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fxus61 kaly 182039 
afdaly

Area forecast discussion
National Weather Service Albany New York
439 PM EDT Wed Oct 18 2017

Synopsis...
high pressure over the mid Atlantic states will drift off the
eastern Seaboard through Thursday, providing dry conditions and
above normal temperatures. A weak cool front will pass through
late Thursday, but dry conditions will prevail due to limited
moisture. Another area of high pressure will then build in from
the south and west Friday into the upcoming weekend, resulting
in continued dry and mild conditions.

&&

Near term /until 6 am Thursday morning/...
as of 400 PM EDT...clear blue skies and warm temperatures in
place across the region late this afternoon. Most locations have
warmed into the 65-70 degree range, which is around 10 degrees
above normal for mid October.

Clear skies will continue overnight, although with surface high
pressure shifting farther south and east there will be a light
persistent southerly breeze in some spots which will keep
temperatures milder in the mid to upper 40s. However, there will
still be favored locations where winds will decouple and
temperatures will drop into the upper 30s to lower 40s. Patchy
radiation fog will be possible in favored spots near warmer
bodies of water.

&&

Short term /6 am Thursday morning through Saturday/...
another warm day in store on Thursday, as south-southwest low
level flow increases as a weak cool front approaches from the
Great Lakes. Forecast soundings indicate good mixing to around
or even slightly higher than 925 mb, so breezy/warm conditions
are expected. Highs should reach the upper 60s to lower 70s,
with just some patchy mid level clouds moving into the
Adirondacks late in the day. Winds could gust to around 25 mph
from the late morning through afternoon hours, as the pressure
gradient increases.

The cool front will cross the region Thursday night, will
little more than just some mid level clouds, mainly north of
I-90. Very limited moisture to work with, so no precip expected.
Winds will shift to the west-northwest behind the front, and will remain
somewhat persistent through much of the night, so temps will be
on the mild side.

Weak cold advection behind the front will lead to only slightly
cooler temperatures for Friday, with plenty of sunshine due to
a building ridge of high pressure both at the surface and aloft.
Temps Friday night will be a bit cooler than Thursday night due
to calm winds and clear skies resulting in good radiational
cooling. Sunny skies and well above normal temps expected again
on Saturday, as the ridge becomes firmly entrenched over the
region.

&&

Long term /Saturday night through Wednesday/...
we start the extended period on Sunday with a 1025 - 1030mb
high positioned off the East Coast. With our County Warning Area on the western
half of the high, southerly flow should lead to warm air
advection in our region with h850 isotherms ranging +11 - 13c.
Therefore, have high temperatures 5-15 above normal in the upper
60s to low 70s throughout the area under mostly sunny skies.
Upstream in the Midwest, we will be monitoring an amplifying
shortwave trough with most guidance in agreement that it'll dig
into the lower Mississippi Valley with its associated surface
cold front slowly progressing eastward.

By Monday, the surface cold front should continue gradually
moving eastward. However, high pressure positioned off shore
could be rather strong around 1030mb which could slow down the
progress of the cold front. The front also looks to slow down
because the previously discussed shortwave trough looks to cut
off at h500 and potentially phase with a larger long wave trough
that digs into the northern plain states. Thus, only have low
end chance pops in the western New York counties on Monday and tapered
down to slight chance pops in western New England. High
temperatures should remain above normal on Monday in the mid-
upper 60s/near 70.

Monday night into Tuesday looks to have the greatest chance for
precipitation of the week as our cold front should finally
arrive into our region. Moisture from the Gulf of Mexico could
stream up along our cold front as the phased upper level
disturbance progresses into our area which could lead to areas
of showers/rain, especially for the daytime. Have widespread
likely pops in place for Tuesday to reflect this thinking. Some
guidance (mainly GFS and canadian) shows signs of a low level
jet around 45-50kts in place which could lead to a more focused
area of rainfall associated with the frontal passage. However,
confidence is not very high regarding this feature so left
likely pops for the entire daytime period. Temperatures could
stay mild in the 60s as the cold front may not pass through
until late.

Sometime Tuesday evening/overnight, the cold front looks to
finally move through the area but the upper level trough could
be slow to exit and still influence our weather for Wednesday.
This could be a rather dynamic system as well so there remains
much uncertainty regarding when it should exit the northeast.
Thus, left chance pops showers for Wednesday with cooler
temperatures in the 50s. The Heart of the cold air looks to lag
behind the initial frontal passage and may not arrive in our
area until after 00z Thursday.

&&

Aviation /21z Wednesday through Monday/...
clear skies in place through the taf period thanks to high
pressure centered over the mid-Atlantic. Fog potential is a bit
unclear tonight. With the position of the high, a light
southerly breeze may persist overnight, and moisture will be
very shallow. On the other hand, localized River Valley fog was
observed over the mid-Atlantic last night under similar
conditions. For now, included MVFR br at kgfl and kpsf. Any fog
that forms should be very shallow and transient.

Wind directions this afternoon will vary from southerly to
westerly at around 5 kt, becoming light southerly or calm
overnight. Some possibility for low level wind shear toward 12z as winds at 2kft
increase to 20-30kt. Low level wind shear would be most likely at kgfl. Winds
will become south-southwesterly Thursday increasing to around
10 kt by the end of the taf period.

Outlook...

Thursday night: no operational impact. No sig weather.
Friday: no operational impact. No sig weather.
Friday night: no operational impact. No sig weather.
Saturday: no operational impact. No sig weather.
Saturday night: no operational impact. No sig weather.
Sunday: no operational impact. No sig weather.
Sunday night: no operational impact. No sig weather.
Monday: moderate operational impact. Chance of rain showers.

&&

Fire weather...
southwest winds will gust to around 25 mph on Thursday...

High pressure over the mid Atlantic states will drift off the
eastern Seaboard through Thursday, providing dry conditions and
above normal temperatures. A weak cool front will pass through
late Thursday, but dry conditions will prevail due to limited
moisture. Another area of high pressure will then build in from
the south and west Friday into the upcoming weekend, resulting
in continued dry and mild conditions.

Relative humidity values will increase to around 80 to 100
percent tonight, decreasing to minimum values of between 35 and
45 percent Thursday afternoon. Relative humidity values will increase to around
90 to 100 percent Thursday night.

Winds will be southerly around 5 mph or less tonight, becoming
south- southwest increasing to 10 to 15 mph with gusts around 25
mph on Thursday. Winds will shift to the west at 5 to 15 mph
Thursday night.

&&

Hydrology...
no precipitation is expected through at least the weekend
thanks to persistent high pressure, with river/stream flows
remaining at normal to below normal seasonal levels.

The next chance of rainfall arrives early next week, as a
widespread rainfall is possible associated with a slow-moving
frontal system. It is much too early for specific details, but
some heavy rain may occur in the Tuesday to Wednesday time
frame.

For details on specific area rivers and lakes, including
observed and forecast river stages and lake elevations, please
visit the advanced hydrologic prediction service /ahps/ graphs
on our website.

&&

Aly watches/warnings/advisories...
CT...none.
New York...none.
Massachusetts...none.
Vermont...none.

&&

$$
Synopsis...kl/jpv
near term...jpv
short term...jpv

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