Area Forecast Discussion
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FXUS61 KBUF 291508
Area Forecast Discussion
National Weather Service Buffalo NY
1108 AM EDT WED JUN 29 2016
High pressure centered over Lake Michigan will promote fair weather
across western New York today. A mid level trough will continue
mostly cloudy skies and scattered showers east of Lake Ontario.
High pressure will bring dry weather for all on Thursday before the
next cold front brings a chance of rain showers on Friday. The
upcoming fourth of July weekend will feature plenty of sunshine with
a day to day warming trend.
.NEAR TERM /THROUGH TONIGHT/...
Considerable cloudiness continues across much of western and north-
central NY late this morning. Moist cyclonic flow within a mid-level
trough is responsible for this cloudiness and the isolated to
scattered showers over eastern Lake Ontario and central NY.
Diurnally driven instability will also support some isolated
afternoon non-severe thunderstorms.
Drier air across Ontario province will gradually work its way across
western NY through this afternoon which will promote clearing from
west to east. The increasing amount of sun will take the edge off an
otherwise cool airmass...as H85 temps in the vcnty of 10c will only
support afternoon highs in the low to mid 70s.
Tonight...high pressure centered over Lake Michigan will gradually
build across the Lower Great Lakes. The relatively fresh dry
airmass will lead to good radiational cooling tonight under
starlit skies...allowing temperatures to fall well below normal.
Temperatures by daybreak will range from the mid 40s across a good
chunk of the Srn Tier to the upper 50s along the immediate lake
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
Surface high pressure will build into the lower Great Lakes on
Thursday and provide subsidence and dry air to support nearly full
sunshine outside of a few flat diurnal cumulus inland from the
lakes. The airmass will modify with 850mb temps returning to around
+10C, which will bring highs into the lower 80s at lower elevations
with deep mixing. The strong differential heating and weak synoptic
scale flow will allow local lake breeze circulations to develop by
afternoon, with cooler temperatures within a few miles of the lakes.
Thursday night the surface high will drift to the east coast and
allow southerly return flow to develop across the lower Great Lakes.
A plume of low level moisture will move northward through PA and
into portions of the eastern Finger Lakes and central NY late
Thursday night, but any scattered showers should remain east of our
area. Otherwise expect mainly clear skies across the bulk of the
area. Lows will range from the upper 50s on the lake plains to the
lower 50s in a few of the cooler Southern Tier valleys.
On Friday a rather sharp mid level trough will move east across
Ontario and Quebec. The stronger forcing for ascent associated with
DPVA and height falls ahead of the trough will remain well north of
the Canadian border. Farther south, the tail end of the trough will
enter western NY by mid to late morning, then move to the eastern
Lake Ontario region by afternoon. A period of modest DPVA ahead of
this trough combined with low level convergence along a pre-frontal
trough will produce a few scattered showers and thunderstorms, first
across western NY by mid to late morning and then central NY and the
North Country by early afternoon. The pre-frontal trough will likely
arrive too early in the day for stable lake shadows to be
established yet, so the risk for a shower or thunderstorm will be
The actual cold front will not arrive until late in the day, but the
bulk of the moisture and convergence appear to be tied to the pre-
frontal trough. The cold front may interact with local lake breeze
boundaries to produce a few more widely scattered showers and
thunderstorms during the afternoon and evening. By this time stable
lake shadows will be established in the southwest flow regime, so
expect the Buffalo and Watertown areas to avoid most of the
afternoon and evening deep moist convection.
The passage of the pre-frontal trough relatively early in the day
will interfere with the destabilization of the atmosphere, with only
modest instability values of less than 1000J/kg in most model
guidance. The limited instability and lack of stronger forcing and
convergence late in the day will keep the severe weather risk very
Any widely scattered showers and storms will end from west to east
Friday evening with the passage of the cold front. Drying and
subsidence will bring clearing skies in most areas overnight, with
some lingering cloud cover across the North Country.
.LONG TERM /SATURDAY THROUGH TUESDAY/...
High pressure will build into the western Great Lakes and Ohio
Valley on Saturday, while a deep trough swings through Quebec. The
pressure gradient between the two will produce a moderate breeze
across the area, especially east and southeast of Lake Ontario where
winds may gust to around 30 mph. Ascent and somewhat deeper moisture
rotating through the base of the Quebec trough may produce a few
scattered showers and increased cloud cover across the North Country
Saturday afternoon and evening. Otherwise expect the rest of the
area to remain dry. A brief push of cooler air will enter the region
with highs in the mid 70s at lower elevations and around 70 across
High pressure will build into the lower Great Lakes Sunday and
Monday with abundant sunshine. Temperatures will warm to around 80
for highs on Sunday, then into the lower or even mid 80s for Monday
on Independence Day. By Tuesday both the GFS and ECMWF suggest the
start of building heat as a much warmer airmass upstream over the
midwest states begins to make headway building into the lower Great
Lakes. This will push highs into the upper 80s at lower elevations
inland from the lakes.
Looking a little farther ahead, a strong ridge building over the
central US will make enough headway eastward to allow very warm
temperatures to reach our region for the second half of next week.
Zonal flow will remain just north of the Canadian border, with a
building ridge just to our south. This may allow for an active
corridor of ridge riding thunderstorm complexes passing through the
Great Lakes for several days late next week.
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
A slow moving mid level trough will gradually push east across the
Adirondacks today while sfc high pressure will approach from Lake
Michigan. MVFR cigs continue at KROC and KJHW at 15z but should lift
to VFR levels by midday...with most of the TAF sites over the
western counties totally losing their CIGS by 18z. For sites east of
Lake Ontario though...cloud cover will be slower to clear with
scattered showers or even a isolated afternoon thunderstorm.
VFR conditions with light winds are anticipated tonight as high
pressure will build across the Lower Great Lakes.
Friday...VFR/MVFR. A chance of showers or thunderstorms.
Saturday and Sunday...VFR.
High pressure over Lake Michigan will gradually build across the
Ohio Valley and Lower Great Lakes later today into Thursday.
This will keep a weak sfc pressure gradient in place over Lakes
Erie and Ontario with relatively light winds and negligible
waves remaining intact.
The favorable conditions for recreational boating will deteriorate
somewhat on Friday...as a cold front will cross the region. This
will support scattered thunderstorm activity...and in the wake of
the front...freshening winds on Lake Erie.
Moderate to fresh winds can be expected throughout the Lower Great
Lakes Friday night and Saturday ahead of the next high pressure
system. Lower winds and waves are anticipated for Sunday into the
fourth of July.