FXUS61 KBUF 190746
Area Forecast Discussion
National Weather Service Buffalo NY
346 AM EDT Thu Sep 19 2019
High pressure will provide us with a prolonged stretch of ideal late
summer weather for the rest of the week, with temperatures climbing
to well above normal by this weekend. The next chance of rain will
not arrive until Sunday night.
.NEAR TERM /THROUGH TONIGHT/...
High pressure will remain across New England with associated
subsidence and dry air dominating our region. After early morning
valley fog dissipates, there will be plenty of sunshine with just
some passing cirrus. Temperatures will be about 5 degree above
normal with most locations reaching the lower to mid 70s, with a few
upper 70s possible across the Niagara Frontier.
Tonight, low temperatures will be a few degrees warmer than previous
nights as low level warm advection slowly increases around the
western periphery of high pressure. River valley fog is likely again
across the Southern Tier.
.SHORT TERM /FRIDAY THROUGH MONDAY NIGHT/...
Dry weather will continue Friday and Saturday as a strong upper
level ridge of high pressure remains across the region. This
ridge axis will not pass us until Saturday night, leaving
Saturday with less of a wind flow and lower daytime mixing
heights. As a result Sunday with higher mixing heights (to near
825 hPa) along with 850 hPa temperatures of +16 to +18C will
likely be the pinnacle of this wave of warm temperatures for
most areas. Daytime highs will likely be in the low to mid 80s.
Clouds will begin to increase later in the day Sunday as surface
high pressure retreats to the SE coastline and an upper level low
approaches us from the western Great Lakes. This upper level low
will not only pick up remnant moisture flowing northward from
tropical system Imelda, but also outer bands of moisture from
Hurricane Lorena which will advance across western Mexico and the
Plains this weekend. All said, PWATS will rise sharply towards 1.50
to 1.75 inches later in the day Sunday and Sunday night.
As the upper level low nears our region, lift ahead of the feature,
combined with a boundary layer pre-frontal trough will likely bring
rain showers into our region in the waning hours of astronomical
summer (which ends at 3:50 am Monday morning). A tropical like
airmass, with warm cloud depth of 12-13k feet along with low level
convergence on a 50 knot LLJ along with favorable jet entrance
region of a 300 hPa jet flow across the Central Great Lakes and into
southern Ontario Canada will make for efficient precipitation
processes and possibilities of brief heavy rainfall. Instability
looks minimal...with just a slight chance for thunder Sunday night
and into Monday as clusters of rain showers pass across the region.
Though some 10 degrees lower Monday, temperatures will still be
above normal with highs in the low to mid 70s.
A surface wave along the cold front is making for a slower exit to
this system...with rain showers likely through at least the first
half of the day Monday...and likely into Monday night east of Lake
Ontario where wrap around moisture and upslope flow will likely
continue light rain showers into Monday night.
.LONG TERM /TUESDAY THROUGH WEDNESDAY/...
High pressure will follow this early week system to again bring
a period of beautiful weather across the Eastern Great Lakes.
Rain chances will be minimal Tuesday and Wednesday with
temperatures a bit above normal...with daytime highs in the
lower 70s across the region.
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
River valley fog through about 14z with local IFR, but this is not
expected to impact the KJHW terminal. Otherwise, high pressure
across New England will allow for VFR conditions with nothing more
than some cirrus at times along with light wind through this
Outlook... Friday through Sunday...Mainly VFR, with localized IFR in
Southern Tier valley fog possible each night/early morning.
Sunday night and Monday...Areas of MVFR with showers likely.
High pressure will provide our region with light winds and minimal
wave action for the rest of the week.
A low pressure system will develop across the upper Great Lakes
region this weekend, with southwest winds increasing to at least 15
to 20 knots by Sunday.
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