FXUS61 KALY 220539
Area Forecast Discussion
National Weather Service Albany NY
1239 AM EST Thu Feb 22 2018
The combination of snowmelt and recent rainfall may lead to
some minor flooding over the higher terrain well north and west
of the Capital District through tonight. Colder and more
seasonable temperatures are expected on Thursday along with some
mixed precipitation in the form of snow, sleet and freezing
rain. More unsettled weather is expected Friday and during the
second half of the weekend.
.NEAR TERM /THROUGH TODAY/...
Winter Weather Advisory from 4 AM until 6 PM Thursday for the
eastern Catskills, Schoharie Valley and the Helderbergs.
As of 1230 AM EST... Rather quiet shortly after midnight with
ample cloud coverage per the Metars and enhanced nighttime
microphysics GOES-16 satellite channel. A northerly wind has
evolved down the Champlain with occasional gusts being observed
at KGFL. Otherwise, did increase cloud coverage in the grids and
to account for those northerly winds. Regional radar reveals a
few widely scattered showers across central and western NY and
into PA. Per the hires radar reflectivity forecasts from the
NAM3Km and HRRR/X suggest this will be on the leading edge of
the strengthening baroclinic zone and overall lift for the
slight chance PoPs into the Catskills, Schoharie Valley and
portions of NW CT toward sunrise with a rain/snow mixture
initially (could be a period of sleet). Remainder of the
forecast remains unchanged at this time.
Prev Disc...Surface high pressure over the Great Lakes will
build eastward into the region, allowing the flow to turn out of
the north and continue to usher in colder air. Lows will be in
the upper teens to mid 30s.
On Thursday some isentropic lift and overrunning precipitation
is expected. Thermal profiles in the lower levels of the
atmosphere will be critical for precipitation type. Expecting a
mixture of snow, sleet and some freezing rain. It may be still
warm enough for some rain in the mid Hudson Valley and
Litchfield county. The freezing rain will be mainly confined to
the advisory area and mainly occurring during the morning hours.
During the afternoon the primary precipitation type will be
snow and some sleet. Highs on Thursday will be slightly above
the overnight lows with highs ranging from the upper 20s to
upper 30s. Temperatures may fall slightly during the afternoon.
Snowfall amounts will range from 1 to 4 inches with up to a
tenth of an inch of ice in the advisory area.
.SHORT TERM /TONIGHT THROUGH 6 PM FRIDAY/...
A round of wintry mixed precipitation is possible Friday into Friday
evening, mainly for areas above 1000 feet elevation. This would
include light accumulations of sleet and freezing rain.
Thursday night, high pressure over southern Canada will expand
southward somewhat, resulting in the precipitation being shunted
south of the forecast area. Cloud cover may clear somewhat for areas
along and north of I-90, but will likely increase again toward
sunrise Friday ahead of the next system. Some spotty very light snow
or sleet is possible over the Catskills and Mid-Hudson Valley after
06Z as a renewed bout of isentropic lift begins.
Friday, the high shifts eastward over Nova Scotia while the low
level jet magnitudes increase. This will result in a renewed round
of moisture transport and isentropic lift, with precipitation
becoming likely late morning into the afternoon. We'll start out the
day cold with early morning temps in the teens and 20s, so some
mixed precipitation is likely especially at the onset. The high is
not in an ideal location to keep cold air locked in place, at least
in the north/south valleys below 1000 feet, so currently do not
expect much in the way of wintry accumulation there, as temps aloft
and at the surface warm enough to support mainly rain as the p-type.
Over the higher elevations of the Catskills and Adirondacks, thermal
profiles support more in the way of a mixture of sleet and freezing
rain for a good portion of the day. This will especially be true
over the Adirondacks where a fairly deep snow pack still exists, and
it has proven very difficult to scour out the cold air in similar
circumstances. Still considerable uncertainty with respect to how
much precipitation falls as sleet vs freezing rain, but additional
winter weather headlines are a good possibility for the higher
terrain above 1000 feet. As the temps aloft increase from west to
east, the higher terrain of western New England may hold onto the
colder temps longer, so perhaps more sleet or even light snow
compared with freezing rain there.
Low-level winds veer Friday night spelling a gradual end to the
isentropic lift, with weak high pressure expanding in late. A good
deal of low-level moisture will still be around, so could see a
continuation of light spotty showers or drizzle. Temperatures Friday
and Friday night are not expected to budge much, remaining mainly in
the upper 20s to upper 30s. Temps across the Adirondacks and western
New England above 1500 feet will likely drop back below freezing at
night, so could see some lingering icy issues there.
Weak high pressure Saturday may result in skies partially clearing
and mainly dry conditions. Temps expected to be fairly mild in the
upper 30s to near 50, or perhaps a bit warmer depending upon the
amount of sunlight received. Clouds will increase in the afternoon
ahead of yet another bout of isentropic lift. May even see some
rain showers breaking out late in the day as the NAM shows. Only
slight to low chance PoPs over southern zones for now.
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
The long term period will feature seasonable temperatures with only
one main threat for wintry mix.
