Area Forecast Discussion
Issued by NWS Buffalo, NY

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423
FXUS61 KBUF 161737
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
137 PM EDT Mon Jul 16 2018

.SYNOPSIS...
A cold front will advance across the area overnight tonight with
showers and thunderstorms ahead of it. Drier air and more
seasonable temperatures will follow this cold front for the
remainder of the week.

&&

.NEAR TERM /THROUGH TUESDAY/...
Heat Advisories remain in effect generally along the NYS Thruway
across western New York for heat index values in excess of 95F
this afternoon and evening. Accompanying this heat/humidity,
afternoon instability has allowed for efficient build ups of
cumulus. Showers and storms are developing on the lake breeze
boundaries and over the terrain of the Southern Tier. Weak shear
and modest CAPE values should keep the severe threat largely in
check except for an isolated collapsing core. However, PWAT
values in excess of 1.75 inches may yield a heavy rain producer
or two.

Going into the evening, a cold front starts to slide from its
current position over central Michigan toward western Lake
Ontario. Further moisture pooling and differential PVA should
facilitate overcoming the lake induced stabilization enough to
yield showers and thunderstorms ahead of the front as it moves
across the area tonight into early Tuesday. PWAT values further
increase ahead of it to just shy of 2 inches, so the heavy rain
threat remains, though it should too be fairly isolated.

The front lags in passing the eastern fringe of the area Tuesday
morning, so showers and low end chances of thunder remain there
after sun up. Otherwise, rapidly drying conditions throughout
the column will yield a drastic improvement in conditions
through the day from west to east. Likewise, cold advection will
knock temperatures back several degrees. This will make heat
index values drop quite a bit more than temperatures, resulting
in fairly comfortable July conditions.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
The broad Canadian-sourced high pressure will continue to
provide a cooler/drier and more comfortable airmass across
western and north- central New York Wednesday and Thursday. This
high along with a mid- level ridge pivoting across the Great
Lakes will support dry weather through the end of the work week.
Daytime highs in the mid to upper 70s Wednesday will climb back
into the low to mid 80s through Thursday. The drier airmass
will also mean cooler nights dipping into the 50s across most
locations. Meanwhile humidity levels will be very comfortable
thanks to surface dewpoints ranging in the lower to mid 50s.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
The center of the surface high will shift off the New England coast
Friday with surface ridging extending west across the eastern Great
Lakes. Expect that the ridging will provide for another dry day
Friday ahead of our next storm system working into the upper Great
Lakes. A general southerly flow on the back side of the surface high
will advect increasing amounts of warmth and moisture into our
region. High temps Friday will return above normal with readings
mainly in the mid to upper 80s while dewpoints make a run for 60F
returning a more humid feel to the air.

Multi-model 00z consensus then shifts a surface low north/northeast
across the upper Great Lakes into Ontario Province over the weekend.
An associated occluded front looks to make a slow push toward or
across WNY over the weekend with the consensus showing a chance for
showers/storms at least across WNY Saturday. By Sunday all of the
forecast area will see a chance for precip from what models are
showing as a coastal low with tropical origins lifting north ahead
of the slow/stalled front. Heat and humidity will linger Saturday.
Sunday will be more tricky with cooling possible if the front were
to push east of the forecast area.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
Showers and thunderstorms are developing on the lake breeze
boundaries and over the Southern Tier this afternoon. These are
already in the vicinity of KJHW, but they are likely to spread
toward KROC in the upcoming hours. Otherwise, most places will
be waiting for the overnight arrival of a cold front for more
organized showers/storms. Visibility restrictions will be more
likely with frontal activity that musters more intensity. With
the frontal passage, winds will rapid switch from SW to NW on
Tuesday, ushering in clear skies as drier air arrives in the
afternoon.

Outlook...

Tuesday...VFR, except MVFR in showers and thunderstorms.
Wednesday through Friday...VFR.
Saturday...VFR, except MVFR in showers and thunderstorms.

&&

.MARINE...
Showers and thunderstorms will move from west to east across the
lakes overnight as a cold front approaches.

A cold front will pass across the Eastern Great Lakes region late
tonight and early Tuesday, with west to northwest winds freshening
Tuesday and Tuesday night. This may bring wave heights and wind
speeds to advisory levels, especially on Lake Ontario on Tuesday.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...Heat Advisory until 8 PM EDT this evening for NYZ001>006-010-
     011-013-014.
MARINE...None.

&&

$$

SYNOPSIS...Fries
NEAR TERM...Fries
SHORT TERM...Smith
LONG TERM...Smith
AVIATION...Fries
MARINE...Fries



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