Area Forecast Discussion
Issued by NWS Buffalo, NY

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FXUS61 KBUF 291847
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
247 PM EDT SUN MAY 29 2016

.SYNOPSIS...
Mid summer conditions will remain in place this afternoon as high
pressure anchored off the East Coast will continue to pump very warm
and humid air northward into our region. This environment will
support the potential for scattered to numerous showers and
thunderstorms this afternoon and evening mainly along and east of
the Genesee Valley as a weak trough crosses the region. A weak cold
front will then cross the area late tonight and bring a return to
somewhat cooler and less humid air for Memorial Day through midweek.

&&

.NEAR TERM /THROUGH MONDAY/...
Radar imagery early this afternoon showing scattered to numerous
thunderstorms filling in from the upper Genesee Valley east across
the Finger Lakes to central NY along an axis of stronger
instability, with SPC objective mesoanalysis showing 2000-2500 J/kg
of SBCAPE. Through late afternoon, expect the majority of convection
to focus from the Genesee Valley east across central NY in this axis
of greater instability. Farther west across western NY, the
combination of a stable lake shadow off Lake Erie and thicker mid
level cloud cover will limit destabilization and likely prevent any
organized deep moist convection.

The environment will again not be favorable for organized severe
storms, with a lack of deep layer and low level shear, and a
tall/skinny CAPE profile suggesting only moderate strength updrafts.
That said, there is always a marginal potential for a storm or two
to approach severe criteria in a moderate to strongly unstable
airmass. The environment will be favorable for some heavy rain
producers however, with short Corfidi storm propagation vectors and
PWAT approaching 1.75 inches. Given the character of some of the
stronger storms on Saturday with instantaneous rain rates of 6
in/hr, heavy rain seems of good bet today as well, most likely from
the interior Southern Tier through the Genesee Valley to central NY
from mid afternoon through evening.

The increase in showers/storms and cloud cover will keep
temperatures down just a little from yesterday, with highs in in the
mid to upper 80s across lower elevations and lower 80s across the
Southern Tier. Southwest flow will again keep the Lake Erie shore
and eastern shore of Lake Ontario cooler.

Through this evening latest high resolution model guidance and
recent radar trends suggest the most concentrated area of showers
and storms will move east across the Finger Lakes into central NY
and possibly the Tug Hill region. There is also some suggestion that
composite outflow from these storms will travel westward and aid in
developing a few scattered storms across western NY, mainly just
east of a Buffalo to Jamestown line as the westward propagating
outflow intersects the Lake Erie breeze. If this does occur, expect
this activity to remain widely scattered at best.

Overnight the stronger area of convection will head towards eastern
NY and the Adirondacks and weaken with the loss of diurnal
instability. Farther west, the surface cold front will enter western
NY after 06Z. The front may produce a few scattered showers or an
isolated thunderstorm, but weak convergence and limited instability
by this time of night should keep the activity weak with limited
areal coverage.

It will remain mild and humid most of the night until the front
arrives, with lower humidity reaching western NY around daybreak
with the cold frontal passage. Expect lows in the mid to upper 60s
on the lake plains, with lower 60s across the cooler Southern Tier
valleys and Tug Hill region.

On Memorial Day Monday the cold front will move east across the area
during the morning, reaching the eastern Lake Ontario region and
central NY by midday or early afternoon. Prior to the frontal
passage there may still be a lingering shower or isolated
thunderstorm east of the Genesee Valley. Otherwise western NY will
dry out by early morning, and the eastern Lake Ontario region will
be dry from early afternoon on. Behind the front skies will
partially clear, although diurnal cumulus will develop along and
inland from the lake breezes during the afternoon yielding a mix of
sun and clouds. Stable lake shadows east of the lakes will bring
more full sunshine along the Lake Erie shore and near Watertown.

Less humid air will filter into the area from west to east through
the day. Temperatures will still top out in the lower 80s across
lower elevations away from the lakeshores, with upper 70s across the
higher terrain.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
Temporary re-establishment of upper level East Coast ridging and
expansion of Hudson Bay centered high pressure across the eastern
Great Lakes will promote fair weather through midweek. The latter
will bring a drier, more comfortable airmass to our region under
northwest flow with plenty of sunshine during the day and mainly
clear skies at night. Breezy northwest winds are possible Tuesday as
the 12z NAM shows good mixing of a 20-30 kt jet aloft. 850 mb
temperatures of about 12C will promote afternoon surface highs in
the upper 70s to low 80s.

