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FXUS61 KALY 161719
AFDALY

Area Forecast Discussion
National Weather Service Albany NY
119 PM EDT Thu Aug 16 2018

.SYNOPSIS...
An area of high pressure will drift across the region today,
providing dry conditions and above normal temperatures,
especially from the Hudson River Valley eastward. The next
widespread threat of showers and thunderstorms arrives late
night into Friday as a low pressure system approaches from the
Great Lakes. Clouds and showers may linger into Saturday, as the
slow moving low pressure system and a cold front track
southward across the region.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
As of 115 PM EDT, Isolated convection has developed across the
northern Taconics and spreading into the southern Greens. This
was the combination of the slowly moving frontal boundary
drifting southward and upslope conditions as low level flow
remains from the west. So did introduce isolated PoPs/Wx for
these areas the remainder of the afternoon. Our special sounding
conducted for maintenance purposes reveals steep low level
lapse rates with a good cap near H750. Forecast highs look on
target.

Prev Disc...Smoke was seen in visible satellite imagery earlier
this morning across New York and into the Atlantic with a few
surface observations reporting haze. This smoke aloft should
gradually push north and east throughout the day and into
tonight as an upper ridge builds into the region. For the near
term, however, expect another warm and muggy day on tap with
temps already in the upper 70s and dew points in the mid to
upper 60s.

With no real change in air mass, temperatures will be very warm
again, especially for valley locations where high in the 85-90
degree range will be common. Dewpoints are still expected to be
in the mid to upper 60s this afternoon for much of the area, so
it will continue to be humid. Cooler/less humid conditions will
occur in the Adirondacks.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
The upper level ridge axis will shift east of the region
tonight as a trough and associated surface cyclone/warm front
approach from the Great Lakes. Isolated to widely scattered
showers and thunderstorms will be possible this evening for
areas west of the Hudson Valley. Otherwise, chances for rain
will increase and spread eastward after midnight into the early
morning hours, as the cyclone tracks into the eastern Great
Lakes and the warm front lifts northward across the Mohawk
Valley and Adirondacks. This is where the better synoptic
forcing and resulting highest pops will be, with lesser chances
from around the Capital District south and east. Some embedded
convective elements are evident in the latest CAMs, so will
mention slight chance of thunder during this time.

Friday looks to be an unsettled day, as the surface cyclone
tracks eastward near the St. Lawrence valley region. The warm
front should lift north of the area, placing us in a warm
sector. PWATs are forecast to surge to around +1 to +2 STDEV,
while a pre-frontal surface trough is expected to develop and
move through our area during the afternoon/evening hours. This
trough will provide a low- level focus for convective
development with high probabilities for showers and
thunderstorms during this time.

There is uncertainty with regards to the severe weather
potential though. There may be a good amount of cloud cover in
the warm sector, which would inhibit significant instability
from developing. With a moist environment, it will only take a
few breaks of sunshine to allow for at least modest values
around 1000-1500 J/Kg of SBCAPE to develop. The wind field will
be increasing through the day as well, which could enhance the
potential for damaging winds associated with any taller
updrafts. A mitigating factor is weak mid- level lapse rates. So
the Storm Prediction Center continues to indicate a Marginal
Risk for severe storms. This seems very reasonable given there
are both favorable and mitigating factors at this time. Locally
heavy rainfall is expected within convective elements due to
anomalously moist air mass. With increasing steering level
winds, cells should be moving thus reducing the flash flood
threat. Our are remains in a Marginal Risk for excessive
rainfall as well. It will be a humid day, but cooler than
Thursday due to more cloud cover and showers/storms around.

Showers and some embedded thunderstorms will continue into
Friday night, as the surface cyclone and its trailing cold front
slowly move SE across the region. The threat for some gusty
winds and locally heavy rainfall within any convection will
continue into the evening before diminishing overnight as
instability wanes.

