Area Forecast Discussion
Issued by NWS Albany, NY

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS61 KALY 221434
AFDALY

Area Forecast Discussion
National Weather Service Albany NY
1034 AM EDT Sun Oct 22 2017

.SYNOPSIS...
Surface high pressure will translate off the east coast today.
Its influence will continue to spread above normal temperatures
for the remainder of this weekend. An approaching cold front and
increasing moisture will bring about a period of unsettled
weather for the upcoming work and school week.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 1030 AM EDT, Other than some passing cirrus clouds, today
will feature above normal warmth and plenty of sunshine.
Temperatures are currently in the mid to upper 50s. That being
said, the forecast remains on track for today. Freshened up the
hourly temps to reflect most recent obs and sent updates to NDFD
and web servers.

Prev Disc...
As of 630 AM EDT...Occasional periods of CI/CS will filter the
sunshine around the periphery of departing ridge axis today. Its
surface reflection over the northeast corridor will track off
the coastline later this afternoon. This sets the stage for a
southerly component to the wind field to increase a bit this
afternoon. Sustained magnitudes will increase and with daytime
heating, mixing layer heights suggest a few gusts could approach
20kts for eastern NY counties. High temperatures today should
once again climb into the 70s for valley locations and 60s
elsewhere.

Those aforementioned southerly winds will eventually tap into
Atlantic moisture per moisture transport vectors and some lower
stratus may quickly advect northward from the Capital Region and
points southward. So some increase in cloud coverage as
temperatures overnight should range within several degrees of
50F.

&&

.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
Monday...The NCEP model suite along with international guidance show
an increase of mainly low level clouds with a tightening low-
level pressure gradient between the offshore anticyclone and low
pressure moving into the central and eastern Great lakes by
late in the day. Low-level moisture will increase further, and
some lower stratus and possibly some light showers/drizzle will
move into locations from the Capital District south during the
day (terrain will likely be the first to experience). A weak
short-wave impulse embedded in the deep southerly flow will
focus the light showers, mainly in the afternoon). Highs will
be still mild in the 60s to lower 70s.

Monday night...Some timing differences with respect to the
upstream cold front approaching as the ECMWF is now the fastest
with shower potential quickly increasing. The NAM/GFS/GGEM are
in better agreement with a bit slower arrival time. We will
follow along this lead which is in excellent agreement with the
previous forecast. Low level jet magnitudes increase toward
50KTS as will moisture transport and higher PoPs. Could be quite
a bit of drizzle developing overnight as ample mixing within the
boundary layer seen in the BUFKIT profiles along with high
mixing ratios. As dewpoints climb well into the 50s and even
some lower 60s, it will be a rather warm and somewhat muggy
night.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
Active weather expected to start the extended period...

A sharply digging upper level trough will be strengthening over the
Ohio Valley on Tuesday, allowing a strong southerly flow across our
area at all levels of the troposphere, as upper level ridging shifts
downstream of the region. At the surface, strong low pressure will
be moving from the Great Lakes towards Ontario and Quebec, with an
occluded/cold front heading towards our area for later on Tuesday.

A strong low-level jet will be in place ahead of this system, with
850 hpa winds of 50 to 60 kts. Based off the latest 00z GEFS, The
meridional wind (v-wind) anomaly looks to exceed 3 STD for Tuesday,
along with a PWAT anomaly of around 2-3 STD above normal as well.
Ahead of the approaching front, we are expecting showers to become
more widespread in coverage through the day, along with gusty
southerly winds. Will continue to mention in the HWO about winds
possibly reaching advisory criteria.  The best chance for this to
occur looks to be just along/ahead of the approaching frontal
boundary, as models suggest the strong sfc forcing should allow for
a narrow cold frontal rainband to develop, with a line of heavy
showers.  Could be some thunder as well, as surface CAPE values
could be up to 300 J/kg according to the latest 00z GFS.  Even
without thunder, some strong winds aloft may mix down within the
heaviest rain showers.  The models still show some subtle
differences in timing but the frontal passage looks to occur
somewhere between Tuesday afternoon and Tuesday evening.  It still
looks pretty mild ahead of the front, with highs well into the 60s
or low 70s and dewpoints in the 60s, which is very high for late
October.

