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000
FXUS61 KBUF 251054
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
654 AM EDT Mon Sep 25 2017

.SYNOPSIS...
High pressure will keep dry and very warm weather across our region
through most of Wednesday. An approaching cold front may finally
bring a chance of a few light showers late Wednesday and Wednesday
night. This front will usher in much cooler temperatures for
Thursday through next weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
Areas of river valley fog will continue across the western Southern
Tier through mid morning. Elsewhere expect more patchy, light fog in
rural areas through early this morning. All of the fog will
dissipate by 9AM-10AM.

High pressure surface and aloft will remain over New England and the
eastern Great Lakes today. This will continue to provide a good deal
of sunshine, although there will be a modest southwest to northeast
increase in high/thin cirrus clouds. Weak easterly flow in the 925mb-
800mb layer may also bring enough Atlantic moisture into the western
Southern Tier to support scattered diurnal cumulus this afternoon
across the higher terrain. 850mb temps around +19C will continue to
support high temperatures almost 20 degrees above normal,
translating to upper 80s to around 90 at lower elevations. Local
lake breezes will develop and keep the immediate lakeshores a little
cooler. The record highs for today are 87 in Buffalo, 92 in
Rochester, and 89 in Watertown. The Buffalo high is most in
jeopardy, while Rochester and Watertown will be difficult to reach.

High pressure remains in place tonight. Diurnal cumulus will
dissipate this evening across the western Southern Tier, with a
continued slow increase in high/thin cirrus clouds. Temperatures
will be very mild given the now humid airmass, with lows in the
upper 60s on the lake plains and lower 60s across the interior
Southern Tier and Lewis County. Expect more river valley fog across
the western Southern Tier late tonight, with patchy lighter fog
elsewhere.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
The region will remain underneath ridging at the surface and aloft
to begin the period. This will maintain the dry weather pattern with
much above normal temperatures. 850 mb temperatures will be around
+18C Tuesday, supporting another day of unseasonably hot
temperatures with most highs generally in the mid to upper 80s, with
a few spots making another run at the 90 degree mark. The warmest
readings are expected across inland areas away from local lake
breeze circulations.

Ridging will weaken Wednesday as a shortwave passes to our north.
This will push a weak cold front across the region Wednesday
afternoon and evening. This timing reflects the slightly consensus
of 00Z guidance. Model guidance continues to show limited moisture
with the front with the best dynamic forcing well to our north.
Expect a few showers with the front Wednesday afternoon and evening,
but these will be scattered in nature with many areas likely to
dodge this small chance of rain.

Temperatures will still be well above normal on Wednesday, with the
front not crossing until late in the day. Even with its passage, the
`cold` front will struggle to lower temperatures to normal.
Temperatures will again climb into the 80s in most areas Wednesday.
Cooler temperatures in Buffalo will be due to the increasing
southwesterly flow which will enhance the lake breeze, but even so
the airport will probably reach the 80 degree mark. Temperatures
will gradually cool Wednesday evening with lows in the 50s Wednesday
night, which is still several degrees above normal for late
September.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
Our stretch of summer-like weather comes to an end on Thursday
behind a cold front. Temperatures are forecast to fall back to more
typical levels for this new Fall season lasting through next
weekend. The front is forecast to be east of western and north-
central NY by Thursday morning and is what will help to steer
Hurricane Maria away from the East Coast. A ridge of high pressure
will shift over our region with any lingering showers east of Lake
Ontario coming to an end leaving dry and much cooler conditons
settling in through the day.

A much sharper longwave trough axis and secondary surface cold front
is shown in the models to drop across our region Friday or Friday
night. This will bring a chance of rain showers and another shot of
cold air advection. 00Z guidance has trended a bit stronger with
this shortwave, supporting slightly higher chances for showers and
slightly cooler temperatures behind the front. 850mb temps could
drop to or a few degrees below zero C Friday night or Saturday night
with a north to northwesterly flow over the lakes. Expect this
airmass to contribute to some lake enhancement behind the cold front
with a chance of showers south of the lakes Friday night into
Saturday.

High temperatures will generally be in the lower to mid 60s
throughout the period, except Saturday which will be a bit cooler
with highs around 60. Overnight lows will generally be in the 40s,
with the typically cooler interior valleys and North Country dipping
into the 30s Saturday night.

&&

.AVIATION /12Z MONDAY THROUGH FRIDAY/...
High pressure will remain over the area through the TAF period.
Expect typical river valley fog across the western Southern Tier
through mid morning with local IFR. Some of this will impact KJHW
for a few hours before sunrise. Elsewhere expect patchy, generally
lighter fog through early this morning. This will produce some areas
of MVFR to IFR VSBY across the region, mainly impacting the KIAG and
KART TAFs.

The fog will dissipate by 13Z-14Z, leaving VFR to prevail with
nothing more than some thin high cirrus, and perhaps some diurnal
cumulus across the higher terrain of the Southern Tier during the
afternoon.

Mainly clear skies and light winds will again allow fog to develop
late tonight with patchy MVFR to IFR VSBY across much of the region,
and more concentrated IFR fog in the river valleys of the western
Southern Tier.

Outlook...
Tuesday...VFR - except local IFR/MVFR conditions in
Southern Tier valley fog during the morning.
Wednesday through Friday...Mainly VFR with a chance of showers late
Wednesday afternoon, Wednesday night, and again on Friday.

&&

.MARINE...
High pressure will remain in place across the Lower Great Lakes
right through Wednesday morning. This will provide a long stretch of
very light winds and flat wave action with ideal boating conditions,
but not much wind for sailing.

A cold front will cross the region late Wednesday. Northwest winds
will increase in the wake of the cold front, and may bring a round
of Small Craft Advisory conditions to Lakes Erie and Ontario late
Wednesday through Thursday.

&&

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

&&

$$

SYNOPSIS...HITCHCOCK
NEAR TERM...HITCHCOCK
SHORT TERM...APFFEL/TMA
LONG TERM...APFFEL/SMITH
AVIATION...HITCHCOCK
MARINE...HITCHCOCK