Saturday looks to be cooler, but continued mostly cloudy with
chances for showers lingering through at least half of the day.
Latest guidance including the 00Z GFS/ECMWF indicating another
short wave moving through the mean upper level trough during the
day. The best chances for showers lingering into the afternoon
will be across the southern half of the area, which is where the
cold front will continue to slowly push SE. Northern areas
should start to clear out during the afternoon with a drier
north wind developing. With residual low-level moisture and weak
instability, will mention a slight chance of thunder, mainly
across the southeast half of the area. Temps will be cooler
ranging from the lower 70s across the higher terrain to upper
70s/lower 80s in valleys.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Slow moving cold front crossing the region Saturday night may
get further delayed by a wave developing along the front. This
wave may bring clouds to most of the area and some light rain or
showers to our New England zones Saturday night and Sunday.
Temperature forecast for Sunday is tricky as clouds and some
rain would keep temperatures about 10 degrees below normal. For
now have partly to mostly cloudy skies with lows in the 50s and
60s and highs generally in the 70s.

Monday could still have some lingering clouds early as wave
lingers over Gulf of Maine, especially over eastern areas, but
clearing should progress to all areas by later in the day. Lows
mainly in the 50s with highs in the 70s to around 80. Monday
night should be generally fair.

On Tuesday, strong low pressure will be moving through the
western Great Lakes. This system will push a warm front across
the Albany Forecast area with the potential for showers and
thunderstorms. Forecast has chance pops northwest part of area
and slight chance to southeast part of forecast area. Lows
Tuesday in the 50s with highs mainly in the 70s.

The low pressure system will have moved into eastern Canada by
Wednesday and will drag a cold front across the area Tuesday
night and Wednesday bringing additional chances for showers and
thunderstorms. Lows Wednesday mainly in the 60s with highs in
the 70s to low 80s.

&&

.AVIATION /17Z THURSDAY THROUGH MONDAY/...
Some patchy MVFR/IFR fog developed overnight in valleys. There
is also a broken low cloud deck, impacting mainly the higher
terrain and KPSF TAF site, at around 2500 ft msl. The mist/fog
should burn off and the lower clouds should lift between 12Z-
14Z, and Mainly VFR conditions are forecast for today into this
evening. Overnight showers are possible after midnight from an
approaching warm front. For now TAFs have VCSH after 07-10Z
Friday.

The winds will increase from the west to northwest at 5-10 kts
with some gusts to around 20kts by the late morning and
continue into the afternoon. KGFL may have a more north to
northeast breeze at 10 kts or less.

Outlook...

Thursday Night: Moderate Operational Impact. Chance of SHRA...TSRA.
Friday: High Operational Impact. Likely SHRA...TSRA.
Friday Night: High Operational Impact. Likely SHRA...TSRA.
Saturday: Moderate Operational Impact. Chance of SHRA...TSRA.
Saturday Night: No Operational Impact. NO SIG WX.
Sunday: No Operational Impact. NO SIG WX.
Sunday Night: No Operational Impact. NO SIG WX.
Monday: No Operational Impact. NO SIG WX.

&&

.FIRE WEATHER...
An area of high pressure will drift across the region today,
providing dry conditions and above normal temperatures,
especially from the Hudson River Valley eastward. The next
widespread threat of showers and thunderstorms arrives late
night into Friday as a low pressure system approaches from the
Great Lakes. Clouds and showers may linger into Saturday, as the
slow moving low pressure system and a cold front track
southward across the region.

&&

.HYDROLOGY...
Dry and warm conditions will occur today with high pressure in
control. Then, more unsettled weather is expected from late
tonight through Friday, as another low pressure system moves
across the region. Showers and thunderstorms with locally heavy
rainfall will be possible again Friday afternoon into Friday
evening. WPC continues with a slight risk of excessive rainfall
for Friday.

Showers may linger into Saturday, before high pressure builds in
with a dry stretch of weather expected for Sunday into early 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.
NY...None.
MA...None.
VT...None.

&&

$$
SYNOPSIS...JPV
NEAR TERM...BGM/JPV/JVM
SHORT TERM...JPV
LONG TERM...SND
AVIATION...SND
FIRE WEATHER...JPV
HYDROLOGY...BGM/JPV
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