000
FXUS61 KBUF 181045
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
645 AM EDT Thu Apr 18 2024

.SYNOPSIS...
Weak high pressure will support improved weather across the
western counties today...but showers will persist for areas east of
Lake Ontario. A wave of low pressure riding up along a slow moving
frontal boundary will then guarantee another unpleasant day across
all of the region for Friday in the form of widespread showers...if
not a few hours of steady rain. While fair dry weather will be
featured for the upcoming weekend...some nuisance showers will be
possible Saturday afternoon.

&&

.NEAR TERM /THROUGH FRIDAY/...
A stacked storm system centered over the Canadian prairies this
morning pushed a weakening sfc occlusion across the western counties
during the overnight...and that boundary will now stall as it
completely dissolves over the Eastern Lake Ontario region. Limited
low level convergence in the vcnty of this boundary...coupled with
some upper level support from a passing mid level shortwave over the
Ottawa valley...should be enough to allow for some nuisance showers/
areas of light rain over that area today...especially through early
afternoon. For the western counties...fair dry weather should be
rule today...although a wealth of low level moisture will severely
limit any partial clearing.

While a couple light showers will be possible across the North
country this evening...a progressive shortwave ridge will move
across our forecast area to support fair uneventful weather.

Unfortunately...conditions will significantly deteriorate on Friday.
A wave of low pressure will track northeast along a slow moving
frontal boundary...and as this next complex frontal system moves
through our region...we can anticipate another round of widespread
showers and possibly a period of fairly steady rain. The main
forcing from this scenario will be provided by a 45kt low level jet
that will establish fairly strong H925-70 frontogenetic lift. Most
basins are forecast to receive less than a tenth of an inch of
rain...although local amounts of up to a quarter inch will be
possible.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/...
An area of low pressure will move from James Bay to northern Quebec
Friday night. A cold front will be located just east of the forecast
area Friday evening. Rain showers will likely extend from north
central NY to the Finger Lakes region and will end from west to east
by midnight Friday night. Drier air will filter into the region as
cold air advection continues behind the exiting cold front. By
Saturday morning, 850mb temperatures will be around -5C across the
forecast area. A mid-level trough will sharpen and move across the
region Saturday. The combination of a secondary cold front and
steepening lapse rates will result in diurnally driven scattered
rain showers. There will be good mixing Saturday with a 35 kt low
level jet overhead. Westerly winds with gusts 25 to 35 mph are
expected across the region. Cooler air will result in high
temperatures staying below normal and in the mid to upper 40s.

The mid-level trough will move east of the forecast area Saturday
night. A large area of high pressure will build into the region.
Winds will diminish and dry and cool conditions will continue
overnight. Lows will likely go below freezing across the higher
terrain.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
Surface high pressure centered across the Central Plains Sunday will
extend east to the Lower Great Lakes region. The high will move east
through Monday night keeping dry conditions across the forecast area
into the start of the work week. A mid-level shortwave trough will
move into the Northern Rockies early next week and low pressure will
move across the Northern Plains, reaching the Mid-West by Tuesday.
Model consensus suggests that rain showers will enter the forecast
area by Tuesday night and continue through Wednesday.

Temperatures fluctuate from below normal Sunday to near to above
normal Monday and Tuesday and back to below normal Wednesday.

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/...
MVFR to IFR conditions will be found through the region this
morning...as a weakening sfc occlusion will limp towards the Eastern
Lake Ontario region.

As we work our way through the morning into the midday...cigs will
grudgingly improve to MVFR to VFR levels. Meanwhile...IFR cigs may
persist east of Lake Ontario at sites like KART and KGTB.

Mainly VFR weather is forecast for the western counties tonight...but
IFR to MVFR cigs are likely to persist east of Lake Ontario.

Outlook...

Friday and Saturday...MVFR/VFR with a chance of showers.
Sunday and Monday...Mainly VFR.

&&

.MARINE...
In the wake of a weakening frontal boundary...southwest winds today
will freshen on Lake Erie. Winds have come up a little higher than
earlier forecasts...so a small craft advisory has been issued
thorugh late this afternoon. Otherwise...gentle to moderate breezes
will be found on Lake Ontario.

A weak sfc pressure gradient in advance of the next wavy frontal
boundary tonight will only support gentle to moderate breezes and
negligible wave action.

Winds will significantly freshen on both lakes on Friday though when
there will likely be the need for small craft advisories.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...None.
MARINE...Small Craft Advisory until 6 PM EDT this evening for LEZ040-
         041.

&&

$$

SYNOPSIS...RSH
NEAR TERM...RSH
SHORT TERM...HSK
LONG TERM...HSK
AVIATION...RSH
MARINE...RSH