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000
FXUS61 KALY 250149
AFDALY

AREA FORECAST DISCUSSION
National Weather Service Albany NY
949 PM EDT Wed Apr 24 2019

.SYNOPSIS...
Weak high pressure will bring fair and seasonably mild
conditions Thursday before another storm system brings widespread
rainfall and cooler temperatures to the region for Friday into
Saturday morning. Breezy and chilly conditions will then be in place
for the remainder of the weekend.

&&

.NEAR TERM /THROUGH THURSDAY/...
Clouds quite persistent from the Mohawk Valley and Berkshires
and points north. There are some breaks in the Hudson Valley due
to some downslope but clouds very slow to erode. Area 00Z
soundings show the cloud layer and the inversion trapping the
cloud layer. Made some adjustments to sky cover and minor
adjustments to temperatures based on current data and trends.
Previous AFD has more details and is below...

Strong low pressure system continues to slowly track into the
Canadian Maritimes as we remain under the influence of moist
cyclonic flow. This has kept much of the region under cloudy
skies today with a large variation in temperatures from the 30s
across the Dacks to the low and mid 60s across the mid-Hudson
Valley.

A weak ridge of high pressure will work its way into the region
this evening into the overnight period, resulting in mostly
sunny skies and seasonably mild temps for Thursday. Afternoon
highs should warm into the mid and upper 60s, with upper 50s to
low 60s across the high terrain. Temps overnight tonight will
dip into the 30s area wide, something we haven`t seen for about
a week.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
Clouds will be on the increase again Thursday night as the next
storm system approaches the region from the southwest. Return
flow will be in place, helping to advect in ample moisture with
PWATs forecast to exceed 1 inch. Latest GEFS indicate PWATS +1
to +3 S.D. for Friday into Friday night.

Rain will overspread much of the region by daybreak on Friday
as a surface low strengthens and tracks along the New
York/Canadian border. Looks like there will be an initial surge
of moderate to heavy rainfall Friday morning associated with the
low track, then a secondary push with a cold front progged to
track through the region Friday evening. Still expect rainfall
throughout the day Friday but may be a few breaks at times.
Total QPF through the event looks to average around an inch
with up to 1.25 inches perhaps in the Dacks into southern
Vermont. Latest MMEFS shows mainly rises to action stage outside
of a few points that are already running high. Will continue to
mention this potential flood threat in the HWO due to the
variations in max model QPF.

Rain will exit to the east Friday night with rain potentially changing
over to snow in the highest elevations. Winds will increase from
the west, become breezy, with temps cooling into the 30s in the
Dacks and lower 40s elsewhere.

Saturday will stay cool and breezy under mostly cloudy skies.
There may be some light showers that linger in the high terrain
as well. Afternoon highs will be in the mid 40s to upper 50s.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
A fairly active weather pattern is expected for late April into
early May with multiple short-waves potentially impacting the
forecast area in a quasi-zonal to zonal mid and upper level flow
late in the weekend and into the early to middle portion of next
week. Temps will likely run cooler than normal.

Saturday Night into Sunday...High pressure at the sfc and a short-
wave ridge briefly builds in Sat night with decreasing winds and
tranquil weather with lows falling off into the upper 20s to lower
30s over the mtns, and mid 30s to around 40F in the lower
elevations.  A quick moving short-wave trough will be approaching
from the Great Lakes Region and lower OH Valley for Sunday.  Some
slight timing differences with the Ensembles /NAEFS and GEFS/ and
the latest CMC/GFS/ECMWF, but overall clouds will be quickly
thickening and lowering with a chance of showers, and perhaps a
little bit of wet snow over the southern Adirondacks with the onset
due to the isentropic lift and the differential cyclonic vorticity
advection. Highs will run below normal in the mid 40s to mid/upper
50s

Sunday night into Monday...The short-wave trough exits quickly
Saturday Night.  There could be a few snow showers over the higher
terrain in the cold advection in the wake of the system and its cold
front.  Initially breezy and cool/cold conditions will be followed
by another potentially brief period of tranquil and fair weather
with a sfc anticyclone building in over the Northeast.  Lows fall
back into the 30s with some mid/upper 20s over the southern
Adirondacks, eastern Catskills, and southern Greens, and 30s over
the rest of the region.  Temps will still likely run about 5-10
degrees below normal across the region to open the week.

