Area Forecast Discussion
Issued by NWS Buffalo, NY

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FXUS61 KBUF 220753

Area Forecast Discussion
National Weather Service Buffalo NY
353 AM EDT Sat Apr 22 2017

High pressure over the northern plains will arch across the Great
Lakes this afternoon...and while the day will start off cloudy...
improving conditions with clearing skies can be anticipated. The
fair weather will continue through Sunday when a solid 15 degrees
can be added to the high temperatures. Our region will continue to
dry out through at least Monday as high pressure will nose south
across the Lower Great Lakes from northern Ontario.


A stacked low over western Quebec early this morning will slowly
push east today while its associated mid level trough will pass
across the forecast area. Nominal hgt falls and a wealth of low
level moisture within this environment will keep skies cloudy
through the first part of today...with a few spots possibly picking
up some sprinkles.

As we make our way through the midday into the afternoon...warming
of the low levels will erase a fairly strong inversion that will
have helped to keep our clouds in place. In the process...the
diurnally induced mixing of drier air from aloft and building
subsidence from high pressure will erode our cloud cover and this
will lead to increasing amounts of sun from west to east. In
fact...mostly sunny skies are anticipated west of the Genesee Valley
by mid afternoon. It will be relatively cool today H85
temps at or below zero c and delayed clearing will only allow
afternoon temperatures to climb to within a few degrees of 50.
Normal highs for this time of year are closer to 60.

High pressure centered over the plains will remain arched across the
Lower Great Lakes tonight...and with continued drying of the low
levels...we can anticipate mainly clear...starlit skies and light
winds. This will translate into a fair chilly night...with
temperatures falling into the mid to upper 30s. The valleys of the
Srn Tier as well as parts of the North Country could experience some
frost with lows near the freezing mark.


High pressure and fair weather will dominate our region during the
first half of this period. While a dying weak cold frontal boundary
could bring some clouds to the Saint Lawrence Valley and adjoining
portions of the North Country Sunday night...dry weather and mostly
sunny/mainly clear skies should otherwise prevail. Temperature-wise...
850 mb temps of +3C to +7C should generally promote highs ranging
through the 60s both days...though developing lake breezes will
result in cooler readings along the immediate lakeshores Sunday...
with a general northeasterly low level flow then similarly bringing
cooler temps to areas along and a bit inland from the south shores
of the lakes on Monday. In between...Sunday night will feature lows
in the mid 30s to lower 40s.

Monday night and Tuesday a cutoff low and its associated surface
reflection will meander its way northeastward along the southeastern
U.S. coastline. An influx of Atlantic moisture around the northern
flank of this system will bring an increase in cloud cover to our
region...along with the potential for some showers later Monday
night and Tuesday. With the 00z/22 guidance suite slowly coming
into better agreement that this system could bring a little light
precip into our region...have bumped PoPs up a little further from
continuity...though these still remain in the chance category and
range from 20s/30s across far western New York to 50s across the
North Country...with the greatest shower potential coming during
the day Tuesday. As this system lifts further northeast and off the
Atlantic coastline Tuesday night...its associated moisture field
should recede off to our east...resulting in a return to mainly
dry and quiet weather for our region. As for temperatures...these
will remain pleasantly above average...with lows mostly in the lower
40s Monday night again followed by highs ranging through the 60s on
Tuesday...with lows then dipping into the mid 40s to lower 50s to
close out the period Tuesday night.


On Wednesday...a sharpening upper level ridge will be found across
our between the weakening cutoff low passing by well to
our east...and the next mid and upper level trough developing into
the Great Lakes and Upper Midwest. The combination of strong subsidence
under this ridge and warm advection attendant to a developing southerly
downslope low level flow will help drive 850 mb temps up to between
+10C and +12C across our region...which should translate into a pretty
nice day with highs warming into the 70s areawide...and widespread
highs in the mid to upper 70s found south of Lake Ontario.

Wednesday night and Thursday the medium range guidance remains in
good agreement on the next modest surface low lifting from the Great
Lakes into north-central Quebec while dragging its associated weak
cold front across our region...though it has also trended a bit slower
with the timing of the frontal passage. As a result...the bulk of
any shower/possible thunderstorm activity with the front should hold
off until Wednesday night and Thursday...when broadbrush chance PoPs
will be in place. Otherwise...temperatures should remain solidly above
average especially when given the slower timing of the front...with
lows in the lower to mid 50s Wednesday night followed by highs in the
mid 60s to lower 70s on Thursday.

Thursday night and Friday a second and potentially stronger surface
low looks to lift northeastward across the Midwestern states and Great
Lakes...albeit a little more slowly than seen in previous guidance
packages. This should eventually result in a surface warm front and
some showers/possible thunderstorms working into our region on Friday...
while temperatures continue to average significantly above normal.

Looking out beyond the end of this period...the 00z/22 guidance suite
still suggests the potential for a period of midsummerlike warmth
sometime next weekend or early in the following week...when daytime
highs could reach well into the 80s.


VFR conditions across the majority of the region at 08z will give
way to at least MVFR cigs as we push towards daybreak. Cigs are
already at MVFR across a portion of the southern tier and Finger
Lakes region. For these areas...IFR cigs will be possible.

After sunrise...the low cigs will lift to VFR levels by midday with
general cigs then giving way to clearing as high pressure will nose
across the region during the afternoon and evening.

VFR conditions are anticipated tonight.


Sunday and Monday...VFR.
Tuesday and Wednesday...Mainly VFR with a chance of showers.


Low pressure will move slowly east across Quebec through the
overnight. Winds will become more northwest into Saturday morning
with choppy conditions continuing on both lakes. High pressure will
then build into the Great Lakes later Saturday through Sunday with
light winds and flat wave action.


Rainfall of 1-2 inches fell Thursday and Thursday evening
across the bulk of the area, with a few locations from eastern
Erie County through Genesee County and northern Livingston
county seeing over 2 inches. This has resulted in extensive
ponding of water in low lying and poor drainage areas, and high
water on many small streams and creeks.

The larger rivers and creeks have also seen significant rises.
The faster responding creeks have already crested and are
receding, with some slower responding rivers and creeks still
rising or near crest. River flood warnings remain in place for
the Genesee River near Avon and also for all of Ellicott Creek.

Dry weather is expected through the weekend into early next
week, which will allow all the rivers and creeks to recede.





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