Area Forecast Discussion

WHAT HAS CHANGED

Have cancelled the Severe Thunderstorm Watch for Cayuga county.

Have added some patchy fog across the Southern Tier and North Country tonight.

Severe weather risk continuing to lower for Friday for much of western New York and the Finger Lakes.

KEY MESSAGES

1) Above normal temperatures and high humidity Friday. Warmest heat index values reaching the lower to mid 90s and possibly allowing for an increased risk in heat related illnesses.

2) Scattered to occasionally more numerous showers and thunderstorms are expected through Friday evening.

DISCUSSION

KEY MESSAGE 1...Above normal temperatures and high humidity Friday. Warmest heat index values reaching the lower to mid 90s and possibly allowing for an increased risk in heat related illnesses.

A mid-level ridge over New York State will exit east into New England Friday. Associated heat and humidity will continue into Friday, however due to the exiting mid-level ridge and approaching surface trough/cold front, any chance of headline-worthy heat appears to be limited to portions of the Finger Lakes/central NY and looks to be very marginal in nature...with confidence in apparent temps reaching Heat Advisory criteria continuing to lower.

In the wake of the aforementioned frontal passage Friday, cooler and more comfortable weather are expected regionwide.

KEY MESSAGE 2...Scattered to occasionally more numerous showers and thunderstorms are expected again Friday.

Upper-level troughing across the upper Great Lakes will make its way across Ontario Province and into western Quebec through Friday... with an associated surface low near Hudson Bay pivoting its trailing cold front across our region between Friday morning and early Friday afternoon. As this occurs...the front will interact with the very warm and humid antecedent airmass and generate scattered to numerous showers and thunderstorms as it pushes east. The progressively faster/earlier timing of the front should help to limit instability and any resultant risk for strong/severe storms to far eastern portions of the CWA...though PWATs of 1.5-2.0 inches will still support a risk of torrential downpours.

AVIATION /00Z FRIDAY THROUGH TUESDAY/

As of early this evening the bulk of the convection has exited to our east. Expect a few more leftover isolated showers through late this evening...with mainly dry weather otherwise expected tonight. As we push through the night...nocturnal cooling of our warm/humid airmass and lightening winds will probably allow for the development of some areas of IFR/MVFR stratus and/or fog across the Southern Tier and areas east of Lake Ontario.

As we move into Friday...low pressure near Hudson Bay will pivot its trailing cold front and possibly a leading pre-frontal trough across the area between the morning and early afternoon hours. The passage of these features will be marked by a period of MVFR/low VFR ceilings...as well as scattered showers and thunderstorms that will become a bit more numerous across the Finger Lakes and central NY as the front/prefrontal trough push eastward and interact with the heating of the day. While the earlier timing of the front will likely help to keep any risk for strong to severe storms confined to far eastern portions of the area...the very humid antecedent airmass will result in a risk of torrential downpours and resultant brief reductions to IFR visibilities within any heavier showers or storms. Following the frontal passage...dry weather will return with flight conditions improving to unlimited VFR from west to east Friday afternoon and evening.

Outlook...

Friday night through Saturday night...Mainly VFR.

Sunday...VFR/MVFR with a chance of showers and thunderstorms.

Monday...Mainly VFR, though there is a slight chance for a few showers.

Tuesday...Mainly VFR, MVFR possible within a few showers/storms that may move across the area

MARINE

Tonight we can mostly expect southwesterly to southerly winds of 10 t0 15 knots out ahead of an approaching cold front...with winds and waves producing locally choppy...but sub-SCA conditions.

On Friday winds will briefly increase some out of the southwest owing to the passage of the cold front...likely resulting in a period of SCA-level conditions across Lake Erie. Otherwise the passage of the cold front will trigger scattered showers and thunderstorms that will become somewhat more numerous as the front crosses the region between the morning and early afternoon hours... with locally higher winds and waves not out of the question within any heavier showers/storms.

BUF WATCHES / WARNINGS / ADVISORIES

NY...None. MARINE...Small Craft Advisory from 8 AM to 5 PM EDT Friday for LEZ040.