


Area Forecast Discussion
Issued by NWS Buffalo, NY
Issued by NWS Buffalo, NY
Versions:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --540 FXUS61 KBUF 191044 AFDBUF Area Forecast Discussion National Weather Service Buffalo NY 644 AM EDT Mon May 19 2025 .SYNOPSIS...-- Changed Discussion --Canadian high pressure over the region will result in cool, dry weather through Tuesday. Clearing skies will likely result in areas of frost tonight, particularly across wind sheltered areas east of Lake Erie. A closed low pressure system will then bring unsettled weather and more unseasonably cool temperatures Wednesday through Saturday.-- End Changed Discussion --&& .NEAR TERM /THROUGH TONIGHT/...-- Changed Discussion --A closed low will churn over the southern Canadian Maritimes through the day today, then pivot southeast into the Atlantic tonight. Cool northerly flow on the backside of this system will result in early clouds and patchy drizzle (S. Tier). Otherwise it`ll be another day with temperatures largely in the 50s, though a wedge of Canadian high pressure extending southward from Hudson Bay will at least finally erode away the cloud cover across Western NY by this afternoon. While the clearing will result in some welcomed sunshine later today, after dusk it will combine with light winds and min temps in the 30s to pose a risk of frost development. Confidence in this occurring is highest across the Southern Tier, especially in the wind sheltered areas which may see widespread frost. Further north across the lower terrain areas frost coverage should be lower, with patchy coverage at best across the counties bordering the southern Lake Ontario shoreline. Overall lower confidence east of Lake Ontario where a lingering gradient wind and cloud cover could preclude frost development entirely.-- End Changed Discussion --&& .SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/... Retreating surface high pressure Tuesday...this between a low pressure system off the Atlantic coastline and an incoming mid level low/surface low over the midwest. This will bring a sunny start to the day, but increasing clouds through the afternoon with the loss of mid level subsidence. This may very well prove to be the start of a lengthy period of cloud cover for our region, so enjoy the sunshine for Tuesday. As the low pressure system to the west and its associated warm front draws closer to the Great Lakes region ongoing convection over the eastern Corn Belt States will attempt to push into our region. There continues to be model disagreement to the arrival timing of convective activity Tuesday night as instability will generally linger well to our west, which is where most of the convective shower activity will likely be concentrated. A few rain showers will become likely later in the night across SW NYS as upstream convection advances farther eastward. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... A slow moving, moisture rich, cool, vertically stacked low through the lower and mid atmosphere will bring an extended period of unsettled weather with on again/ off again rain showers through this period. There may be some improvement for Sunday with less duration/coverage area of showers as the low moves off the New England coastline, but moist cyclonic flow will maintain cool conditions with still chances for showers. && .AVIATION /12Z MONDAY THROUGH FRIDAY/...-- Changed Discussion --A closed low pressure system will remain over the southern Canadian Maritimes today. Cyclonic NW flow and residual low level moisture on the backside of this system will result in a wealth of patchy stratocu with variable bases through at least the first half of the morning. Patchy drizzle in the Southern Tier should taper off after 12z. Conditions will improve to mainly VFR generally from north to south across Western NY as clouds scour out late morning into the early afternoon. Confidence is lower in the timing and amount of clearing that will occur east of Lake Ontario in closer proximity to the lingering area of low pressure. OVC/BKN cigs will likely prevail at KART through this afternoon, then SCT/FEW tonight. Outlook... Tuesday...Mainly VFR. Wednesday and Friday...IFR to MVFR with showers.-- End Changed Discussion --&& .MARINE...-- Changed Discussion --A light to modest chop at times along the the southern half of Lake Ontario as a north to northwest wind persists on the backside of a low pressure system over the Canadian Maritimes. Surface high pressure building southward from northern Canada should keep winds light enough to preclude SCA conditions on the lakes through Tuesday. A low pressure system moving into the eastern Great Lakes from the Ohio Valley Wednesday will then very slowly cross the lakes through Friday. This will cause northeast winds to strengthen starting Tuesday night. The greatest wave action is expected to remain mostly offshore through Wednesday night, though SCA conditions could be reached for a time along the southwestern shoreline of Lake Ontario.-- End Changed Discussion --&& .BUF WATCHES/WARNINGS/ADVISORIES...-- Changed Discussion --NY...Frost Advisory from 2 AM to 8 AM EDT Tuesday for NYZ010>014- 019>021-085. MARINE...None.-- End Changed Discussion --&& $$ SYNOPSIS...PP NEAR TERM...PP SHORT TERM...Thomas LONG TERM...Thomas AVIATION...PP MARINE...PP