Area Forecast Discussion
Issued by NWS Buffalo, NY

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000 FXUS61 KBUF 151905 AFDBUF Area Forecast Discussion National Weather Service Buffalo NY 305 PM EDT Fri Oct 15 2021 .SYNOPSIS... A deepening area of low pressure will pass to our west tonight, shoving a cold front across the region and bringing showers and thunderstorms with it. Following the cold front, breezy conditions will remain through the weekend while also bands of lake effect rain oscillate to the east and southeast of the Lakes through early next week. && .NEAR TERM /THROUGH SATURDAY/... ...Severe Thunderstorms Possible Late This Afternoon and Evening... The regional radar mosaic indicates clear signs of a northward migrating warm front from the Southern Tier back into central Lake Erie as of this time. North of this boundary, showers will continue to translate ENE through southern Ontario and occasionally enter the Niagara Frontier early this afternoon. Low pressure centered over western Ohio will continue to surge NNE, allowing the aforementioned warm front to surge northward. Hi-res guidance suggests convection that has blossomed in western PA will continue to blossom as it moves northward. This make sense give the 12z KPBZ raob with 259 m2/s2 of 0-3 km storm relative helicity and 40 kts of 0-6 km shear. This is precisely the environment the hi-res guidance translates into the Southern Tier behind the warm front that surges northward toward the Thruway corridor by later in the evening. As a result, severe thunderstorms will become possible first along the PA/NY border generally after 4 PM, then farther north as we get deeper into the evening. Organized rotating cells will be possible, which would bring the entire gamut of severe weather into the range of possibilities...damaging wind gusts, large hail, and even a tornado or two. This has been covered by a slight risk from SPC, which seems warranted given the atmospheric conditions, even with instability likely to be on the lower end of things. As the warm front continues to surge northward with the approach of low pressure to the west of the area, atmospheric conditions will become less favorable once it moves into the North Country, so severe weather will be less likely there. Then, as the low moves farther along, a cold front will start to bear down on the area by later tonight. Behind activity this evening, a lull looks to be at hand as we wait for the trailing cold front to cruise toward the area. This eventually happens overnight toward morning. Forcing along the front is solid, and shear is also impressive, however instability will not be. A rumble or two of thunder will be possible, but the forcing along the front may be enough to mix out some of the momentum to the ground in the shallow instability along the front. This may yield another short window gusty winds overnight toward morning. The best moisture surge along the cold front does look to wait until Saturday, so mentions of heavy rain with the cold frontal passage have been pulled from the forecast until the better moisture surge arrives on Saturday afternoon over the eastern half of the area. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/... A strong cold front will exit to the east Saturday afternoon while cold air advection moves into western and central NY. The associated upper level trough will become negatively tilted as the trough axis swings across the region Saturday afternoon-Saturday evening. Strong forcing with diffulent flow aloft will result in showers across the region with the chance for thunderstorms east of the Genesee Valley. High PWATS will be diminishing from west to east across the region as the front moves to the east. A few strong storms are possible from interior Southern Tier, Finger Lakes and into the North Country with a threat of gusty winds and heavy rain. High temperatures will be met Saturday morning across western NY with highs in the low 60s. A longer period of warming will occur east of the Genesee Valley into Saturday afternoon where highs in the mid to upper 60s are expected. Temperatures will fall Saturday afternoon-Saturday night under westerly flow. Boundary layer mixing will likely continue Saturday night with gusty, westerly winds. Temperatures at 850mb will be falling to the low single digits (Celsius) by Sunday morning. A lake response will kick in Saturday night as delta T`s are easily met with Lake Erie temperatures in the 15-19 C and Lake Ontario temperature in the 12-16C. An upper level trough will be overhead Saturday night through Sunday night. Synoptic moisture combined with a cold airmass moving over the warm Lakes will result in lake enhanced rain showers across the region. Scattered rain showers are expected across the region Saturday night into Sunday morning with lake enhanced bands east-southeast of the Lakes. Winds become west- northwest Sunday afternoon as a cold front moves through the region. Temperatures at 850mb will further fall to the minus low single digits. This will increase the coverage of showers across the entire region with enhancement southeast of the Lakes. The trough will move into New England Sunday night and synoptic moisture will diminish overnight. Lake effect rain showers will continue southeast of the Lakes into Monday. A shift in temperatures expected through Monday night as temperatures fall below normal. Highs will rise into the mid 50s Sunday and Monday with lows in the 40s Saturday night and Sunday night. Breezy conditions expected Sunday and Monday with gusts up to 25-30 mph. && .LONG TERM /TUESDAY THROUGH FRIDAY/...
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Strong ridge of high pressure still looks to influence our weather for the Tuesday/Wednesday timeframe, however the large upper trough looks to possibly get hung up over New England for an additional 12- 18 hours as ridge to the west over the upper Great Lakes tries to nudge it eastward. That said, our area should be under the anticyclonic umbrella of the eastern side of the ridge, so still expecting dry weather for at least Tuesday through Wednesday. Caveat being that if this trend continues, small chance for a shower could creep back in the forecast across areas east of Lake Ontario toward the start the period. The other side of this coin is that this would possibly lead to a delay in the next system that`s due to impact our area by the same amount of hours. This would possibly hold off the next chance of showers associated with the next storm system until sometime Thursday versus Wednesday night. Will continue with generally Chc PoPs for the second half of the period at this time. However, if this trend continues, may need to trend back on PoPs for Wednesday night and Thursday with future packages. Temperatures will be a bit above average for the majority of the period, before trending back to near normal for the end of the work week.
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&& .AVIATION /19Z FRIDAY THROUGH WEDNESDAY/... Showers and thunderstorms will increase from the SW as a warm front moves northward through the region. A brief lull will then follow before additional showers and thunderstorms along a cold front late tonight and Saturday. This will be accompanied by IFR cigs and increased winds from the west with gusts. Outlook... Saturday...Areas of MVFR with showers and possible thunderstorms. Breezy. Sunday...VFR/MVFR with a chance of lake effect rain showers east of the lakes. Breezy. Monday...MVFR in lake effect rain showers southeast of the Lakes, otherwise VFR. Tuesday and Wednesday...VFR. && .MARINE... Southwest wind tonight ahead of a strong cold front. While winds may occasionally reach small craft criteria on Lake Erie ahead of the front, the long duration small craft conditions will be behind the cold front Saturday and into the beginning of next week. Winds will average from a WNW direction with 15 to 25 knots. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...None. MARINE...Small Craft Advisory from 10 AM Saturday to 6 AM EDT Tuesday for LEZ040-041. Small Craft Advisory from 1 PM Saturday to 8 AM EDT Tuesday for LOZ043>045. Small Craft Advisory from 10 AM Saturday to 6 AM EDT Tuesday for LOZ042. && $$ SYNOPSIS...Fries/Thomas NEAR TERM...Fries SHORT TERM...HSK LONG TERM...JM AVIATION...Fries/Thomas MARINE...Fries/Thomas is the U.S. government's official web portal to all federal, state and local government web resources and services.