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fxus61 kaly 241744 
afdaly

Area forecast discussion
National Weather Service Albany New York
1244 PM EST Fri Feb 24 2017

Synopsis...
mild conditions with well above normal temperatures will
persist into Saturday. A warm front lifting through the region will
bring scattered showers and possibly a thunderstorm this morning
before we dry out this afternoon. A strong cold front will cross the
region Saturday afternoon and evening, bringing with it locally
heavy rainfall and perhaps a thunderstorm, gusty winds, and much
colder temperatures by Sunday.

&&

Near term /through tonight/...
Flood Watch in effect for the western Mohawk Valley, the upper
Hudson, the southern Adirondacks, Lake George Saratoga region and
southern Vermont from tonight through Sunday. See hydrology
section for details...

Showers and isolated thunderstorms tracking across the southern
Adirondacks and Lake George region. The position of the front
to the north is quite evident with kgfl and krme around 50 and
points south well into the 60s. Satellite and radar imagery does
show a slow lifting north of the west/east oriented old frontal
boundary and associated clouds and rain, with those trends,
adjusting temperatures upward a degree or so in many areas.
Minor adjustments to sky cover and rain chances as well through
this afternoon. Previous afd has a few more details and is
below...

Tonight, as the surface low works its way from Southern Lower
Michigan across Lake Huron, we become solidly in the warm sector
with a light to moderate south wind, setting the stage for a
very mild night. Low-level moisture advection may result in some
areas of drizzle or a few light showers.

&&

Short term /Saturday through Sunday night/...
Saturday morning, we continue to be located in the warm sector
with little forcing under strong upper ridging. Low-level wind
field will be increasing with time into the afternoon, with 925
mb winds increasing to 35-40 kt. As of now, expect the strong
warm air advection and low clouds to limit mixing into this layer, but this
will have to be monitored for stronger gusts if any breaks in
the clouds can develop. Otherwise, a few light showers are
possible before the front moves through. Temperatures will once
again be in the 50s and 60s.

Models are in very good agreement that a very strong cold front
will track through the local area roughly 21z Saturday to 03z
Sunday. Forecast temp contrasts across this front are
impressive - for instance, NAM shows 2-M temp difference across
the front of around 20f, and 850 mb temp difference near 10c, as
it tracks through the local area. Though forecast instability
is expected to be very little, there is some concern for a
strongly forced, narrow frontal rain band that could mix some of
the strong wind field down to the surface. Various hi-res models
show this band. Midlevel lapse rates are projected to actually
be pretty good, up around 6.5-7 c/km ahead of the front. Also
have to worry about the downward momentum transport immediately
behind the front. NAM cross section shows the front- normal
component of the winds of 35-40 kt just off the surface, along
with strong postfrontal descent. NAM also shows 3-h pressure
rise center of 6-7 mb tracking through the area. Will continue
to mention gusty wind potential in the severe weather potential statement. A period of moderate
to heavy rainfall is likely along and behind the front (see
hydrology discussion below for more details), tapering to
showers a few hours after frontal passage. The cold advection is
so strong that the rain showers could end as snow Showers. Lake
effect snow showers will commence downstream of Lake Ontario
late in the night with 850 mb temps falling toward -15c. Windy
conditions will continue overnight, as forecast soundings and
cross sections show potential for mixing past 850 mb, where
winds will be 35-45 kt. Wind headlines may be necessary along
and behind the frontal passage Saturday into Saturday night.
Will let the day shift re- evaluate.

Sunday will be a blustery day with temperatures finally near
normal. Lake effect snow showers for the western Adirondacks and
western Mohawk Valley will continue in the morning and taper
off in the afternoon as high pressure builds in from the south.
A couple of inches of accumulation are possible, limited by the
marginal cold air and inversion heights generally below 2 km
above ground level. The airmass already begins to moderate Sunday night as the
upper trough/midlevel cold pool exits east and a clipper tracks
across southern Canada, turning surface winds to the west and
southwest. This will put a floor on low temperatures, with
above-normal values expected.

&&

Long term /Monday through Thursday/...
a very active period of weather is expected during the long term
period as several frontal boundaries will be crossing the region.

On Monday...a cold front will be dropping southeast from the Saint
Lawrence River valley. While there is not much precipitation
associated with this system, there will be the chance for some light
snow across the northwestern third of the forecast area Monday
morning before the precipitation mixes with rain during the
afternoon. Otherwise expect mainly dry conditions across the
remainder of the forecast area. Highs on Monday will be in the mid
30s to around 50.

For Monday night...expect mainly dry conditions although the frontal
boundary will become stationary across the northern portion of the
forecast area. Lows will be in the mid 20s to mid 30s.

