Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/07/21

Area Forecast Discussion

National Weather Service Gray ME

 940 PM EST Wed Jan 6 2021

.SYNOPSIS...
Coastal storm continues to meander south of the Canadian
Maritimes and will only slowly continue to lift out through
Saturday. Aside from some stray rain or snow showers no
significant precipitation is expected. Another trough will drop
south through the area Saturday and may bring some more rain or
snow showers, but again it should remain dry for most.
Seasonable weather is expected to dominate.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
930 PM update... Radar and ASOS reports are indicating that an
area of light snow continues to move south with light snow now
falling at KWVL, KIWI, and KAUG. This area of snow is likely not
going to amount to more than a coating to perhaps a few tenths
of an inch but with road temperatures at or below freezing a few
slick spots will be possible. Generally increased PoPs through
the first half of the overnight hours, especially along the
coastal plain and immediate coast. Interestingly, there is a
secondary area of precipitation now moving into portions of
Aroostook and Piscataquis counties in Maine and this area will
need to be watch over the next couple of hours as it is moving
in the same general direction as the first round. Other than
minor adjustments to wind and temperature grids the rest of the
forecast remains largely on track.

700 PM update... Radar is showing an area of precipitation
currently moving over Penobscot County, ME and drifting
southeastward into Somerset and Waldo counties. There is decent
agreement from high resolution model guidance including the NAM
and HRRR that this activity will continue to move southward
before approaching the Portland region between around 03-05Z.
Therefore PoPs and QPF were increased in this update. The KGYX
00Z sounding shows a fairly impressive dry layer aloft but based
on recent radar scans and ASOS reports this precipitation does
appear to not be having too much trouble making it to the
surface. Minor adjustments to temperatures, dew points, winds,
and sky cover were also made.

Impacts:Minimal. Light snow accumulations possible in far
eastern portions of Waldo and Knox counties early tonight.

After mostly sunny skies for a large portion of the region this
morning, clouds have filled in across the region as an area of low
pressure spins off of Nova Scotia while remaining just about
stationary throughout the day. An area of light reflectivity
continues to push southwest through the Gulf of Maine and is nearing
the coast, but would not expect any precipitation from this when it
reaches the coast.

The main forecast focus tonight is the possibility for some light
snow accumulations from an area of showers which is currently
entering eastern Maine from New Brunswick. It looks to pass over our
eastern zones between 7pm and midnight, and could bring a dusting up
to a tenth of snowfall as it does so to far eastern portions of
Waldo and Knox counties. Do have slight chance PoPs as far west as
Portland, but even if these areas do see some brief light snow from
these showers, not expecting any accumulation beyond the previously
mentioned areas. The rest of the region should remain dry but cloudy
as low temperatures drop into the teens in the mountains and the
lower to mid 20s elsewhere.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
Impacts: No impacts anticipated.

The low off of Nova Scotia finally begins to move off to the
northeast into the far northern Atlantic tonight into tomorrow
morning and broad high pressure builds into the eastern U.S. from
the Great Lakes and Canada. Clouds will finally give way to mostly
sunny skies by early afternoon for those areas outside of the
mountains and perhaps far eastern areas of the CWA and no
precipitation is expected. Highs will be similar to Wednesday, near
30 in the mountains to the upper 30s to near 40 south. Clouds
continue to hang tough in the mountains tomorrow night in the north-
northwesterly flow, but skies will remain mostly clear elsewhere
with lows ranging from the lower teens north to near 20 south.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Overview: Anomalous ridging to the N of the region will keep
storm track well to the S and the wx quiet thru the extended.

Impacts: No widespread significant wx impacts are anticipated
for the next 7 days. Generally near normal temps expected.

Forecast Details: Anomalous blocking continues to start the
period. That will keep upper low pinwheeling to our NE and give
us our only real shot at precip thru day 7. S/WV trof will drop
Swd thru Nrn New England Fri night into Sat. While at this time
the bulk of the forcing looks to remain to our E...scattered
snow showers are possible across parts of Wrn ME as it does so.

The Srn stream S/WV trof will remain too far S on Sat to be a
threat for precip. High pressure slowly builds in from the W in
its wake...and dry forecast continues thru Tue. The next best
chance at precip will be Wed as an upper low ejects out of TX.
At this time ensemble guidance is more in favor of this missing
to the S than bringing widespread QPF to the area. But a
few...generally less than 20 percent...of ensemble members do
bring appreciable QPF to the area so it cannot be ruled out at
this time.

&&

.AVIATION /03Z THURSDAY THROUGH MONDAY/...
Short Term...VFR conditions generally expected at all terminals.
LEB is currently MVFR, but should improve to VFR later this
evening. RKD could see brief MVFR conditions in light snow
showers late this evening, but otherwise will be VFR through
tomorrow morning. With high pressure building into the region
tomorrow, expect winds to be less gusty than today but still in
the 5-10 kt range. No precipitation is expected through the
short term except for possible light snow showers at RKD late
this evening.

Long Term...Widespread VFR conditions expected thru the weekend.
Aside from some local MVFR CIGs in the mtns with upper trof
passage Fri night into Sat...no precip is expected.

&&

.MARINE...
Short Term...SCA remains in effect for all marine zones. Casco
Bay may be able to be dropped later this evening, but Penobscot
Bay and the outer waters will likely remain up through the
tomorrow evening. Seas are forecast to decrease tonight into
tomorrow, but winds will remain gusty to 25-30 kt through
Wednesday.

Long Term...Some wind gusts near 25 kt possible N of Port Clyde
Fri will diminish during the day. The passage of the next
offshore storm may allow winds to increase again Sat to near 25
kt outside the bays with seas increasing to near 5 ft.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...Small Craft Advisory until 7 PM EST Thursday for ANZ150>154.

&&

$$
NEAR TERM...Tubbs