Area Forecast Discussion
Issued by NWS Buffalo, NY

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
FXUS61 KBUF 200515

Area Forecast Discussion
National Weather Service Buffalo NY
115 AM EDT Tue Mar 20 2018

Surface high pressure over Canada will bringing an extended period
of dry weather to the region and below normal temperatures through
the end of the week.


IR satellite imagery showing clear skies across almost the entire
region, with just some thin/high cirrus near the PA state line. This
will continue to be the case overnight as surface high pressure will
continue to build east and southeast and become positioned near
James Bay/Ontario Canada. Lows will dip into the teens across
Western New York, to near or below zero in the North Country.

Tuesday, surface high pressure will be position over James
Bay/Ontario Canada and the aforementioned low pressure over
Oklahoma/Kansas will move into the Mid-Atlantic region. Latest
guidance packages continue to show this system remaining well to our
south with very little impact other than strengthening northeasterly
flow between the two features and the introduction of a fair amount
of cloud cover across Western New York. Again, highs will remain
below normal with temperatures peaking in the low/mid 30s areawide.


A closed 500 mb low centered near West Virginia on Tuesday night
will gradually slide eastward off the mid-Atlantic coast on
Wednesday. Meanwhile at the surface, a weak surface reflection will
re-develop into another coastal low along the eastern seaboard. This
low is forecast to track southeast of Cape Cod Wednesday and then
weaken as it moves into the Canadian Maritimes on Thursday.

There is still some spread in the guidance with a consensus of 12Z
guidance shifting perhaps slightly northward with this system. Even
so, it will have minimal impact on our area, with perhaps some light
snow just clipping the NY/PA border Tuesday night. Otherwise the
forecast period is expected to be dry. There is a risk if the system
backs closer to our region on Wednesday night and Thursday that
there may be some light lake enhanced snow showers, but it still
appears that the moisture will be too shallow to support any
precipitation. Instead, this will result in cloud cover south of
Lake Ontario.

There will be a cool northeasterly flow during this time, with this
most noticeable across the lake plains on Tuesday and Wednesday. This
will result in below normal temperatures, especially daytime highs
which will only be in the 30s during the period. Fairly persistent
winds and cloud cover will limit radiational cooling, but even
without it lows will generally range from the teens to mid 20s.


A strong area of Canadian high pressure will expand southward across
the Great Lakes region this period. This feature will bring mainly
dry conditions Friday and Saturday. Exceptions will possible light
upslope snow showers along the western foothills of the Adirondacks
early Friday, and possible flurries south of Lake Ontario Saturday

While the next storm system should remain well to our south (across
the lower Ohio Valley and towards VA/NC) Saturday night and Sunday,
isentropic lift cutting over the shallow colder air of the surface
high pressure may bring some light snow to near the state border
Saturday night and into Sunday morning.

This system will pass to our east Sunday, with dry air and sunshine
returning. How fast the high pressure scoots by to our east will
determine the next threat for precipitation. If the faster GFS
verifies, moisture returning on the back side of the surface high
may bring chances for light precipitation to WNY later Monday. The
slower ECMWF would maintain a dry day.

Temperatures will begin the period averaging below normal. Highs
Monday may reach into the lower 40s with a return southerly flow.


Surface high pressure will remain in place across northern Ontario
and James Bay Tuesday and Tuesday night, with a ridge extending down
into the Great Lakes. This will provide dry weather and VFR to our
region. Low pressure will move across the central Appalachians
Tuesday, with a secondary low taking shape off the Mid Atlantic
coast. Some high clouds will stream north across our region from
these systems, with the thicker cloud cover near the PA state line.

Wednesday through Saturday...Mainly VFR.


Low pressure will push through the Tennessee Valley tonight, while
surface high pressure settles near James Bay/Ontario Canada. A
tightening surface gradient between the two features will prompt the
northeasterly flow to strengthen across the region. Winds on the
lakes will approach 25 knots with occasional gusts to over 30 knots
at times Tuesday. Winds will then remain elevated through Wednesday.
Small craft advisories will remain in effect during this time period
on Lake Ontario, with headlines possibly needed during the same time
for Lake Erie.

Additionally, a significant portion of Lake Erie from Ripley to the
Buffalo Harbor remains ice covered. With strengthening northeasterly
flow this ice pack will likely shift and break apart becoming a
hazard to anyone that might try to venture out onto the ice.


MARINE...Small Craft Advisory from 8 AM this morning to 5 AM EDT
         Thursday for LOZ043-044.
         Small Craft Advisory from 8 AM this morning to 8 PM EDT
         Wednesday for LOZ030-042.



NEAR TERM...AR/Hitchcock/TMA
LONG TERM...Thomas
MARINE...AR/TMA is the U.S. government's official web portal to all federal, state and local government web resources and services.