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000
FXUS61 KBUF 130713
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
313 AM EDT Sat Apr 13 2024

.SYNOPSIS...
Deep low pressure will continue to progress northward into Quebec
tonight and Saturday. Periods of rain will continue to produce a
soaking rainfall this afternoon into tonight. Cold air arriving
tonight will change rain to wet snow, with some slushy accumulations
possible across the higher terrain tonight and Saturday morning.
Additionally, windy conditions will prevail into Saturday afternoon.
Expect some dry time Saturday night before the next clipper system
brings rain and possible thunder back into the region Sunday.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A very large and dynamic low pressure system centered north of
Lake Ontario will continue to gradually broaden into a deep
longwave trough over the eastern CONUS through Saturday. As it does
so, its 985mb surface low centered north of the forecast area will
slide northeast further into Quebec tonight. The aforementioned
trough will then translate east of the region tonight, with a cooler
airmass accompanying a secondary cold front to cross the region
tonight into Saturday.

Rainfall associated with a secondary cold front is moving across the
Southern Tier. Colder continues to work in and we have seen some wet
snowflakes across the higher terrain of the interior Southern Tier,
but nothing on the ground as of 3am. This will likely knock
total snowfall amounts down at least some from the earlier storm
total snow forecast for 4 to 8 inches across the interior areas
away from Lake Erie across interior Southern Tier and higher
terrain of Southern Erie and Wyoming counties. Winter Weather
Advisory remains in effect through 2 PM Saturday.

A switch over to snow will also occur across the higher terrain east
of Lake Ontario with some accumulating snow late tonight through
Saturday, however due to the later arrival of the cold air to the
eastern half of the area giving a shorter window for cold air to
remain across the area and mid April diurnal effects, don`t expect
accumulations to become impactful and mainly be on the top of the
Tug Hill.

Snow will then change back over to rain Saturday shortly after
sunrises and continue to pull east out of the area throughout
Saturday afternoon. This will support the start of a short dry
period Saturday evening.

In the wake of the secondary cold front, winds will shift westerly
tonight and continue to ramp up across WNY, the Genesee Valley and
Finger Lakes region. Winds again will gust up into the 45 to 50 mph
range tonight through Saturday morning. Wind Advisory remains in
effect for these areas through 2 PM Saturday.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
The mid-level trough finally exits east of the region Saturday night
and then is briefly replaced by ridging aloft. This should wrap up any
remaining precipitation lingering across the forecast area as we
head into Sunday but the break will be short-lived.

A shortwave trough and compact area of low pressure is advertised to
drop across western and northcentral NY on Sunday. This will bring
another shot of rain to the region to finish out the weekend. We
even could see a few rumbles of thunder within the warm sector and
also with the cold frontal passage. This would mainly be focused
across western New York (Finger Lakes region and points west) and
closer to the NY/PA line. This is where models continue to advertise
roughly 300-600 J/kg of CAPE. In terms of rainfall amounts...basin
averages will range between 0.25"-0.50" with very localized higher
amounts given any thunderstorm. There will also be quite the
dichotomy in high temperatures found across the region. Highs east
of Lake Ontario will `likely` struggle to make it out of the 40s,
with a much warmer airmass found across the Finger Lakes region and
western New York with 50s to low 60s.

Drier weather returns Sunday night as high pressure builds into the
region behind this lastest system. Dry weather will continue
Monday and we should see a gradual day to day warming trend with
highs climbing into the 60s.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
The medium range guidance packages have been trending slower with
the large cutter-type low forecast to track northeastward from the
central Plains in the Tuesday-Wednesday period...with the latest
consensus suggesting that this system will reach the Upper Great
Lakes by later Wednesday afternoon and evening. Owing to this slower
progression...the bulk of Tuesday now looks to be dry...with just an
outside chance of a couple showers reaching far southwestern New
York later in the day. Better chances for some showers should then
overspread the area from west to east Tuesday night and especially
Wednesday as this system pushes one or more warm frontal segments
across our region...with some limited instability potentially also
allowing for a few thunderstorms across portions of the area south
of Lake Ontario Wednesday afternoon. Have generally upped PoPs into
the likely range as we push through the day Wednesday...though have
undercut NBM probabilities somewhat given the above mentioned
slowing trend in the guidance...which if continued would result in
the precip arriving even more slowly than currently forecast.

