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FXUS61 KBUF 142103

Area Forecast Discussion
National Weather Service Buffalo NY
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.


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 H85 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.


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 CONUS. 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. H85 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. 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.


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 NY 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 SD 
above normal across the Northeast Sunday. Model guidance suggests 
850mb temperatures reaching +10-12 C across western and north 
central NY 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 


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.


Tuesday...Mainly VFR.
Wednesday...Showers likely with areas of MVFR. Gusty 
Thursday...A chance of lake effect showers and MVFR CIGS east 
of the lakes, otherwise VFR.
Friday...Mainly VFR. Slight chance of a lake effect shower east of 
Lake Ontario.


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.




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