Forecast Discussion for BUF NWS Office
FXUS61 KBUF 191152

Area Forecast Discussion
National Weather Service Buffalo NY
652 AM EST Fri Jan 19 2018

A few snow showers will be possible across the North Country through
early afternoon, as an upper level disturbance moves away from the
region. Otherwise, look for generally dry conditions and warming
temperatures through most of the weekend, as low-amplitude ridging
takes hold across the region. There will be a chance for light
precipitation Sunday night as a warm front lifts across the region,
with more widespread rainfall and seasonably mild temperatures
expected Monday into Monday night as a low pressure system tracks
from the Missouri valley to the Great Lakes.


The upper level disturbance that moved through the area overnight
has moved off to New England early this morning. Southerly flow east
of Lake Ontario is expected to veer to the west this morning, re-
introducing at least a chance for a few upslope/lake-enhanced snow
showers across the North Country through this afternoon. However,
have backed off on pops, as latest model soundings indicate that the
shallow moisture may not reach into the dendritic growth layer,
suggesting than many areas may just end up with cloudy skies.

Elsewhere, expect a dry with increasing sunshine as low-amplitude
ridging takes hold across the region. Strengthening southwesterly
return flow around high pressure over the southeastern U.S. will
advect warmer air into the region, causing temperatures to climb
above freezing across much of the forecast area, with the exception
of the North Country, which will run a little cooler, in the upper
20s to lower 30s. The sunshine will aid in mixing down stronger
winds associated with a persistent low level-jet that is overhead
the region, and this will lead to the development of gusty winds of
30 to 40 mph by this afternoon, which will keep wind chills in the
teens to 20s, somewhat negating the warmer temperatures and

Dry conditions will persist through tonight, with passing mid and
high clouds associated with the jet stream centered just to our
north. Ongoing warm advection will limit temperature falls, with
readings only falling into the upper 20s inland, with temperatures
bottoming out around 30 along the lake plains.


Saturday, gusty winds will continue as a tight pressure gradient
lingers between Low pressure moving across Quebec and High pressure
over the Southeast states. Gusts to around 40mph, especially across
the Niagara Frontier, can be expected only slackening some through
the day as the pressure gradient begins to relax. Surface ridging
extending north over our region should promote mainly dry weather
beneath mostly cloudy skies. The exception to this may be east of
Lake Ontario where a very weak southward pressing cold front and
upslope flow may drive a slight/low chance for some either some
light sprinkles or higher elevation flurries. There may even be a
risk of some freezing drizzle as BUFKIT soundings continue to show
the cloud bearing layer may be too warm to support ice nuclei. The
gusty southwest flow will promote warm air advection which should
help surface highs to push to near or about 40F. Saturday night,
expect more mainly dry weather with the exception again being east
of Lake Ontario and perhaps the western Southern Tier with some
sprinkles or perhaps freezing drizzle. Mostly cloudy skies will keep
overnight lows limited only falling back to within a few degrees
either side of freezing.

Sunday into Sunday night, an increasing moisture connection from the
Gulf of Mexico under southwesterly flow across Western and Central
NY will bring similar mild temperatures to what we also expect on
Saturday. This warmth will be ahead of a warm front associated with
low pressure lifting out of the Central Plains states. Despite the
moisture, lift will remain rather weak Sunday only increasing
slightly into Sunday night. Slight chance/Chance POPs for some
sprinkles or flurries spread from the western Souther Tier north and
east later Sunday into Sunday night. Highs in the upper 30s to low
40s Sunday will only slip a few degrees into the 30s Sunday night.

The warm front is forecast to lift across western NY to the North
Country Monday where it might stall through Monday night. Very mild
air in the wake of the warm front should help boost temps into the
upper 40s in WNY with lower 40s more likely east of Lake Ontario.
Have held onto likely POPs for rain across WNY with rain/snow/mix
changing to rain in the North Country. Expecting that a cold front
and low level jet, tied to low pressure lifting across the western
Great Lakes, will force widespread rain Monday night. PWATs near 3/4
of an inch should bring some moderate to possibly heavy rainfall.
Temperatures ahead of the cold front will keep very mild temps
Monday night lingering in the 40s before falling some late.

The combination of rain, and increased snowmelt from higher
temperatures and dewpoints may bring some flood concern by later
Monday and Monday night. This warm-up is not as dramatic as last
weekend, and rain amounts are also likely to be lower given the fast
passage of the cold front. Nonetheless, there may be some potential
for ice jam flooding by late Monday and Monday night.


Tuesday into Wednesday, colder air will rush back into the region
with a blustery west wind behind the cold front. This will bring a
return to more typical mid-winter temperatures for mid-week. High
temps in the 30s and low temps in the 20s. Moisture and lift
associated with a passing mid-level trough axis will drive a chance
for some scattered snow showers Tuesday with lake effect snow also
becoming more likely. By Wednesday, much of the synoptic moisture
looks to be removed but mesoscale processes will leave chances for
lake effect snow east of the lakes into Wednesday night. Will have
to keep an eye on how the ice cover on Lake Erie evolves over the
early week warmup, as it will have an impact on the magnitude of
whatever lake effect snows develops in Western NY.

Thursday we expect a continuation of mid-winter temperatures. Both
GFS and EC show a shortwave trough passing across the eastern Great
Lakes Wednesday night or Thursday but timing between the models is
spread a bit to far for any higher confidence than slight chance
POPs at this range.


A fast-moving upper level disturbance will continue to track east of
Lake Ontario early this morning. Veering southwesterly flow behind
this system will allow for the re-development of a MVFR cigs along
with a few lake enhanced snow showers east of Lake Ontario this
morning east of Lake Ontario, including KART. Any lingering snow
showers should dissipate after 18Z, as temperatures aloft warm in
the wake of the disturbance, though MVFR cigs will linger through
much of the day, before lifting into a VFR deck after 00Z Sat.

Elsewhere, aside from morning MVFR cigs in the Niagara Frontier, VFR
conditions should prevail throughout the TAF period, as dry air and
warm advection aloft will stifle any lake effect activity. However,
strong westerly flow aloft will also continue throughout the period.
These winds will mix down during the day on Friday, producing gusts
to 30 kts. Gusts will subside after sunset on Friday, however the
strong winds aloft will remain, and the low-level jet will
strengthen to in excess of 50 kts Friday night, resulting in
widespread areas of LLWS after 00Z Sat.


Saturday through Sunday...Widespread MVFR ceilings redeveloping on
Saturday...then persisting through Saturday night and Sunday.
Monday and Monday night...VFR/MVFR with rain showers developing.
Tuesday...MVFR/IFR with rain showers changing to snow showers before
ending...then areas of lake effect snow also developing east of the
lakes Tuesday night.
Wednesday...VFR/MVFR with a chance of snow showers.


A persistent pressure gradient will maintain brisk west-
southwesterly flow across the lakes into the upcoming weekend, and
small craft advisories remain in place into Saturday night. In
addition, a slight strengthening of already brisk southwest flow
ahead of another weak upper level disturbance may push winds just
above gale force on the open waters of the western end of Lake
Ontario for a time Friday night into early Saturday morning, and a
gale watch has been hoisted in anticipation of this possibility.
Otherwise, high pressure nosing across the region will relax the
winds Sunday before winds freshen once again on Monday ahead of a
strong low pressure system tracking out of the central Plains.


MARINE...Small Craft Advisory until 10 PM EST Saturday for LEZ040-041.
         Gale Watch from this evening through Saturday morning
         for LOZ062-063.
         Small Craft Advisory until 4 AM EST Sunday for LOZ042>045.




NWS BUF Office Area Forecast Discussion