As the frontal boundary heads towards western New England, it may
start to slow down and possibly even stall, as a wave of low
pressure starts to develop along the boundary across the mid-
Atlantic and rides up the front, as the upper level trough becomes
negatively tilted. This could prolong rain for eastern areas for all
of Tuesday night and even into Wednesday.  As a result, rainfall
amounts look to be higher than previously forecasted due to longer
duration of rain, as we have leaned closer to WPC and the
operational 00z GFS/ECMWF. We have generally forecasted 1 to 2
inches of rain across eastern New  York with 2 to 3 inches for
western New England. Although these amounts are close to the
operational models, they are still higher than most members of the
00z GEFS, so some refinement is still possible, as it will
ultimately depend exactly on where the front stalls. Even with these
higher amounts, widespread river flooding isn`t expected due to
recent dry weather and lower flows, but minor flooding of urban,
poor drainage and low lying areas is certainly possible, especially
during the periods of heaviest rainfall and in areas where leaves
and other debris block drainage.

Due to the uncertainty with the exact timing and placement of the
front, have gone with generally just CHC pops for Wednesday into
Thursday, with the highest chances across eastern areas, due to the
nearby boundary and passing surface wave. Even western areas will
still see some showers, as the cyclonic flow could still allow for
some passing showers, along with plenty of clouds.  The core of the
upper level trough should be over the area on Thursday, so temps
will finally be noticeably cooler and closer to seasonal normals on
Thursday, with most areas only reaching into the 50s.

Dry weather should finally return for Friday into Saturday, as
surface high pressure returns to the area, as upper level heights
start to build once again. Temps should be back above normal once
again, especially by Saturday, as valley highs reach into the mid
60s.  Another system, similar to one coming Tuesday, looks to impact
the region at some point Sunday into early next week, with much
colder air behind that front for the end of the month.

&&

.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
An upper level ridge is currently in place over the eastern
seaboard. With surface high pressure located nearby the region,
winds are calm and there is just some passing thin high cirrus
clouds. Some radiational fog has occurred overnight at KGFL, but
with sunrise underway, this should be completely dissipated by
12z-13z.

During the day today, VFR conditions are expected for all sites
with light southerly winds. Just few-sct passing cirrus clouds
are expected throughout the day.

Winds will decrease for this evening with the loss of daytime
heating and winds should become very light or calm once again
for tonight. Although it looks mainly VFR for much of the
overnight hours with some additional passing high cirrus,
cannot rule out some mist/fog for late tonight at KGFL thanks to
the good radiational cooling once again. Also, thanks to the
persistent southerly flow, some low stratus may advect northward
from the coastal areas and impact KPOU/KPSF towards 09z-10z
with MVFR conditions.

Outlook...

Monday Night: Moderate Operational Impact. Breezy Chance of
SHRA...DZ.
Tuesday: High Operational Impact. Breezy Definite SHRA...TSRA.
Tuesday Night: High Operational Impact. Definite SHRA...TSRA.
Wednesday: Moderate Operational Impact. Chance of SHRA.
Wednesday Night: Moderate Operational Impact. Chance of SHRA.
Thursday: Moderate Operational Impact. Chance of SHRA.
Thursday Night: Low Operational Impact. Slight Chance of SHRA.
Friday: No Operational Impact. NO SIG WX.

&&

.FIRE WEATHER...
High pressure will drift eastward this afternoon as it
continues to influence our fair and dry weather with above
normal temperatures across the region. Clouds begin to increase
late tonight into Monday. A slow moving cold front impacts the
area late Monday night through Tuesday night with periods of
showers and windy conditions.

The RH values will lower to 25 to 40 percent this afternoon. An
excellent recovery is expected by Monday morning with max RH
values in the 90 to 100 percent range.

Winds will be light to calm this morning, and then will be
south to southwest at 5 to 10 mph today with a few higher gusts
this afternoon. Expect southerly winds of 10 mph or less Sunday
night.

The next widespread soaking rainfall will be Monday night into
Tuesday night.

&&

.HYDROLOGY...
No precipitation is expected prior to Monday with high pressure
in control, as river flows will remain at normal to below
normal levels.

The next chance of widespread rainfall arrives Monday night
into Tuesday night associated with a cold  front. Rainfall
amounts may range from three quarters of an inch to an inch and
three quarters from this system. Some locally heavy rainfall is
possible. The heaviest totals may be along or east of the
Hudson River Valley across western New England. Some ponding of
water on roadways is possible as well as clogged drains from
fallen leaves.

Another round of wet weather is possible later in the week, but
there remains quite a bit of uncertainty with evolution and
track of the system and the QPF with it. For now, light amounts
of additional rainfall are expected. Overall, a trend to drier
weather is 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.
NY...None.
MA...None.
VT...None.

&&

$$
SYNOPSIS...BGM
NEAR TERM...BGM/JVM
SHORT TERM...BGM/Wasula
LONG TERM...Frugis
AVIATION...Frugis
FIRE WEATHER...BGM/Wasula
HYDROLOGY...BGM/Wasula



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.