Scientific Forecaster Discussion
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Area forecast discussion
National Weather Service Buffalo New York
503 PM EDT Mon Oct 14 2019
high pressure over the Ohio Valley will push across the mid Atlantic
region overnight and will then make its way off the coast on
Tuesday. This will promote improving weather across our region with
temperatures climbing to nearly 60 during a sun filled Tuesday. A
strong cold front will cross the area on Wednesday...producing
numerous showers and even a gusty thunderstorm or two in the
process. Chilly air in the wake of the front will then support lake
effect rain showers Wednesday night and Thursday.
Near term /through Tuesday/...
high pressure centered over the upper Ohio Valley this evening will
move east across the mid Atlantic region overnight. Mid level dry
air associated with this feature will help to clear our skies in the
process...but given 850 mb temps in the vcnty of -2c...lake induced
clouds and nuisance rain showers will be found east of both lakes.
Temperatures tonight will generally range from 35 to 40. This will
allow for patchy frost...but given the potential for lake effect
cloud cover...this coverage should be sparse enough to keep from
issuing a frost advisory.
Tuesday, some early morning showers may linger east of Lake Ontario,
but will continue to decrease in coverage and potential through the
morning. Elsewhere, most locations will experience a rain free day
with partly to mostly sunny skies. Clouds will start to increase
from the late afternoon Onward from northwest to southeast as an
approaching area of rain gets closer to the region. Temperatures on
Tuesday will briefly rebound to the upper 50s to near 60 for most
areas. The higher terrain east of Lake Ontario will struggle to get
out of the low 50s.
Short term /Tuesday night through Thursday night/...
northern stream shortwave now ejecting out of the northern rockies
will strengthen over the next 24 to 36 hours as it digs southeast
across the northern tier Continental U.S.. the resulting deep mid level
circulation will then pivot across the Great Lakes Tuesday night
into early Wednesday. There will be surge of warm air advection
developing downstream of the associated height falls Tuesday night
as 850 mb temperatures near +12c. Northward moisture transport while
at first looks lacking looks to get better overnight.
There looks to a window starting late Tuesday night into Wednesday
afternoon for a band of widespread showers to emerge within the
ongoing isentropic ascent tied to the attendant cold frontal passage
and associated increase in mid level dynamics with the inbound upper
circulation. Though instability will be somewhat lacking, forcing
looks strong enough to support some embedded thunder. Severe
potential looks limited but not zero, as healthy low level jet near
50 knots could support the potential for a few gusty thunderstorms.
Cold cyclonic flow will develop behind the frontal passage later
Wednesday and continue Wednesday night. Modest mixing of a firm west
to northwest gradient will bring rather gusty conditions,
potentially seeing wind gusts of 35 to 45 mph at times. Cold
advection will also lead to favorable over-lake instability with
lake equilibrium levels eventually increasing to 15-20 kft by
Wednesday evening before lowering to around 10kft by Thursday
morning. This will easily support the development of lake effect
rain bands east and northeast of the lakes and perhaps a chance
for some graupel/lightning.
Stacked storm system over northern New England moves toward Atlantic
Canada Thursday into Thursday night. A deep cyclonic flow of chilly
air will remain over the lower Great Lakes which will continue to
support a fairly Strong Lake response...with lake to cloud base
Delta T values averaging 15 deg c. 850 mb temps only down to -3c will
not be low enough to support any snow...but the resulting lake
driven convection could include some heavier rain showers.
Otherwise...it will be a poor day to be out and about as a gusty
northwest wind and fairly widespread lake driven rain showers within
the ongoing cold advection will prevent many areas from climbing out
of the 40s.
Surface ridging will start to cross the lower Great Lakes Thursday
night. This will lower the limiting subsidence inversion to under 5k
ft while the bulk of the synoptic moisture above 5kft will be
stripped away. Leftover rain showers southeast of both lakes will
taper off as a result (esp off lk erie) with temperatures generally
dropping into the upper 30s and lower 40s.
Long term /Friday through Monday/...
a mid-level trough over the northeast will track to the east while a
ridge builds into the Great Lakes region Friday. Northwest flow will
taper off across western and north central New York through the day. Warm
air advection and subsidence will put an end to any leftover lake
effect rain southeast of Lake Ontario through Friday morning.
Surface high pressure will move overhead Friday night making for a
chilly night with temperatures in the 30s and the potential for
frost across the region.
The ridge will track across the Great Lakes region Saturday before
becoming amplified off the northeast coast Sunday into Monday. Warm
air advection will move into the region Saturday and with surface
high pressure in place, a lot of sunshine, light winds and
temperatures in the 60s are expected. The ridge will become +1 South Dakota
above normal across the northeast Sunday. Model guidance suggests
850mb temperatures reaching +10-12 c across western and north
central New York Sunday and Monday. Maximum temperatures may reach the
upper 60s to low 70s. A caveat in the expected warm temperatures
is that there will likely be a surge of moisture moving north
from the Gulf of Mexico and depending on the evolution of
disturbances within a large trough to the west, clouds and rain
showers are possible Sunday through the start of the next work
Aviation /21z Monday through Saturday/...
while VFR cigs will be found across the bulk of the region late this
afternoon and evening...MVFR cigs will still be in place across
parts of the southern tier. During the course of the night...the
cloud cover should at least partially clear. This should enable all
areas to experience VFR conditons for the overnight hours.
High pressure passing to the south will then support VFR weather
with light winds on Tuesday.
Wednesday...showers likely with areas of MVFR. Gusty
Thursday...a chance of lake effect showers and MVFR ceilings east
of the lakes, otherwise VFR.
Friday...mainly VFR. Slight chance of a lake effect shower east of
a moderate to fresh westerly breeze across the lakes behind an
earlier passing cold front is causing small craft conditions on Lake
Ontario. Winds will subside though as we push through the overnight.
Winds and waves will then be light Tuesday with the surface high
nearby before increasing once again as a deeper and colder storm
system passes through the lower Great Lakes midweek.
Marine...Small Craft Advisory until 5 am EDT Tuesday for loz043-044.
Small Craft Advisory until 2 am EDT Tuesday for loz042-045.