Area Forecast Discussion
Issued by NWS Buffalo, NY

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FXUS61 KBUF 202035

Area Forecast Discussion
National Weather Service Buffalo NY
435 PM EDT Thu Jul 20 2017

Clearing skies and dry weather expected tonight into Friday as weak
high pressure builds in from the northwest. 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.


All convection has shifted well to the southeast of western NY late
this afternoon with a very stable atmosphere in place in the wake of
the storms. Some lingering convective debris clouds linger over
western NY but skies are clear in the North Country. Expect skies
clear across the entire region overnight with weak high pressure
beginning to build southeast. Low temps are forecast to dip into the
mid to low 60s as dewpoints only slowly slip overnight.

Friday, an area of weak central Canadian-sourced high pressure will
settle southeast from the Upper Great Lakes. While an isolated
leftover shower cannot be totally ruled out across the western
Adirondacks the day should generally be dry and feature a decent
amount of sunshine. Temperatures will be seasonable in the upper 70s
to mid 80s with a little more comfortable humidity levels as
dewpoints drop back into the lower 60s with northwest flow.


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.


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
or so.


Drying is occuring across the region in the wake of earlier storms.
Some patches of MVFR low clouds linger at KBUF/KIAG but should
lift/scatter out before 00z. All sites will then run VFR as high
pressure builds in from the northwest tonight with partial clearing.
VFR will continue on Friday with high pressure settling over our

Friday night...VFR.
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 tonight 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 light side.





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