Area Forecast Discussion
Issued by NWS Albany, NY

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615
FXUS61 KALY 290556
AFDALY

Area Forecast Discussion
National Weather Service Albany NY
156 AM EDT Thu Jun 29 2017

.SYNOPSIS...
As an upper level trough departs, dry and comfortable weather is
expected tonight. Clouds will increase on Thursday morning, as a
warm front approaches from the west. This frontal boundary will
be allowing for some showers and thunderstorms, some with heavy
rainfall, for northern parts of the area for late tomorrow into
tomorrow night. A warm and humid air mass will be in place for
Friday into the weekend, with some additional showers and
thunderstorms each day, especially in the afternoon and evening
hours.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
As of 1250 AM EDT...High and mid level clouds continue to
increase ahead of a warm front approaching from the upper Great
Lakes region. Temperatures did drop off quickly tonight though,
due to a dry air mass in place. So lowered min temps by a few
degrees based on observations at many locations already below
forecast lows. Temperatures should steady out early this morning
as clouds thicken across the region. Any showers look to hold
off until around or shortly after sunrise for areas north and
west of the Capital District.

High pressure was off to our south and east across the middle
Atlantic region. The center of the area of high pressure will
drift off the eastern seaboard overnight as a warm front moves
into the eastern Great Lakes region late tonight. Dry and
comfortable weather is expected through later tonight. Lows
tonight will generally be in the 50s.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY/...
Active and Unsettled Weather Expected Through the Weekend...

Clouds will rapidly be increasing on Thursday morning,
especially across northern areas, as a surface warm front starts
to head towards the area from the Great Lakes and Ohio Valley. A
strong W-SW low-level jet will be advecting plenty of moisture
and warmer temps aloft towards the area. With strong isentropic
lift in place, an area of rain showers will be spreading
eastward towards northern parts of the area from the upper
Great Lakes and Ontario. Some showers will start spreading into
the Adirondacks by the mid to late morning hours and they will be
increasing in coverage/intensity for the afternoon and evening
hours, as the warm front lifts closer to the area and a subtle
wave slides through the flat flow at 500 hpa.

PWAT values will be increasing throughout the day, with the NAM
suggesting values as high as 1.75 inches across the northern
parts of the CWA by the early evening hours. With rising
freezing levels, warm rain processes will becoming more and more
dominant, and the threat for locally heavy rainfall across the
western Mohawk Valley, Adirondacks and Lake George-Glens Falls
area will be increasing. Further south (such as for the Capital
Region on southward), rainfall looks to be less of an issue, as
the better lift will be focused across far northern areas. The
main time period for the heaviest rainfall looks to be the mid
afternoon through late evening hours.

There won`t be much instability initially across the area, but
as the warm front starts to work its way across the area, some
elevated instability will be in place. A strong stable layer
around 900 hpa looks to be in place according to model soundings
for Thursday evening into Thursday night, which should help
prevent much of the stronger winds aloft from mixing down.
Still, cannot rule out a rogue strong storm on Thursday evening
into Thursday night, but the main threat looks to be the heavy
rainfall for far northern areas.

By late Thursday night, the threat for locally heavy rainfall
may be diminishing as the best forcing shifts away from the
area. All areas could see some showers or t-storms, as our area
fully enters into the warm sector. Overnight lows only look to
fall into the 60s.

On Friday, it will be noticeably warmer and more humid than the
past few days, with highs getting into the 80s in many valley
areas and dewpoints into the 60s. With plenty of instability in
place, some showers and thunderstorms look to develop during the
afternoon and evening hours. Coverage looks somewhat limited due
to the fact that there won`t be any strong surface boundaries
nearby, but the combination of weak disturbances sliding through
500 hpa flow and lake-breeze boundaries initiating convection
over western and central New York could allow for some t-storms
to develop. The warm and moist environment should allow for
plenty of instability and 0-6 km bulk shear values look to
reach around 30 kts, so some isolated strong to severe storms
are certainly possible. Activity should start to lower for Fri
night, so will lower POPs somewhat, but it will remain rather
warm and sticky into Friday night.