Our period begins Saturday night with a low pressure system from the
Midwest amplifying as it travels into southern Canada with high
pressure over eastern Quebec slowly retreating eastward. Upper level
divergence from a strengthening 300mb jet positioned over the Ohio
Valley should aid in the low's intensification as the system becomes
positioned in the jet's right exit region during the second half of
the weekend. There are still discrepancies among the current
guidance on how quickly and how strong the low becomes with the GFS
the most aggressive, showing it cutting off at 500mb with the
Canadian showing a much weaker wave. The ECMWF was still not
available for this newest forecast update.
Warm air advection associated with the system should bring
widespread precipitation into our CWA from southwest to northeast
Saturday night into Sunday. Given that the antecedent high should be
positioned well to our north in Quebec leading to east-southeast
winds over eastern NY/western New England, the air mass ahead of the
precipitation should be a bit mild with temperatures in the 40s.
While initial precipitation may be rain in many spots outside of the
Adirondacks, current guidance suggests cold air damming and
evaporative cooling transitioning precipitation to wintry mix by
Sunday morning from north to south. The warm front may be stubborn
to traverse the area as most guidance shows weak southeast winds
persisting in the boundary layer until 18z Sunday. Thus, the wintry
mix may continue thru the first half of Sunday. By 18z Sunday, the
850mb jet strengths to 40-50kts which may help warm air mix into the
boundary layer as the warm sector moves closer to our CWA. Thus,
there is more confidence in the precip type changing to rain after
18z Sunday but still this is a low confidence forecast as cold air
is often stubborn to scour out. The GFS and Canadian both show a
secondary low developing in southern New England Sunday afternoon
which would keep the warmest air of the warm sector to our south and
east. Thus, I knocked Sunday's high temperatures a few degrees to
reflect this thinking. The cold front should finally move through
Sunday night, ending the precipitation from west to east.
High pressure noses into the Northeast from the Ohio Valley in the
wake of this system which would lead to breezy conditions Monday
with temperatures slightly above normal in the upper 30s to mid 40s.
A secondary cold front associated with the 500mb trough axis should
then arrive by 00z Tuesday with colder air in the 20s following for
Monday night. Despite northwest flow setting up for the mid-week
period, temperatures remain seasonable with highs in the mid 30s to
low 40s and overnight lows in the 20s. Ridging also sets in mid-week
which should keep eastern NY/western New England mainly dry.
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
VFR ceilings and visibilities are expected through tonight
until around 10Z-15Z when some intermittent mixed precipitation
is expected to begin at all TAF sites. There could be a mix of
snow, sleet and rain.
After about 15Z, mixed precipitation is expected to become
steadier and ceilings and visibilities will lower to the
MVFR/IFR levels. KGFL may have VFR bordering on MVFR since much
of the precipitation could track mainly south of KGFL. By
this afternoon, precipitation type should be snow at KGFL and
KALB but may remain a mix at KPSF and KPOU. Precipitation
should taper off by 00Z/Fri with conditions potentially
improving towards the end of the TAF period, especially at KALB
North winds at less than 10 Kt are expected through the TAF
Wednesday Night: Moderate Operational Impact. Breezy Chance of SHRA...RA...SN.
Thursday: Moderate Operational Impact. Likely RA...SN.
Thursday Night: No Operational Impact. NO SIG WX.
Friday: High Operational Impact. Likely RA...SN...SLEET.
Friday Night: Moderate Operational Impact. Likely RA.
Saturday: Moderate Operational Impact. Chance of RA.
Saturday Night: Moderate Operational Impact. Chance of RA.
Sunday: High Operational Impact. Likely RA.
A cold front tracking through the region this afternoon and
evening will usher in more seasonable temperatures tonight into
Thursday, with temperatures falling below freezing over the
Adirondacks tonight and ending the runoff from snowmelt. Will
maintain Flood Watch over the Adirondacks and western Mohawk
Valley as the Mohawk at Little Falls has risen a bit lately, but
the overall flood threat in these areas appears to be
We will also continue to monitor where current ice jams are in
place for possible movement through tonight. Flooding has occurred
in areas near the Stockade in Schenectady and Scotia due to water
backing up near the ice jam on the Mohawk. Parts of this ice jam
have broken up, but it is unclear whether this will result in
additional flooding or water levels receding. Water levels will
continue to be monitored, and additional flood products will be
issued if necessary.
Snow and wintry mixed precipitation is expected Thursday, with a
quarter to half inch of QPF expected mainly along and south of I-90.
More rounds of precipitation are expected Friday into the weekend.
Current forecasts call for around a quarter to three quarters of an
inch during this timeframe, highest south of I-90. This may result
in additional river rises. Temperatures are expected to average
above normal during this time, but not as warm as we have seen the
last two days.
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.
High temperature records were broken in many areas on
KALB reached 73 degrees at 244 PM EST
KGFL reached 66 degrees at 243 PM EST
KPOU reached 76 degrees at 415 PM EST which broke the all-time
February high temperature.
Wed Feb 21st Previous record highs:
KALB 65F set in 1981
KGFL 65F set in 1981
KPOU 67F set in 1953
All-time February highs:
KALB 74F set Feb. 24, 2017
KGFL 70F set Feb. 25, 2017
KPOU 73F set Feb. 24, 2017
RECORDS FOR KPOU DATE BACK TO 1949... HOWEVER...DATA IS MISSING
FROM JANUARY 1993 - JULY 2000.
NY...Winter Weather Advisory from 4 AM early this morning to 6 PM
EST this evening for NYZ047-051-058-063.