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000
FXUS61 KALY 310839
AFDALY

AREA FORECAST DISCUSSION
National Weather Service Albany NY
439 AM EDT Sun May 31 2020

.SYNOPSIS...
Much cooler and drier air will infiltrate the region
today and tomorrow with temperatures averaging about 10 degrees
below normal. A few showers are possible tomorrow, mainly north of
Interstate 90. Then, temperatures slowly return to normal by the
middle of the week as chances for more widespread showers also
returns to the forecast.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
As of 3:30 AM EDT, latest GOES16 water vapor imagery shows our
upper level trough continuing to push into the Northeast. With
low and mid-level channels capturing the abundant dry air and
surface observations showing dew points falling into the 40s,
it`s no wonder that skies have remain mostly clear overnight.
The one exception remains the southern Adirondacks where the
nighttime fog channel shows stubborn low stratus lingering. The
combination of mainly clear skies and low dew points within the
cold air advection regime, has allowed temperatures overnight to
drop into the 50s with low to mid 40s in the hill towns and
higher terrain. However, temperatures have not cooled to their
respective dew points and we do not have any concerns of frost due
to breezy west to northwest winds. Still, it will be a chilly
Sunday morning with morning lows in the 40s and 50s.

As the parent trough moves overhead today, its associated cold
pool will influence our sensible weather. 850hPa isotherms will only
range -0.5C to +1.5C which is 2 to 3 standard deviations below
normal, as per the 00UTC GEFS. As high pressure centered over
the Upper Great Plains noses eastward, a tightening pressure
gradient over the Northeast will yield breezy northwest winds
today reaching 8 to 15 with gusts to 20-25mph (strongest down
the Mohawk Valley). Thus, high temperatures today will only
rise into the low to mid 60s with mid to upper 50s in the hill
towns and higher terrain. Our typical high temperature for May
31 is in the mid 70s so today will be roughly 10 degrees cooler
than normal and significantly cooler than recent days. Humidity
levels will also remain very low as PWATs stay below 0.50".
Luckily, we should remain mostly sunny as morning sun should
only mix with a few afternoon clouds as we reach our convective
temperature.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
Our parent trough will gradually exit into New England tonight
and with northwest flow ushering an even cooler Canadian air
mass, overnight lows should turn quite chilly by early June
standards. Expecting Monday morning lows to range from the mid-
30s to low-40s. However, with one last weak shortwave rotating
into the cyclonic flow towards the Northeast and bringing
increased mid-level moisture, clouds should increase overnight.
This should impede temperatures from becoming as low as they
could have and should mitigate frost formation. Thus, we agree
with the previous shift in removing any frost mention for the
southern Adirondacks and southern Greens.

Monday should feature partly sunny skies and below normal
temperatures once again, although not as cool as Sunday. Highs
should reach into the mid to upper 60s (mid to upper 50s in the
hill towns and higher terrain areas). In addition, a few
scattered showers are possible Monday afternoon as the
aforementioned shortwave rotates into the Northeast with
guidance showing a pocket of increased 700hPa RH with it. For
now, we only show slight chance POPs given QPF amounts from the
global guidance only shows a few hundredths materializing from
any showers. The GFS, NAM80 and CMC-NH all show once last area
of scattered showers moving into southern VT Monday evening
as the main trough becomes negatively tilted and finally exits
into the Atlantic. Since the ECMWF remains dry and the latest
blended guidance painted a dry forecast, we limited POPs to
slight chance into Monday evening for this area. Otherwise,
overnight lows should be slightly milder than previous nights
due to increased clouds, only falling into the mid to upper 40s.

Very broad upper level ridging centered over the country builds
eastward on Tuesday. With the Northeast remaining on its westward
side, we should be in the northwest flow regime. Guidance shows
a few weak shortwaves rounding the periphery of the ridge into
the Northeast (the "ring of fire") which should keep clouds in
place but should allow temperatures to moderate in the upper 60s
to low 70s. A warm front looks to push into the region Tuesday
afternoon with a decent temperature gradient analyzed at 700hPa
on the latest global guidance. We thus placed widespread chance
POPs for the entire region from 18 UTC Tuesday to 12 UTC
Wednesday to account for an increased chance of showers. Since
the best instability gradient looks to remain over the mid-
Atlantic, we did not mention the potential for thunderstorm.
However, we will closely monitor trends since this pattern could
favor elevated instability rounding rounding the periphery of
the ridge into our area.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
The extended forecast begins with a short-wave in the west to
northwest flow aloft impacting the region for the mid week, but then
an increasing trend for fair and tranquil weather for THU into FRI
before a cold front may bring some isolated showers to open the
weekend.  A warming trend is also expected late in the week into the
weekend.

