible from Pittsburg NH through to Jackman.
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
A few remaining light flurries across the higher terrain Thursday
evening will come to an end as high pressure settles over the
forecast area. This ridge of high pressure will be slow to exit
the region, bringing dry conditions to the Maine and New Hampshire
Clouds will spill over the ridge from an approaching large and
complex area of low pressure in the Plains region over the
weekend. This will set the stage for an upper level low to wobble
towards the region. Initially, the atmosphere may be cool and dry
enough to allow for some wet bulbing effects and snow across the
interior Sunday night. By Monday, remaining pocket of cool dry air
will be diminishing with a mixture of snow, sleet and rain across
the region. Plain rain is expected along the coast, however
precipitation amounts will continue to be light.
A gusty northeast flow will develop by Monday night, allowing for
additional rain along the immediate coast with a mix inland. As
the system enters the Mid Atlantic region, the ptype becomes
mainly in the form of rain as gale force easterlies develop.
Confidence levels are not overly high for this forecast early next
week. There are some model to model and ensemble discontinuities.
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --Short Term...IFR cigs/vsbys continue today mainly in snow and
mainly on the coastal plain.
Long Term...Possible MVFR conditions Thursday evening as any
upslope flurries come to an end. Otherwise, VFR conditions will
prevail through Sunday. Mixed rain and snow begins to enter the
region Sunday night.
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Short Term...SCA in effect as storm system moves to our south
tonight through Wednesday. High pressure builds in for the end of
Long Term...SCA criteria (for seas) possible Thursday night,
mainly over the outer waters. Winds and seas should be below SCA
criteria Friday through Sunday. Increasing southeasterly flow
will allow seas to build early next week.
ME...Winter Weather Advisory until noon EST today for MEZ012-013-
NH...Winter Storm Warning until noon EST today for NHZ006-008-009-
Winter Weather Advisory until noon EST today for NHZ002>005-
MARINE...Small Craft Advisory until midnight EST tonight for ANZ150>154.
NEAR TERM UPDATE...Ekster