Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Buffalo New York
347 PM EDT Thursday Jul 31 2014
the Fall like weather pattern that we have been in the past couple
days will gradually modify during the remainder of the week. In the
meantime...the cool unstable airmass will support a passing shower
or thunderstorm through this evening and again on Friday.
Near term /through Friday/...
convection over western New York away from the lakes...especially along
the lake plain from Niagara County to Wayne County...will weaken
toward sunset. Otherwise expect a dry night with some light fog in
The upper level low to our north will slowly works its way across
eastern Canada on Friday. Daytime destabilization Friday will lead
to additional scattered afternoon convection away from the lakes.
Short term /Friday night through Sunday night/...
a positively tilted full Continental U.S. 500mb trough will extend from the
Great Lakes to the northern Gulf over the weekend with its axis
slowly shifting east with time. Cool temperatures aloft combined with moist
surface dewpoints and diurnal heating will keep a threat for chances
of showers and thunderstorms right through the period. The highest
chances will be focused during the afternoon hours when lapse rates
are the highest. Lack of strong wind shear will prevent a severe
weather threat. Cool air aloft...850mb temperatures around 13c will keep
high temperatures just slightly below normal while overnight temperatures
will run mild with dewpoints holding in the upper 50s to middle 60s.
Long term /Monday through Thursday/...
the upper flow pattern is forecast to open up to a broad trough as
the jet stream stretches across the Great Lakes through next week.
This Pacific sourced flow pattern will keep temperatures near to
slightly below average with highs ranging from the middle 70s to around
80 and lows falling into the upper 50s to low 60s. While much of the
time will likely feature dry weather with at least some high clouds
streaming overhead...any subtle shortwave disturbances passing
through the upper flow may trigger a shower or thunderstorm. Have
kept low chances in the forecast through the period with low
confidence on timing and location of any precipitation.
Aviation /20z Thursday through Tuesday/...
scattered convection continues along the lake plain from Niagara
County to Wayne County...and along the Saint Lawrence River. Any
thunderstorms should quickly dissipate toward sunset. Areas under
showers/thunderstorms may see some ceilings down to 3k feet and visibility
1-2sm. Scattered-broken 8-10k feet cloud bases expected after sunset...although
may have to be wary of valley fog development in the southern tier
Friday will start tranquil with scattered-broken SC/ac clouds...but with
daytime heating and southerly flow...scattered convection will
develop away from the lakes in the afternoon.
Friday night through Tuesday...other than scattered thunderstorms
Saturday and Sunday afternoons...no significant weather expected.
southwest winds have increased to Small Craft Advisory on Lake Erie but will diminish
around sunset. Otherwise winds and waves should remain below Small
Craft Advisory criteria through the weekend.
Marine...Small Craft Advisory until 8 PM EDT this evening for lez040-