Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Albany New York
639 am EST Monday Nov 30 2015
high pressure will allow for plenty of sunshine today
along with seasonable temperatures. Clouds will increase tonight as
a storm system moves towards the area...which will bring some rain
to the region for Tuesday into Wednesday. Dry weather will return
for later in the week...with temperatures near or slightly above
Near term /until 6 PM this evening/...
as of 639 am EST...high pressure is located northeast of the
region over northern New England. This high pressure area is
allowing for dry weather and typical late November temperatures
this morning...with current temperatures in the upper teens to middle 20s.
Low level moisture trapped beneath the inversion is allowing for
some patches of stratus clouds over the Adirondacks. Outside of
these areas...skies are generally clear.
After sunrise...any lingering lower clouds over the Adirondacks should
start to break up thanks to daytime mixing...allowing for plenty
of sunshine throughout the day. Mixing to about 900 hpa will allow
for maximum temperatures to reach seasonable levels...with highs in the upper
30s to low 40s for most areas. The high pressure area will
continue to gradually shift eastward through the day...reaching
just off the Maine seacoast by early this evening.
Short term /6 PM this evening through Wednesday night/...
skies will start out fairly clear early this evening...but
increasing warm air advection ahead of an approaching frontal
system will allow clouds to spread across the area by later this
evening and into the overnight hours. Temperatures will fall quickly this
evening into the middle 20s to low 30s...but look to hold steady by
late tonight due to the clouds moving in. Although winds will
initially be light from a north-NE direction thanks to an
aegostrophic response...winds will eventually switch to the S-southeast
by late tonight...as the high pressure continues to move east and
away from the area...and the increasing southerly flow at low and
middle level takes over.
Some light precipitation will be moving up from the south for late
tonight. Precipitation looks to begin after 5 am for southern areas...in
the capital region by 8-9 am...and for northern areas by 9-11 am. In
some sheltered valleys of the high terrain and other outlying
areas...this precipitation may begin as a brief period of freezing rain.
This will mainly occur in the Catskills...Adirondacks...and
Berkshires. Precipitation looks to be just a plain rain for the Hudson
Valley...including the capital region...although cannot rule out a
few sleet pellets at the very onset. Even areas that see freezing
rain will see just a trace of ice accretion before precipitation changes
to rain...as this initial burst of precipitation will be fairly light and
quantitative precipitation forecast looks just a few hundredths.
With warm air advection/isentropic lift continuing...a steady
light rain looks to occur through the day Tuesday with cloudy
conditions...as the surface warm front slowly lift northward towards
the area. A secondary area of low pressure looks to develop just
off the middle Atlantic/Jersey Shore...helping to increase the threat
of rainfall. With the precipitation/clouds occurring...high temperatures will
only reach the upper 30s to low 40s...making for a rather raw day.
The warm front will finally lift north of the area for Tuesday
night. This will end the steady rainfall...and allowing precipitation to
become more showery in nature by late Tuesday night.
However...the continued southerly flow will keep temperatures fairly
steady...or even have them rise slightly for Tuesday night...with
temperatures in the upper 30s to low 40s.
Showers will continue into the day Wednesday ahead of the storm/S
approaching cold front from the west. It/S possible that another
wave of low pressure develops along this boundary...which could
bring another period of steady rainfall...although it/S still
unclear if/where this will occur. It will remain cloudy...although
temperatures will be slightly milder with highs in the low 40s to low
Precipitation will be tapering for Wednesday night as the storm/S cold front
finally crosses the area. Cannot rule out a few lingering showers
due to the cyclonic flow associated with the upper level low that
will be moving over the area. With colder air working into the
region...the rain showers may change to snow showers over the
highest elevations of the southern Adirondacks and southern greens with
a light accumulation possible. Any valley areas...including the
capital region and Hudson Valley...will stay mainly rain and see
little to no snow accumulation as precipitation tapers off. Min temperatures
look to be upper 20s to upper 30s for Wednesday night.
Long term /Thursday through Sunday/...
overall guidance is in agreement with the longwave pattern across
the region. A low pressure system that will bring a widespread
rainfall to the region Tuesday through Wednesday will be slow to
exit. The upper level low is expected to open as it moves across
the region Thursday with some lingering rain/snow showers especially
down wind from Lake Ontario.
The trough axis is expected to move off the New England coast Thursday
night. However...a short wave will follow on its heals...passing over
New England Friday. At this time only have slight chance probability of precipitation for rain/snow
showers across the southern Adirondacks and western Mohawk Valley.
Ridging is then expected to build in at the surface and aloft as we head
into the weekend. The upper flow is expected to flatten across the region
as the ridge axis shifts to the east and a short wave passes well to our
north across eastern Canada Sunday. Looking dry weather for the weekend.
Seasonably temperatures are anticipated with some moderation on Sunday.
Aviation /12z Monday through Friday/...
Surface high pressure centered over New England will shift off the
coast this afternoon into evening...as aloft heights rise as ridging
builds in. A storm system will approach from the southwest late Monday
night/early Tuesday morning.
Scattered to broken VFR clouds continue to move across the area. These
clouds are located under an inversion which can be see on the 00z/alb
sounding around 850 mb. Some high level cirrus clouds will streaming in
during day. Guidance indicates an increase in low level moisture from
the southeast during the day. Have addressed this threat with scattered
MVFR clouds at kpou. Otherwise clouds will be in the increase tonight
as storm system approaches. MVFR conditions are expected to develop at
kpou by around 10z/Tuesday as precipitation/rain starts.
Light north-northeast low will shift to the east during the day as the
surface high shifts off the New England coast..with winds becoming light
and variable to calm tonight.
Tue: high operational impact. Rain becoming likely. Slight chance freezing rain early
in the am.
Tuesday night: high operational impact. Definite rain.
Wed: moderate operational impact. Likely rain showers.
Wednesday night: moderate operational impact. Chance of rain showers...shsn.
Thu: low operational impact. Slight chance of rain showers...shsn.
Thursday night-Sat: no operational impact. No sig weather.
with high pressure in control...plenty of sunshine is expected
this afternoon...allowing relative humidity values to fall to 40 to 50 percent
over the region. S-southeast winds will be around 5 miles per hour today.
Relative humidity values will rise to 85-95 percent tonight as a storm system
approaches the region. A steady light rainfall is expected on
Tuesday into Tuesday night with relative humidity values generally around 70-80
percent throughout the day. S-southeast winds will be 5-10 miles per hour.
Relative humidity values will remain elevated through Wednesday with a continued
threat for rain. S-SW winds will switch to the west by late
Wednesday at 5-10 miles per hour. Most areas will see at least a half inch of
storm total rain by Wednesday night.
The fire weather season officially ends today. The National
Weather Service at Albany will end our fire weather
discussion...fire weather forecast (fwf) and nfdrs (fwm) forecast
with the afternoon issuance today for the season. These products
will return in the Spring.
no hydrologic problems are expected over the next five days.
High pressure will allow for dry weather tonight. An approaching
frontal system will bring an extended period of light rain to the
region beginning early on Tuesday...and continuing Tuesday night
and into the day on Wednesday. By Thursday morning...rainfall
amounts will generally range between one half inch and one inch.
This rainfall will allow for rises on rivers and streams...but no
flooding is expected...as the light intensity and limited quantitative precipitation forecast will
keep rivers and streams within their banks.
Dry weather will return for later in the week...allowing for river
levels to recede.
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