Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 290247
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
1047 PM EDT SAT MAY 28 2016

.SYNOPSIS...
Mid summer conditions will remain in place through Sunday...as high
pressure anchored off the East Coast will continue to pump near
record warmth and moderately high humidity northwards across our
region. This environment will support the potential for more
widespread showers and thunderstorms Sunday afternoon and evening as
a weak trough crosses the region. A weak cold front will then cross
the area Sunday night and bring a return to somewhat cooler and less
humid air early next week.

&&

.NEAR TERM /THROUGH SUNDAY/...
Given the lack of large scale forcing for ascent, expect the
majority of the convection to diminish this evening as the boundary
layer stabilizes. A number of various models keep scattered storms
going through much of tonight and into Sunday morning, including the
NAM, Canadian GEM, and GFS. With little or no synoptic scale
forcing, this just doesn`t seem plausible. With this in mind, have
gone with a dry forecast from mid evening through the overnight with
skies becoming partly cloudy. It will remain very mild overnight
with lows in the upper 60s to around 70 on the lake plains, and mid
60s in the cooler Southern Tier valleys and Lewis County. The very
moist low levels will promote some patchy fog, especially in the
typical Southern Tier river valleys.

On Sunday expect mainly dry weather to last through mid to late
morning, with morning convection seen in some model guidance again
not very plausible given the lack of synoptic scale forcing and time
of day. Through the course of the day this will change as the strong
mid/upper level ridge drifts to the east coast, allowing a
convectively augmented mid level shortwave and vorticity maxima to
drift across western and central NY during the afternoon. The
increase in large scale forcing will interact with the mesoscale
lake breeze and terrain boundaries to produce a better chance of
more widespread deep moist convection than has developed over the
past few days. Moderate instability will be in place, as SBCAPE
reaches around 2000J/kg inland from the lakes by early afternoon.

The combination of large scale and mesoscale features along with
moderate instability supports high likely POPS for the afternoon
from the Southern Tier into the Genesee Valley and western/northern
Finger Lakes. Expect more widespread coverage than today or recent
days in this area. Southwest flow will again force stable lake
shadows to develop northeast of the lakes, with a much lower chance
of convection near Buffalo and Niagara Falls, and also near
Watertown. By late in the day a few scattered storms may develop in
these areas despite the stable lake shadows as the mid level
shortwave approaches.

The environment will again not be favorable for severe storms, with
a lack of deep layer and low level shear, and a tall/skinny CAPE
profile suggesting only moderate strength updrafts. The environment
will be favorable for some heavy rain producers however, with short
Corfidi storm propagation vectors and PWAT approaching 1.75 inches.

The increase in showers/storms and cloud cover will keep
temperatures down a little, 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.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
A shortwave trough and surface cold front crossing the Great Lakes
will continue across western and central NY on Memorial Day
suppressing the upper level ridge to off the East Coast. This will
bring some relief to the mid-summer like weather of recent with more
seasonable conditions although temperatures will still run a bit
above normal through the first part of next week. Sunday night looks
to still run very mild and humid as the cold front should not arrive
until late in the night of Sunday morning. The shortwave and
approaching front will still support chances of showers and
thunderstorms overnight and possibly into Monday morning but limited
instability and shear should keep activity sub-severe.

The front and shortwave trough pass east across the forecast area
Monday. Timing of the front looks to only support a chance of
showers and thunderstorms mainly over or east of the Finger Lakes
with much of western NY dry for Memorial Day. Any severe potential
should be limited to east of the forecast area. Models show 850mb
temps slipping back toward 10-12C which should hold surface high
temperatures to the mid 70s to about 80F. Drier air behind the front
will also help to scale back humidity levels into Monday night with
dewpoints slipping from the 60s back into the 50s. Mainly clear
skies Monday night should allow for lows to slip back to more
comfortable level for the first time since mid-last week.

High pressure and ridging building back overhead on Tuesday will
bring dry conditions through Tuesday night with Highs peaking in the
70s and more comfortable humidity levels with dewpoints in the low
50s. Overnight lows will slip back into the 50s with another night
of mainly clear skies.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
Dry and increasingly warm weather will characterize the middle
portion of next week as upper level ridging amplifies and crests
across the region Wednesday into Thursday. Look for highs to run in
the low to mid 80s on Wednesday with Thursday potentially being the
warmest day of the week next week with readings once again reaching
into the mid 80s...and possibly higher...as 850mb temps potentially
climb as high as +14 to +16C on increasing southerly flow.

This warm and moist southerly flow will be increasing ahead of a
robust upper level trough and associated surface cold front that is
currently progged to move across the Lower Great Lakes sometime
Thursday night into Friday. This in turn will bring a return of
showers and thunderstorms to Western and North-Central NY. The
remnants of Tropical Storm Bonnie and the position and strength of
downstream upper level ridging just off of the East Coast will
affect the speed of the aforementioned front and its progression
across the forecast area at the end of next week, with the GFS
stalling out the front across out area while the ECMWF pushes the
front east into New England across a weaker, flatter East Coast
ridge. For the time being, will maintain chance pops across Western
New York Friday into Saturday with slightly cooler temperatures
owing to the presence of clouds and showers in the vicinity of the
front with cooler and drier air behind.

&&

.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
Isolated thunderstorms over the western So Tier will diminish late
this evening. This will leave mainly dry conditions overnight. With
high surface dewpoints, expect plenty of light BR to develop with
MVFR VSBY late tonight and Sunday Morning. Some Southern Tier river
valley fog is also likely, with local IFR including KJHW. The fog
and BR will burn off by mid morning Sunday, with a return to mainly
VFR.

From late Sunday morning through the afternoon expect showers and
thunderstorms to become more numerous from the Southern Tier into
the Genesee Valley and Central NY, after about 17Z including KJHW
and KROC. This will bring areas of MVFR with local IFR. Stable lake
shadows northeast of the lakes will again keep areas near KBUF-KIAG-
KART drier with VFR prevailing through the afternoon.

Outlook...
Monday...Mainly VFR with a chance of showers and thunderstorms
eastern areas.
Tuesday through Thursday...VFR.

&&

.MARINE...
Light winds and flat wave action will continue through the weekend
with winds generally 12 knots or less and waves less than 2 feet.

On Sunday a weak trough will cross the region and may produce
somewhat more widespread showers and thunderstorms. A few of these
storms may impact lakes Erie and Ontario with locally higher winds
and waves.

A cold front will then cross the region Sunday night 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 28th...Record High Maximum...86F...2012
......................Record High Minimum...69F...1911

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


ROCHESTER...

Today......May 28th...Record High Maximum...93F...1911
......................Record High Minimum...68F...1939

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


WATERTOWN...

Today......May 28th...Record High Maximum...85F...2012
......................Record High Minimum...64F...1987

Sunday.....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...CHURCH/HITCHCOCK
NEAR TERM...CHURCH/HITCHCOCK
SHORT TERM...SMITH
LONG TERM...WOOD
AVIATION...CHURCH/HITCHCOCK
MARINE...CHURCH/HITCHCOCK
CLIMATE...THOMAS



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