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fxus61 kaly 140156 
afdaly

Area forecast discussion
National Weather Service Albany New York
956 PM EDT sun Oct 13 2019

Synopsis...
the stretch of tranquil weather will continue through Tuesday.
A widespread rainfall appears likely on Wednesday with chilly
and blustery conditions by Thursday.

&&

Near term /until 6 am Monday morning/...
as of 1015 PM EDT, temps have already dropped into the upper
30s/lower 40s across portions of the southern Adirondacks and
Lake George region, where patchy high clouds are gradually
thinning. However, low clouds were noted on infrared satellite
imagery across eastern PA and northern NJ, with some expansion
noted to the north and east. Near-term models suggest these clouds may
continue expanding northeast through midnight across the Mid
Hudson valley, southern Taconics and northwest CT, so have increased
cloud coverage in these areas from earlier forecast. There could
be a few breaks in these areas after midnight, before
additional low clouds potentially redevelop and/or expand
northward closer to daybreak as an upper level disturbance
tracks south and east of the region. The northwest edge of these
lower clouds should also extend into portions of the
central/southern Berkshires around daybreak as well.

Otherwise, mainly clear skies are expected farther north and
west. Winds are expected to be light to nearly calm, so
temperatures should be able to fall to the lower/mid 30s to
lower 40s. However, milder min temps are expected across the Mid
Hudson valley/northwest CT region where more clouds are expected, where
mins may only drop into the mid/upper 40s.

&&

Short term /6 am Monday morning through Wednesday/...
upper low will retreat into eastern Canada and a weakening cold
front with very little moisture will track through our region.
Boundary layer southwest flow along with a partly to mostly
sunny sky should help temperatures warm into the mid 60s to
around 70 but 50s to lower 60s northern areas. Any isolated
showers would be in northern areas Monday afternoon.

Cooling and clearing expected Monday night but with some steady
boundary layer winds from the west to northwest and boundary
layer temperatures cooling considerably, some lake effect
clouds could extend into the southern Adirondacks and parts of
the western and central Mohawk Valley. Guidance is not showing
much cloud cover as winds will not be strong and will be more
west than northwest but any clouds off the lakes could prevent
temperatures from falling as much as they could into early
Tuesday morning.

The core of coldest air is over our region Tuesday with very
light winds expected. Based on mixing potential and the
potential for some scattered to broken clouds in some areas,
highs in the mid 50s to around 60 but lower 50s higher terrain.

Wednesday morning should be tranquil and dry as warm advection
strengthens. Upper energy diving out of Canada will approach
through Wednesday afternoon and rapid warm advection along with
deep moisture advection ahead of the upper energy should result
in clouds and precipitation arriving in western areas perhaps
by midday and the rest of our region through the afternoon. Most
areas will see the start of a period of soaking rain by late
afternoon, that will continue into Wednesday night. Highs
Wednesday in the upper 50s to lower 60s.

&&

Long term /Wednesday night through Sunday/...
our intensifying parent trough over the Great Lakes within the
northern jet stream looks to phase with a southern stream
shortwave and become negatively tilted Wednesday night. Strong
consensus between the NCEP model suite and the European model (ecmwf) and CMC-New Hampshire
continues with guidance suggesting this interaction results in
rapid cyclogenesis of a coastal low off the Carolinas. Strong
isentropic lift ahead of the advancing coastal low continues
into Wednesday evening with the south-southeast 850mb jet
strengthening to 40-50kts. This should allow widespread rainfall
to continue and expand into western New England. Guidance
generally shows the coastal low tracking northward overnight
and moving into eastern New England which would spare most of
eastern New York/western New England from the brunt of this "bomb"
cyclone.

The cold front from the parent trough looks to quickly advance
eastward through New York Wednesday night which should push
widespread/steady rain out of area with just some lingering
showers in its wake. However, guidance continues to hint that
the advancing cold front could enter into New England in time to
meet up with the coastal low which could tighten the baroclinic
zone over western New England and enhance rainfall amounts
there. The latest wpc quantitative precipitation forecast guidance also hints at this
enhancement as well. Still too early to give specifics but it's
something Worth monitoring. Otherwise, most of the rainfall
should transition to showers late Wednesday night into Thursday
morning with total quantitative precipitation forecast amounts ranging 0.75 to 1.50" with
locally higher amounts on the eastern Catskills which tend to
see terrain enhanced amounts in this flow regime. This should be
a very progressive system with most of the rain falling between
18z Wednesday and 12z Thursday.

