Albany Office Forecast Discussion

949
FXUS61 KALY 220526
AFDALY

AREA FORECAST DISCUSSION
National Weather Service Albany NY
126 AM EDT Wed May 22 2019

.SYNOPSIS...
High pressure over the region with result a pleasant day with
dry conditions and normal temperatures with highs in the mid 60s
to lower 70s. The next chance of widespread showers and
thunderstorms arrives late Thursday into Thursday night, as a
strong disturbance approaches from the Great Lakes.

&&

.NEAR TERM /THROUGH TODAY/...
Updated at 1:20 am...Ridging will continue to build in at the
surface and aloft resulting in fair weather and light winds.
Temperatures overnight will bottom out in the mid 30s to upper
40s, which are slightly below normal.

Wednesday will be a pleasant day with sunny skies and seasonal
temperatures with afternoon highs from the mid 60s to lower 70s.

&&

.SHORT TERM /TONIGHT THROUGH FRIDAY/...
Clouds will increase Wednesday night associated with a weak
disturbance as the upper ridge starts to flatten out. Limited
forcing and moisture should only result scattered showers.
Better chances will be south/west of Albany, so have mentioned
chance pops in these areas.

The next period of active weather looks to arrive Thursday
afternoon or evening, as a strong upper level disturbance
approaches from the Great Lakes region. The energy from this
system is actually originating in the southern Plains, where
severe weather has occurred, and is now beginning its trek over
the upper ridge. So there is a strong convective footprint
associated with this system. Model guidance differs with timing,
as the GFS is on the fast side of the envelope and the NAM
slower. NAM even has most of the day Thursday being potentially
dry. Timing could matter for strength/coverage depending on when
convection moves into the area. Models are indicating at least
moderate CAPE developing across central NY Thursday afternoon,
with an instability gradient from Albany and points west
developing later in the day. Storms could weaken in our area,
but may be borderline strong/severe as they approach from
central NY. 0-6 km shear is impressive > 50 kt, so given
sufficient buoyancy mode of convection could be supercells. Will
mention potential for severe storms from the Hudson Valley
westward in the HWO, which is where the Storm Prediction Center
has issued a Slight Risk outlook.

Any showers and storms should exit the region by daybreak on
Friday as the upper level disturbance exits quickly to our east.
This will lead to another breezy and seasonable day on Friday
behind the passage of a cold front. Temperatures Thursday should
reach the mid 60s to lower 70s but clouds may linger, especially
across the high terrain. By Friday evening, high pressure will
once again be building in from the west.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
A typical early summer-like pattern is shaping up for our Memorial
Day holiday weekend with seasonably warm high temperatures in the
70s most days with overnight lows staying mild in the 50s. Eastern
NY and western New England looks to remain in fast zonal flow along
the northern periphery of an impressive large scale 500mb ridge
centered over the Gulf States. Multiple shortwaves and surface
boundaries look to pass through, resulting in a few chances for
showers and some. thunderstorms. However, there will be plenty of
dry time for those interested in spending time outdoors during the
holiday weekend. Read on for details.

We begin the long term period Friday evening with a shortwave ridge
over the Northeast leading to surface high pressure and mainly dry
conditions. A weak low pressure system from the Upper Great Lakes
travels into Ontario and its associated warm front gradually pushes
into the Northeast overnight. With increased warm air advection and
some moisture noted at 700mb, we slowly cloud coverage and increased
POPs to slight chance/low end chance (mainly north/west of the
Capital Region) late Friday night into Saturday morning to account
for a few isolated showers. Our aforementioned surface high shifts
off the coast of southern New England during the day Saturday with
our region in the warm sector. Expect high temperatures a few
degrees warmer than Friday in the mid 70s (60s terrain) with
increased humidity in the west-southwest flow. While the main parent
low looks to pass well to our north near Hudson Bay, 500mb height
falls move from NW to SE into our region after 18z Saturday into the
evening as a pre-frontal trough gradually shifts into eastern NY and
western New England. Its main cold front looks to still be well to
our west over the Great Lakes. Depending on how much sunshine we see
during the day Saturday in the warm sector, there could be enough
instability to lead to some thunderstorms so we included slight
chance for thunderstorms both Saturday afternoon and evening. While
we included chance POPs Saturday afternoon, we held off likely POPs
until after 00z Sunday to show that confidence for precipitation is
higher after sunset when the best forcing arrives. Otherwise, expect
a mild Saturday night with cloud coverage remaining in place.

