Area Forecast Discussion
Issued by NWS Buffalo, NY

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FXUS61 KBUF 221843

Area Forecast Discussion
National Weather Service Buffalo NY
243 PM EDT FRI JUL 22 2016

Hot, humid, but generally rain-free conditions will persist through
the coming weekend as high pressure moves across the Lower Great
Lakes. A disturbance and associated front crossing the region will
bring at least a chance for showers and thunderstorms Monday before
dry weather and above-average temperatures return to the area.


It will be a quiet period across Western and North-Central New York
as upper level ridging currently centered over the northern Plains
gradually shifts to the western Great Lakes. Subsidence and very dry
air aloft ahead of this ridging will effectively stifle any nascent
convection across much of the forecast area over the next 24 hours.
The lone exception will be across the St. Lawrence Valley, where a
subtle upper level shortwave over the northern Ontario will drop
southeast across the lower St. Lawrence Valley and northern New
England. There is a chance that convection associated with this
system may clip Jefferson and Lewis counties during the day on

Regarding temperatures, it will be another warm night across the
region, though a weak front sagging south across Lake Ontario will
bring some nominal relief from the humidity, with dewpoints dropping
into the low to mid 60s, resulting in temperatures that should run
about 5 degrees cooler than last night...though all that really
means is that temperatures will fall into the mid to upper 60s,
instead of the upper 60s to mid 70s.  Abundant sunshine on Saturday
will offset slightly cooler temperatures aloft to produce highs that
will still run in the mid 80s to around 90 in the warmer spots of
the Genesee valley and Lake Ontario plain.


The bulk of the short term period will be characterized by continued
heat and humidity into early next week. Spotty shower and
thunderstorm chances increase late Sunday night into Monday before a
subtly less hot and humid airmass returns for Tuesday.

An amplified ridge axis will build across the region Sunday with a
sharp increase in 850 mb temperatures to around +20 to even +22 over
the Southern Tier by the afternoon. This will result in widespread
max temperatures about 90 across western NY and the Genesee Valley.
Low to mid 80s will remain across the North Country where the warmer
airmass is slower to arrive. Humidity will increase again,
especially toward Sunday evening as deep southwesterly flow becomes
established ahead of the next wave tracking through Ontario. Despite
the increasing heat and humidity, Sunday will remain a dry day with
rising heights aloft and large scale subsidence in place under
surface high crossing the region. This will also allow for light,
lake-breeze dominated, winds.

Sunday night into Monday, the aforementioned trough will track from
Ontario toward Quebec near the Hudson Bay with a trailing cool front
that will cross the region on Monday. A very warm night is in store
Sunday night ahead of this front as dew points climb to near 70 by
Monday morning, and low temperatures in the low to mid 70s, again
not a comfortable sleeping night. Shower and thunderstorm chances
will increase across the region early Monday morning, with the focus
likely shifting toward our east by Monday afternoon. Despite the
potential for a few stronger storms featuring locally heavy rain and
gusty winds, expect these will again be widely scattered, with may
locations seeing little if any precipitation. Again weakly forced
frontal passage should be rather lackluster and will offer little if
any drought relief.

High pressure builds in on Tuesday with northwesterly winds in place
across the region. This will bring a slightly cooler and drier
airmass into the region as dew points fall into the lower 60s and
850 mb temperatures around +16C promote high temperature in the low
to mid 80s.


Model consensus continues to bring an upper-level shortwave across
the Great Lakes on Monday. This trough will drive a surface cold
front across our forecast area with renewed chances of showers and
thunderstorms. Southwest winds ahead of the front will increase
humidity levels with dewpoints again pushing toward the 70 degree
mark. The combination of heat and humidity with frontal timing
working with the diurnal heating cycle could lead to an unstable
environment for storms to work with. GFS forecast SBCAPE of 1000-
2000 j/kg and 0-6km bulk shear increasing to 30-35 kts may even
support the risk for a few strong to severe storms if these levels
or higher can be reached. High temperatures are expected to reach
into the mid to upper 80s ahead of the front with 850mb temperatures
forecast to build toward +20C.

The front will push east Monday evening with chances of showers and
thunderstorms tapering off west to east. Temperatures will remain on
the mild side overnight as humidity will be slow to scour out behind
the front. Modified continental polar air building in with high
pressure behind the cold front should lead to a string of mainly dry
days Tuesday through Thursday with more comfortable temperatures
running closer to but still a touch above 30-year normal levels.
Humidity levels will also be a touch more comfortable but still
noticeable with dewpoints hovering around 60. High temps should run
in the upper 70s to low 80s with overnight lows ranging through the
60s. Have included a slight chance for showers on Thursday with a
weak mid-level wave to the west.


As expected, lower cigs have mixed out across much of the forecast
area this afternoon. Conditions should continue to improve across
remaining TAF sites as mixing continues. The arrival of slightly
drier air from the north in the form of a weak cold front should
prevent the development of IFR cigs overnight, though a few
scattered areas of low cloud may be possible late tonight across the
Southern Tier where rain fell this morning.

Otherwise, look for VFR conditions to persist through the remainder
of the TAF period with strong southwesterly winds this afternoon
diminishing this evening as the lake breeze circulation weakens.
Expect lake breezes to re-develop Saturday afternoon, though not
quite as strong as high pressure moves across the region.

Saturday Night and Sunday...VFR.
Sunday night and Monday... Mainly VFR with a chance of showers and
thunderstorms and associated brief MVFR/IFR.
Tuesday and Wednesday...VFR.


Fresh southwesterlies will continue to bring small craft advisory
conditions to the eastern end of Lake Erie through this evening,
before winds diminish overnight as the lake breeze circulations
weaken. While lake breezes should once again bring a light to
moderate chop to nearshore waters Saturday afternoon, high pressure
moving overhead should keep associated winds lighter, negating the
need for any SCAs or beach hazard statements. In fact, generally
tranquil conditions should persist across the lakes at least through
the balance of the weekend before a weak cold front crosses the
lakes on Monday, bringing showers and thunderstorms.


NY...Beach Hazards Statement until 8 PM EDT this evening for NYZ010-
MARINE...Small Craft Advisory until 8 PM EDT this evening for LEZ020-



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