Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Albany New York
1246 PM EST Friday Nov 28 2014
high pressure will briefly build into the region this afternoon into
tonight...accompanied by below normal temperatures...during the
first half of the weekend. A warm front will bring some scattered
rain and snow showers Saturday night into Sunday with milder weather
to close out the Holiday weekend.
Near term /through tonight/...
as of 1246 PM EST...disorganized lake effect/enhanced snow showers
and flurries continue in the northwest flow across parts of er New York and western
New England. Some scattered snow showers continue to impact the western
Mohawk Valley...northern Catskills...and helderbergs. A few snow
showers have made it far enough downstream into the Hudson River
valley and Taconics. Not expecting much in accumulation...but
added some slight chance probability of precipitation to the capital
district...Taconics...and Berkshires. Temperatures look on track with 20
to l30s. Sunshine continues to mix with clouds especially from the
Hudson River valley eastward...as surface high pressure continues to
ridge in from the southeast of the lower 48.
lake effect snow diminishing into tonight...
Meanwhile...surface ridge axis will be building into upstate New
York through the day. Per the bufr soundings...favorable inversion
level heights and moist low levels will allow lake bands to track
inland through the day. That ridge though will limit the inland
extent somewhat so we will continue to confine the probability of precipitation mainly
into portions of the western Mohawk Valley and western dacks. As
for those crucial low level wind trajectories...the flow will
generally be between 280-310 per the latest rap13/hrrr
Tonight...the aforementioned ridge axis will slide across the
region. This will shut down the lake effect inland extent through
the early evening hours. Thereafter...a warm front will be
approaching during the overnight hours. This too will bring
additional cloud cover along with the slight chance for light snow
to develop across the western portions of the County warning forecast area. So where
clouds do break up...temperatures should quickly fall back into
the teens before steadying off with the cloud cover increasing.
Short term /Saturday through Saturday night/...
the remainder of the Holiday weekend will feature a passage of a
warm front and likely higher levels of low level moisture. Model
qpfs are rather light but do indicate the potential for either
some very light snow/flurries and/or light rain/drizzle depending
on thermal profiles. Isentropic analysis depicts the best lift and
low cpd/S will be across the dacks region into the St Lawrence
Valley. So we will go with slight chance to chance probability of precipitation along with
a mainly cloudy sky through the weekend.
As for temperatures...due to the cloud cover expected along with
the warming thermal column...we will favor the cooler side of the
guidance envelope. Highs mainly into the 30s on Saturday then into
the lower half of the 40s on Sunday. We will follow a non-diurnal
temperature trend Saturday night with lows likely attained in the
evening with slowly rising temperatures overnight.
Long term /Sunday through Friday/...
at the start of the extended period...a frontal boundary will be
approaching the region for Sunday night into Monday. With a
southerly flow ahead of this boundary...temperatures will be relatively
mild for Sun night...with many locations above freezing in the middle
to upper 30s. This front won't have a lot of moisture associated
with it...but will allow slight to low chance probability of precipitation for rain or snow
showers. The models are unclear in the exact timing of the boundary.
If it waits until later on Monday to pass through...temperatures may wind
up being mild for Monday with middle to upper 40s for valley areas
/upper 30s to low 40s for high terrain locations/.
Behind this frontal system...high pressure will build into the area
for Monday night into Tuesday. This will end the threat for any
precipitation and allows clearing skies and colder temperatures. With a cold
Canadian air mass moving into the region...overnight lows look like
they may wind up dropping down into the teens to low 20 for Monday
night. Highs on Tuesday will be noticeably colder...with many
locations remaining below freezing for most of the day...with highs
in the middle 20s to middle 30s.
Within the fast zonal flow...another storm system will rapidly be
approaching the region for Tuesday night into Wednesday. Although
some precipitation may start as light snow showers...precipitation looks to change
to rain for Wednesday as warmer air moves into the region. There may
even be a period of sleet or freezing rain with the transition...but
will not put it in the grids quite yet...as there is a great deal of
uncertainty regarding the timing/extent of this. Any precipitation looks
fairly light...with limited moisture preventing much quantitative precipitation forecast in general.
Any precipitation looks to end by Wednesday night.
Mins Tuesday evening will be in the 20s...with temperatures rising to the
middle 30s to low 40s for Wednesday. Mins Wednesday night will be in the middle
20s to low 30s.
Another brief area of high pressure looks to build into the region
for Thursday will quiet and dry weather. Highs will be
seasonable...with middle 30s to low 40s for valley areas. Any dry
weather will be brief...as yet another storm with light precipitation will
be approaching for the late week period.
Aviation /18z Friday through Wednesday/...
mainly VFR conditions expeted at the kgfl/kalb/kpou/kpsf taf sites
throught he taf period ending at 18z Saturday as a high pressure
ridge moves across the region during the period. The exception will
be at kpsf where ceilings may occasionally lower to MVFR during the rest
of the afternoon. Some lake effect moisture...cold temperatures aloft and
diurnal heating could produce a -shsn at the kgfl/kalb/kpsf taf
sites so have included vcsh at these sites into the eevening. Mainly
just scattered clouds overnight...with increasing middle level cloudiness
Saturday morning as a warm advection pattern takes hold.
Winds will be west to northwest winds at 8 to 12 kts...with gusts of
around 20 kts at kpsf/kalb through late this afternoon. Mainly light
winds overnight...generally less than 5 kts. Winds will shift to
southerly on Saturday at 5 to 8 kts.
Saturday night: low operational impact. Slight chance of shsn.
Sunday: low operational impact. Slight chance of rain showers...shsn.
Sunday night: low operational impact. Slight chance of rain showers.
Monday: low operational impact. Slight chance of rain showers.
Monday night: low operational impact. Slight chance of shsn.
Tuesday: no operational impact. No sig weather.
Tuesday night: moderate operational impact. Chance of shsn.
Wednesday: moderate operational impact. Chance of rain showers...shsn.
no significant hydrologic problems are expected the next 5 days
Additional light precipitation amounts are expected with basin
averages at a tenth of an inch or less the next few days. Snowfall
accumulations will be a coating to a few inches in a few spots
through today...a little higher downwind of Lake Ontario into
portions of the western Mohawk Valley and western Adirondacks.
Milder temperatures are expected Sunday with some snow melt. However...
temperatures are expected to cool off quickly during Monday with
the passage of a strong cold front.
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