We won`t see much of a temperature change once the pre-frontal
trough exits by Sunday morning as winds remains westerly in the warm
sector with the main cold front still well to our west near the
NY/Canadian border. Therefore, daytime temperatures Sunday should be
quite warm as we remain in westerly flow with highs reaching in the
mid-upper 70s, potentially near 80 in the mid-Hudson Valley and
southern areas of Litchfield County, NY. We`ll see winds shift to
the NW as the main front pushes through the region and while the
main broad upper level trough will also be pushing through, lots of
dry air at 700mb should prevent much in the way of showers. Thus, we
only have slight chance POPs on Sunday.

Weak high pressure builds in for Sunday night into the Memorial Day
holiday with a more pronounced 500mb shortwave trough digging
southeastward from Canada towards the Northeast. Model guidance has
trended stronger with this trough over the past few models runs with
now the ECMWF, GFS and CMC-NH all generally showing the same
intensity. The first half of the day should be mainly dry as high
pressure remains in place but 500mb height falls arrive after 18z
Monday, mainly on the ECMWF and GFS. The CMC-NH is slower with the
trough`s arrival. It`s also worth noting that the GFS and ECMWF both
show this initially positively trough becoming negatively tilted
into Monday night, suggesting strong forcing. However, the sytem`s
origins come from northern Canada which means it will be moisture
starved and 700mb RH shows a lack of moisture. Thus, we only have
chance POPs in the latest update mainly for Monday afternoon into
the evening.

Large scale Canadian high pressure quickly builds in behind our
departing cold front Monday night into Tuesday. The tight pressure
gradient between the two systems could lead to breezy northwest
winds in the wake of the frontal passage. Strong NW flow continuing
into Tuesday should lead to cooler high temperatures in the 60s to
near 70 with lower dew points/humidity. Mainly dry conditions are
expected as well.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
High pressure will remain in control, resulting in VFR
conditions persisting through the 24 hour TAF period ending 06Z
Thursday. Just some SCT high level cirrus clouds will move in
today, with mid level clouds increasing ahead of an approaching
warm front this evening.

Winds will be north-northwest around 5 kt, increasing to 5-10
later this morning.

Outlook...

Wednesday: No Operational Impact. NO SIG WX.
Wednesday Night: Low Operational Impact. Slight Chance of SHRA.
Thursday: Moderate Operational Impact. Chance of SHRA...TSRA.
Thursday Night: Moderate Operational Impact. Likely SHRA...TSRA.
Friday: Low Operational Impact. NO SIG WX.
Friday Night: Low Operational Impact. NO SIG WX.
Saturday: Moderate Operational Impact. Chance of SHRA...TSRA.
Saturday Night: Moderate Operational Impact. Chance of SHRA...TSRA.
Sunday: Low Operational Impact. Slight Chance of SHRA.

&&

.FIRE WEATHER...
Northwest winds will gust between 30 and 40 mph for the
remainder of the afternoon and early evening...

Cool and windy conditions expected for the remainder of the
afternoon and early evening, but then should start to weaken as
high pressure builds into the region. The high will will be in
place tonight through Wednesday, providing dry conditions and
near normal temperatures. The next chance of widespread showers
and thunderstorms arrives late Thursday into Thursday night, as
a strong disturbance approaches from the Great Lakes.

Relative humidity values will increase to maximum values of
around 65 to 85 percent tonight, and to around 70 to 90 percent
Wednesday night. Minimum RH values will be around 30 to 40
percent Wednesday afternoon, with 55 to 75 percent Thursday
afternoon.

Winds today will be northwest around 15 to 25 mph, with gusts
of 30 to 40 mph, decreasing to around 5 to 15 mph late tonight.
Winds on Wednesday will be north-northwest between 5 and 10 mph.

&&

.HYDROLOGY...
Dry weather will prevail through Wednesday as high pressure
gradually builds into the region. Widely scattered light
showers are possible late Wednesday night mainly south and west
of Albany, as a weak disturbance moves through.

The next chance of more widespread showers and thunderstorms is
expected late Thursday into Thursday night, as a stronger
disturbance approaches from the Great Lakes. While brief
downpours are possible within any thunderstorms, the rainfall is
not expected to be hydrologically significant.

Additional showers and some thunderstorms will be possible
again over the upcoming weekend.

Please visit our Advanced Hydrologic Prediction Service /AHPS/ web
page for specific area rivers and lakes observations and
forecasts.

&&

.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
MA...None.
VT...None.

&&

$$
SYNOPSIS...IAA/JPV/JLV
NEAR TERM...IAA/MSE/Frugis/JLV
SHORT TERM...JPV/JLV
LONG TERM...Speciale
AVIATION...JPV
FIRE WEATHER...JPV/JLV
HYDROLOGY...JPV/JLV

NWS ALY Office Area Forecast Discussion