Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Albany New York
423 PM EDT Thursday Jul 30 2015
with a cold front moving across the region...some showers
and thunderstorms will continue into the early evening hours. Behind
this boundary...less humid air will move into the area for tonight
into Friday...although temperatures will continue to be warm on
Friday. The chance for showers and thunderstorms will return on
Saturday...with temperatures slightly above normal levels.
Near term /until 6 am Friday morning/...
as of 423 PM EDT...cold front is in the process of moving across
the County Warning Area. The boundary is already through the western and central
parts of the region. Winds have switched to the west-northwest behind the
boundary...including the capital region...and dewpoints are
slowing starting to fall.
Meanwhile...along and ahead of the boundary...some showers and
thunderstorms are still ongoing. The steadiest/heaviest
thunderstorm activity is south of the area over the lower Hudson
Valley...and coastal and central CT. However...some activity
continues over Dutchess/Litchfield counties...and some additional
isolated to scattered showers/thunderstorms are possible along the
immediate frontal boundary over the next few hours...as it
continues to slowly settle south and east. The 3km hrrr suggest
this will continue to be a possibility for these far southeastern
areas till about 8 to 10 PM...when finally the front will be
through the region.
Behind the front...dewpoints will continue to fall overnight with
decreasing clouds. Some patchy fog will be possible...especially for
southern and eastern areas where the front will move through
last...as well as across areas that saw significant rainfall on
Thursday as well.
Min temperatures look to be in the upper 50s to middle 60s in many
areas...although temperatures will be slightly cooler over the
Adirondacks and southern greens.
Short term /6 am Friday morning through Saturday night/...
quiet weather is expected for Friday as high pressure over the
Ohio Valley and middle Atlantic region noses into the region. Skies
will be partly to mostly sunny and temperatures look warm in the 80s. It
will be noticeably less humid as well with dewpoints only in the
50s as well.
An upper level disturbance will start approaching the area for
Friday night. It should remain dry for most areas...although
cannot rule out a shower over the Adirondacks for late Friday night.
Min temperatures look to be in the middle 50s to middle 60s.
Shortwave trough will be situated over the northeast for Saturday
with a surface frontal boundary moving across the area as well. There
will be a chance for showers and thunderstorms during the day with
the passage of this boundary...especially for northern areas. Highs temperatures
look to be in the 80s...with some 70s over the higher elevations.
Instability may be somewhat limited to clouds around and timing
of the front may not be ideal for severe storms to occur...although
will continue to monitor model trends.
The shortwave should be moving away for Sat night...so clearing
looks to occur with any showers/thunderstorms ending during the
evening hours. Temperatures look to fall in the middle 50s to low 60s
across the region.
Long term /Sunday through Thursday/...
it still looks as if a long wave trough will be developing during
the extended period over the eastern Continental U.S.. this deepening trough
will compromise of a series of short waves...diving from central
Canada to the middle Atlantic region. The specific timing of these
short waves is difficult at this time.
Sunday...the first of these short waves and associated frontal
boundary will brush our region late into the day and early evening
(mainly staying north of forecast area). We kept slight to low
chances from the capital region northwestward...no probability of precipitation southeast of
the capital region.
A stronger disturbance and eventually cold front is forecast to
approach on Monday or Monday night. This could pack more of punch
with more in the way of scattered showers and thunderstorms across
most areas by Monday night.
It looks as if push of significantly cooler air will infiltrate
behind the cold front (or series of cold fronts) late Tuesday as
h850 temperatures look to get pushed from typical middle teens values
of early August...to about +6c! This cooling will produce increased
low level instability which could trigger some additional showers and
perhaps a thunderstorm on Tuesday into Tuesday evening.
Wednesday will be noticeably cooler and with the cold pool
aloft...there still could be additional instability showers...mainly
across the Adirondacks.
By Thursday the 12z European model (ecmwf) still indicated a wave along the front
across the middle Atlantic region...producing a band of rain across
mainly our southern areas. This idea is not supported by the 12z GFS
so for now...only included a 20 percent chance of showers (slight).
High temperatures will start out with seasonable readings from the
upper 70s to middle 80s across most of our area Sunday through Tuesday
with lows ranging from middle 50s to middle 60s. However...by Wednesday
and Thursday...high temperatures will only range from the upper 60s
across the Adirondacks...to 70s across most of the remainder of the
region. Lows will dip into the 50s...with some upper 40s in the
coolest spots well away from the Hudson Valley.
Aviation /20z Thursday through Tuesday/...
broad area of showers and a few embedded thunderstorms was making
its way southeast across kgfl and kalb at 1730z. Expecting activity
to clear out of these two airports around 18z...put popcorn showers
will linger with what leftover daytime heating interacts with slowly-
departing moisture at the low and middle levels...carrying just vcsh
At kpsf...and particularly at kpou...thunderstorms starting
shortly after 18z as cells within rain area gain a little
strength...should last until 20z. Cold front lags behind a couple of
hours...then things improve more...especially around
sunset...until MVFR/IFR fog develops at the airports during the
Winds will pick up briefly behind the front...with light winds then
allowing for the fog...which will burn off quickly after sunrise due
to lack of cloud cover and early mixing. Through the column...speed
shear is just enough at kgfl and kalb to include ws for the evening/
Friday night: no operational impact. No sig weather.
Saturday: moderate operational impact. Chance of rain showers...tsra.
Saturday night: low operational impact. Slight chance of rain showers...tsra.
Sunday: low operational impact. Slight chance of rain showers...tsra.
Sunday night: low operational impact. Slight chance of rain showers.
Monday: low operational impact. Slight chance of rain showers...tsra.
Monday night: moderate operational impact. Chance of rain showers...tsra.
Tuesday: moderate operational impact. Chance of rain showers...tsra.
no fire weather concerns over the next few days. Many areas saw a
wetting rainfall on Thursday. A few more lingering showers or
thunderstorms are possible over southern areas this
evening...otherwise dry weather looks to return for tonight
through tomorrow night. Some showers or thunderstorms are possible
over the weekend.
After relative humidity values return to near 100 percent tonight...they are
expected to drop to 35 to 45 percent on Friday afternoon with west
winds of 10 to 15 miles per hour. Relative humidity values look to return to around 100
percent on Friday night. Relative humidity values will drop to 40 to 50 percent on
Sat afternoon with S-SW winds at 5 to 10 miles per hour.
no main Stem river flooding is forecast through the next five days.
With a cold front moving across the region...some lingering
showers or thunderstorms are ongoing over the middle Hudson Valley
and western New England for the late afternoon through the early
evening hours. With a humid air mass in place...and the showers
and thunderstorms moving rather slowly...locally heavy downpours
may allow for some minor flooding of urban or poor drainage areas.
Isolated flash flooding is possible over the next few hours...but
is not expected to be widespread...as the boundary should be
crossing the entire area soon.
Mainly dry weather will return for tonight through Friday night.
Some additional scattered showers and thunderstorms are possible
for Saturday into early next week. Widespread heavy rain isn/T
expected...but any thunderstorm is capable of producing locally
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