The better chance for more widespread showers and t-storms look
to be on Saturday. Although the surface cold front to our west
still won`t be crossing the area just yet, it appears that a
pre-frontal surface trough will initiate some convection for
Saturday afternoon and evening. With temps well into the 80s and
dewpoints near 70, plenty of surface-based instability look to
be in place. 0-6 km bulk shear should be around 30-35 kts or so,
so the threat for more strong to possibly severe storms looks
to be around once again. Otherwise, it will remain partly to
mostly cloudy with warm and humid conditions.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
The long term period is expected to start out unsettled as a cold
front crosses the region and stalls just to the south as a wave of
low pressure moves eastward along the frontal boundary.

Showers along with scattered thunderstorms are expected Saturday
night into Sunday as a low pressure system and a cold front move
across the region. Lows Saturday night are expected to be in the 60s
with highs on Sunday in the mid 70s to mid 80s.

Sunday night through Wednesday...There is still a great deal of
uncertainty during this time frame as it will depend on how far
south and east the frontal boundary progresses before a wave of low
pressure moves east along it. If we can get some separation between
our forecast area and the frontal boundary that would allow high
pressure to build across our region. If not then there will be move
showers and perhaps a few thunderstorms. For now will forecast dry
weather for Sunday Night through Monday night and the gradually
increase pops Tuesday into Wednesday. Highs on Monday and Tuesday
will generally be in the 70s to mid 80s with highs on Wednesday in
the upper 60s to lower 80s. Lows Sunday night through Tuesday night
will generally be in the mid 50s to mid 60s.

Overall expect temperatures and precipitation to average above
normal during the long term period.

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
High pressure continues to move off the Mid Atlantic Coast this
morning, as a warm front continues to approach from the lower
Great Lakes Region and the Ohio Valley. The warm front will
focus some showers and isolated to scattered thunderstorms late
this afternoon into this evening.

VFR conditions are expected until about 20Z for
KGFL/KALB/KPSF/KPOU with increasing mid and high clouds through
the morning hours and into the early afternoon. Some showers
may move into KGFL by 20Z with MVFR vsbys and cigs in the 3.5-6
kft AGL range.  Some showers and possibly isolated to scattered
thunderstorms may reached KALB/KPSF btwn 23Z/THU-00Z/FRI.
PROB30 groups were used from 00Z-04Z for these two sites, as
well as KGFL. KPOU will likely continue VFR into Thursday
evening with mid-level cigs around 12 kft AGL.

The winds will be light from the south to southeast at 4 kts or
less this morning. They will increase from the south at 7-13 KTS
with some gusts in 18-22 KT range at KALB/KPSF in the late
morning and through the afternoon.

Outlook...

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

&&

.FIRE WEATHER...
After a relatively dry and breezy on Wednesday, RH values
should recover to near 100 percent tonight. RH values will only
fall to 40 to 70 percent on Thursday afternoon, with the lowest
values across southern areas. Some rain showers are possible for
northern areas on Thursday, with the best chance in the late
afternoon and evening hours. All locations have the chance to
see a shower or t-storm for Thursday night. Winds will become
southerly at 5 to 15 mph on Thursday into Thursday night.

More showers and thunderstorms are possible Friday with RH
values only fall to 50 to 75 percent and south to southwest
winds at 5 to 10 mph.

&&

.HYDROLOGY...
Dry weather is expected tonight, but a warm front will be
making its way across the area for tomorrow into tomorrow night.
As this front moves through the area, showers and thunderstorms
may produce locally heavy rainfall for the western Mohawk
Valley, Adirondacks and Lake George and Glens Falls area for
tomorrow afternoon through late tomorrow evening. This rainfall
may cause minor flooding of urban, low lying and poor drainage
areas.

Some additional showers and thunderstorms are possible Friday
and Saturday as well, especially during the afternoon and
evening hours. With a warm and humid air mass in place, any
thunderstorm will be capable of producing locally heavy rainfall
once again. Some showers or t-storms may be possible on Sunday
as well, although the cold front will be coming through. It`s
still clear if it will be clearing out enough by Monday or
Tuesday.

By the end of the weekend, the heaviest rainfall looks
to be across northern areas, where basin average amounts look to
at least one to two inches of rainfall. However, thunderstorms
may allow for locally higher totals in some spots.

&&

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

&&

$$
SYNOPSIS...Frugis
NEAR TERM...Frugis/11/JPV
SHORT TERM...Frugis
LONG TERM...11
AVIATION...Wasula
FIRE WEATHER...Frugis
HYDROLOGY...Frugis



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