After that time disagreement amongst the medium range packages
increases rather sharply for the Thursday-Friday period...resulting
in a correspondingly sharp increase in forecast uncertainty and
decrease in forecast confidence. In general the initial cutter low
should lift by to our north and weaken...though the guidance
disagrees on the path of the low and how quickly all this occurs...
as well as on the degree/location/timing of any secondary
cyclogenesis that takes place along its trailing cold front. As a
result the guidance envelope suggests a cold frontal timing for our
area that ranges anywhere from later Wednesday night/Thursday
morning on the fast end to Friday on the slow end...a difference of
24-36 hours. Given this degree of uncertainty...will need to keep
precip chances in place through both Thursday and Friday...while
also keeping these confined to the chance range.

With respect to temperatures...highs on Tuesday look to be a bit
cooler than previously forecast given the slower approach of the
cutter low...however these should still average out solidly above
normal. Warm advection associated with the low will then help to
pump readings up to unseasonably warm levels in the mid 60s to mid
70s on Wednesday. After that time a general downward trend in temps
is expected through the end of the work week...though the speed of
this will be heavily dependent upon the timing of the cold front/
secondary surface low. For now have just pulled temps back a bit for
Thursday given the amount of forecast uncertainty...before dropping
these back further into the 50s by Friday.

&&

.AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...
Rain showers occuring at most terminals with the higher terrain of
the Southern Tier now seeing some wet snow, including KJHW as next
next mid level shortwave and secondary cold front crosses the
region. Mainly MVFR CIGS across the lower terrain with IFR CIGS
higher terrain, although a period of IFR CIGS is possible across the
lower terrain sites late tonight into a portion of Saturday morning.
VSBYS will also be reduced to MVFR/IFR at times in snow showers. It
will remain windy with westerly gusts 30-40 knots south of Lake
Ontario, 20-30 knots expected across the North Country.

Large low pressure system that has been responsible for the wet
and windy conditions over the past couple of days will finally
pull away from the area Saturday. Rain and higher terrain wet snow
showers will taper off from west to east across western NY
through early afternoon, then from the Finger Lakes east through
the mid and late afternoon. Expect MVFR/IFR CIGS to linger
through much of Saturday, before gradual improvement to VFR
begins from west to east starting mid to late afternoon, with
KART last to come up to VFR sometime during the evening hours.
Windy conditions will continue through much of the day with
30-40 knot gusts south of Lake Ontario and 20-30 knots toward
the North Country.

It will dry out Saturday evening along with winds will coming down
through the evening hours with mainly VFR expected at all sites by
late in the 06Z TAF period.

Outlook...

Sunday...VFR/MVFR with a chance of showers and possibly a
thunderstorm.
Monday...Mainly VFR.
Tuesday...Mainly VFR with a chance of showers late.
Wednesday...MVFR/VFR with showers likely.

&&

.MARINE...
The second of two cold fronts will currently crossing the region
with a wind shift to the west behind the boundary.

Gale force winds continue on Lake Erie and are currently ramping up
from west to east on Lake Ontario. Gale Warnings are in effect for
all of Lakes Erie and Ontario with high end Small Craft Advisories
for the Upper and Lower Niagara River. Gale Warning on Lake Erie
expires late Saturday morning, while Gale Warnings on western Lake
Ontario expire Saturday afternoon and late Saturday evening for
eastern Lake Ontario. These will be replaced by Small Craft
Advisories that will last until winds come from west to east through
Saturday evening and Saturday night.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...Wind Advisory until 2 PM EDT this afternoon for NYZ001>004-
     010>014-019>021-085.
     Winter Weather Advisory until 2 PM EDT this afternoon for
     NYZ012-019>021-085.
MARINE...Small Craft Advisory until 2 AM EDT Sunday for LEZ020.
         Gale Warning until 11 AM EDT this morning for LEZ040-041.
         Small Craft Advisory until 11 PM EDT this evening for
         LOZ030.
         Gale Warning until 2 PM EDT this afternoon for LOZ042-062.
         Gale Warning until 11 PM EDT this evening for LOZ043>045-
         063>065.

&&

$$

SYNOPSIS...EAJ/JM
NEAR TERM...EAJ/JM
SHORT TERM...AR
LONG TERM...JJR
AVIATION...JM
MARINE...JM