Wed-Wed Night...In the northwesterly flow aloft, a short-wave will
be diving southeast from southeastern Canada across upstate NY and
New England with some showers and possibly a few thunderstorms, as
the warm and cold fronts move through the region.  The region will
likely get into a warm sector with sfc dewpts in the 50s to lower
60s. The latest 00Z GFS has MUCAPEs mainly less than 500 J/kg with
Showalter Stability Indices of 0C to -2C. Some elevated instability
is present.  The 00Z ECMWF has the best instability suppressed south
and west across PA and the Mid Atlantic Region. Enough synoptic
forcing with falling heights and some moisture convergence with the
sfc boundaries supports at least high chance PoPs with temps in the
mid 70s to lower 80s in the valleys, and mid 60s to lower/mid 70s
over the higher terrain.  The cold front moves through early Wed
night with the threat for showers diminishing.  Some weak cold
advection occurs in the wake of the front for lows in the 50s to
around 60F in the Capital Region south into the Mid Hudson Valley
and NW CT.

Thursday into Friday...High pressure builds in from the Great Lakes
Region on Thursday.  A lingering isolated shower is possible on THU
especially over the higher terrain,  but a mixture of sun and clouds
is expected with comfortable humidity levels with sfc dewpts in the
40s to mid 50s.  Max temps will be a little above normal with 70s to
lower 80s in the valleys, and mid 60s to mid 70s over the higher
terrain. Fair and cool weather is possible THU night into early FRI
with the sfc anticyclone building in over NY and PA.  Lows will be
in the upper 40s to mid 50s across the region.  The mid and upper
level flow begins to flatten and be more zonal late Friday.  Another
dry day is expected and H850 temps rise to about +13C to +15C based
on the 00Z GFS, as sfc temps may get about 5 to 8 degrees above
normal with lower 80s in the valleys, and upper 60s to upper 70s
over the hills and mtns.

Friday night into Saturday...The next short-wave trough moving
through the amplifying mid and upper level trough impacts the
forecast area Fri night into Saturday.  The cold front will approach
and move through some time early in the weekend.  Temps will open
the weekend a little above normal similar to FRI.  The drier half of
the weekend may end up Sunday, but timing these impulses in
northwest flow is tricky and the amount of low-level moisture
available is challenging.  For now, we have mainly slight chance
PoPs heading into Saturday.

&&

.AVIATION /09Z SUNDAY THROUGH THURSDAY/...
A cold front continues to move east of New England early this
morning.  Cyclonic flow continues aloft associated with an upper
level trough today into tonight.  High pressure will be building in
at the surface from the Great Lakes Region today.

Some post frontal stratus continue this morning for KALB-KPSF
northward with a brief period of MVFR stratus at KALB/KPSF 06Z-
09Z/SUN with cigs 2.5-3.0 kft AGL.  Dry air aloft will continue to
rapidly move into the region causing the skies to clear with few-
scattered stratocumulus/cumulus and VFR conditions the duration of
the TAF cycle.  The skies may become sct-bkn at 5.0-6 kft AGL during
the late morning into the afternoon with the diurnal instability
cumulus due to the cool air aloft. The skies will clear shortly
before daybreak, as the anticyclone ridges in.

The winds will be west to northwest at 8-12 kts this morning with a
few gusts around 20 kts at KPSF/KALB.  The winds will increase from
the northwest to north at 10-15 kts with some gusts close to 25 kts
at KALB/KPSF due to deeper mixing.  The winds will decrease around
or shortly before 00Z/MON to less than 10 kts.

Outlook...

Monday Night: Low Operational Impact. NO SIG WX.
Tuesday: Moderate Operational Impact. Chance of SHRA.
Tuesday Night: Moderate Operational Impact. Chance of SHRA.
Wednesday: Moderate Operational Impact. Chance of SHRA...TSRA.
Wednesday Night: Moderate Operational Impact. Chance of SHRA.
Thursday: Low Operational Impact. Slight Chance of SHRA.
Thursday Night: No Operational Impact. NO SIG WX.
Friday: No Operational Impact. NO SIG WX.

&&

.FIRE WEATHER...
Dry and much cooler conditions are expected today. RH values
this afternoon should drop to between 30 to 40 with breezy
northwest winds increasing to 8 to 15mph including gusts to
20-25mph (strongest down the Mohawk Valley) in the afternoon.
Clouds increase tomorrow with RH values dropping to 30 to 35
percent. Northwest winds stay a bit breezy between 5 and 15mph,
gusts to 20mph. Our next chance for more widespread showers
looks to arrive Tuesday into Wednesday.

&&

.HYDROLOGY...
The weather pattern remains devoid of any appreciable rainfall
today and tomorrow but chances for showers increases by the
middle of the work week. There remains uncertainty on the
coverage and intensity of the next potential rainfall event for
Tuesday into Wednesday but at this time, it does not look to be
particularly significant. Thus, river levels should remain
nearly steady through mid-week.

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.
NY...None.
MA...None.
VT...None.

&&

$$
SYNOPSIS...Speciale
NEAR TERM...Speciale
SHORT TERM...Speciale
LONG TERM...Wasula
AVIATION...Wasula
FIRE WEATHER...Speciale
HYDROLOGY...Speciale