Area Forecast Discussion
Issued by NWS Buffalo, NY
FXUS61 KBUF 310602
Area Forecast Discussion
National Weather Service Buffalo NY
202 AM EDT TUE MAY 31 2016
High pressure will build across the region through Wednesday
bringing a stretch of fair weather and near-normal temperatures.
Warm and humid conditions will return Thursday ahead of the next
cold front that will move through the region by Thursday evening.
.NEAR TERM /THROUGH TODAY/...
High pressure building into the region behind a cold front to our
east is resulting in mostly fair weather across western and north
central NY. Mostly clear skies and diminishing winds will combine
with low level moisture in the southern tier valleys to produce some
valley fog overnight. Temperatures tonight will run a bit cooler
than the last few nights, with radiational cooling and a cooler
airmass in place, lows will bottom out mainly in the 50s.
Very dry airmass from H8 to H4 over the Great Lakes will remain in
place through Tuesday. Scattered stratocumulus clouds will reform
Tuesday afternoon along and inland from the lake breezes. Highs on
Tuesday will recover to the mid to upper 70s.
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
Tuesday evening a weak mid level trough and surface front will swing
east through Quebec, with the trailing weak surface boundary sagging
slowly south across the area. This system will be moisture starved
with nothing more than a few evening clouds across the North
Country, and a subtle wind shift for the remainder of the area. High
pressure will then build into Quebec overnight with clearing skies.
The clear skies and drier airmass will allow for good radiational
cooling with lows in the low to mid 50s in most areas, and upper 40s
in some of the cooler Southern Tier Valleys and Tug Hill region.
On Wednesday high pressure will build east across Quebec and
northern New England, with subsidence and drying extending down into
the lower Great Lakes and providing ample sunshine and low humidity.
High temperatures will reach the upper 70s in most areas, with
northeast flow keeping the south shore of Lake Ontario cooler.
Later Wednesday night and Thursday a mid level trough and surface
low will move into northwest Ontario province just north of Lake
Superior, while a surface cold front moves into the central Great
Lakes Wednesday night and crosses our region on Thursday. The latest
12Z model runs continue to speed up this system by a few hours over
previous runs, with showers possibly reaching far western NY as
early as late Wednesday night. A better chance of rain will arrive
Thursday as the cold front moves from west to east across the area.
The stronger large scale forcing will remain over the western Great
Lakes in closer proximity to the mid level trough, but there is
enough large scale ascent from a weak mid level shortwave and upper
level jet combined with low level convergence along the front to
justify increasing POPS into the likely range for Thursday and
Thursday evening. Instability will increase just ahead of the front
with SBCAPE reaching 1000J/kg, supporting a few scattered
thunderstorms as well.
Thursday night any showers and scattered thunderstorms will end from
west to east following the passage of the cold front as drier air
advects into the lower Great Lakes. Expect the last of the rain to
clear the eastern Lake Ontario region by daybreak Friday.
On Friday humidity will be on the way down again behind the front as
a drier airmass builds into the region. Skies will partially clear,
although diurnal cumulus will likely form along and inland from the
lake breeze boundaries yielding a mix of sun and clouds for the
afternoon. Highs will reach the mid to upper 70s in most areas.
.LONG TERM /SATURDAY THROUGH MONDAY/...
It will be a dry and pleasant start to next weekend as the forecast
area will be located just downstream of an shortwave upper level
ridge. Models are currently in good agreement on translating the
ridge across Western and North-Central New York Saturday, preserving
one more day of fair weather across the region, perhaps with the
exception of a few innocent afternoon cu and an increase in high
clouds across the West late in the day. Temperature-wise, we will
still be running a shade above average, thanks to the aforementioned
Moving on into the latter half of the coming weekend, things will
become more unsettled across the Lower Great Lakes as a pronounced
shortwave progged to dive out of the Canadian Rockies and across the
Upper Great Lakes arrives on our doorstep Saturday Night. Guidance
begins to diverge slightly from this point onwards, with the 12Z
ECMWF favoring a slightly faster and less amplified solution...a
logical assumption given our time of year and the GFS tendency to
over-do these kinds of systems early on. Either way, expect at least
a chance of showers breaking out Saturday night across Western NY.
By Sunday, the entire forecast area will be in the bullseye of the
upper level trough and accompanying surface low. While airmass
running out ahead of this system will not be nearly as hot/muggy as
we saw the last few days, temperatures on Sunday will still run 5
to 10 degrees above average. Given abundant synoptic forcing and
decent instability, expect scattered to numerous showers and
thunderstorms Sunday. Aforementioned synoptic forcing may allow
convection to linger well into Sunday night with another round
possible Monday as the upper level low center potentially stalls
over New England.
Looking farther out, the pattern shaping out next weekend may well
be slow to change in the following week, as the classic blocking
ridge over the Rockies and troughing over the Northeast tends to be
climatologically favored. This will likely lead to generally cooler
and more unsettled weather moving into the second week of June.
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
High pressure building into the region will allow for light winds
overnight, with mostly clear skies. Widespread VFR will prevail
tonight and again on Tuesday as the high continues to build across
the region. The only exception is a low chance for IFR fog at KJHW
tonight as Southern Tier valley fog forms between 08Z and 11Z. Have
included some MVFR fog in the KJHW TAF to highlight this potential.
Tuesday night and Wednesday...VFR.
Thursday and Friday...Mainly VFR with a chance of showers and
Mainly dry conditions expected through Wednesday under high
pressure. Winds will increase to around 15 knots which will produce
choppy wave action but still well below small craft advisory
criteria. A cold front passing through late Thursday may bring
thunderstorms with gusty winds and higher waves. High pressure will
build into the area late Friday and Saturday.