Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Albany New York
1037 PM EDT Thursday Jul 30 2015
a cold front has crossed all of our region. 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 1037 PM EDT...no echoes at this time...nor or we expecting any. The
front has cleared the entire region. However...dewpoints were still elevated
around 70 in our extreme southern areas...as this area never really mixed
the drier air aloft. We still think the dewpoint should come down a little
in these areas...but much slower than the rest of the areas where
dewpoints have dipped well down into the 60s...and even upper 50s.
For this update only very minor tweaks of the hourly grids...removed
any mention of showers. Left overnight lows alone.
Overnight low 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 /02z Friday through Tuesday/...
a tough call tonight as to how much and how dense fog will form.
Dewpoints were still around 70 at kpou while the other sites were well down
into the 60s. There was not much of a breeze left at any taf sites.
The crossover temperatures from aly's 00z sounding looked to be
in the lower 50s...a little lower than before. Still with a moist ground
the clear sky and little wind...fog could still form
For now...we kept IFR fog in the kgfl but not until after 08z. At kalb...
we decided enough of a breeze and slightly higher temperatures should keep any fog shallow
so (mifg). The tougher challenge was at kpsf since they did not pick up much rain. We continued
with IFR fog at 06z there and at kpou...still went with MVFR fog at 08z where the
surface dewpoint remained elevated.
Confidence in these scenarios is lower than average so ammendments are quite
possible overnight. Please check back if you plan to fly out
of any of the airports overnight or early this morning.
Due to a breeze picking up...we end all fog by 11z Friday...which should leave US
with VFR day with unrestricted visibility as well as few if any sensible clouds.
The wind will be light and variable generally under 5kts overnight.
The wind will then go back to west or west
southwest 5-10kts on Friday morning...with gusts to near 20kts
by afternoon (especially at kalb)...before going back to light
and variable by 00z Friday.
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