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fxus61 kaly 161047 
afdaly

Area forecast discussion
National Weather Service Albany New York
647 am EDT sun Jun 16 2019

Synopsis...
a cold front with a low pressure system moving along it
will bring occasional showers and isolated thunderstorms especially
from the capital region south and east today with locally heavy
rainfall. The frontal boundary will drift south of the region
tonight with weak high pressure building for Monday with mainly fair
and dry weather. Another disturbance moving along the stalled
frontal boundary south of the region will bring renewed chances of
showers Monday night through Tuesday.

&&

Near term /until 6 PM this evening/...
as of 647 am EDT...the mid and upper level flow continues to be
nearly zonal aloft with a closed upper level low over south-
central Quebec. A cold front continues to slowly drift
south/southeast across western and central New York into northern Vermont.
A rain shield over west-central New York and and northern PA will
quickly spread east/northeast with a low pressure system over
northeastern Ohio and northwest PA according to the latest rap.
This wave of low pressure will move along the boundary bringing
periods of showers in the late morning into the early to mid
afternoon.

The atmosphere has moistened with sfc dewpts into the 50s to
lower 60s. The wave will move along the rather tight low to mid
level thermal gradient and tap into elevated precipitable waters in the
1.25-1.75" range. The low-level convergence and isentropic lift
will focus some moderate to locally heavy rain showers. The
pwats are 1-2+ stdevs above normal based on the latest gefs. The
NAM more than the fv3 indicates some elevated instability is
likely ahead of the wave riding the front with showalter
stability indices in the 0 to -2c range from roughly the capital
district south and east. The latest 00z hrefs indicate small
amounts of mean MUCAPE values generally 300 j/kg or less. A
slight chance of thunderstorms is possible from the capital
region/eastern Mohawk Valley south and east into southern Vermont and
Berkshires.

Some hourly rainfall rates of a half an inch and hour or
slightly greater will be possible. The 00z NAM and some of the
more recent 3-km hrrr runs are painting a narrow axis of 1-2+
inches of rainfall through the central portion of the forecast
area into the the Berkshires and southern greens. These are on
the higher range of the guidance, except the 00z hrefs mean
24-hr quantitative precipitation forecast is also indicating 1-2.5" in the same corridor. Due to
high gridded ffg values, and not super wet antecedent we think
flash flooding should not be a big issue. An isolated one can
never be completely ruled out in these environments. Wpcs day 1
excessive rainfall graphic has most of the aly forecast area in
a marginal risk. Please the Hydro discussion below with more
details on rainfall.

The pops were lowered over the northern zones considerably in
the afternoon with the front and better moisture convergence
sliding south and east with the wave moving through in the
afternoon. Highs will be below normal with the abundant cloud
cover and rain cooled air with highs only in the upper 60s to
lower 70s in the valleys, and 60s over and spotty upper 50s over
the higher terrain.

&&

Short term /6 PM this evening through Tuesday/...
tonight...the consensus from the latest cams and the NAM, ECMWF,
fv3, CMC and several ensembles is for the showers to taper off
fairly quickly from the capital region south and east. A few
could linger past midnight closer to the I-84 corridor.
Additional rainfall will be on the light side, as the better
dynamics and synoptic forcing with the wave depart downstream
early in the evening. Some partial clearing is possible north
of the Mohawk Valley, and capital region. Some patchy fog was
added especially near the CT River Valley east of Windham County
as well as north and east of Albany. Low-level cold advection
occurs with the frontal passage with h850 temps falling to +8c
to +10c from Albany north and west, and +10c to +12c south and
east. Lows will fall back into the 50s with some upper 40s over
the southern Adirondacks and a few lower 60s in the Mid Hudson
valley.

Monday...it still is a bit unclear if any Post frontal low
stratus clears out quickly from the capital region south and
east. Some subsidence in the wake of the front, and modest
mixing should allow for more sunshine north of Albany with
perhaps some intervals of sun with clouds for southern areas
with a 1016 hpa or so sfc anticyclone briefly ridging in from
southeast Ontario and northern New York. Max temps with some sunshine
will nudge up close to mid June normals with upper 70s to around
80f below 500 ft in elevation, and upper 60s to low/mid 70s
above it. A few showers or an isolated thunderstorm may pop-up
near the I-84 corridor late in the afternoon based on some of
the cams.

Monday night into Tuesday...the pesky front in the relatively
flat flow aloft drifts slightly further north across PA and New Jersey
with another mid-level short-wave and a decaying mesoscale convective system or sfc low
moving along it. Some scattered showers will increase over the
southern zones with some isolated thunderstorms near the Mid
Hudson valley and northwest CT. The northern zones may remain dry Mon
night. Lows will range from the upper 40s over the southern
Adirondacks to lower 60s over the Mid Hudson valley and northwest CT.
The guidance is variable on the northward extent of showers with
this wave. The best chance of widespread rainfall with some
isolated thunderstorms due to weak elevated instability appears
to be from the from the eastern Catskills, southern reaches of
the capital region and southern Vermont south and east. Some sunshine
could even occur over the northern tier of the forecast area on
Tuesday if there is sharp gradient with the rainfall with the
wave, and if it moves through fast by the early PM. Max temps
will be slightly cooler than Monday with upper 60s to upper 70s
over the region.