Tuesday through Wednesday night...another system approaches from the
Great Lakes region bringing increasing chances of precipitation. At
this point it appears it will be cold enough for some snow or a mix
of snow and rain across the mountains Tuesday night and Wednesday
night, but the precipitation will likely be all rain for most of
Tuesday and during the day on Wednesday. Highs on Tuesday are
expected to be in the upper 30s to lower 50s with lows Tuesday night
in the upper 20s to around 40, highs on Wednesday in the upper 40s
to mid 50s with lows Wednesday night in the mid 20s to upper 30s.

For Thursday...expect more seasonable conditions as the cold front
associated with the system is southeast of the forecast area off the
Atlantic coast. There still may be a chance of snow showers across
the northern mountains as a trough of low pressure drops south from
southern Canada. Highs on Thursday will be in the upper 20s to mid
40s.

Overall expect temperatures to average above normal with
precipitation well above normal during the long term period.

&&

Aviation /18z Friday through Wednesday/...
a warm front has pushed north of the kalb/kpou/kpsf terminals,
with warmer air surging in and lower clouds scouring out.
However, the front remains just south of kgfl, so lower clouds
in MVFR range have lingered but should tend of scour out this
afternoon as the warm pushes northward. So VFR conditions
expected at all terminals the rest of the day. However, as
unseasonably high moisture levels move into the region tonight,
conditions are expected to deteriorate to MVFR this evening,
then IFR overnight. Depending on if thicker fog can form, LIFR
will even be possible.

Low clouds and/or fog will linger through much of the morning
and possibly into the afternoon with the moist air mass in
place. Conditions should improve from IFR to MVFR by late
morning though.

Winds will be southerly around 5-10 kt through tonight,
increasing to 10-15 kt by late Saturday morning with higher
gusts around 20-25 kt at kalb. Some low level wind shear may
develop toward afternoon where surface winds are relatively
light and a southerly low level jet moves overhead. Low level wind shear may
need to be mentioned in subsequent taf issuances.

Outlook...

Saturday night: high operational impact. Windy. Likely rain showers...shsn...ra.
Sunday: low operational impact. Breezy no sig weather.
Sunday night: no operational impact. No sig weather.
Monday: low operational impact. Slight chance of rain showers.
Monday night: low operational impact. Slight chance of rain showers...shsn.
Tuesday: moderate operational impact. Chance of rain showers...shsn.
Tuesday night: moderate operational impact. Chance of rain showers.
Wednesday: high operational impact. Likely rain showers.

&&

Hydrology...
Flood Watch in effect for the western Mohawk Valley, the upper
Hudson, the southern Adirondacks, Lake George Saratoga region and
southern Vermont from Friday night through Sunday. Runoff will
result from a combination of snow melt over the next couple days and
heavy rainfall Saturday afternoon/evening.

At this time minor flooding of some main Stem rivers is expected,
including the Upper Mohawk, smaller rivers/streams in areas with
significant snow depth in the southern Adirondacks and southern
Green Mountains of Vermont, and possibly even portions of the upper
Hudson basin. There remains the potential for flooding for areas
south of the watch, but confidence is much lower. So will continue
to mention the threat in the severe weather potential statement for possible expansion of the watch
if conditions warrant.

A warm and increasingly moist air mass will be in place through
Saturday evening. Showers with mainly light quantitative precipitation forecast possible through
Saturday morning, though some areas of the western Adirondacks
could pick up around 0.25" this morning in showers and a few
thunderstorms. This will cause gradual snow melt and subsequent
runoff. Then a quick-moving, strong cold front is expected to
bring a period of moderate to heavy rainfall Saturday afternoon
and evening. Total quantitative precipitation forecast forecast of 0.50 to around 1.50 inches is
forecast through Saturday night, with the lowest amounts in the
Mid-Hudson valley and northwest Connecticut, and the highest
amounts over the western/southern Adirondacks. The time frame
for greatest potential for flooding is during and after the cold
front passage due to heavy rain/snow melt combination and
subsequent runoff.

Drier and colder air will filter in behind the cold front for
Sunday, with some lake effect snow possible across the western
Adirondacks and western Mohawk Valley.

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.

&&

Climate...
record high temperatures could be broken once again today. Here
are the daily record highs for February 24:
Albany 65 (1985)
Poughkeepsie 71 (1985)
Glens Falls 55 (1985)

All-time February high temperature records set yesterday at
Albany and Glens Falls.

Albany reached 69 degrees, which broke the old all-time February
record of 68 set back in 1997 on February 22nd. Glens Falls reached
68 degrees, which broke the all-time February record of 65 set back
in 1981 on February 21st.

A daily record high of 68 degrees was set at Poughkeepsie
yesterday, breaking the old daily record of 66 set in 1985.

&&

Aly watches/warnings/advisories...
CT...none.
New York...Flood Watch from 7 PM EST this evening through Sunday evening
for nyz032-033-038>043-082>084.
Massachusetts...none.
Vermont...Flood Watch from 7 PM EST this evening through Sunday evening
for vtz013>015.

&&

$$
Synopsis...Thompson
near term...NAS/Thompson

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