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fxus61 kaly 212005 
afdaly

Area forecast discussion
National Weather Service Albany New York
405 PM EDT Sat Sep 21 2019

Synopsis...
high pressure will be near the mid Atlantic region
tonight with mostly clear and cool conditions. The surface high
will move eastward away from the coast with continued sunny and warm
conditions with temperatures well above normal to close the weekend.
A cold front and an upper level disturbance will bring scattered
showers and isolated thunderstorms Monday into early Tuesday before
dry and seasonable conditions return.

&&

Near term /until 6 am Sunday morning/...
as of 405 PM EDT...a beautiful day will be followed by a lovely
night, as high pressure near the mid Atlantic states will
slowly drift eastward over the western Atlantic. Mostly
clear/clear skies with light to calm winds should promote near
ideal radiational cooling conditions again. A light southerly
breeze may start to increase in the capital region after
midnight. Lows will be in the 50s with some upper 40s across
southern VT, the southern Adirondacks, and the Lake George/Glens
Falls area. Some patchy fog may form near the Hudson River
Valley, Lake George, CT River Valley near southeast VT, and the
Mohawk River valley.

&&

Short term /6 am Sunday morning through Tuesday/...
tomorrow...warmth and humidity increases as the retreating sfc
anticyclone pumps northward higher dewpts and temps. H850 temps
increase to +1 to +2 stdevs above normal based on the 12z gefs.
The actual values will be around +15c to +16c. The NAM/GFS are
indicating a weak prefrontal sfc trough or lake breeze
disturbance may trigger a few showers/isold thunderstorms over
west/central New York. A few of these showers may reach the western
periphery of the forecast area /western Adirondacks...west-
central Mohawk Valley...and the northern Catskills/. We placed a
slight chance in for the late PM. Overall, warm/hot conditions
will prevail with dewpoints rising into the upper 50s to mid
60s. Highs will be in the lower to mid 80s in the valleys, and
70s to around 80f over the hills and mtns. It will become
breezier during the afternoon.

Sunday night...a mild and muggy night, as we countdown the
beginning of fall/autumn, as it begins at 350 am EDT. It will
feel like Summer, as low temps will be in the mid/upper 60s in
the valleys, and upper 50s to lower 60s over the higher terrain.
A few prefrontal showers may graze the western Adirondacks
before sunrise.

Monday...a cold front and its associated upper trough approach
the forecast area with the best chance for widespread showers in
over a week. The timing of the front and short-wave varies a
bit on the guidance, but there is a decent consensus to go with
likely and high chc pops in the afternoon. Pwats surge above
normal, which is typical with frontal passages. Some splashes of
rain may occur with any isolated convection that pops up due to
frontal convergence, negative showalter values and weak
instability in general. The low-level lapse rates due steepen so
will have to watch for some gusty winds from any thunderstorms,
but the severe threat looks very low at this time. Tall
updrafts will be tough to achieve with weak instability despite
favorable dynamics. A slight chance of thunder was placed over
the entire area. Highs will be 10 to 15 degrees above normal
again with upper 70s to mid 80s in the valley areas, and upper
60s to upper 70s over the mtns.

Monday night into Tuesday...any isolated thunderstorms should
diminish early Monday night. The cyclonic vorticity advection
with the upper trough will keep isolated to scattered showers
going most of the night. The cold pool and upper low will focus
some instability showers over the higher terrain over the
northern half of the forecast area on Tuesday, and it will be
much cooler. Lows Mon night will drop back into the upper 40s to
50s with highs Tue in the upper 50s to upper 60s with a few 70s
sprinkled in the Mid Hudson valley and northwest CT.

&&

Long term /Tuesday night through Saturday/...
the period begins as an upper low pulls away from the region. This
will lead to a period of dry and near seasonable weather on
Wednesday. Lows Tuesday night will be on the cooler side, in the
lower 40s to lower 50s. Afternoon highs on Wednesday should reach
the mid 60s to lower 70s.

An upper level trough and surface cold front approach the region
Wednesday night into the day on Thursday. Showers will be possible
as the cold front passes through the region on Thursday but there
are some timing differences between global models. The GFS is the
quicker solution and also brings the upper trough further south into
New York which could add additional shower chances. Whereas the
European model (ecmwf) is slower with the frontal passage and keeps most of the upper
energy north of the forecast area. Both of these solutions would
lead to the best chances for showers across the northern half of the
forecast area. So for now, have stayed with a blended approach and
chance pops until models come into better agreement.

The front should exit the region by Thursday night, as high pressure
builds in from the west. This will result in a dry start to the
weekend with slightly above normal temperatures. Highs Friday and
Saturday will be in the upper 60s to lower 70s, with overnight lows
generally in the lower 50s.

&&

Aviation /20z Saturday through Thursday/...
VFR conditions are expected through much of the taf forecast
period as high pressure holds its influence on the region. We
can therefore expect generally clear skies throughout the
period, with perhaps some passing high level clouds. Under clear
skies with light winds, patchy fog will once again form
overnight and will mainly impact kgfl/kpsf. IFR/LIFR visbys are
possible with any fog.

Winds will remain light and variable through the overnight
period then begin increasing from the southwest between 5 and
10 kts towards 18z/sun.

Outlook...

Sunday night: no operational impact. No sig weather.
Monday: moderate operational impact. Breezy chance of rain showers...tsra.
Monday night: moderate operational impact. Chance of rain showers.
Tuesday: low operational impact. Slight chance of rain showers.
Tuesday to Wednesday night: no operational impact. No sig weather.
Thursday: moderate operational impact. Chance of rain showers.

&&

Fire weather...
high pressure will be near the mid Atlantic region
tonight with mostly clear and cool conditions. The surface high
will move eastward away from the coast with above normal
temperatures. A cold front and an upper level disturbance will
bring scattered showers and isolated thunderstorms Monday into
early Tuesday.

The relative humidity values will rise to 80 to 100 percent tonight with dew
formation and patchy fog. The minimum relative humidity values tomorrow
afternoon will be in the 45 to 65 percent range, and then rise
to 85 to 100 percent Monday morning.

The winds will become light to calm tonight. They will become
southerly at 5 to 15 mph Sunday into Sunday night.

&&

Hydrology...
problems are not foreseen on the Albany hsa waterways the next 7
days.

Much of the hsa has been very dry the past few weeks. A cold
front and upper level disturbance will bring a tenth to a third
of an inch to portions of the hsa Monday into Tuesday. Isolated
thunderstorm may yield locally higher amounts.

Overall, rivers and streams may rise a few inches, but then
quickly recede Tuesday into the mid week as dry weather returns.
Flows continue at normal to below normal levels for late
September.

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...wasula
near term...wasula
short term...wasula

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