-- Discussion containing changed information from previous version are highlighted. --
554
FXUS61 KALY 062003
AFDALY

AREA FORECAST DISCUSSION
National Weather Service Albany NY
403 PM EDT Thu Jun 6 2024

.SYNOPSIS...
Humid today as showers and thunderstorms track from west
to east through early evening. Any thunderstorm can produce heavy
downpours. Initial morning sun tomorrow fades behind increasing
clouds as our closed low moves overhead resulting in additional
areas of showers and perhaps a few thunderstorms. Even cooler,
breezy, and mostly cloudy conditions return for Saturday with some
enhanced lake effect and scattered diurnal driven rain showers.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
As of 1:40pm EDT, a warm and very humid day continues today
with temperatures reaching around 80 in the Hudson Valley and
mid to upper 70s elsewhere thanks to some limited breaks of sun
and thinning of cloud coverage (cooler upper 60s in the high
terrain). Convection out ahead of the abrupt wind shift boundary
in Central NY is spilling eastward into the Mohawk Valley and
northern Catskills early this afternoon. Also, our warm front
near the I-84 corridor is lifting northward as seen via sfc
observations with winds shifting to the south in the mid-Hudson
Valley. The true warm sector is located well to our south and
with only limited sun so far, ML CAPE and SB CAPE remain low
ranging just 500 - 1000 J/kg despite the moisture rich
environment. Given this and the strong low and mid-level jet
being located within the warm sector over the mid-Atlantic, SPC
maintains a "marginal risk" for severe weather today and
upgraded the mid-Atlantic to a slight risk. Still expecting an
area of rain and thunderstorms to increase in coverage and
spread across eastern NY and into western New England this
afternoon through early evening (2 - 10pm) with the P.M commute
likely featuring periods of rain and rumbles for much of the Hudson
Valley. Will maintain a watchful eye on storm intensification
as the wind shift boundary pushes eastward but with it moving
into an environment with weak instability and deep layer shear
values only topping out around 30kts, we do not expect
widespread severe weather.

The very moist environment today will also support heavy
downpours from any storms. Storms should not train over a given
area and should be progressive so not expecting widespread
flooding. However, poor drainage flooding is certainly possible
for quick heavy downpours producing a 0.50 - 1 inch of rain in a
short period of time from the efficient warm rain processes.

Most of the rain should be east of the region by 10-11pm. Winds
sharply shift to the west in the wake of the wind shift boundary
and should briefly become breezy with gusts up to 20kts
possible. Clouds quickly clear in the wake of the boundary
late this afternoon into the evening from west to east with dew
points dropping as dry air quickly ushers into the region.
Humidity levels drop with dew points and temperatures remaining in
the 50s to around 60. Patchy fog may develop given the clearing
clouds and afternoon rainfall but with drier air moving into
the region, only expecting patchy coverage.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
For Friday, our closed low finally pushes eastward towards
Eastern NY with the leading edge of the cold pool pushing into
the area by 15 UTC or so. Morning sun will fade behind
increasing clouds as the mid-level moisture spills overhead.
Scattered showers develop along the leading edge of the
intruding cold pool and mid-level moisture and sfc cold front
by 15 - 18 UTC for areas mainly north and west of the Capital
District. Forecast soundings show we will have a very shallow
boundary layer under the cold pool with equilibrium levels only
around 15kft or so. This will shrink our CAPE potential and lead
to very shallow low-level convection. Thus, we do expect any
severe weather but a few lightning strikes are likely as up to
around 500 J/kg of CAPE develop. Some small hail is also not
ruled out as wet-bulb zero heights drop under 10kft. Winds shift
to the northwest behind the leading edge of the cold in the
afternoon leading to slightly breezy conditions as wind becomes
sustained 10-15kts and gusts up to 20-25kts.

Scattered showers and possible storms spread south and east of
Albany by 21 UTC and expand into western New England as the cold
front shifts southeastward. Given the delayed onset of
showers/storms, temperatures here will have a better chance of
reaching into the low 80s. With dew points only in the 50s, it
will feel much less humid as well. Areas north/west of the
Capital District should be cooler only reaching into the low to
mid 70s with 60s in the southern Adirondacks.

Skies turn partly to mostly clear tomorrow night with areas
south of I-90 becoming mainly clear. With overnight lows
cooling into the low to mid 50s and dew points also dropping
into the 50s, it will feel much more comfortable Friday night.
The southern Adirondacks and southern Greens drop even cooler
into the 40s. With a westerly wind fetch continuing off the
lakes and cool air advection ongoing, some lake enhanced
showers likely generate off Lake Ontario into the western
Adirondacks. Maintained likely POPs in northern Herkimer County
and high end chance in northern Hamilton given this potential.
Some scattered lake enhanced showers may spill into the Upper
Hudson Valley and southern VT.