As our coastal low continues to "bomb" out by Thursday morning
(intensifying from ~1005mb 12z Wed to ~975mb by 12z thurs), the
upper level parent trough becomes a closed 500mb low over the
Gulf of Maine with the coastal low becoming the dominant surface
feature. Eastern New York and western New England on Thursday should
experience a colder and windy day with wrap around showers. High
temperatures should be 5-10 degrees cooler than normal, only
rising a few degrees above the morning low temperatures into the
low to mid 50s, thanks to a tightening pressure gradient
between the departing coastal low and strengthening high
pressure from the Tennessee Valley. Deep boundary layer mixing in the
cold air advection regime should lead to windy conditions with
westerly sustained winds ranging 10-18mph and gusts up to
25-35mph (highest in the terrain). While some lake enhanced
showers are possible, the wrap around cold air at 850mb, as per
the gefs, does not deviate from normal, so the Delta-T between
Lake Ontario and the 850mb isotherms only barely meets the ~13c
criteria.

Breezy conditions look to continue into Thursday night as sufficient
pressure rises continue over our region behind the closed low
in the Canadian Maritimes. While the strong west-northwest flow
should maintain the cold air advection regime, overnight lows
should be around normal, falling into the mid 30s to low 40s,
due to breezy winds. A strengthening upper ridging should build
into the northeast on Friday with surface high pressure taking
control of the region which should weaken winds. Even still, the
cool air mass should remain in place with high temperatures
once again about 5 degrees below normal in the 50s. The upper
level ridge axis moves overhead Friday night leading to clearing
skies and a good radiational cooling set-up. Expecting Saturday
morning lows should be quite chilly with all areas falling into
the 30s with upper 20s for parts of the Adirondacks, greens
sand Catskills.

Temperatures quickly moderate back towards and even a bit above
normal for the weekend as southwest return flow returns and high
pressure maintains control. The next chance for showers looks to
hold off until early next week.

&&

Aviation /02z Monday through Friday/...
a weak ridge of high pressure will shift east of the region
overnight, while a cold front passes east across the taf sites
Monday afternoon. Moisture will be limited, so only a few clouds
and a wind shift are expected to accompany the frontal passage.

Patchy ground fog is expected to develop at kgfl after 02z/Mon,
and may intermittently drop vsbys to IFR levels through
daybreak. Elsewhere, mainly VFR conditions are expected through
around 10z/Mon. However, some lower clouds may drift northward
and produce MVFR cigs at kpou and kpsf between 10z-16z/Mon. VFR
conditions should otherwise prevail into Monday evening.

Winds will be light/variable overnight, then become south to
southwest at 5-10 knots Monday morning through early afternoon.
Winds will shift into the west in the wake of the cold front
later Monday afternoon, and increase to 8-12 kt, with some gusts
up to 20 knots possible.

Outlook...

Monday night: no operational impact. No sig weather.
Tuesday: no operational impact. No sig weather.
Tuesday night: no operational impact. No sig weather.
Wednesday: high operational impact. Definite rain.
Wednesday night: high operational impact. Definite rain showers.
Thursday: moderate operational impact. Breezy chance of rain showers.
Thursday night: low operational impact. Breezy slight chance of rain showers.
Friday: no operational impact. No sig weather.

&&

Fire weather...
the stretch of tranquil weather will continue through Tuesday.
A widespread rainfall appears likely on Wednesday with chilly
and blustery conditions by Thursday.

Relative humidity values will be 50 to 70 percent Monday afternoon and 45 to 60
percent Tuesday afternoon with 80 to 100 percent at night.

Winds will be light tonight, then south at 15 mph or less Monday
morning shifting to west. West winds at less than15 mph Monday
night become light south to southeast late Tuesday afternoon.

&&

Hydrology...
the forecast area is expected to remain mainly dry through Tuesday
night with any precipitation being spotty and hydrologically
insignificant. A widespread soaking rainfall appears likely by
Wednesday into Wednesday night.

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.
New York...none.
Massachusetts...none.
Vermont...none.

&&

$$
Synopsis...NAS
near term...kl/NAS
short term...NAS

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