Area Forecast Discussion
Issued by NWS Albany, NY

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FXUS61 KALY 190045
AFDALY

AREA FORECAST DISCUSSION
National Weather Service Albany NY
845 PM EDT Sun Aug 18 2019

.SYNOPSIS...
Thunderstorms will move east and dissipate later this evening. Some
storms will contain very heavy downpours and strong, gusty winds.
The heat and humidity will become oppressive on Monday with a
continued threat of a shower or thunderstorm.  Cooler and drier
weather will arrive Thursday after a cold front moves through
eastern New York and western New England.

&&

.NEAR TERM /THROUGH MONDAY/...
Updated at 845 pm. Rough evening in terms of severe weather.
localized walls of wind, (WOWs) and lightning were impressive.
Also had some 1 to 1.25 inch hail reports. Storms still ongoing
mainly east of the Hudson River, with a couple of isolated cells
also over the southern Adirondacks. Storms will likely affect
all of our forecast area to the east before exiting into New
England.

Thunderstorms and showers have cooled the air this evening to
near the dewpoint. Any clearing that occurs overnight will lead
to patchy dense fog and low cloud development. Lows tonight
forecast to be in the 60s to around 70. It may be noon before
the clouds and fog burn off on Monday.

&&

.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY/...
On Monday, another round of storms will be possible. A mid-
level short wave will approach once again from the west, however
the 500 mb heights will actually be rising a bit during the day
so the mid- level short- wave energy will not be as strong as
the past few days. However with the dew points up into the lower
and even mid 70s during the day MLCAPE values will likely be
well over 2000 J/kg once again and the mid- level flow will be
moderately strong from the west with deep layer shear 30 to 35
kts. This could set the stage for another severe thunderstorm
risk during the afternoon Monday. With temperatures in the
valleys near 90 and dew points in the lower to mid 70s we have
issued a heat advisory for the Hudson Valley up to the Capital
District during the afternoon for heat advisories up to 95 to
100 degrees.

The main mid-level trough axis will remain west of our area on
Tuesday, setting the stage for the chance for yet another short
wave approaching the area from the west. The atmosphere will
not be quite as moist on Tuesday as today and Monday, but a few
storms will remain possible. Overall, Tuesday appears to be the
least active of the next few days, as another short wave and
associated cold front will approach the area on Wednesday. The
models appear to be in pretty good agreement on a significant
cold frontal passage on Wednesday which could certainly set the
stage for another round of significant thunderstorms with
severe potential. This front appears to be strong enough to
actually change the air mass hopefully setting the stage for a
more settled late week period.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
An upper level low pressure system and a surface cold front
will continue to move across the N Northeast on Thursday. This
will usher in cooler and a less humid airmass into the
Northeast.

Thursday...There will be the threat of some showers early in the day
with wrap around moisture from the uper level low pressure system.
Temperatures on Thursday will be in the 70s from the Greater Capital
Region northward and around 80 across the mid hudson valley.

By Thursday night into Friday...drying will take place as the upper
level low pressure system moves out of the region and is replaced by
an area of high pressure.  As the high pressure builds into the
region, our flow will shift to the north/northwest bringing cooler
temperatures to the region.  Thursday nights lows will generally be
in the 50s across the region.  On Friday...high temperatures will be
in the upper 60s across the Adirondacks to the low to mid 70s across
much of the region.

Saturday into Sunday will remain quiet with high pressure.
Temperatures will still remain cool early Saturday and start to inch
closer to normal by Sunday.  Saturdays highs will be in the mid to
upper 70s.  By Sunday....high temperatures will be in the upper 70s
to lower 80s.

&&

.AVIATION /01Z MONDAY THROUGH FRIDAY/...
Showers and thunderstorms are possible at the TAf sites for the
next 1-2 hours before moving east.

Temperatures have already cooled to near the dewpoint from the
rain. Expect fog and low level clouds overnight. Expect IFR
ceilings and vsibilities after 08Z with the potential for BR/FG.

Strong gusty winds still possible at KPSF from thunderstorms
this evening. Elsewhere, winds will be south to southwest at
5-10 kt before midnight. Winds will become calm to light and
variable overnight. On Monday winds will be westerly at 10 to 20
kt.

Outlook...

Monday Night: Low Operational Impact. Slight Chance of SHRA...TSRA.
Tuesday: Moderate Operational Impact. Chance of SHRA...TSRA.
Tuesday Night: Moderate Operational Impact. Chance of SHRA...TSRA.
Wednesday: Moderate Operational Impact. Chance of SHRA...TSRA.
Wednesday Night: Moderate Operational Impact. Chance of SHRA...TSRA.
Thursday: Moderate Operational Impact. Chance of SHRA.

&&

.FIRE WEATHER...
A warm and humid air mass will continue to impact the region
into tonight with another upper level disturbance bringing late
afternoon and evening showers and thunderstorms. The heat and
humidity will become oppressive on Monday with still the threat
of a shower or thunderstorm. A weak cold front will move through
Tuesday with the best chance of showers or isolated
thunderstorms from the Mohawk Valley southward.

The RH values will lower to 50 to 65 percent this afternoon and
Monday afternoon. The maximum RH values will be close to 100
percent with fog and dew formation Monday morning.

The winds will be south to southwest around 5 to 10 mph today
into tonight. The winds will be southerly at 5 to 10 mph on
Monday.

&&

.HYDROLOGY...
Widespread hydrological problems are not expected on the main
stem rivers the next several days.

With thunderstorms in the forecast this evening into Monday
night and also on Wednesday, there is the threat of isolated
flash flooding across the region. The threat for locally heavy
downpours is possible, as humidity levels and dew points remain
high, and with thunderstorms possibly repeatedly moving over the
same area.

Any thunderstorm will be capable of producing flooding of
urban, low lying or poor drainage areas. Some temporary elevated
flows may be briefly possible from thunderstorms on brooks,
streams, creeks and other small bodies of water.

Drier and cooler weather may return by Thursday when a cold
front sweeps through the region.

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...Heat Advisory from 11 AM to 8 PM EDT Monday for NYZ049-050-052-
     053-059-060-064-065.
MA...None.
VT...None.

&&

$$
SYNOPSIS...SND
NEAR TERM...SND
SHORT TERM...MSE/Wasula
LONG TERM...VTK
AVIATION...SND
FIRE WEATHER...Wasula
HYDROLOGY...VTK/Wasula


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