Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Albany New York
511 PM EDT Friday Sep 19 2014

Synopsis...
the high pressure over the region will slide eastward off the
coast tonight. A low pressure system will approach from the west
over the weekend...with its cold front crossing the region Sunday
bringing some needed rainfall to the area along with the threat of
thunder. It will be mild over the weekend ahead of the
system...however with the passage of the cold front a cooler air
mass will be ushered back in.

&&

Near term /until 6 am Saturday morning/...
surface high pressure will continue to shift eastward off the
coast tonight resulting in a southerly return flow across the
region. Clouds will be in the increase in this flow especially
after midnight. It will not be as chilly of a tonight with low
mainly in the 40s. However upper 30s are expected across the
higher terrain of the southern Adirondacks and particularly across
much of southern Vermont where the clouds will in later.

&&

Short term /6 am Saturday morning through Monday/...
mild/warm temperatures this weekend along with some needed rainfall.

It will be much warmer Saturday by some 10 to 15 degrees as the
region will be under seep southwestern flow located between an
approaching low pressure system and surface ridge centered off the
New England coast. Looking at highs from the middle 60s to middle 70s.

Saturday night's low will be similar to today's (friday's) highs
middle 50s to lower 60s. Chances for showers will begin to increase
late at night. The situation gets complicated as a vigorous short
wave energy dives into the longwave resulting in the development
of a low on the cold front to our west and by the development of
an area of low pressure along the southeast coast Saturday. The
system remains progress with the front and its associated low
passing over the area Sunday as the coastal low passes south of
Long Island and Cape Cod.

Have added a chance of thunderstorms to the forecast as the
boundary and low move through during the afternoon utilizing
heating. Sref indicates the probability for MUCAPE of 500 j/kg at
50-70 percent with the chances for 1000 j/kg at 10 percent or
less. 0-6km bulk shear of 30 to 40 knots is expected.

Despite cloud cover and showers highs Sunday will be mainly in the
70s with 80 degrees possible for locations in the middle Hudson
Valley. However...it will be cooler with middle/upper 60s across the
western Adirondacks.

With passage of this system a much cooler air mass will be ushered
back in. High Monday are expected to be around 15 degrees cooler
than Sunday...around 10 degrees below normal...plus a northwest
winds will only add a chill.

&&

Long term /Monday night through Friday/...
a very quiet period of weather looks to be setting up Monday night
through Friday. A weak reinforcing cold front could support an
isolated shower in the southern Adirondacks Monday night into
Tuesday but there should not be too much cloud cover across most of
the region associated with the weak front. High pressure gradually
builds in and again...relatively little cloudiness through the
entire period.

Some gradual warm advection begins Thursday and Friday as the mean
upper trough axis slowly builds east and lifts out of eastern
Canada. Boundary layer temperatures will warm as a result. Highs
Tuesday and Wednesday in the middle 60s to around 70...50s in higher
elevations. Highs Thursday and Friday in the 60s to lower 70s.

&&

Aviation /21z Friday through Wednesday/...
VFR conditions with mainly clear skies will persist into the this
evening with high pressure remaining in control. However...after
midnight low stratus clouds in MVFR range will likely advect
northward into the region as a return southerly flow develops around
high pressure shifting eastward off the New England coast. The
expected increasing clouds should preclude radiational fog
formation. However...if the clouds increase later than expected
there is a chance of some fog forming at kgfl/kpsf. Will only
mention VFR visibility at these sites for now...with higher confidence in
stratus clouds moving in before fog can develop. Ceilings should tend to
become broken by late Saturday morning or early afternoon...and
rising to VFR levels.

Winds through tonight will be light and variable...then shifting to
the south and increasing to around 10-15 knots on Saturday...with gusts
up to 25 knots possible at kalb.

Outlook...
Sat night: no operational impact. No sig weather.
Sun: high operational impact. Likely rain showers...tsra.
Sun night: moderate operational impact. Chance of rain showers.
Monday-Wed: no operational impact. No sig weather. &&

Fire weather...
the high pressure over the region will slide eastward off the
coast tonight. A low pressure system will approach from the west
over the weekend...with its cold front crossing the region Sunday
bringing some needed rainfall to the area. It will be mild over
the weekend ahead of the system...however with the passage of the
cold front a cooler air mass will be ushered back in.

Relative humidity values are expected to recover to near 100
percent tonight. Minimum values are expected to be in the 55 to 65
percent range on Saturday...with a recovery to 90 to near 100
percent Saturday night. Minimums values of 60 percent and higher
are expected on Sunday.

&&

Hydrology...
no widespread Hydro problems are expected through the weekend and
into next week.

A low pressure system will approach and cross the region this
weekend bringing some much needed rainfall to the area Sunday into
Sunday night. Rainfall amounts are anticipated to generally be a
quarter to a third of an inch with higher amounts of 1/2 to 1 inch
across the southern Adirondacks and lower amounts of less than a
quarter inch across the middle Hudson Valley and Litchfield County.

A return to dry weather is expected for next week.

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...iaa
near term...iaa
short term...iaa
long term...NAS
aviation...jpv
fire weather...iaa
hydrology...iaa

National Weather Service Glossary of Abbreviations