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Area forecast discussion 
National Weather Service Buffalo New York
734 PM EDT Friday may 22 2015

high pressure will provide western and north central New York
with fair weather and cooler than average temperatures through
Saturday...before warmer weather returns for the rest of the
Memorial Day weekend...along with the potential for some showers
and thunderstorms by Monday.


Near term /through Saturday/...
a well defined batch of convective showers ahead of a weak shortwave
pivoting around the upper level low are pushing through the Saint
Lawrence valley along the Lake Ontario lake breeze. Some spotter
reports indicate the stronger showers are actually producing
graupel...which is not much of a surprise given the cool surface
temperatures and relatively dry air near the surface producing cool
wet bulb temperatures. Expect these showers will die out quickly
after 8 or 9 PM local time as the shortwave passes and diurnal
instability weakens.

Tonight...clearing skies...plenty of dry air...and diminishing winds
will then set the stage for near ideal radiational cooling tonight.
Overnight lows continuing to look like they will range from the middle
and upper 20s across interior sections of the southern tier and
north country to the middle 30s along the immediate lakeshores. This
will result in frost or a freeze in most locations away from the
immediate lakeshores tonight...for which frost advisories and freeze
warnings remain in effect as outlined below.

A dome of surface high pressure will slide over the lower Great
Lakes/Ohio Valley Saturday. Sunny skies will help maximize late
may insolation and with 850 mb temperatures rising to around 6c...should
help temperatures get into the lower to middle 60s...albeit 5 to 10
degrees below normal.


Short term /Saturday night through Monday night/...
Saturday night and Sunday a surface high pressure will drift off
the southern middle Atlantic coastline. A southerly flow behind this
area of high pressure will bring warmer air temperatures northward
starting Saturday night such that there should not be a risk for
any frost for most areas. Only the coldest valleys of the inland
southern tier may have patches of frost.

Sunday will start cool and clear...but should warm into the 70s.
Clouds will begin to thicken through the afternoon as a warm front
lifts northward through the Ohio Valley.

This warm front will near the eastern Great Lakes region Monday
morning. There may be a few showers over far wny Sunday night...but
all areas will have chances for precipitation Monday as the warm
front lifts northward across the County Warning Area. Greatest quantitative precipitation forecast will be near Lake
Ontario and east of Lake Ontario where a general half inch or more
of rain may fall within thunderstorms. Basin-wide across the County Warning Area
most areas will have lighter amounts generally a tenth or two.

In addition to warmth behind the front Monday...we will also begin
to see an increase in humidity. Air temperatures Monday in the middle
70s to lower 80s...combined with dewpoints in the upper 50s will
bring a touch of humidity. Greater humidity come within the extended
time period though.


Long term /Tuesday through Friday/...
a Bermuda high parked off the southeast coast will guarantee that
this will be a warm and humid a continual feed of air
out of the deep south will make its way over our region. This will
also mean that our airmass will inherently be more unstable...
particularly during the heat of the day. Given the lack of any
synoptic boundaries though...convection will have to rely largely
on lake breeze boundaries or orographics to initiate.

That being said...have backed off on probability of precipitation for much of the long
term period. The majority of the time period should be rainfree...
so will only use 30-40 chance probability of precipitation.

Temperatures will average 10 to 15 degree f above normal through the
entire period...with dew points in the low to middle 60s giving US a
taste of sticky Summer humidity.


Aviation /00z Saturday through Wednesday/...
aside from a few showers in the vicinity of kart within the first
hour or two of the 00z taf period...all taf sites will remain VFR
with diminishing winds and clearing skies overnight.

Saturday and Sunday...VFR.
Monday...VFR/MVFR with showers likely and a chance of thunderstorms.
Tuesday and Wednesday...VFR with a chance of showers and
thunderstorms/attendant MVFR.


fresh west to west-northwest winds in the wake of a weak cold front
will reach advisory levels through early tonight. Conditions will
improve overnight as high pressure builds across the region and
winds diminish.

After that...light to modest winds and relatively minimal waves are
then expected durinf the weekend as sprawling high pressure slowly
drifts from The Spine of the Appalachians to a position just
offshore of the middle Atlantic coastline.


Buf watches/warnings/advisories...
New York...freeze warning from midnight tonight to 9 am EDT Saturday for
Frost advisory from midnight tonight to 9 am EDT Saturday for
Marine...Small Craft Advisory until 11 PM EDT this evening for lez040-
Small Craft Advisory until 11 PM EDT this evening for



short term...Thomas
long term...Thomas

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