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fxus61 kaly 220456 
afdaly

Area forecast discussion
National Weather Service Albany New York
1256 am EDT Thu Aug 22 2019

Synopsis...
for tonight, expect partly cloudy skies with isolated showers
and patchy dense fog. Scattered showers with isolated
thunderstorms are possible on Thursday into Thursday night,
mainly for areas south of Albany as a cold front slowly crosses
the area. Drier, cooler and less humid conditions are expected
for Friday into Saturday.

&&

Near term /until 6 am this morning/...
as of 1255 am EDT, areas of low clouds/fog have developed across
the upper Hudson Valley and eastern Mohawk Valley, while
remaining more patchy elsewhere. With a moist boundary layer
combined with clear skies and light winds, expect low stratus
and some fog to continue developing through daybreak. Fog may be
locally dense in sheltered areas, included the Mohawk Valley,
however it may be more of a low stratus situation given a
persistent south wind within and above the boundary layer,
especially within north/south oriented valleys which will be
more prone to the effects of the persistent light south wind.

Meanwhile, some showers and isolated thunderstorms have
developed across Lake Ontario and into the St Lawrence Valley
region, just ahead of the incoming cold front. Some of these may
reach into the western Adirondacks by 3 am, and if they hold
together, could even extend into the Mohawk Valley and Lake
George/Saratoga region closer to sunrise. Have kept slight
chance to low chance pops to account for this possibility.

Temps have already cooled into the upper 50s to lower 60s across
portions of the western Adirondacks, with mainly 60s to around
70 elsewhere. Temps will likely only fall off another couple of
degrees from present levels in most areas, and in fact, could
even rise a bit closer to sunrise as mid level clouds increase
and a light wind persists.

&&

Short term /6 am this morning through Friday night/...
Thursday will start out dry, although the main cold front will
still have to push through the eastern 2/3 of the area.
Mid/upper level winds will be generally parallel to the
boundary, so it will take until evening to push through the southeast
part of the area. Models including the href indicating potential
for isolated to widely scattered thunderstorms, as SBCAPE
values of around 500-800 j/kg along with 0-6 km shear of 40+ kt.
If updrafts can grow tall enough, there would be a threat for
gusty winds. The Storm Prediction Center has placed areas south
and east of Albany in a marginal risk for severe storms. High
temps will range from cooler 70s north and west of the Hudson
Valley, to 80s from the Hudson Valley into northwest CT.

A weak wave of low pressure may develop along the cold front as
it passes south and east of our region Thursday night. Some
showers may spread northward into southeast portions of our area. Will
mention chance pops for this area, although these may need to be
raised with subsequent forecasts if trends continue.

Unsettled weather should finally end on Friday, as an upper
level trough settles in, with northerly surface winds pushing
any remaining surface boundaries well south of our region.
Humidity levels will be noticeably lower, with dewpoints
dropping through the 50s. Temperatures will be seasonable for
late August, with upper 60s in the higher terrain and upper 70s
in the Hudson Valley. Dry and cool conditions will continue
through Friday night, with a northerly flow persisting.

&&

Long term /Saturday through Wednesday/...
on Saturday, a positively tilted long wave trough will be over
the northeast U.S. As the trough tries to cross the area
Saturday night into Sunday, deterministic model guidance
suggests that the trough closes off over New York. Only the
21/12z gefs does not close off the low. This closed low then
wobbles around New York, New Jersey and New England into Monday
before lifting northeast into northern New England later Monday.



Fair weather is expected on Saturday, but by Sunday and Monday,
the cyclonic flow aloft coupled with a cold pool of -10 to -15c
and afternoon heating, will likely result in isolated to
scattered showers and thunderstorms, especially in the afternoon
and evening.

For Monday night and Tuesday morning, upper level ridging
should build back in resulting in fair weather. However,
additional showers and thunderstorms are possible later Tuesday
as a warm front approaches.

Temperatures Saturday through Monday should be slightly below
normal as 850mb temperatures remain in the single digits through
the period. Lows during this period mainly in the 50s with 40s
in the normally cold spots. Highs mainly in the 70s with 60s
across the higher elevations. Tuesday will be warmer with lows
in the 50s to around 60 and highs mainly in the 70s to near 80.

&&

Aviation /06z Thursday through Monday/...
thunderstorm threat remains for kpou for 1-2 hours. Thunderstorm
threat for this evening is over for kgfl, kalb and kpsf.

During a thunderstorm at kpou, brief periods of IFR vsby and
MVFR ceilings are possible but outside of thunderstorm expect
mainly VFR conditions.

Since winds will remain under 5kts and rain today has led to
moist ground and low level conditions, some mist and MVFR
ceilings or brief IFR ceilings (especially 06z/22 to 12z/22) may
develop, especially at kgfl/kpsf. Visibility restrictions after
06z are also possible at all taf sites. Did not include reduced
visibility at kalb and kpou during this update but next cycle may
adjust.

After sunrise, IFR/MVFR ceilings and/or visibility should return to
VFR as winds shift to west or northwest generally after 13z-15z
with the frontal passage. Winds will also increase to 5-10kts
with gusts to 20 kt during the afternoon.

Outlook...

Thursday night: low operational impact. Slight chance of rain showers.
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: low operational impact. Slight chance of rain showers.
Sunday night: no operational impact. No sig weather.
Monday: no operational impact. No sig weather.

&&

Fire weather...
showers and thunderstorms, some severe, will continue to move
eastward across the region into this evening. After a break in
the active weather overnight, scattered showers with isolated
thunderstorms are possible on Thursday into Thursday night,
mainly for areas south of Albany as a cold front slowly crosses
the area. Drier, cooler and less humid conditions are expected
for Friday into Saturday.

Minimum relative humidity values will increase to around 100
percent tonight. Relative humidity values will decrease to minimum values of
around 45 to 55 percent on Thursday, and increase to around 85
to 100 percent Thursday night.

Winds tonight will be south-southwest around 5 mph, shifting to the
west around 5 to 10 mph on Thursday. Winds Thursday night will be
northwest around 5 mph.

&&

Hydrology...
numerous showers and thunderstorms will continue to gradually
move eastward across much of the region into this evening.
Storms will be capable of producing heavy rainfall, as a humid
air mass is in place. Though individual storms may be fast
moving, there is potential for repeated rounds of storms which
will lead to the threat of urban/poor drainage flooding and
possible isolated flash flooding. Localized rainfall amounts of
1 to 3 inches will occur in some areas.

Scattered showers and isolated thunderstorms are possible
Thursday into Thursday night, mainly for areas south of Albany.
Most of this activity will be light, but brief downpours will be
possible in any thunderstorms.

Dry conditions are expected Friday into Saturday.

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...sand
near term...snd/kl/jpv
short term...jpv

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