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000
FXUS61 KBUF 190600
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
200 AM EDT Thu Jul 19 2018

.SYNOPSIS...
High pressure will settle across our region through Thursday
resulting in dry and comfortable weather. This high will then slide
off the New England coast with a southerly return flow supporting
increasing heat and humidity on Friday. Chances for showers and
thunderstorms will then be on the increase for the weekend as a
slow-moving low pressure system will approach the area.

&&

.NEAR TERM /THROUGH TODAY/...
Sprawling high pressure will move across the region with dry weather
through Thursday.

Aside from a few thin wispy patches of cirrus from time to time,
mainly clear skies will prevail through the overnight. The
combination of both a dry airmass and dry soil conditions will lead
to a fairly wide diurnal temperature range by mid-July standards.
Will hedge forecast lows a bit below guidance as good radiational
cooling conditions will allow temperatures to fall into the lower to
mid 50s along the immediate lakeshores and into the mid 40s across
the interior valleys, with a few of the coolest spots possibly
touching the lower 40s. This will also result in some fog
developing in the typical river valley locations across the Southern
Tier and east of Lake Ontario.

Dry and pleasant conditions will continue for Thursday, with mainly
sunny skies and just a light breeze through the afternoon. Will tack
on about 5 degrees as 850mb temperatures warm to around +12C by
Thursday afternoon. This will yield high temperatures on Thursday
ranging from the mid 70s to lower 80s.

&&

.SHORT TERM /TONIGHT THROUGH SUNDAY/...
Thursday night high pressure will drift off the New England coast,
with enough subsidence and dry air hanging back across our region to
bring another clear night. Increasing southeast flow and warm
advection will keep temperatures milder, with lows in the upper 50s
to lower 60s on the lake plains, and low to mid 50s in some of the
cooler Southern Tier valleys and east of Lake Ontario.

Friday high pressure will remain off the New England coast.
Meanwhile a cutoff upper level low and associated surface low will
drift slowly towards the southern end of Lake Michigan. Deeper
moisture and better forcing will remain west of the area through
late Friday afternoon, keeping any shower chances away from our
region. There will be some increase in mid level clouds across
Western NY as moisture begins to spread into the area. 850mb temps
rise to +15C to +16C in the southerly flow ahead of the next system.
This will support highs in the upper 80s to lower 90s on the lake
plains with an added boost from southeast downslope flow, and mid
80s farther inland.

Friday night and Saturday the vertically stacked low to our west
will spin in place across Indiana, keeping the bulk of the deeper
moisture and better forcing west of our area across Ohio and far
western PA. Some model guidance including the lastest 12Z NAM and
GEM suggest a few scattered showers or a thunderstorm may clip far
Western NY later Friday night and Saturday. If this does occur,
coverage will remain very spotty. The rest of the area will remain
dry with lingering subsidence and dry air from the departing high
keeping moisture at bay. Lows will remain warm Friday night with
ongoing southeasterly flow and some increase in clouds. Expect upper
60s on the lake plains and lower 60s across interior areas. Highs on
Saturday will reach the mid to upper 80s on the lake plains, and
upper 70s to lower 80s across higher terrain.

Saturday night and Sunday the vertically stacked low to our west
will make only very slow progress drifting to the southeast across
the lower Ohio Valley. Meanwhile a separate low will move northward
along the eastern seaboard, reaching New England on Sunday. Some of
the deeper Atlantic moisture associated with this system may get
captured by the Ohio Valley low, spreading deeper moisture into at
least eastern portions of our area. The overall increase in moisture
and weak forcing ahead of these two systems will bring a gradual
increase in shower and thunderstorm chances from south to north
across the area later Saturday night and Sunday. The increase in
clouds and shower coverage will bring temperatures down some for
Sunday, with highs in the upper 70s to lower 80s at lower elevations
and mid 70s on the hills.

&&

.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
The low pressure system over the Ohio Valley on Sunday will slowly
drift southwest toward the lower Mississippi Valley and weaken to an
open wave through Tuesday morning. An abundance of moisture will
remain in place over the eastern third of the U.S., as this area of
low pressure combined with an area of high pressure off the Atlantic
coast provides a southerly flow along most of the east coast.
Expected precipitable water values of 1.50" or greater during this
time frame will be near or above values in the 90th percentile for
these days. During this time a stationary boundary will also stall
over the area and combined with the moisture over the region provide
at least chance POPs for most of this time period. Depending on
exactly where the best moisture axis establishes during this time
period, some locally heavy showers or thunderstorms will be
possible.

Temperatures during this time period will generally range from the
upper 70s to low 80s, with cloud cover and rain showers affecting
some of the potential warming. Low temperatures during this time
period will generally range from the upper 60s to around 70.

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
High pressure will build across the region through Thursday with
generally VFR conditions and mainly clear skies.

The only exception to widespread VFR conditions could be across the
river valleys of the Southern Tier and east of Lake Ontario where
some fog and stratus may develop between 08 and 12z. This could
impact sites such as KJHW and KELZ. Any leftover valley fog will
lift out by mid-morning Thursday, leaving widespread VFR conditions
area-wide through the end of the TAF period.

Outlook...
Thursday night and Friday...VFR.
Saturday...Mainly VFR...with just a chance of showers and
thunderstorms/attendant MVFR across far western New York.
Sunday and Monday...VFR/MVFR with a chance of showers and
thunderstorms.

&&

.MARINE...
High pressure over the Lower Great Lakes early this morning will
drift to the coast by Thursday evening. The area of high pressure
will become anchored along the New England coast Thursday night and
Friday. This will result in continued light winds and negligible
waves across the Lower Great Lakes. While this will translate into
nice conditions for most recreational boating activities...winds may
actually be too light today for ideal sailing.

Looking ahead to the weekend...low pressure will make its way from
the Upper Mississippi Valley to about Ohio by Saturday. This will
promote deteriorating conditions with scattered showers and
thunderstorms over Lake Erie and the western third of Lake Ontario
with winds freshening from the southeast. Meanwhile fair weather
should persist over the bulk of Lake Ontario. Unsettled weather is
expected to become more widespread across all of the Lower Great
Lakes for the second half of the weekend.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...None.
MARINE...None.

&&

$$

SYNOPSIS...JM/RSH
NEAR TERM...JM/RSH
SHORT TERM...Hitchcock
LONG TERM...SW
AVIATION...JM/RSH
MARINE...RSH