&&

Long term /Tuesday night through Saturday/...
a wet and unsettled weather pattern will continue into the first
days of Summer with shower chances almost every day.

Shower are possible on Wednesday as a weak shortwave interacts with
a stalled surface boundary, particularly in the afternoon. There may
be a break in shower activity Wednesday night into Thursday morning.
Temperatures on Wednesday will be near seasonable, in the low to mid
70s.

The main weather maker during this period will arrive during the
Thursday-Friday time frame in the form of a low pressure system
tracking across the Ohio Valley. Moisture will increase ahead of the
low with precipitable waters increasing to +1 to +2 S.D. Above normal. Rain looks
to overspread the forecast area Thursday afternoon and continue into
Friday morning, with the potential for some moderate to heavy
rainfall at times. Rain should end as the associated cold front
passes through the region but there is still some discrepancies with
the timing of the actual low so showers may continue through Friday
as well. Temperatures Thursday and Friday will be slightly below
normal, with highs in the mid 60s to mid 70s.

In the wake of this system, high pressure, along with cooler and
drier air, will slide into the region. This should allow for a dry
day on Saturday, potentially continuing into Sunday, with
temperatures in the 70s and partly sunny skies.

&&

Aviation /12z Sunday through Thursday/...
a few light rain showers possible early this morning before an
area of steadier rainfall moves into the forecast area. A period
of moderate to locally heavy rain is possible between roughly
14z-21z, with best chances at kalb and kpsf. Rain should then
taper to showers or drizzle this evening. Ceilings are expected
to lower to IFR through the morning as the rainfall increases.
Low ceilings will likely persist tonight even after the rainfall
ends with some patchy fog/low stratus possible.

Southwest to south winds should average 5-10 knots through most of the
day today before shifting to the north to northeast behind a cold
front late in the afternoon, with speeds of 5-10 knots.



Outlook...

Monday night: moderate operational impact. Chance of rain showers.
Tuesday: moderate operational impact. Chance of rain showers.
Tuesday night: low operational impact. Slight chance of rain showers.
Wednesday: moderate operational impact. Chance of rain showers...tsra.
Wednesday night: moderate operational impact. Chance of rain showers.
Thursday: high operational impact. Likely rain showers...tsra.

&&

Fire weather...
a cold front with a low pressure system moving along it
will bring periods of showers and isolated thunderstorms
especially from the capital region south and east today with
locally heavy rainfall. The frontal boundary will drift south of
the region tonight with weak high pressure building for Monday
with mainly fair and dry weather. Unsettled weather returns
Monday night through the mid week.

The minimum relative humidity values will be high today in the moist air mass
in the 50 to 80 percent range, and expect maximum relative humidity values
Monday morning close to 100 percent. The minimum relative humidity values will
be lower Monday afternoon in a drier air mass in the the 40 to
55 percent range.

The winds will be south to southwest at 5 to 10 mph today, then
shifting to north to northwest at less than 10 mph tonight into
Monday.

A widespread soaking rainfall is likely today.

&&

Hydrology...
no widespread hydrological issues are expected in the Albany
Hydro service area into the mid week.

Periods of rain showers with isolated thunderstorms are expected
associated with a slow moving cold front with a wave of low
pressure moving along it today into tonight. The best chance of
a few thunderstorms are from the capital region south and east
and some locally heavy rainfall is possible. Ponding of water on
roadways and poor drainage flooding of low lying areas is
possible with heavier bursts of rain. A narrow corridor of 1 to
2 inches of rainfall is possible, which may occur from the
capital region, northern Catskills, northern Taconics into
southern Vermont and the Berkshires. 3-hr nerfc gridded ffg values
remain high in the 1.9-3.0", so flash flooding is not
anticipated at this time. Outside this potential narrow ribbon
of heavy rain expect a few tenths to possibly an inch.

The front settles south Sunday night with a brief period of dry
weather returning for most of Monday. Another disturbance moving
along the front will bring showers back into the region Monday
night into the mid week. The heavier rainfall amounts may occur
over the southeast Catskills, Mid Hudson valley, and northwest CT with
much lighter amounts further north.

Another wave of low pressure may bring a widespread soaking
rainfall Thursday into Friday, but the amount of rain is still
uncertain. Within bank rises on the main Stem rivers is likely.

Please visit our advanced hydrologic prediction service /ahps/
web Page for specific area rivers and lakes observations and
forecasts.

&&

Aly watches/warnings/advisories...
CT...none.
New York...none.
Massachusetts...none.
Vermont...none.

&&

$$
Synopsis...wasula
near term...wasula
short term...wasula

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