Monday Night into Wednesday...Uncertainty increases with the
forecast heading into the Tue-Wed time frame. Some moisture may over
run a boundary south of the region over the Mid Atlantic States for
MON night into TUE, and the latest ECMWF has a wave moving along it
a bit further north than the GFS and some of the Ensembles. The day
could end up cloudy with just a few light showers around especially
south of the I-90 corridor. We went with low chance PoPs at night,
and a slight chance during the day. A stronger cyclone may eject out
of the lower Plains into the Upper MS River Valley and then the
western Great Lakes Region for the mid-week with a warm front and a
sfc wave bringing a more widespread rainfall for WED-WED night. We
kept the trend of chance PoPs here. Temps continue to run cooler
than normal for the first couple of days of May.

&&

.AVIATION /02Z THURSDAY THROUGH MONDAY/...
Cloud layer hovering between 2500-3500 feet this evening will
become scattered between midnight and daybreak. The after
daybreak Thursday, there should just be few to scattered clouds
above 3000 feet, through the afternoon. Visibilities will be VFR
through the period.

West to northwest winds at 10 to 15 Kt will gust occasionally
to near 20 Kt at KALB and KPSF this evening. Winds become nearly
calm by daybreak. Winds shift to south and southwest at around
6 Kt around midday Thursday and through the afternoon.

Outlook...

Thursday Night: Moderate Operational Impact. Likely RA.
Friday: High Operational Impact. Breezy Pds RA.
Friday Night: High Operational Impact. Breezy Likely SHRA...RA.
Saturday: Low Operational Impact. Breezy NO SIG WX.
Saturday Night: No Operational Impact. NO SIG WX.
Sunday: Moderate Operational Impact. Chance of SHRA.

&&

.FIRE WEATHER...
Weak high pressure will bring fair and seasonably mild
conditions Thursday before another storm system brings widespread
rainfall and cooler temperatures to the region for Friday into
Saturday morning. Breezy and chilly conditions will then be in place
for the remainder of the weekend.

RH will then recover to 80-100 percent tonight and Thursday
night. RH will then drop to 25-35 percent Thursday afternoon but
will be near 100 percent Friday afternoon with rain showers.

Winds will be west to northwest at 15-25 mph this afternoon
with gusts of 25-35 mph. These winds will become light/variable
after midnight. Light/variable winds Thursday morning will
become south to southwest at 5-10 mph in the afternoon.

&&

.HYDROLOGY...
Flood Warning remains in effect on the Schroon River at
Riverbank. The Schroon River at Riverbank will continue to
gradually fall and is forecast to go below 8 feet, moderate
flood stage, by around 7 AM Thursday. Please visit our Advanced
Hydrologic Prediction Service /AHPS/ web page for specific area
rivers and lakes observations and forecasts.

Mainly dry conditions are expected through Thursday evening.

Another storm system is expected to bring widespread rainfall
to the region early Friday morning into early Saturday morning.
Looks like total QPF from this system will average from 0.75
inches to 1.25 inches area wide. This may result in renewed
river rises late Friday into the upcoming weekend, especially
across portions of the Adirondacks into the Mohawk Valley where
river levels are already running high from recent rainfall and
snowmelt. However, the latest MMEFS shows mainly within bank
rises across these areas with the exception of Riverbank and
Hinckley Dam which could rise into at least minor flood stage
on Saturday. Trends will need to be watched closely, and if this
potential for heavy rain increases further, then a Flood Watch
may be issued.

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

&&

$$
SYNOPSIS...JLV
NEAR TERM...NAS/JLV
SHORT TERM...JLV
LONG TERM...Wasula
AVIATION...NAS
FIRE WEATHER...JLV
HYDROLOGY...JLV