Area Forecast Discussion
Issued by NWS Albany, NY

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FXUS61 KALY 221755
AFDALY

Area Forecast Discussion
National Weather Service Albany NY
1255 PM EST Wed Feb 22 2017

.SYNOPSIS...
Mild conditions with well above normal temperatures are
expected to build in for the remainder of the week. There will be
increasing chances for rainfall late in the week into the weekend
with a strong cold front expected to cross the region late
Saturday.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
As of 1255 PM EST, Skies have become partly to mostly sunny
across much of the region early this afternoon, as a weak ridge
of high pressure is in place. Still some patchy clouds across
the eastern Catskills and parts of the mid Hudson Valley, but
even these areas should have some breaks of sunshine through the
afternoon. Due to temperature trends, raised max temps up a few
more degrees for this afternoon, with lower to mid 50s now
expected for most locations. Otherwise, the forecast remains on
track today.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
For tonight...Clouds will gradually increase. There will be
widely scattered to scattered showers across the western
Adirondacks. There also will be patchy fog around mainly after
midnight. Another warm front will be lifting north of the
region across southern Canada late at night. Lows will be in the
mid to upper 30s.

Thursday and Thursday night...Will see an increase in clouds and
chances of rainfall mainly across the northern half of the
region as a cold front drops southeast through the region. It
will continue to be very mild ahead of the front with highs on
Thursday in the mid 50s to mid 60s and lows Thursday night in
the mid 30s to mid 40s.

Friday and Friday night...The frontal boundary will return
north as a warm front lifting into southern Canada by late
Friday night. There will be a chance of rain across the region
through the period although any rainfall is expected to be
light. Highs on Friday will be in the upper 40s to upper 50s
with lows Friday night in the 40s to around 50.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
Main focus in the long term will be on the strong cold front
crossing the local area Saturday.  The system will feature strong
dynamics as a surface low deepens from around 990 to around 980 mb
within a coupled jet structure as it tracks from southern Ontario to
near Hudson Bay. Spread among the deterministic models and GEFS
members continues to be small for a system as dynamic as this,
lending confidence to the forecast. A very warm airmass will be in
place within the ridging ahead of this system, with 925/850 mb temps
in the upper single digits over the local area resulting in high
temperatures some 20-25 degrees above normal. With the strong low-
level moisture advection, fog developing over the areas that still
have snow pack is a good bet. It appears the upper ridging will
allow for only limited shower activity until the main upper
wave/cold front swings through. Deterministic models have slowed
down the frontal passage slightly, favoring late on Saturday or
early Saturday evening. Have adjusted PoP timing accordingly. Good
moisture pooling along the front with PWAT values near 1 inch along
with convective potential as Showalter values go slightly negative
should allow for some heavier rainfall, though the progressive
nature of this system will limit widespread heavy rain potential.
The potential for convection to mix the strong low-level wind field
to the surface is always a tough call with very little instability,
especially this far out, but with the strong front there is at least
the possibility of a narrow squall line that could produce gusty
winds.

The temperature contrast along the front looks impressive, with 850
mb temps forecast to fall 15-20C in 24 hours. This should allow
some lake-effect snow showers to develop late Saturday night into
Sunday. Winds will also increase and become quite gusty during this
time frame as deep mixing develops in the cold advection behind the
front. Temperatures will ease back toward normal, at least for
Sunday and Monday. Still high uncertainty for the beginning of next
week as we transition from cyclonic to fast zonal flow. A surface
anticyclone will expand into the region somewhat Monday, but there
is potential for a quick clipper system to develop somewhere across
the eastern US. Slight chance PoPs for now.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
VFR conditions will prevail through this evening as a warm front
lifts through our region. This will allow for good low level
moisture advection late this evening/overnight and increased fog
potential. Combined with calm winds and snowpack on the ground,
MVFR/IFR fog is possible. Latest model guidance indicates some LIFR
fog at GFL/PSF as well. Since this is more of an advective fog
event, cloud cover shouldn`t impact the potential for fog
development overnight. Conditions should gradually improve after
daybreak tomorrow.

Winds will be light and variable/southerly throughout the TAF period.

Outlook...

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

&&

.HYDROLOGY...
No widespread hydro problems are expected through the rest of the
work week, with just light precipitation forecast and overnight
temperatures falling into the 30s to mid 40s the next few
nights.

However, mild temperatures that will be well above normal, are
expected for later this week. This will cause snowmelt and
subsequent runoff. Also, a strong storm system may bring a period of
moderate to heavy rainfall on Saturday. The Meteorological Model
Ensemble River Forecasts /MMEFS/ continue to suggest significant
river rises will occur, with flooding possible Saturday into Sunday
due to the combination of snow melt and locally heavy rain.

At this time, at least minor flooding appears likely for a few to
several points along main stem rivers. Depending on the degree
of snow melt, flooding could reach moderate levels in some
locations. We will have more specific information as the weekend
draws nearer.

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...11/JPV
NEAR TERM...11/JPV/JVM
SHORT TERM...11
LONG TERM...Thompson
AVIATION...JVM
HYDROLOGY...11/JPV



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