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FXUS61 KGYX 161936

Area Forecast Discussion
National Weather Service Gray ME
336 PM EDT Wed Oct 16 2019

A major Nor'easter will move across New Hampshire and Maine
tonight into Thursday. Heavy rain and strong winds are expected
across the area with damaging winds possible along the coast. 
The low will move out on Friday with upslope showers lingering 
to start the weekend. High pressure will build in for the 
weekend before another cold front moves through next week.


At 18z...a 997 millibar low was in the vicinity of Georgian Bay
with a trailing cold front through the mid Atlantic region and 
DELMARVA. Three hour pressure falls were on the order of 6 
millibars vicinity of the DELMARVA as a 1000 millibar secondary 
low was rapidly developing in response to upper system 
transitioning to negative tilt. Latest numericals are in good 
agreement on evolution and track of the coastal system. Clouds 
will quickly overspread the area this evening ahead of the 
deepening coastal low will rain developing from southwest to 
northeast across the entire area by shortly after midnight. The 
strong onshore flow and upslope will result in rainfall heavy at
times ahead of the approaching 70 knot low level jet. By 
morning...the 973 millibar low will be centered over southern 
New Hampshire with heavier precipitation quickly tapering to 
light rain or showers as dry slot wraps into the area. There 
will be a narrow timeframe of strong winds with the low level 
jet with coastal sections likely to see wind gusts of warning or
advisory criteria. Higher terrain above 1500 feet may also see 
a brief period of winds near 45 mph towards morning. While the 
band of heavy rain will be brief...amounts of 1 to 2 inches are 
likely across southern and western New Hampshire with HREF 
suggesting some localized 3 or 4 inch amounts. Have issued a 
flood watch for that area overnight into Thursday. 



On Thursday...we'll see a lull in the winds as the low center
meanders across the area with areas of light rain or showers
pivoting around it. highs will range from the upper 40s to mid
50s. Across the White Mountains...the summits will likely see a
decent amount of wet snow as the column cools during the day. 
Thursday night the system will begin to exit to our north and 
east with gusty westerly flow developing in the cold air 
advection behind this system. We'll see some leftover rain and
snow showers across the higher terrain with snow levels
gradually lowering overnight. Lows will range from the mid 30s
to lower 40s. 


Overview: The nor'easter should be out of our region by Friday 
morning, but northwesterly flow in its wake will keep scattered rain 
or snow showers in the mountains throughout the day. High 
pressure arrives for the weekend and holds through Monday with 
good radiational cooling conditions expected at night. By 
Tuesday morning, a cold front and mid-level disturbance are 
expected to be approaching our region, bringing a round of rain 
and showers that will persist through Tuesday night.

Impacts: No significant impacts anticipated, but the mid-week system 
has some potential to produce significant rainfall.

Details: Friday morning begins with our region on the backside of the 
nor'easter as it moves through New Brunswick. As is typical 
with these systems, the flow will be rather brisk out of the 
northwest. While much of our region will be dry under this 
regime, scattered showers will remain possible throughout the 
day in the mountains of northern NH and northwestern ME. While 
lower elevations will likely remain warm enough to only see 
rain, higher elevations look to be cold enough for light (<0.5 
inch) accumulations of snow. 

Chances for precipitation will gradually wane Friday night as the low 
continues to pull away and high pressure builds into our 
region. The high pressure is nearly overhead by Saturday evening
and it should remain there through Saturday night. Early 
Sunday, a cold front extending south from a low pressure system 
pulling north into Canada will wash out before it arrives in our
region; high pressure again builds into our region through the 
day on Sunday. Overall, the weekend looks rather nice with 
mostly sunny skies and seasonable temperatures. With high 
pressure centered nearly overhead Saturday night, have gone 
cooler than the blended guidance as it looks like a potentially 
ideal setup for radiational cooling conditions.

The surface high pressure gets pushed to the north on Monday as
another potent low pressure system moves toward the Great Lakes.
Our region should remain dry albeit with clouds increasing
during the evening. However, as the system's cold front
approaches, precipitation chances will begin to increase Monday
night an continue to increase from south to north during the day
on Tuesday. There is some disagreement on when the 
precipitation may end between the faster GFS and the slower 
Euro, but Tuesday looks like the most likely period for 
precipitation with lower PoPs in the forecast Tuesday night to 
account for that uncertainty.

Overall, temperatures will be seasonable to slightly above
average for the long term period with the exception of the
weekend low temperatures.


Short Term /through Thursday Night/...Conditions lowering to
widespread IFR in RA and fog tonight. LLWS developing tonight
through Thursday morning with surface gusts near the coast 
approaching 50 kt for a brief window early Thursday morning.
Gusts up to 25 kt expected at remainder of terminal sites.
Conditions improving to MVFR from SW to NE Thursday morning in
cigs and -SHRA. Westerly winds gusting to 25 KT Thursday night. 

Long Term...MVFR/brief IFR conditions will be possible at 
northern terminals on Friday as clouds and showers persist on 
the back side of the nor'easter. Otherwise, high pressure builds
into the region on Saturday and allows for VFR conditions at 
all terminals with generally light winds through the weekend and
into Monday. 


Short Term /Through Thursday Night/...A band of strong winds
with the low level jet crossing the waters late tonight and
Thursday morning with a period of storm force winds likely even
in the bays. winds will drop off but with Gales likely for much
of the remainder of the period as the system begins to pull

Long Term...SCA conditions will be possible Friday and Friday
night, primarily due to winds. The weekend and Monday look quiet
as high pressure dominates, but winds and seas will build to SCA
criteria late Monday and remain elevated through Wednesday.


Widespread rainfall will move into the region tonight. Overall 
looking at widespread 1.5- 2" with areas of 3-4". Highest 
precipitation totals will be focused along the terrain where an
easterly low level jet will help to focus rainfall. Overall dry
antecedent conditions will substantially lower the flood threat
for both river and flash flooding, however some minor flooding 
is likely.

The flashier rivers in the mountains may see minor flooding 
including the Saco and upper Pemi. Further south, the highest 
rainfall totals are expected along the Hillsborough Cheshire 
county border in the headwaters of the Contoocook and Souhegan 
which will also need to be monitored for minor flooding. 

Across the region minor flooding of low lying areas is likely, 
especially in urban areas where leaves and debris from the winds 
will result in clogged drains. Localized flash flooding is possible, 
however the progressive nature of the system means that threat is 
more limited. Have issued a flow watch for southwest New Hampshire
where models continue to advertise the highest QPF amounts
overnight and early Thursday. 


ME...Wind Advisory from 11 PM this evening to 11 AM EDT Thursday 
     for MEZ018>022.
     High Wind Warning from 11 PM this evening to 11 AM EDT 
     Thursday for MEZ023>028.
NH...Flood Watch from 2 AM EDT Thursday through Thursday afternoon 
     for NHZ007-008-011-012-015.
     Wind Advisory from 11 PM this evening to 11 AM EDT Thursday 
     for NHZ010-013.
     High Wind Warning from 11 PM this evening to 11 AM EDT 
     Thursday for NHZ014.
MARINE...Storm Warning from 11 PM this evening to 2 PM EDT Thursday for 


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