Comfortable dewpoint temperatures falling back to the upper 40s and
low 50s along with clear skies will promote cooler overnight
temperatures dipping into the low to mid 50s Monday and Tuesday
nights along with some patchy fog in the Southern Tier. By Wednesday
night an increasing southerly flow ahead of a cold front approaching
from the west will help hold temperatures a bit milder with
increasing clouds and humidity. Lows should only dip into the upper
50s to low 60s.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
Expanding ridging across the western US will force downstream
troughing across the eastern states heading into next weekend. This
digging trough will promote cooler temperatures working back toward
early June climatological levels along with a few chances of
precipitation.

The first chance will be associated with a weak cold front currently
forecast to shift across the forecast area mainly later Thursday
into Thursday night. Some weak instability forecast to build ahead
of the front calls for chances of showers and thunderstorms. Low end
to slight chance POPS then extend from Friday through Saturday
mainly due to the trough overhead. A shortwave trough digging into
the base of the trough on Sunday will support broadbrush chance
POPs.

Temperatures on Thursday will be the warmest ahead of the
front with upper 70s to mid 80s possible before the arrival of the
cool air limits highs to the low to mid 70s through the weekend.
Overnight lows will again dip into the 50s each night coolest inland
away from the lakes.

&&

.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
Expect numerous thunderstorms to move slowly east across the Finger
Lakes and central NY this afternoon and early evening, eventually
filling in east of Lake Ontario mainly southeast of KART. These
storms will produce local MVFR/IFR conditions, but should largely
miss the TAF sites. By late afternoon or early evening a few
thunderstorms may also develop as far west as KROC and KJHW, but
KBUF and KIAG will likely avoid most of the storms with a southwest
flow of stable air off Lake Erie. Outside of convection VFR will
prevail.

Tonight the more numerous thunderstorms will continue east towards
eastern NY. A weak cold front will cross the area late tonight and
early Monday with a few more showers and perhaps an isolated
thunderstorm, but with sparse coverage. There will likely be a brief
period of MVFR CIGS with IFR higher terrain just behind the front
for a few hours early Monday morning across western NY. By mid to
late morning VFR should prevail with drier air moving into the
region.

Outlook...
Tuesday and Wednesday...VFR.
Thursday and Friday...Mainly VFR with a chance of showers and
thunderstorms.

&&

.MARINE...
Light winds and flat wave action will continue today with winds
generally 12 knots or less and waves less than 2 feet. Scattered
thunderstorms will stay mainly over the land with little impact to
the lakes, as the cool lake waters yield more stable air over the
lakes.

A cold front will then cross the region tonight and clean out the
heat and humidity, with mainly dry conditions expected on Memorial
Day. Winds will increase somewhat on Memorial Day, up to about 15
knots which will produce choppy wave action but still well below
small craft advisory criteria.

&&

.CLIMATE...
The first extended period of summer`s warmth will be upon us this
weekend. Temperatures will climb well into the 80s, of which some
of these daily readings may near record levels. Listed below are
the records for our three climate stations.

BUFFALO...

Today......May 29th...Record High Maximum...87F...1987
......................Record High Minimum...68F...1987


ROCHESTER...

Today......May 29th...Record High Maximum...92F...2006
......................Record High Minimum...69F...1908


WATERTOWN...

Today......May 29th...Record High Maximum...87F...2012
......................Record High Minimum...63F...2006


A climatic day is between 1 AM EDT to 1 AM EDT.

Temperature records for Buffalo and Rochester date back to 1871,
while records for Watertown start in 1949.

&&

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

&&

$$

SYNOPSIS...HITCHCOCK
NEAR TERM...HITCHCOCK
SHORT TERM...SMITH
LONG TERM...SMITH
AVIATION...HITCHCOCK
MARINE...HITCHCOCK
CLIMATE...THOMAS


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