Albany Office Forecast Discussion

229
FXUS61 KALY 161418
AFDALY

AREA FORECAST DISCUSSION
National Weather Service Albany NY
1018 AM EDT Thu Jul 16 2020

.SYNOPSIS...
High pressure will shift east off the coast today as a low pressure
system approaches. The low pressure system will move across the
region tonight and Friday bringing showers and some thunderstorms to
the area. It will become hot and humid as we head through the
weekend into early week with dangerous heat conditions expected to
develop.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
As of 1000 AM EDT...Stratus deck lingers across the majority of
the region per the hires GOES 16 visible channel 2 imagery this
morning. 12Z sounding reflects the steep cap in place at and
just above H750 which may be the culprit for these clouds
lingering longer. Some breaks in the overcast should occur with
strong July sunshine as we watch upstream convective development
and initiation. At the moment, atmos is stable per the wave
patterns seen in the GOES. However, 12Z reflectivity forecasts
just arrived as western into central NY will likely see
additional destabilization for convective initiation to commence
with some showers approaching our Dacks CWA at or after 21Z. So
main update was to cloud coverage this morning with some
improvements from the Capital Region and points southward
through the Hudson River Valley and portions of Litchfield
County. Forecast highs look good per our 12Z sounding.

Prev Disc..
The surface high centered over New Brunswick and extending down
the eastern seaboard will shift off the coast as a low pressure
system approaches from the Great Lakes Region today. The upper
ridge axis over the region will also shift off to our east
today.

There is widespread stratus across most of the local area. It
will lift and break up as the morning progresses. However high
and mid levels will stream in ahead of the approaching low
pressure system this afternoon. By later in the afternoon, there
will be chances for some showers in the western Adirondacks.

Looking at seasonably warm temperatures today with highs in the
lower 80s in the Hudson and Mohawk Valleys with 70s across the rest
of the local area. Winds will be southerly.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
The low pressure system will move across the region tonight and
Friday. The system`s warm front and cold front are expected to
move across the region on Friday. Chances for showers will
increase tonight as isentropic lift increases ahead of the
system`s warm front and as the strengthening low level jet
moves into the region. An 850 mb 35 to 50 knot jet will move
across the region overnight into early Friday morning. The
best chances for showers will be along and north of I-90. Surface
instability won`t develop until the passage of the warm front
Friday. However, elevated instability is expected as guidance
indicates negative Showalter values so have slight chances for
thunderstorm mentioned for much of tonight. Precipitable water
values are expected to rise to 1 1/2 to near 2 inches in the
evening so heavy downpours can be expected.

The local area will be in the warm sector for much of Friday
with the passage of the cold front expected late in the day into
the early evening. Have chance pops of convection based on the
expected coverage. In the evening, any lingering convection
should be confined to areas to the south and east of the Capital
District. Due to the extensive cloud cover only expecting highs
in the mid 70s to lower 80s however it will become very humid
with dew points rising into the mid 60s to around 70 degrees.

Ridging builds in at the surface and aloft as we head into the
weekend. 850 mb temperatures are forecast to be in the mid to
upper teens Saturday with a westerly flow. Expecting highs into
the lower 90s up the immediate Hudson River Valley with 80s
elsewhere. Any readings in the 70s are expected to limted to
above 2500 feet. Heat indices into the mid 90s are possible for
some locations in mid Hudson Valley Saturday afternoon.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
Sunday is shaping up to be the hottest day of the long term period
and also driest. 850 hPa temperatures are projected to rise to 19-
21C. This will equate to high temperatures rising into the mid- to
upper 80s in the higher terrain and low to mid-90s in the valleys.
With the addition of high humidity levels (dew points 65-70F), heat
index values are expected to range from 85-95 in the higher terrain
to 95-102 in the valleys.

From Sunday night to Monday, an area of low pressure will move
across Quebec as a "cold" front attempts to work its way across at
least a portion of the region. Any lingering showers and
thunderstorms may pass across the region Sunday night with the best
chances north and west of the Capital District. With the front
potentially stalling across the area on Monday, additional showers
and thunderstorms may develop during the afternoon and evening.

There remain model differences with regards to precipitation chances
on Tuesday and Wednesday, mainly due to the strength of the ridge
and if there is any upper-level support. Wednesday may be the better
chance of the two for additional showers and thunderstorms due to an
approaching upper-level shortwave from the Great Lakes. Regardless,
will go with a blended approach and chance pops both days as the
very warm and humid conditions will continue.

High temperatures starting on Monday will be mostly in the 80s (with
some lower 90s in the valley locations from the Capital District to
the mid-Hudson Valley) and then trend a degree or two lower each day
for Tuesday and Wednesday. Lows will generally be in the 60s (except
some lower 70s in the valleys Sunday night).

&&

.AVIATION /14Z THURSDAY THROUGH MONDAY/...
Through 12z/Fri...Cloud deck is lifting across the terminals and now
all sites with the exception of KPSF are now VFR. The deck will
gradually lift to VFR at KPSF this morning. Once it lifts, VFR
conditions will continue across the terminals through this evening.

Later tonight, an approaching system will bring scattered showers
(greatest concentration at KGFL) and cigs back into the MVFR range.

Wind will be out of the south to southeast at 5-10 kt early this
morning, then increase to 8-16 kt with gusts 20-25 kt later this
morning through the afternoon. Wind will remain out of the south to
southeast at 8-15 kt tonight with possible higher gusts (especially
at KALB).

Outlook...

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

&&

.FIRE WEATHER...
High pressure will shift east off the coast today as a low pressure
system approaches. Minimum relative humidity values are expected to
be in mainly in the 50s this afternoon. The low pressure system will
move across the region tonight and Friday bringing showers and some
thunderstorms to the area. It will become hot and humid as we head
through the weekend into early next week.

&&

.HYDROLOGY...
A low pressure system will move across the region tonight and Friday
bringing showers and some thunderstorms to the area. Storms will be
capable of heavy downpours as precipitable water values rise 1 1/2
to near 2 inches. This could result in some flooding of urban areas,
low-lying and poor drainage areas. Widespread flooding is not
expected as system will be progressive. Turning hot and humid over
the weekend with mainly fair weather expected.

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...IAA
NEAR TERM...IAA/BGM
SHORT TERM...IAA/Speciale
LONG TERM...Rathbun
AVIATION...Rathbun
FIRE WEATHER...IAA
HYDROLOGY...IAA

NWS ALY Office Area Forecast Discussion