Scientific Forecaster Discussion
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Area forecast discussion
National Weather Service Albany New York
1047 am EDT sun Apr 21 2019
mild weather will continue through Tuesday. Mainly dry weather
is expected today aside from a few stray showers. There will be
a chance of showers Monday afternoon into Monday night
especially east of the Hudson. Tuesday will be dry and mild, but
showers and a few thunderstorms will be likely overnight.
Near term /through tonight/...
as of 1025 am, the upper low was situated over western PA this
morning and is expected to shift to the mid Atlantic coast this
evening as short wave energy rotates about it. While at the
surface a very weak low remain over the region. The plume of
deep moisture will remain just to our east with showers across
central CT and Massachusetts clipping southern Vermont this morning. A weak
boundary was located across the area noted by north flow at
Johnstown/Syracuse and southerly flow at Albany/Ithaca. It may
act as the focus for scattered light showers this afternoon
mainly to the west of the Hudson River valley. Still expecting
highs mainly in the 60s with 50s above 2000 feet.
Tonight, the upper low will slide southeast offshore of the
mid-Atlantic. Surface winds over the local forecast area will
turn west-northwesterly along with weak cold air advection as
lower surface pressures set up to our east. This may usher in
areas of stratus overnight, especially over the higher terrain.
Still, it will be mostly dry aside from a stray light shower or
two. Low temps will continue to be well milder than normal as
the airmass upstream isn't all that cold.
Short term /Monday through Tuesday night/...
Monday into Monday night, the upper low will push northeastward
from the mid Atlantic coast to near Cape Cod to the Gulf of
Maine. Bands of rain will develop within the deformation region
of the attendant surface low. There are still model differences
with how close to the coast the low tracks, and how far inland
the rain bands penetrate. It appears that dry midlevel air will
be entrained into the circulation, so the westward extent of the
rain bands will be limited. Will continue with likely pops
mainly confined to western New England with chance pops tapering
to slight chance with westward extent. Despite northerly flow,
there is just a lot of mild air associated with this system, so
advection will be neutral and another mild day is expected.
Rainfall chances look highest from about 18z Monday to 00z
Tuesday, but lingering showers will continue to be possible
especially over western New England. Another mild night is
expected Monday night.
Tuesday, the closed upper low will finally push off to the east
as shortwave ridging builds in. However, a pair of shortwave
troughs will quickly arrive from the western Great Lakes later
Tuesday into Tuesday night. The latter trough is forecast to
become compact and quite vigorous. The attendant surface low
will strengthen as it heads from Lake Huron into southwestern
Quebec, pushing a cold front through the forecast area Tuesday
night. Ahead of the front, much of Tuesday looks to be pleasant.
Forecast highs from the mav MOS may be a bit overdone looking at
GFS forecast soundings deepening the boundary layer to near 750
mb. Feel this is a bit too deep given that strong low-level
southwesterly flow doesn't develop until later in the evening
per the GFS. So we backed off a bit from the mav MOS, but sided
toward it rather than the met/NAM. The NAM is a notably slower
solution with respect to both the departing and arriving lows,
such that a cool easterly component to the flow exists most of
the day which, along with increasing mid clouds, keeps temps in
the 50s and low 60s during the day. This solution was discounted
at this time.
Models are in good enough agreement with this system to go with
likely pops for most of the forecast area Tuesday night. Most
of the precipitation expected with the approaching wave and
front is expected at night, although some of it could reach
areas west of the Hudson Valley by Tuesday evening. Midlevel
lapse rates are projected to become fairly steep, so combined
with the dynamic nature of this system, at least some embedded
thunder appears a good bet.
Long term /Wednesday through Saturday/...
the long term portion of the forecast looks active, with frequent
shortwaves traversing the U.S./Canada border. Temperatures overall
look to average below seasonal levels.
A compact upper level low should track east across northern New
England/southeast Canada Wednesday. Although the system's cold front and
best forcing will have shifted east of the region, the passing core
of the shortwave and cold pool aloft should allow for some clouds,
and perhaps isolated/scattered showers across higher terrain
northern areas. Elsewhere, breezy and cool with a mix of sun and
clouds. Highs ranging from the upper 40s/lower 50s across higher
elevations of the Adirondacks/southern VT, to the mid 50s to
lower/mid 60s elsewhere, warmest across the Mid Hudson valley.
Cool conditions for Wednesday night, with lows mainly in the 30s and
40s. Thursday should feature a sunny start, before clouds increase
later in the day. Highs reaching lower/mid 60s in valleys, with 50s
across higher elevations.
The next upstream shortwave should pass across the region Friday,
again with some showers. In its wake, another shot of unseasonably
cool air should overspread the region. It should become quite
breezy, with Friday highs reaching the lower/mid 50s across higher
elevations, to the lower/mid 60s in valleys. Colder for Friday night
with lows in the 30s and 40s for most areas. Breezy and cool for
Saturday with mainly diurnally-driven cloud formation. Highs
reaching the 50s and 60s.
Aviation /15z Sunday through Thursday/...
low pressure across southeast Canada will gradually weaken as it
tracks east through tonight.
Mainly VFR conditions are expected for today, however some MVFR
have developed at kpou and should linger into the early afternoon
and some patchy MVFR cigs possible at kpsf this morning.
14z/sun. Cigs should become mainly MVFR for tonight, with
possible areas of IFR cigs at kpsf and kpou after 08z/Mon.
As for rain chances, isolated/scattered showers may pass across kpsf
through 14z/sun. Additional isolated/scattered showers should
develop this afternoon, but should remain mainly west of the taf
sites (remaining across the eastern Catskills, Mohawk Valley and SW
Winds will be south to southeast at 5-10 knots through today, then
should become light/variable tonight.
Monday: moderate operational impact. Chance of rain showers.
Monday night: moderate operational impact. Slight chance of rain showers.
Tuesday: low operational impact. Slight chance of rain showers.
Tuesday night: moderate operational impact. Likely rain showers...tsra.
Wednesday: low operational impact. Breezy isolated rain showers.
Wednesday night: no operational impact. No sig weather.
Thursday: no operational impact. No sig weather.
another seasonably mild day is expected today with some isolated
showers possible in the afternoon. A few peeks of sunshine and
moderate southerly winds may allow for some drying outside of
the showers. Relative humidity values will fall into the 50 to 60 percent
range this afternoon.
Mild weather will continue Monday and Tuesday. Monday will
feature bands of showers pivoting into the area from low
pressure off the New England coast. These showers are most
likely across western New England, but could drift over areas
further west as well. Moderate northerly winds are expected, and
relative humidity values will fall to 50 to 60 percent. Tuesday will be dry
and mild with showers likely at night.
flood warnings continue on the west Canada creek, Sacandaga
river, Schroon river, and upper Hudson River. Most rivers in the
area have crested or will crest later today. Just a few light
showers are expected today. A system Monday into Monday night
will bring some showers especially to areas east of the Hudson,
and another system Tuesday night will bring showers and a few
thunderstorms. Basin average rainfall from these two systems is
expected to mainly remain around a half inch or less, although
there is an outside chance that some areas in western New
England could approach an inch. Regardless, renewed flooding
concerns are not expected at this time.
Please visit our advanced hydrologic prediction service /ahps/
web Page for specific area rivers and lakes observations and