Text Products for ESF Issued by BUF

Flood Potential Outlook
Issued by NWS Buffalo, NY
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Winter/Spring Flood Potential Outlook
National Weather Service Buffalo NY
825 AM EST Thu Feb 29 2024

....BELOW NORMAL FLOOD RISK THROUGH MARCH 14TH...

This is the fifth flood potential outlook of the 2024 season. Flood
outlooks will be issued every two weeks into early spring to
summarize basin conditions and to assess the potential for flooding.
The outlooks are based on current and forecast hydrometeorological
conditions. This includes snow cover and water equivalent, creek and
river levels and the amount of ice on them, along with the expected
conditions during the next two weeks.

...CURRENT CONDITIONS SUMMARY...

Up until today, there was virtually no snow pack in any basin except
for the higher terrain in the Black River Basin. Lake effect snow
has left some snow on the ground this morning, but snow water
equivalent (SWE) values will be generally less than a half inch,
with most of this snow in the Western Finger Lakes. These SWE values
are well below normal for late February.

The only significant SWE is in the Black River basin where there is
generally 2 to 4 inches, but this is confined to the higher
terrain of the Tug Hill and Western Adirondacks. This only covers
roughly a third of the headwaters. That`s also the only basin
where there is any river/creek ice in place, with recent warm
weather melting it in our other basins.

Flows are mainly above normal due to recent rainfall and snow melt
in the Black River basin.

The following is a summary of the conditions at 8 a.m. Thursday
morning, February 29th:

...BUFFALO AREA CREEKS / LAKE ERIE BASIN...
.SNOW COVER..........1 to 3 inches.
.WATER EQUIVALENT....Less than a third of an inch.
.CREEK FLOWS.........Above normal.
.CREEK ICE...........Little to none.
.GROUND FROST........Less than 2 inches.
.GROUND STATE........Mainly frozen.

...GENESEE RIVER BASIN / FINGER LAKES / ROCHESTER AREA...
.SNOW COVER..........Less than 2 inches except 3 to 6 in the
Western Finger Lakes.
.WATER EQUIVALENT....Less than a quarter inch except a quarter
to a half inch in the Western Finger Lakes.
.CREEK FLOWS.........Near normal.
.CREEK ICE...........Little to none.
.GROUND FROST........Less than 2 inches.
.GROUND STATE........Mainly frozen.

...ALLEGHENY RIVER BASIN...
.SNOW COVER..........1 to 3 inches.
.WATER EQUIVALENT....Less than a third of an inch.
.CREEK FLOWS.........Above normal.
.CREEK ICE...........Little to none.
.GROUND FROST........Less than 2 inches.
.GROUND STATE........Mainly frozen.

...BLACK RIVER BASINS / TUG HILL...
.SNOW COVER..........1 to 3 inches, except 8 to 14 inches on the Tug
Hill.
.WATER EQUIVALENT....About a quarter inch, except 2 to 4 inches on
the Tug Hill.
.RIVER/CREEK FLOWS...Above normal.
.RIVER/CREEK ICE.....Mainly open with patchy frozen areas.
.GROUND FROST........6 to 12 inches.
.GROUND STATE........Frozen.

...TEMPERATURE AND PRECIPITATION OUTLOOK...

There will be some lake effect snow today which will taper off this
evening. Additional snow accumulations will mainly be less than an
inch with nominal SWE values. However, southeast of Lake Ontario in
Wayne, Cayuga, and southern Oswego counties significant additional
accumulations of several inches are expected which could add a
quarter inch of SWE in most persistent bands.

After this, it will be a mainly dry pattern with a warming trend
Friday through Monday. A weak system may bring light rain or snow
showers Friday night and Saturday with nominal amounts less than a
tenth of an inch water equivalent. After this it will be dry and
progressively warmer with high temperatures back in the 60s Sunday
and Monday at most locations.

During the middle of next week, a cold front will slowly move across
the area with it`s passage most likely on Wednesday. There`s a
chance a wave of low pressure will develop on this front, which
could bring additional rainfall to the area. Rainfall amounts
will depend on this evolution, and precipitation amounts of an
inch or more can`t completely be ruled out even though much less
than that is the most likely outcome.

The 8 to 14 day outlook favors above normal temperatures and above
normal precipitation. Overall the pattern should have the main jet
stream well to our north, which will keep colder air masses from
moving into our area. However, there will be some slow moving
systems cut off from this flow which could bring rain or wet snow
at times during the outlook period. The overall risk of a
significant rain producing system during this timeframe is low,
but non-zero.

...FLOOD POTENTIAL OUTLOOK...

Through March 14th the overall risk for flooding is below normal.

Even with the recent snows, snow pack is well below normal.
Typically, SWE values are near peak levels in the snow belts in late
February. This year, there`s been hardly any persistent snow pack in
Western NY, with significant SWE values confined to the Tug Hill and
Western Adirondacks.

Flows will be high to start the period, especially in the Black
River basin, where recent rains have combined with snow melt.
Rises to near action stage are possible through the weekend.

Otherwise, the first week of the outlook period will be uneventful.
Precipitation amounts through Tuesday of next week will not be
enough to cause any flooding. The progressively warmer weather will
gradually melt all of the snow in most basins, and it will lower
SWE values on the Tug Hill and Western Adirondacks heading into
the middle of next week.

After this, the risk for flooding will mainly depend on if a major
rain producing system develops. For most basins, temperatures will
not be a factor since there will not be any snow pack in place.
The only exception will be the Black River basin, where there will
be some SWE which could add to run-off some. With flows on rivers
and creeks running fairly high, there would be a limited risk for
flooding in the Black River basin late next week, depending on
the evolution of the front and potential low pressure system
during that time. Otherwise, the risk for a major rain producing
system is low but non-zero. This overall leads to a lower than
normal risk for flooding for the outlook period.

...ADDITIONAL INFORMATION...

Real time river information and probabilistic forecast for specific
locations along rivers across Western New York can be found on the
internet at www.weather.gov/buf. Since conditions can change, please
refer to the latest flood watches, warnings, and statements for
additional information.

The next Winter/Spring Outlook will be issued on March 14th. We
would like to thank all the observers and agencies which have
helped gather data in support of this outlook.

$$

Apffel
National Weather Service Weather Forecast Office
