FXUS61 KBUF 192226

Area Forecast Discussion
National Weather Service Buffalo NY
626 PM EDT Sun May 19 2019

Very warm and humid conditions will support another round of showers
and possibly a stray thunderstorms this evening into tonight. A cold
front will cross the area Monday with a few more scattered showers.
Much cooler and drier air will move into the region Tuesday and
Wednesday as high pressure builds into the Great Lakes.


The first round of convection is rapidly exiting to the east of the
forecast area this evening. Behind it, local radars are relatively
quite with the brief lull occuring before the next round of mainly
showers shows up a bit later this evening. This second round will
likely not be severe, if any SVR storms at all. The timing is just
NOT conducive for SVR wx and falling fairly late in the diurnal
cycle. Furthermore, it will be crossing the cool stable lake air
mass which as usual keeps convection in check. Although, a stray
strong storm can't be ruled out as the pre-frontal trough rolls
across the forecast area.

Tonight, the second round of storms will move east across the area
overnight, with rain tapering off from west to east behind the pre-
frontal trough. After that, there will again be another lull in
shower activity behind the pre-frontal trough then the cold front
arrives on Monday. Otherwise, it will be a mild and a muggy night
with lows nudging back only into 60s across the forecast area

Monday the mid level trough will move east across the eastern Great
Lakes, with a surface cold front moving east across the area. The
majority of the better moisture and convergence will be found along
the pre-frontal trough tonight, with much less in the way of deep
moisture and forcing for the actual cold front to work with.
Nonetheless, the cold front will produce a few scattered showers as
it crosses the area from morning through early to mid afternoon.
Enough instability may develop across Central NY and east of Lake
Ontario to support a few thunderstorms during the early to mid
afternoon. Western NY will dry out during the afternoon behind the
cold front, with clearing and drying aided by an expansive lake
shadow developing northeast of Lake Erie.

It will become quite windy Monday along and behind the cold front
given the favorable low track across southern Quebec, and a 50+ knot
low level jet lingering behind the cold front. Expect gusts of at
least 40 mph, with the strongest winds northeast of Lake Erie. If
enough sunshine develops prior to the stronger winds aloft moving
out, wind gusts may reach advisory criteria in some areas.


One last lobe of moisture is set to rotate through the North
Country on Monday night, allowing for a continuation of
chances for showers there as much cooler air advances into the
region behind the cold front. This will be short lived, however,
as the upper low will quickly transition into maritime Canada
with a sprawling upper anticyclone builds in the southeastern
U.S. The pronounced upper ridge along the northern periphery of
this will be the dominant player in our weather through midweek,
resulting in decidedly dry conditions over our area as surface
high pressure and the attendant subsidence rule the roost
through the interval.

With the progression of the surface high across the area, low
level flow will quickly back of from the brisk 20-25 kt boundary
layer flow of early Tuesday, toward much lighter flow by
Tuesday evening, and eventually to southerly flow as the surface
high pushes to the east on Wednesday. This will allow for warm
advection to resume by midweek, as well, which will allow
temperatures to come out of the cool values of Tuesday morning
and rebound above normal by midweek.


A sprawling upper level anti-cyclone will continue to take
residence over the southeast U.S. through the long term period.
A deepening trough over the west coast and intermountain west
will initiate active weather over the western half of the
country. Active weather from the western trough will trek
northeast over the ridge resulting in mostly weak waves of low
pressure to pass over/near the western and north central NY area
for most of this period. At the moment, the best timing for
showers to move through our region seems to be centered around
Saturday from this activity.

Temperatures will warm from the low to mid 60s on Wednesday to the
upper 60s and 70s for the rest of this period through the weekend.


Tonight, there will be a lull in between storm activity behind the
first round before the next round of showers and/or a stray
thunderstorm arrive across the area. Although, this go around the
convection will be considerably weaker and of which may only bring a
period of low end VFR to MVFR CIGS and possibly lower VSBYS with the
arrival of the precipitation. With that said, there will also be
another period of lower CIGS likely late tonight through Monday
morning as low level moisture moves into the eastern Great Lakes
with the approach of the cold front. This cold front will produce a
few scattered showers Monday. It will become quite windy Monday,
with gusts of over 35 knots from late morning through the afternoon,
especially northeast of Lake Erie.


Tuesday and Wednesday...Mainly VFR.
Thursday and Friday...Mainly VFR with a chance of showers and


Pre-frontal trough will cross the lower Great Lakes with showers and
a stray thunderstorms into the first half of tonight. Low pressure
will then move across southern Ontario and Quebec late tonight and
Monday, with a trailing cold front crossing the eastern Great Lakes
Monday. Southwest winds will increase as the low passes by to our
north, likely producing southwest-west winds of 20-25 knots and
Small Craft conditions on Lakes Erie and Ontario. The moderate winds
will last into Monday night and early Tuesday before diminishing by
Tuesday as high pressure builds into the Great Lakes.


A cold front will move across the eastern Great Lakes Monday as
low pressure moves east across Ontario and Quebec. Southwest
winds will increase around midday Monday across Lake Ontario,
then become more westerly during the afternoon and evening
following the cold frontal passage. The increase in westerly
winds will bring higher waves on Lake Ontario, combining with
very high lake levels to bring an increased risk of lakeshore
flooding on the east half of Lake Ontario.

For Monroe, Orleans, and Niagara counties, the westerly winds
will be shore parallel Monday and early Monday night, which
will likely not increase lakeshore flooding and erosion as much
as the eastern portion of the lake.

There still is a slight chance that the winds may become more
northwest late Monday night and Tuesday. The GFS is strongest
and also most northwest, which would bring lakeshore flood
potential to the entire south shore of the lake, but it all by
itself in forecasting this scenario. The rest of the model
guidance maintains more westerly flow. Thus, the lakeshore flood
warning will only be issued for the eastern end of the lake at
this time and the western half of the lake will continue to be
watched as further guidance rolls in.


NY...Lakeshore Flood Warning from 2 PM Monday to 8 AM EDT Tuesday
for NYZ007.
Lakeshore Flood Warning from 5 PM Monday to 11 AM EDT Tuesday
for NYZ004>006.
MARINE...Small Craft Advisory from 10 AM to 11 PM EDT Monday for LEZ020.
Small Craft Advisory from 8 AM to 11 PM EDT Monday for
Small Craft Advisory from 10 AM to 11 PM EDT Monday
for LOZ030.
Small Craft Advisory from 1 PM Monday to 8 AM EDT Tuesday
for LOZ043>045.
Small Craft Advisory from 10 AM Monday to 8 AM EDT Tuesday
for LOZ042.
Small Craft Advisory from 1 PM to 8 PM EDT Monday for



NEAR TERM...AR/Hitchcock
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