Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Buffalo New York
740 am EST Thursday Dec 25 2014
strong winds will continue to affect much of western and
north-central New York today in the wake of strong cold frontal
passage. Winds will gradually diminish later today even as
temperatures fall as colder air filters into the region with any
lingering light rain showers mixing with or changing over to snow.
Any remaining precipitation should end tonight as high pressure
moves across the region with seasonably mild temperatures for the
first half of the coming weekend. A weaker system is expected to
swing another cold front across the lower Great Lakes this
weekend...bringing a return to more winter-like temperatures for
Near term /through tonight/...
the blustery Christmas morning will continue across western and
north-central New York in the wake of the strong cold frontal
passage that occurred overnight. While the strongest gusts have
moved off to the east in association with the pronounced area of
Post-frontal subsidence...a well-mixed boundary layer coupled with a
decently strong wind field aloft featuring 850mb winds in the 45kt
range will keep winds quite gusty at least through the morning
hours. However...with the main southwesterly push over with and lake
levels showing significant signs of receding...have canceled the
Lakeshore flood warnings.
Otherwise...lingering low level moisture combined with
upslope flow and the approaching upper level trough will keep
showers in the forecast into the afternoon hours...mainly across the
typical westerly upslope areas...before the upper trough swings
through and negative vorticity advection and surface ridging help to dry things out. Precipitation
type should remain mainly rain across lower elevations with some wet
snow mixing in across higher terrain. Elsewhere...plenty of clouds
are expected to linger into this evening as lingering low level
moisture may once again become trapped under the encroaching high
pressure before the arrival of drier air upstream allows ceilings to
scatter out...at least well inland from the lakes. Otherwise it
should be dry night with winds that will continue to diminish as
high pressure moves overhead the lower Great Lakes.
Regarding temperatures...readings will continue to slowly fall
through the day as cold air advects across the region behind the
cold front with temperatures falling into the middle to upper 30s
across much of the forecast area...though a few areas along the
Eastern Lake Ontario shore may hold out around the 40 degree mark
thanks to strong flow off the lake. Temperatures will continue their
slow downward trend tonight with lows in the low to middle 30s...with
the falling readings being mitigated by the fact that weak warm
advection will already be taking place across the area.
Short term /Friday through Saturday night/...
high pressure will be centered over the North Carolina coast on
Friday. Southwest winds rounding the northwest quadrant of this high
will bring warm advection with weak moisture transport aloft. Mild
temperatures will be felt across our region with partly to mostly
sunny skies. Temperatures will warm into the middle 40s Friday for
highs then fall back into the upper to middle 30s Friday night with the
interior southern tier and Tug Hill dipping to near freezing.
On Saturday a middle-level shortwave disturbance will eject out of a
West Coast trough. This will generate a surface low over the central
Great Lakes which is forecast to deepen while crossing southern
Quebec. This low center is not forecast to be nearly as deep as the
current low so no high wind threat is expected...just some breezy
winds. The increase of moisture aloft combined with synoptic lift
and isentropic upglide could touch off some light sprinkles during
the day Saturday but any more notable precipitation will hold off
until Saturday night with a cold front crossing upstate New York.
Temperatures Saturday and Saturday evening will range through the
40s so the cold front will bring the chance for plain rain showers.
Temperatures will fall behind the front back into the 30s with some
wet snow possibly mixing in late Saturday night and Sunday morning
before ending. Some precipitation enhancement may be observed across
the higher terrain with upsloping but 850mb temperatures only falling to
around -6c with dry air moving in should largely prevent much of a
lake enhancement Saturday night.
Long term /Sunday through Wednesday/...
the overall theme leading into the New Year looks to feature mainly dry
weather with a return to below normal temperatures as a push of
Arctic air surges across our region. On Sunday the cold front will
quickly exit off the New England coast with weak high pressure
building in behind the front. A chance of mixed rain and snow
showers early in the morning will taper off into the afternoon with
drier air and subsidence from the surface high arriving. 00z models
show agreement in dropping a stronger and broader Arctic surface
high south from western Canada into the Central Plains by midweek.
Ridging from this high would extend east across the lower Great
Lakes with a northwest fetch of Arctic air.
While 850mb temperatures dropping into the negative teens will support some
lake induced instability the synoptic moisture and lift will be
greatly lacking. This precludes any significant lake snows.
Otherwise...model guidance continues to struggle with showing
consistency in any other sources of synoptic lift. While the 25/00z
GFS and European model (ecmwf) keep any southern stream surface waves suppressed
across the southeast states...the Canadian shows a more significant
surface wave lifting across the Middle-Atlantic States that may spread
some moisture as far north as New York. Have dropped all probability of precipitation back
to slight chance favoring a mainly dry forecast with the Arctic high
likely staying in control of the pattern until a clearer signal is
seen in the models later this week. Temperatures will average near
normal Sunday and Monday then falling below normal Tuesday and
Aviation /13z Thursday through Monday/...
winds have begun to subside this morning as the initial surge of
cold air and downward motion associated with Post-frontal
subsidence has moved off to the east. Nonetheless... a strong wind
field aloft coupled with good mixing in the lower 3-5kft of the
atmosphere will continue to bring gusty west-southwest winds to 40kt this
morning. Winds will gradually diminish this afternoon...and more so
tonight as high pressure moves across the lower Great Lakes. In
addition...MVFR ceilings will continue to be found across the forecast
area this morning as low level moisture will remain in place with
little sign of clearing upstream as moisture will likely remain
trapped underneath high pressure moving in from the west. Winds will
gradually diminish through the day as the deep low pressure system
responsible for the winds continues to move away from the region and
high pressure moves in from the upper Great Lakes. Ceilings will also
gradually improve...returning to VFR this afternoon before
eventually scattering out across portions of wny tonight as drier
low level air moves into the region.
Friday and Saturday...mainly VFR.
Saturday night...scattered rain
Sunday and Monday...VFR/MVFR with a chance of snow showers.
Tuesday...mainly VFR with a slight chance of snow showers.
gales will continue into today in the wake of a strong cold frontal
passage that occurred overnight. Winds will gradually diminish later
today as high pressure begins to move into the lower Great Lakes
with gale warnings giving way to small craft advisories before
relaxing enough for waves to diminish below advisory levels Friday.
A weaker low pressure system is currently expected to develop across
the western Great Lakes and lift across Georgian Bay and the Ottawa
Valley this weekend...swinging another cold front across the lower
Great Lakes Saturday night and potentially bringing another round of
small craft advisories by Sunday.
significant warming over the last 24 to 36 hours significantly
increased rain and snow melt across the Tug Hill region and this
coupled with widespread moderate to heavy rainfall associated with a
strong cold frontal passage overnight has pushed the Black River
above action stage at Boonville overnight. The river is forecast
to crest below flood stage this evening. This crest will
eventually work its way down to Watertown by Saturday...with the
river cresting just slightly above action stage Saturday evening.
New York...High Wind Warning until 4 PM EST this afternoon for nyz001>003-
High Wind Warning until 7 PM EST this evening for nyz007.
Wind Advisory until 7 PM EST this evening for nyz004>006-008.
Wind Advisory until 4 PM EST this afternoon for nyz013-014-020-
Marine...Gale Warning until 4 PM EST this afternoon for lez020-040-041.
Gale Warning until 4 PM EST this afternoon for loz030-
Gale Warning until 10 PM EST this evening for loz043>045-
Small Craft Advisory until 10 PM EST this evening for