Our very broad upper level low remains straddled across
southern Canada into the Great Lakes for Saturday. As the
initial shortwave trough rotating around the low exits into the
Canadian Maritimes, subsidence in its wake builds over much of
the Northeast. While this reduces forcing for ascent aloft, the
cold pool remains overhead and will support diurnally driven
showers, especially north of I-90 closer to the cold pool.
Westerly flow remains strong throughout the column which will
support a continued fetch off the lakes and generate lake
enhanced showers off Lake Ontario that extend into the Upper
Hudson Valley at times. The cold pool will also support mostly
cloudy skies and cooler temperatures that struggle to rise out
of the low to mid 70s for much of the area. A tight pressure
gradient in the wake of Friday`s cold front will also keep
west to northwesterly winds rather breezy on Saturday. Sustained
winds range 10 to 15kts and gusts up to 25-30kts, strongest
winds will likely be down the Mohawk Valley, Capital District
into western New England thanks to channeled flow. The breezy
winds will make it feel even cooler on Saturday. The cold pool
aloft will keep chance POPs in play (especially north of I -90)
thanks to isolated to scattered diurnally driven showers
developing. Areas south of the interstate should have drier
conditions with the mid-Hudson Valley and NW CT mainly dry.
Thunderstorms appear unlikely.

The first half of Saturday night starts dry as we lose daytime
heating with temperatures cooling into the 50s once again.
Clouds quickly increase after Midnight as a potent shortwave
trough rotating around our parent closed low and attendant sfc
cold front tracks south and eastward through eastern NY towards
western New England. Another area of rain likely develops in
Western and Central NY and overspreads into areas west of the
Hudson River before sunrise. Given ongoing uncertainty on exact
timing and coverage, we have widespread chance POPS throughout
the region from 06 - 12 UTC Sunday but may trim it back to focus
on western areas in future updates.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
-- Changed Discussion --
Long term period begins at 12z Sunday with the broad upper low
located in southeastern Canada. An upper shortwave will rotate
around the periphery of the upper low Sunday, bringing increased
chances for showers and perhaps a few rumbles of thunder, especially
in the afternoon. An associated weak cold frontal boundary will also
help to increase coverage of showers during the afternoon. Coverage
of showers should diminish overnight with the loss of daytime
heating. Highs will be mainly in the 60s (high terrain) to 70s
(valleys) with overnight lows in the 40s (terrain) to 50s (valleys).

Monday, the upper low pulls away further to the east, although a
piece of the upper low will break off and linger over our region as
an upper trough. This will result in continued chances for a few
afternoon showers and perhaps a rumble of thunder, although coverage
of showers and storms will be less than on Sunday. Temperatures will
be similar to those on Sunday for both daytime highs and overnight
lows.

Tuesday through Thursday...Upper ridging builds overhead Tuesday as
the upper low finally departs from our region. This should result in
a much drier day Tuesday, although a rogue afternoon showers till
can`t completely be ruled out especially if the upper low is a
little slower to depart than currently expected. Forecast confidence
decreases for the Wednesday into Thursday timeframe, as most sources
of guidance keeps us dry through Wednesday, although upper troughing
will be approaching from the west and could bring increased chances
for showers Wednesday night or Thursday. We will continue to refine
the forecast in the coming days as we get a better handle on the
timing and evolution of this approaching trough. Temperatures
Tuesday will be a couple degrees warmer than on Monday. Wednesday,
temperatures may climb to around 80 for valley areas, with mid 80s
possible Thursday. Overnight lows also trend warmer, from 40s to 50s
Tuesday night to 50s to around 60s for Wednesday and Thursday nights.
-- End Changed Discussion --

&&

.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
Through 12z Friday...MVFR conditions prevail at all terminals
with the exception of KPSF whose ceiling has dropped to IFR
heights. Showers have not been as extensive thus far this
morning as what was previously expected, so outside of a stray
sprinkle or two, expect primarily dry conditions into this
afternoon. There is some uncertainty with ceiling heights today
as model soundings show some pockets of dry air cutting into the
lower levels later this morning. However, generally ceiling
heights should remain within MVFR thresholds with brief
improvements to VFR possible throughout this morning.

This afternoon, MVFR heights should steadily return as scattered
thunderstorms develop. PROB30 groups were added to the TAF
groups for expected convection between 21z-01z. Thunderstorms
could drop ceilings to IFR heights with MVFR visibilities.
However, IFR visibilities are also possible should a heavier
downpour cross into the terminals. Once convection ceases
shortly after sunset due to lack of daytime heating to drive
instability, conditions will gradually improve possibly back up
to VFR conditions.

Winds throughout the 12z TAF period will be light and variable
to start, then increasing to sustained speeds of 5-10 kt out of
the southeast by this afternoon. By the end of the 12z cycle,
winds will decrease to speeds of 2-5 kt at variable directions.

Outlook...

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

&&

.HYDROLOGY...
Showers and thunderstorms through early evening will result in
rainfall amounts ranging from 0.50 to 1.50 inch with localized
amounts up to 2 inches. Given the moisture rich environment, some
thunderstorms will produce heavy downpours and high rainfall
rates leading to localized ponding of water on roadways, urban
and small stream flooding and standing water in low lying areas.

No flooding of main stem rivers is expected. Additional showers
and thunderstorms will occur tomorrow but less widespread
coverage and lighter rates expected. Additional amounts of
perhaps up to a half inch of rain through the weekend.

&&

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

&&

$$

SYNOPSIS...Speciale
NEAR TERM...Speciale
SHORT TERM...Speciale
LONG TERM...Main
AVIATION...Main
HYDROLOGY...NAS/Speciale