Scientific Forecaster Discussion

NWS Discussion
			
				

Area forecast discussion 
National Weather Service Buffalo New York 
1029 PM EDT Wednesday may 22 2013 


Synopsis... 
a warm and humid airmass will remain in place through tonight with 
showers and thunderstorms at times. Rain will continue through 
Thursday night as a cold front moves slowly across the region. The 
rain will end Friday morning with much cooler and drier air moving 
into the region for Friday into the weekend. 


&& 


Near term /through Thursday/... 
radar imagery showing a broken line of convection about to exit the 
east end of the County Warning Area across the Eastern Lake Ontario region. This 
line continues to weaken as the boundary layer stabilizes with the 
onset of nocturnal cooling. Elsewhere the rest of the County Warning Area has dried 
out for the most park except for one shower moving through northwest 
Monroe County. 


Upstream radars show a broken line of showers and a few isolated 
storms over Northern Ohio and Central Lake Erie...in association 
with the main middle level trough. Ascent will slowly increase across 
western New York later tonight with the approach of this trough...so 
shower chances will again increase. With ongoing stabilization 
however...expect coverage to remain scattered in nature. Any storms 
should remain isolated and tame given the slackening instability. 


For tomorrow an area of low pressure will lift north of Lake Ontario 
and drag a cold front across the western half of New York state. 
While instability will be less tomorrow additional lift along the 
cold front boundary should produce more widespread showers. Will 
mention thunder across The Finger lakes region where the greatest 
instability within the County Warning Area will be found...with sbcapes around 500 
j/kg. Showers will likely continue after the cold front passage with 
the upper level cool pool still to the west. 


Cooler tomorrow with highs reaching the lower 70s. 


&& 


Short term /Thursday night through Saturday night/... 
northern stream trough will be digging southeast through Ontario and 
the northern Great Lakes at the start of the period. Secondary cold 
front will be just off to our west Thursday evening...then pass 
across the area Thursday night. Widespread shower activity Thursday 
night and early Friday ahead of the front will taper off behind the 
frontal passage...with drier and much cooler air advecting into the 
region...as a broad and strong Canadian surface high builds 
southward through the Great Lakes and toward the East Coast. This 
will put an end to the precipitation threat for the beginning of the 
Holiday weekend. 


Mainly clear and cool conditions for Friday night and Saturday. 
Overnight lows Friday night falling into the middle 30s and lower 40s 
and highs Saturday in the lower to middle 60s. The gradient may stay 
up enough Friday night to keep the potential for frost to a minimum 
but a few locations may nudge toward the freezing mark. 


&& 


Long term /Sunday through Wednesday/... 
cool Canadian high pressure will reside over the area through the 
period. This will result in a quiet weather pattern with no 
precipitation expected. The dry airmass in place will likely result 
in a wide diurnal range in temperatures. The coolest period looks to 
be Sunday and Monday with overnight lows falling into the middle 30s 
and lower 40s and highs in the lower to middle 60s. These 
temperatures would suggest some frost potential especially for the 
normally colder locations of the southern tier and areas east of 
Lake Ontario. It is likely that headlines will be needed at some 
point during this period. 


A gradual warming trend will then occur through middle week as the high 
shift slightly to the east allowing for a more southerly flow with 
highs reaching normal or slightly above normal by middle week with 
readings in the 70s. 


&& 


Aviation /03z Thursday through Monday/... 
a broken line of storms will exit the Eastern Lake Ontario region 
through 0330z with brief/isolated IFR coming to an end there. 
Otherwise the rest of the area has dried out this evening with VFR 
prevailing. 


A few more showers upstream over Ohio and Central Lake Erie may 
spread into western New York overnight as a middle level trough approaches 
the region. Coverage should remain scattered in nature with VFR 
prevailing most of the time. 


There should be enough wind overnight in the boundary layer to 
preclude much in the way of fog formation despite the very moist 
airmass in place. 


Through Thursday a cold front will slowly sag south across the 
region. This will provide additional focus for showers...especially 
during the afternoon as the bulk of the rain begins to take 
residence behind the surface cold front. Ceilings/visibility should initially 
be VFR...although a drop to MVFR is possible late Thursday following 
the surface cold front as the low levels moisten. 


Outlook... 
Thursday night IFR/MVFR in showers. 
Friday...mainly VFR with a chance of showers. 
Saturday through Monday...VFR. 


&& 


Marine... 
a few spotty showers or an isolated thunderstorm are expected 
overnight with southwest winds generally in the 10-15 knot range 
away from the influence of any storms. An area of low pressure will 
cross just to the north of Lake Ontario tomorrow and drag a cold 
front across the lakes on Thursday. Colder air behind this frontal 
boundary will bring a slight increase in waves heights on both 
lakes...though waves will likely remain below 4 foot through 
Thursday night. Small crafts may be needed early Friday when wave 
heights peak...possibly at the 4 foot mark. 


&& 


Buf watches/warnings/advisories... 
New York...none. 
Marine...none. 


&& 


$$ 


Synopsis...Hitchcock/Thomas 
near term...Hitchcock/Thomas 
short term...tma 
long term...tma 
aviation...Hitchcock 
marine...Hitchcock/Thomas