Scientific Forecaster Discussion
fxus61 kaly 211759
Area forecast discussion
National Weather Service Albany New York
1259 PM EST Thu Nov 21 2019
high pressure will bring fair and dry conditions this afternoon.
However, another storm system is approaching with clouds returning along
with the increase chance for wintry precipitation tonight into Friday morning.
The brisk conditions expected later Friday behind the passage of a strong cold
front. Then the weekend will feature a dry and tranquil start before
additional mixed precipitation arrives on Sunday.
Near term /until 6 PM this evening/...
as of 1230 PM EST...high pressure continues to build in over New York
and New England with mostly clear to clear skies. Some patchy
clouds and isolated mist continues over the Lake George area and
we did add it back in based on the New York state mesonet observations near
Queensbury and kgfl ASOS (this should burn off over the next
hour or two), but the subsidence from the ridge should allow for
a period of mostly sunny/sunny conditions before the mid and high
clouds start approach from the south and west late in the day.
The 12z kaly sounding is very dry with a precipitable water of 0.26" and a few
subsidence inversions below 700 hpa. Max temps look good this
afternoon. Highs this afternoon will range from the upper 30s
to mid 40s in the valleys, and 30s over the higher terrain with
light to calm winds.
Short term /6 PM this evening through Saturday/...
the aforementioned ridge axis will quickly track off the
Atlantic coastline early this evening. Upstream storm
developing across the Great Lakes will advance a warm front
northward through tonight. Per previous forecast discussions,
weak isentropic lift and low level upslope conditions should
provide a wintry mixture to the north and west of Albany.
Elsewhere, boundary layer temperatures and warm advection aloft
should limit the wintry mixture with mainly light rain expected.
Some patchy fog may redevelop as dewpoints are expected to climb
above freezing overnight. Low temperatures mainly into the 30s
across the entire region.
Friday, a strong cold front is expected to cross the region from
west to east. Per forecast profiles, seems the lapse rates are
not too high but enough where a couple of squalls may develop
along the boundary. Otherwise, a scattered line of showers are
expected with some snow mixing in across the dacks before the
cold advection quickly transitions any mixture to just snow
showers. Some Lake Ontario contributions may bring about some
lake effect snow showers during the afternoon, however, not much
accumulation expected. As for the winds in the wake of the
fropa, mixing layer potential taps into the 40+kt range as some
funneling down the Mohawk may enhance those magnitudes a bit. At
this time, we will hold off any headlines with respect to the
wind magnitudes and watch for trends. Early highs on Friday
mainly into the 40s.
Friday night into Saturday, Ridge of high pressure will once
again crest across the region for another period of tranquil
weather. Overnight lows mainly into the 20s with highs Saturday
ranging from the 30s across the higher terrain to lower 40s for
the immediate capital region and points southward through the
Hudson River valley and northwest CT.
Long term /Saturday night through Wednesday/...
the main forecast challenge will be right at the beginning of the
long term period Saturday night through Sunday. Synoptically, a
cyclone will be tracking northeastward from the Ohio Valley region
towards the lower Great Lakes Saturday night. By Sunday morning,
secondary cyclogenesis is expected to occur just south of Long
Island. The main question and difference in model guidance is how
much the coastal cyclone strengthens and when it becomes the
dominant low. The GFS is initially weaker with the secondary low,
and thus is indicating overall lower quantitative precipitation forecast compared to the European model (ecmwf). The
European model (ecmwf) shows the secondary low deepening faster with stronger
forcing/f-gen and higher quantitative precipitation forecast.
In terms of sensible weather, there are likely to be precip type
challenges, as there is expected to be warm enough air aloft
initially for a wintry mix in at least part of the area. At this
time, took a blended approach with regards to the thermal profile
from the GFS/ECMWF, which indicates a mix of snow, sleet and/or
freezing rain for mainly higher terrain areas outside the Hudson
Valley late Saturday night into Sunday morning. There could be minor
accumulation of snow/sleet and possibly ice. As the coastal cyclone
deepens, cooling aloft will allow for more of a rain or snow
scenario by Sunday afternoon with mainly rain in the valleys and
rain/snow mix in the higher terrain. However, there could end up
being a plowable snowfall, especially in the mountains, if the
stronger coastal cyclone solution occurs. Will need to watch for
possible mix/ice early, then accumulating snow through Sunday. Will
mention this potential in the severe weather potential statement.
Lingering isolated to scattered snow showers will be possible Sunday
night, as the upper level trough associated with the storm system
moves over our area while the surface cyclone tracks into the
Canadian Maritimes. Drying conditions expected on Monday, as a ridge
both at the surface and aloft moves in from the west. Fair/dry
weather should persist through Tuesday, as the ridge slowly moves
east into New England. Temperatures look to be close to normal
through the early week period.
The next chance of precipitation will be late Tuesday night into
Wednesday, as the next cyclone approaches from the west. Significant
differences in the model guidance for this system, but since it is
nearly a week away there is plenty of time to sort out the details.
The GFS is indicating a cyclone track well north of our region,
while the European model (ecmwf) has it tracking very close. So there is considerable
model spread at this time, which will have an impact on
precipitation types, amounts and duration. At least some milder air
is expected to arrive, especially if a track close to the GFS
Aviation /18z Thursday through Tuesday/...
localized fog and low cloud patch over gfl will be burning off
around 19z, then VFR conditions will prevail at the taf sites
into this evening. Clouds with cigs at or above 5000 feet will
increase ahead of a warm front this evening, then scattered
light showers will develop overnight at gfl/alb/psf. A little
freezing rain is possible with these showers at gfl as
temperatures will be near freezing. Cigs and vsbys may briefly
lower to MVFR in showers after midnight tonight. VFR conditions
will continue on Friday as a cold front moves east of the area.
Gusty westerly winds will develop along and behind the front
later Friday evening with speeds increasing to 15 to 25 kts
along with a few higher gusts into the afternoon.
Friday night: moderate operational impact. Windy no sig weather.
Saturday: low operational impact. Slight chance of rain showers...shsn.
Saturday night: moderate operational impact. Chance of
rain showers...shsn. Sunday: moderate operational impact. Chance of
rain showers...shsn. Sunday night: no operational impact. No sig weather.
Monday: no operational impact. No sig weather.
a return to partial sunshine as a ridge of high pressure slides
across the region. However, another storm system is approaching
with clouds returning along with the increase chance for wintry
precipitation tonight into Friday morning. The brisk conditions
expected later Friday behind the passage of a strong cold
front. Then the weekend will feature a dry and tranquil start
before additional mixed precipitation arrives on Sunday.
precipitation amounts will generally be less than a tenth of an
inch through the rest of the week and into the first half of the
weekend. An approaching storm system for the second half of the
weekend may bring a more widespread precipitations amounts to
the region. River levels will be steady or slowly falling
through the first half of the weekend.
For details on specific area rivers and lakes, including latest
observed and forecast river stages and lake elevations, please
visit the advanced hydrologic prediction service /ahps/ graphs
on our website.