Area Forecast Discussion
Issued by NWS Buffalo, NY

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FXUS61 KBUF 311545
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
1145 AM EDT TUE MAY 31 2016

.SYNOPSIS...
Canadian high pressure will remain in control keeping fair
weather...above normal temperatures and comfortable humidity levels
going across the region through Wednesday. Warm and increasingly
humid conditions will then return later Wednesday night into
Thursday ahead of the next cold front that will move east of the
region by Thursday night. A return to dry weather and lower humidity
will then return for the end of the week into the first part of the
weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
Weak moisture starved cold front will press south across New York
State this afternoon with Canadian high pressure once again building
across the region as we head into this evening. Visible satellite
imagery now showing some diurnal cumulus clouds along and inland
from the lake breezes, as well as across the higher terrain. The
northern edge of a thin cirrus shield will also be seen western New
York. Highs today will be in the mid 70s to around 80.

The high pressure centered north of our region will press further
into New York State and the northeastern states. This will maintain
a dry and cool flow across the area on north to northeast winds,
generally less than 10 mph overnight. Low temperatures will fall to
the upper 40s to lower 50s across inland regions and to the mid 50s
along the shores of Lakes Erie and Ontario. Expect to see valley fog
in the Southern Tier once more.

&&

.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
Our stretch of fine weather will continue on Wednesday...as the axis
of expansive high pressure centered over Hudson Bay will cross our
forecast area. Weak warm advection will set up on the backside of
the passing ridge line with H85 temps climbing into the mid teens
over the western counties. While this would suggest a warmer day...
most of the guidance packages are surprisingly low with their max
temps. Given the dry antecedent conditions (for all but portions of
the Finger Lakes)...see no reason why the airmass will not fully mix
and allow temps to climb abv 80 for most areas. That being said...
will aim a solid 5 deg above guidance by going 80 to 85 over the
western counties with 70s forecast within 10 miles of the south
shore of Lake Ontario and across the north Country. While dew points
will gradually climb during the course of the day...the higher
temps will be offset by dew points that will remain below 55.

As the aforementioned ridge drifts across New England Wednesday
night...a robust shortwave over the Upper Great Lakes will push a
cold front across Lower Michigan. The southerly flow between these
features will strengthen in the process and effectively hold our
temperatures some 10 deg higher than the previous night. Mins will
generally be within a few degrees of 60. Otherwise...dry weather
should persist with the warmer night being accompanied by a gradual
increase in cloud cover...especially over the far western counties.

Our stretch of fair dry weather will likely come to an end Thursday
and Thursday night as a cold front will ease across our region. The
eastward progression of the front will slow during this time period
though...as its mid level support will start to shear out to the
south of James Bay. The progressively weaker push could also allow a
wave or two to develop along the boundary...so will back off a
little on the timing of the associated convection. Will concentrate
the likely pops for showers and thunderstorms over the western
counties Thursday afternoon and evening...with the Finger Lakes and
Eastern Lake Ontario Regions being affected more Thursday night.
Synoptically...the convection will aided by the passing of an 80kt
H25 jet to our north...while on a more localized scale...`skinny`
SBCAPEs will climb to as high as 1000 j/kg. The kinematic profile is
not impressive for severe storms though...as 0-6km shear values will
generally be under 30 knots.

The cold front will nearly stall just to the east of our forecast
area on Friday...so will raise pops for sites east of the Genesee
Valley. Since the airmass is not really expected to change now until
at least Friday night...will make a subtle upward push to both temps
and dew points.

&&

.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
ridging aloft.

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 further down the road...there remains strong consensus among
the GFS and ECMWF ensemble members that a closed low will be found
within a significant (if not anomalously deep) longwave trough over
eastern Canada during the first full week of June. This will favor
cooler than normal conditions for much of the week...especially in
regards to daytime highs. Normal max temps for this time of year are
generally in the mid 70s.

&&

.AVIATION /16Z TUESDAY THROUGH SATURDAY/...
Widespread VFR will prevail this afternoon through Wednesday as
high pressure continues to build across the region from the north.
There will some scattered diurnal stratocumulus found along and
inland from the lake breezes again this afternoon, as well as
across the higher terrain. The only exception will be a low chance
for MVFR/IFR VSBY in 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.

Outlook...
Tonight and Wednesday...VFR.
Thursday and Friday...Mainly VFR with a chance of showers and thunderstorms.
Saturday...VFR.

&&

.MARINE...
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.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...None.
MARINE...None.

&&

$$

SYNOPSIS...JM/WCH
NEAR TERM...JM/WCH
SHORT TERM...RSH
LONG TERM...RSH/WOOD
AVIATION...JM/WCH
MARINE...CHURCH/WCH



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