FXUS61 KBUF 210519
Area Forecast Discussion
National Weather Service Buffalo NY
119 AM EDT Fri Jul 21 2017
Weak high pressure will build over the area through Friday. A
frontal boundary is then forecast to set up in the vicinity of the
lower Great Lakes this weekend, potentially bringing wet and
unsettled weather at times. Temperatures will remain near average
through the end of the week and this weekend.
.NEAR TERM /THROUGH TODAY/...
Clear skies will persist through the overnight hours as weak surface
ridging builds into the area. Mainly clear skies and light
winds will promote radiational cooling, and with surface
dewpoints still in the mid to upper 60s across many areas,
patchy fog can be expected to develop overnight - particularly
across the usual trouble spots in the river valleys of the
Southern Tier and Niagara county. Areas where heavy rain fell
Thursday afternoon will also be more prone to fog formation
overnight. The aforementioned dewpoints will limit temperature
falls, yielding another muggy night across the region, with lows
in the mid 60s, with lower 60s to be found in the North
Look for plenty of sunshine to wrap up the work week on Friday, as
high pressure will continue to drift east across the lower Great
Lakes. A modestly cooler airmass advecting across the region will be
offset by greater insolation, and the net result will be
temperatures that will be close to what we saw today, with highs in
the upper 70s to lower 80s.
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
High pressure to our east will maintain quiet conditions Friday
night across our region. It will be a muggy Friday night, and this
warmth and humidity will only increase Saturday as a warm front from
the west begins to push towards our southern counties. A ribbon of
much higher theta-E along this warm front will likely produce
showers and thunderstorms later Saturday and Saturday night. This
activity will need to be watched for severe potential as 0-6 km bulk
shear values reach 40 to 45 knots, SB CAPE values increase to 1500
to 2000 J/KG. Greatest threat for severe weather in our CWA will be
along Lake Erie and across the So. Tier. We will continue to mention
this possibility within the HWO produce for now.
Sunday and Sunday night we will remain humid, and as the main
surface low tracks across the region, additional showers and
thunderstorms will remain possible.
Temperatures will remain at or just above normal through the period,
especially Saturday night where a few locations may not drop below
70F across WNY.
.LONG TERM /MONDAY THROUGH THURSDAY/...
As we move into the longer term portion of the forecast...general
chances for showers and thunderstorms should linger through both
Sunday night and Monday as upper level troughing digs across our
region...and as the axis of the surface low settles southeastward
to the Mid-Atlantic coastline. Any leftover showers should then come
to an end between Monday night and early Tuesday as high pressure
and cooler/drier air begins building into our area...with fair and
dry weather then following for the rest of the period as the high
first settles directly overhead...then slowly drifts eastward to
the Atlantic coastline.
Regarding temperatures...the digging upper trough and arrival of
cooler and drier air will translate into temperatures and humidity
levels falling off through Tuesday...which should feature daytime
highs generally be in the mid 70s and comfortable dewpoints in the
mid to upper 50s. Both will then begin to rebound some on Wednesday
as the axis of the ridge slides to our east and a southwesterly
return flow develops on its backside...resulting in temps climbing
back to around 80 degrees and dewpoints recovering to around 60
.AVIATION /05Z FRIDAY THROUGH TUESDAY/...
High pressure will build into the lower Great Lakes overnight.
However, the combination of light winds, clear skies, and high
dewpoints in the mid to upper 60s will promote areas of fog/stratus
formation that may end up bringing IFR and potentially LIFR
conditions at times, especially KJHW and KBUF. Patchy fog may end up
being an issue at KART/KIAG/KROC as well. For Friday, expect
widespread VFR conditions to persist throughout the day, as high
pressure continues to slide east across the forecast area.
Saturday and Sunday...VFR/MVFR with some showers and thunderstorms.
Monday...Mainly VFR but with a chance of showers.
High pressure over the upper Great Lakes overnight will expand
across the lower Great Lakes for Friday and Friday night. This will
result in fine conditons for recreational boating to end the work
week. A frontal boundary is then expected to stall near the lower
Great Lakes this weekend with chances of showers and storms again
becoming a threat but winds/waves are expected to remain on the
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