Area Forecast Discussion
Issued by NWS Buffalo, NY
FXUS61 KBUF 260533
Area Forecast Discussion
National Weather Service Buffalo NY
133 AM EDT Sun Mar 26 2017
A frontal boundary near the Mason Dixon line this early Sunday
morning, will lift northward as a warm front across New York State
today. Scattered rain showers this morning and early afternoon will
be followed by a brief break before another wave of rain showers
passes across the region late this afternoon and overnight. Another
cold front may bring additional scattered rain showers to the region
Tuesday before an area of high pressure brings drier air, cooler
temperatures and a return to sunshine mid to late week.
.NEAR TERM /THROUGH TODAY/...
Overnight...the frontal boundary to our south will begin to
lift back northward as a warm front. Modest warm air advection
out in advance of this feature will allow for increasing chances
of some spotty light precipitation from southwest to northeast
through the overnight hours...for which chance PoPs remain in play
as confidence in measurable precipitation at any given location
remains low. Expected thermal profiles suggest that this should
primarily fall in the form of plain rain...though a little freezing
rain cannot be totally ruled out late tonight or Sunday morning
across the Eastern Lake Ontario region...which could ultimately
require another winter weather headline if the precipitation
becomes widespread enough/well enough developed.
With respect to temperatures...expect nighttime lows to generally
fall before midnight across most areas south of Lake Ontario...with
readings then rising through the balance of the night as the frontal
boundary lifts back into our region. The exception to this will be
across the North Country...where clearing skies should allow for
decent radiational cooling and a more typical nocturnal temperature
trend...with overnight lows falling into the lower to mid 20s.
As we move through the day Sunday...the precipitation should briefly
wane for a time south of Lake Ontario within the burgeoning warm
sector. Closed/occluded low in the plains expected to finally open
up and advance up into the western Ohio Valley/lower Great Lakes
during the day. This will bring a northward bulge of warmer air back
up into western New York while opening up a feed of Gulf moisture into
the Great Lakes, which will in turn spread rain back into the region
during the late afternoon and early evening hours. Temperatures in the
west will approach or potentially exceed 60 degrees....particularly if
any breaks of sunshine are realized.
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
A large low pressure system than has been meandering through the
central plains over the last couple of days will finally eject
northeastward across the Great Lakes region Sunday night and Monday,
as it rejoins the mean mid-latitude flow. In the process, increased
moisture advection will bring Gulf of Mexico sourced air into the
region with ample synoptic forcing as the cold front and vorticity
advection ahead of the upper level low approach the area Sunday
night into Monday morning. This will bring an area of widespread
showers across the forecast area, and will maintain categorical PoPs
for that time period. By Monday mid-day and afternoon, height rises
behind the trough passage and drier low-level air will end the
widespread rain showers in favor of just some widely scattered
showers and lingering cloudiness. With respect to temperatures,
Sunday night will remain mild with downslope flow and warm advection
ahead of the wave, with lows ranging from the low 40s in the North
Country to around 50 in western NY. By Monday, the airmass in the
wake of this largely cut-off low pressure system will not be much of
a contrast to the day prior, as better mixing and 850 mb temps to
around +5C will result in highs in the upper 40s in the North
Country to the low 60s in the Genesee Valley and northern Finger
Monday afternoon through much of Monday night will remain dry in the
wake of the initial trough passage, but then by Tuesday morning a
trailing open wave will cross the region. Global models remain
conflicted in the exact track of the wave and where the best forcing
will coalesce. Overall there has been a bit of a southward trend,
which increased the northeasterly flow and push of cooler air into
the region for Tuesday. Thus have lower temperatures some for
Tuesday with highs in the 40s to low 50s. Showers will accompany
this wave, but their coverage across the region will be guided by
the track of the wave, with a more southerly track favoring a drier
.LONG TERM /TUESDAY THROUGH SATURDAY/...
The very lengthy period of unsettled weather will finally come to an
end by Wednesday as a mid level trough digs southeast across Quebec
and forces the frontal zone well south of our area. This will bring
an end to any lingering showers by Wednesday morning, but will also
deliver another push of cooler air into our region. The GFS is far
colder Wednesday than the ECMWF or GEM with its more amplified and
southerly trough position. Have followed the ECMWF/GEM consensus
with temperatures a little milder than the GFS would suggest, but
still on the cool side with highs in the 40s.
Surface high pressure will build across Quebec Wednesday night and
Thursday with a ridge extending down into the eastern Great Lakes
and New England. This will provide a continuation of dry and cool
weather with highs in the 40s again Thursday and lows Wednesday
night and Thursday night in the upper 20s to lower 30s for most.
Model guidance diverges significantly by Friday and Saturday. The
GFS continues to suppress the next system well south of our area
with the moisture and forcing moving through the southeast states.
The ECMWF and Canadian GEM meanwhile are vastly different, taking a
surface low through the central Great Lakes. Have continued to lean
towards the ECMWF/GEM consensus for this period with rain chances
increasing again later Friday through Saturday. Temperatures will
begin to rebound if this farther north low track verifies, with
highs back in the 50s by Saturday.
.AVIATION /05Z SUNDAY THROUGH THURSDAY/...
For the 06Z TAFS pockets of IFR/MVFR CIGS are found, especially to
the south of Lake Ontario where a moist, northeast flow has created
a deck of low stratus. This activity should improve to MVFR/VFR
towards sunrise, as the deeper low level moisture decreases some. A
wave of scattered rain showers will pass across the TAF sites
through the next 12 hours, with only KART containing low
possibilities of any freezing rain.
As winds continue to veer today, the northeast winds will become
east, then southeast which should bring a period of VFR flight
conditions to the region through the afternoon hours.
Another wave of rain with likely MVFR/IFR or lower flight conditions
will reach WNY this late afternoon and evening as a stalled frontal
boundary to the south lifts northward as a warm front. This activity
will pass across the region tonight. CIGS will likely lower to IFR
across the higher terrain of SW NYS tonight, while the lower
elevations on a southerly, downslope flow will likely on lower to
MVFR within rain shower activity.
Monday...MVFR/IFR to start in rain showers, then improving in P.M.
Tuesday...MVFR/IFR cigs with periods of rain.
Wednesday and Thursday...VFR.
Northeast winds will continue today across the Lower Great Lakes,
with a strong breeze and increasing wave heights continuing the
small craft advisory on the western waters of Lake Ontario.
Winds have come down a bit on Lake Erie, and will drop the SCA here
with this update.
Later today and tonight winds will veer to southeast and then
southerly as an area of low pressure tracks across the central Great
Lakes and towards NW Lake Ontario. As these winds veer, they will
increase some on the eastern half of Lake Ontario, such that low end
SCA wind thresholds will be met. Will issue a SCA for the eastern
waters for late this afternoon through tonight.
This area of low pressure will track north of Lake Ontario Monday,
and in its weaken state, and warm air over the cold lake waters,
both winds and waves should remain below SCA criteria.
MARINE...Small Craft Advisory until 2 AM EDT early this morning for
Small Craft Advisory until 11 PM EDT this evening for