Area Forecast Discussion
Issued by NWS Buffalo, NY
FXUS61 KBUF 180830
Area Forecast Discussion
National Weather Service Buffalo NY
330 AM EST Wed Jan 18 2017
Low pressure with track up the Saint Lawrence Valley this morning,
while low cloud cover and areas of drizzle and scattered rain
showers linger across western and North Central NY today. It will
then remain mild through the rest of the week, with even warmer air
for the weekend. The next chance of widespread rain comes Monday
into Monday night as a large low pressure system approaches.
.NEAR TERM /THROUGH TONIGHT/...
Surface analysis shows a surface low centered near the east of Lake
Ontario early this morning, with a frontal boundary trailing back
across the lake toward southern Ontario province. Areas of light
rain showers and drizzle will continue to move through western and
North Central NY near the surface low and trailing boundary this
morning. WV and IR satellite imagery also indicate drier air in the
mid and upper levels to our northwest that will move into the region
this afternoon. This should pretty much end the any linger light
rain showers by this afternoon, and the increasing subsidence and
decreasing depth of low level moisture should end the drizzle.
However, it will remain overcast today with low cloud cover. This
cloud cover, combined with the weak cold advection in the wake of
the departing low and frontal passage will result in near steady
temperatures today that will likely rise little, if any, from their
morning readings by this afternoon. This means temperatures stuck
in the mid to upper 30s for most locations today.
Continued trapped low level moisture will keep the low overcast in
place tonight with light southwesterly winds in place. The result
will be little temperature change overnight, with lows tonight only
in the low to mid 30s.
.SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/...
Increasing amplitude within the southern stream upper height field
will yield a period of rather benign weather Thursday and Thursday
night. Increasing subsidence and dry air advection will allow for
some sunny breaks Thursday especially during the afternoon.
Otherwise, looking at a continuation of above normal warmth, as even
neutral or weak warm air temperature advection of the resident air
mass yields afternoon readings of upper 30s to lower 40s.
An upper level low lifting northward through the Central Plains on
Friday will bring a chance for rain to western New York as a upper
level wave and weak surface low lift northward through the Great
Lakes. Some uncertainty remains among latest model solutions
regarding rain probabilities. European favors a higher chance of
rain with a stronger wave and surface low lifting northward. GFS/CMC
favor lower chances with a weaker low. A developing southerly flow
over the eastern Great Lakes will bringing unseasonably mild
temperatures with highs in the 40s to near 50 both Friday and
.LONG TERM /SUNDAY THROUGH TUESDAY/...
A progressive...yet highly amplified upper level pattern will be
found across the country during this period...with the Great Lakes
region being dominated by mild Pacific modified air. While this will
mean that temperatures will remain well above normal...the period
will be highlighted by what could be a soaking to problematic rain
on Monday into early Tuesday. More on this in a moment.
A ridge axis over eastern New York will support one more fairly nice
day across our forecast area on Sunday...although clouds will likely
prevail across the western counties. Temperatures will be some 15
deg F above normal values...with highs ranging from the upper 40s
across the far western counties to the lower 40s on the Tug Hill
The fair weather will deteriorate Sunday night as a deep stacked low
over the Deep South will start to work its way up the western slopes
of the Appalachians. Ahead of this very dynamic system...a plume of
sub tropical moisture will stream northward from the Caribbean and
Gulf stream of the western Atlantic to Virginia and Pennsylvania. As
the leading edge of this moisture will make its way across our
western counties late Sunday night...it will be lifted by a strongly
divergent upper level flow. This will start the process whereby our
region could pick up a soaking rain.
On Monday...the vertically stacked storm system will slowly drift
north across the Upper Ohio Valley while the plume of sub tropical
moisture off the Atlantic will edge over our region. This will lead
to some widespread rain for our forecast area Monday and Monday
night. The highest risk for significant rains will be east of the
Guidance continues to suggest that this storm system will also
support strong...potentially damaging...downslope winds between Lake
Erie and the Chautauqua Ridge. A southeast low level jet of 50-55
knots just above a staunch inversion is very similar to events that
local research has shown to be problematic. Stay tuned.
The slow moving storm system is forecast to cross Pennsylvania on
Tuesday while its plume of moisture will push across far eastern New
York into New England. Meanwhile..drier air in the mid levels will
advect across the western counties on Tuesday with dynamics
weakening considerably in the process. This will lead to a tapering
off of the rain from east to east.
.AVIATION /09Z WEDNESDAY THROUGH SUNDAY/...
Expect IFR/LIFR or lower CIGs at BUF/IAG/ART, with a potential
for a period of dense fog. This has the potential to lower vsby to
1/4SM at times in BUF/IAG, with increasing winds possibly
providing enough mixing to keep vsby in the 1/2SM - 1SM range.
Poor conditions should continue through at least midnight, with
gradually improving conditions likely late tonight as slightly
drier air moves in. Otherwise IFR conditions will prevail at
ROC/JHW overnight with mainly low CIGS.
There still should be plenty of moisture remaining trapped beneath
an inversion to result in widespread IFR cigs which will last most
of the day Wednesday. The one exception may be ROC where
southwesterly downslope winds may help improve to MVFR for the
afternoon. There will also be periods of showers and drizzle as
another weak disturbances crosses the area late tonight. Showers
will taper off from west to east Wednesday.
Wednesday night through Friday...Mainly VFR.
Friday night and Saturday...chance of rain and some MVFR/IFR.
Small craft conditions will continue on Lake Erie through midday in
the wake of a surface low currently departing across eastern Lake
Ontario. Winds will taper off on Lake Erie this afternoon and
evening. However, winds will pick up on Lake Ontario by this
afternoon and evening behind the surface low, and will result in a
period of small craft conditions for the south central shoreline.
MARINE...Small Craft Advisory until 1 PM EST this afternoon for LEZ040-
Small Craft Advisory from 1 PM this afternoon to 1 AM
EST Thursday for LOZ043-044.