Scientific Forecaster Discussion
fxus61 kaly 211743
Area forecast discussion
National Weather Service Albany New York
1243 PM EST Tue Feb 21 2017
a weak disturbance approaching from the west will move across the
area tonight, bringing chances for light rain and or freezing rain
in some spots. Mild conditions with well above normal temperatures
are then expected to build in for the remainder of the week.
Near term /until 6 PM this evening/...
as of 1230 PM EST...a Freezing Rain Advisory has been issued
for portions of the southern Adirondacks, Lake George Saratoga
region, central Mohawk Valley, western Schenectady County,
northern Taconics, southern Vermont and the Berkshires from 8 PM
this evening to 6 am Wednesday.
Mid level clouds have increased across the area with temperatures
warming through the 30s. Temperatures should climb into the low
to mid 40s this afternoon for most areas. It will remain dry
through the daylight hours, although a disturbance moving in
from the west will result in thickening clouds.
Short term /6 PM this evening through Thursday night/...
main change for tonight was to issued a Freezing Rain Advisory
for the southern Adirondacks, Lake George Saratoga region,
central Mohawk Valley, western Schenectady County, northern
Taconics, southern Vermont and the Berkshires from 8 PM this
evening to 6 am Wednesday.
An upper level disturbance and jet streak moving across the
region this evening and overnight will result in some light
precipitation developing. Output from hi-res guidance such as
the hrrr and the 4km NCEP WRF indicating greater coverage of
precip than the lower resolution models. So have increased pops
to around 40-60 percent with scattered to likely coverage. Also
lowered min temps to around or slightly below freezing for
portions of the area, mainly north and outside of the capital
district. So with the likelihood of at least some light freezing
rain, we have opted to issue a Freezing Rain Advisory.
Light rain will occur for areas outside the advisory, with
precip ending before sunrise Wednesday as the disturbance
quickly moves eastward.
Lows tonight will generally be in the upper 20s to mid 30s with
temperatures rising a few degrees towards sunrise Wednesday.
On Wednesday...expect morning clouds to give way to partly sunny
skies as a ridge of high pressure builds across the region. It
will be another mild day with highs in the mid 40s to mid 50s.
For Wednesday night...clouds will gradually increase although it
should remain dry. Another warm front will be lifting northeast
toward the region late at night. Lows will be in the mid to
Thursday and Thursday night...will see an increase in clouds and
chances of rainfall mainly across the northern half of the
region as several frontal boundaries cross the region. It will
continue to be very mild with highs on Thursday in the upper 40s
to mid 60s and lows Thursday night in the mid 30s to mid 40s.
Long term /Friday through Monday/...
an active period in the long term as a strong Pacific jet carves out
a deep, progressive trough over the center of the Continental U.S.. ridging
downstream of the trough over the eastern Continental U.S. Will continue to
favor temperatures well above normal through Saturday, becoming
closer to normal for Sunday and Monday.
As the trough becomes neutrally to negatively tilted from the
Central Plains to the western Great Lakes Friday into Saturday, a
strong cyclone will develop and track well to our west, keeping US
solidly in the warm sector. There are still model discrepancies and
some ensemble spread as to the exact track, strength, and timing of
the surface low; but consensus is nearly unanimous that wintry
precipitation won't be a concern for our local area. On Friday, some
rain showers may break out along the nose of a strengthening low-
level jet as moisture is lifted over a developing warm front. Still
disagreement on whether the frontal forcing will extend this far
east, so mainly just chance pops for now. A very warm airmass will
be in place with 925 mb temps up around +10c, although mixing will
be hampered by warm/moist advection and cloud cover. Chance pops
again Friday night when we are solidly in the warm sector with
little forcing, though there could be some drizzle/light showers
Things get more interesting on Saturday as height falls associated
with the main upper wave approach and a sharp cold front crosses the
area. Rain is likely, possibly heavy at times, along the front with
plenty of moisture as pwats near 1 inch. With the strong forcing and
showalter values slightly negative, kept slight chance of thunder in
the forecast as well.
Current indications are that 850 mb temps drop around 20c in 24
hours from 18z Saturday to 18z Sunday (+8 to -12c). Some lake effect
snow showers may develop in the western Adirondacks Saturday night
into Sunday. It appears there is potential for some strong winds
along and behind the front Saturday night into Sunday with the
strong cold advection, deep mixing, and surface pressure rises. Will
add to severe weather potential statement. Large model spread by Monday as cyclonic upper flow
transitions to zonal. Slight chance pops with temps near normal for
Aviation /18z Tuesday through Sunday/...
VFR expected into the evening hours tonight as high clouds increase
and gradually lower throughout the day. A weak system has the
potential to bring some light/MVFR rain showers after 03z tonight,
with a chance for some freezing rain in the high terrain, mainly at kpsf.
There is also potential for IFR conditions to develop prior to dawn
with moisture becoming trapped beneath a lowering inversion. Have
included prevailing IFR at kgfl/kpsf after 09z for the time
being with gradual improvement back to MVFR towards the end of
Winds are expected to increase this afternoon from the south to 5 to
10 kts with some gusts up to 20 kts for kalb/kpsf. Winds will then
slacken overnight tonight.
Wednesday night: no operational impact. No sig weather.
Thursday: low operational impact. Slight chance of rain showers.
Thursday night: low operational impact. Slight chance of rain showers.
Friday: moderate operational impact. Chance of rain showers.
Friday night: moderate operational impact. Chance of rain showers.
Saturday: high operational impact. Likely rain...tsra.
Saturday night: moderate operational impact. Chance of rain showers...shsn.
Sunday: low operational impact. Breezy no sig weather.
no widespread Hydro problems are expected into the middle of
this week with light precipitation forecast and overnight
temperatures falling into the upper 20s and 30s most nights.
Milder temperatures are expected for later this week. This will
cause snowmelt. Also, a large storm system may bring a moderate
to heavy rainfall on Saturday. The long term meteorological
model ensemble river forecasts /mmefs/ suggest that significant
river rises along with some flooding is possible Saturday into
Sunday due to the combination of snow melt and locally heavy
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.
New York...Freezing Rain Advisory from 8 PM this evening to 6 am EST
Wednesday for nyz033-039>043-048-054-082>084.
Massachusetts...Freezing Rain Advisory from 8 PM this evening to 6 am EST
Wednesday for maz001-025.
Vermont...Freezing Rain Advisory from 8 PM this evening to 6 am EST
Wednesday for vtz013>015.