Marine Weather and Tide Forecast for Oswego, NY

KEY MESSAGES
1) Summer-like heat today through Tuesday.

2) A strong cold front will bring round of showers and thunderstorms late Tuesday into Wednesday morning, a few of which could reach severe limits Tuesday evening into Tuesday night.

3) Drier and cooler conditions behind the behind the cold front Wednesday afternoon through Friday, before unsettled weather potentially returns for the weekend.

DISCUSSION
KEY MESSAGE 1...Summer-like heat today through Tuesday.

Mid and upper level ridging will amplify over the eastern third of the CONUS and western Atlantic early this week, setting up a deep southwesterly flow right into our region. A couple of low pressure systems will cut northeast through the upper Great Lakes in between the eastern ridge and western trough first part of this week forcing a strong push of mid-summer like air into the lower Great Lakes and Northeast on their eastern flank. This will help boost temperatures well into the 80s across much of western and northcentral NY today and Tuesday, with a run at 90F not out of the question for some of our traditionally warmest locations across the Genesee Valley/Finger Lakes region. Today will likely be the warmest day with the mid and upper level ridge axis cresting over our region, with upper level heights then falling a bit Tuesday as the ridge axis slides east of the area. NBM max temperature output continues to be too warm, but not as overdone as previous runs. Thus, in coordination with surrounding offices as has been done over the past several days, daytime highs were lowered a couple to few degrees both days. The potential for reaching heat headline criteria continues to be low, as dew points are expected to peak in the low to mid 60s for most of the area, helping to keep heat indices/humidity in check. However, this is the first time this season our area will experience true, summer-like heat and humidity levels. Expect temperatures along and close to the lakeshores to be a bit cooler, especially with the still chilly lake water surface temperatures.

It will turn breezy both this afternoon and Tuesday afternoon with gusts 25-30 mph E and NE of the lakes today, with 25-30 mph gusts areawide Tuesday afternoon. A 35 or even 40 mph gust is not out of the question NE of Lake Erie Tuesday afternoon, especially a bit further from the lake away from the cool dome over and closer to the lakeshore.

Best chances for a few showers or storms will be late today and tonight as a weak shortwave riding the western periphery of the ridge just grazes the western fringes of our area. The eastern fringe of a 40-50 knot LLJ will just graze western portions of our area during this time, so if any storm does manage to develop, it may produce some localized gusty winds late today and this evening.
Another chance for a few showers and storms will be Tuesday afternoon as peak diurnal heating works in tandem with another weak mid-level shortwave, this time passing over the the area ahead of a strong cold front approaching from the west. Scattered convection would be mainly along and inland of any lake breeze circulations.

KEY MESSAGE 2...A strong cold front will bring a round of showers and thunderstorms late Tuesday into Wednesday morning, a few of which could reach severe limits Tuesday evening into Tuesday night.

Despite the timing being past the peak diurnal heating hours, confidence in a few strong to severe storms continues to grow for Tuesday evening and Tuesday night just ahead of a strong cold front.
CAPE values of 1500-2000 J/kg with 30-40 knots of 0-6km shear will foster the potential for damaging wind gusts, which will be the biggest threat. Local BUFKIT soundings also advertising "fat" CAPE profiles, which indicates the potential for large hail as well.
Finally, 0-3km SRH values of 200-300 mean there will also be the chance for an isolated tornado. SPC currently has the bulk of our area outlined in a Slight Risk during this period.

KEY MESSAGE 3...Drier and cooler conditions behind the behind the cold front Wednesday afternoon through Friday, before unsettled weather potentially returns for the weekend.

A large area of high pressure will build into our region in the wake of the cold frontal passage, bringing a mainly dry, but much cooler airmass back in across the area for the middle and later half of the week. Coolest day will be Thursday, with many locations not getting out of the 50s. Expect a slow rebound in temperatures into the holiday weekend with 60s and some low 70s, however an area of low pressure approaching from the southwest may bring unsettled weather back into our region for at least a portion of this weekend.

AVIATION /12Z MONDAY THROUGH FRIDAY/
For today, mainly VFR flight conditions are expected, with just low chances for a shower or rogue storm along and inland of any lake breeze circulations through the afternoon. It will become breezy later this morning into this afternoon with SW gusts 20-25 knots E and NE of the lakes.

There will be a better chance for a few showers or storms very late today into this evening as a weak shortwave riding the western periphery of the ridge just grazes the western fringes of our area.
The eastern fringe of an associated 40-50 knot LLJ will just graze western portions of our area during this time, so if any storm that does manage to develop may produce some localized gusty winds late today and through the first half of tonight. This will also bring the threat for a period of LLWS this evening into the overnight.
Otherwise, mainly VFR conditions expected tonight.

Outlook...

Tuesday..Mainly VFR. A chance of a few showers and thunderstorms later in the afternoon.

Tuesday night through Wednesday...Areas of MVFR/local IFR with showers and thunderstorms of which a few storms may contain gusty winds, with this activity ending from west to east and improving to VFR Wednesday morning.

Thursday through Friday...VFR.

MARINE
The pressure gradient will gradually tighten across the lower Great Lakes today through Tuesday. Moderate southwesterlies will bring very choppy conditions to the west end of Lake Ontario by this afternoon, with lighter winds elsewhere.

Winds will increase further on Tuesday ahead of an approaching cold front. Winds and waves will likely support Small Craft Advisory conditions by afternoon on the western portion of Lake Ontario, with the stronger winds and greater wave action then spreading east to the east end of Lake Ontario later Tuesday night through Wednesday as the cold front crosses the lake. Winds on Lake Erie will be somewhat lighter, but still strong enough to produce a moderate chop Tuesday through Wednesday.

BUF WATCHES/WARNINGS/ADVISORIES
NY...None.
MARINE...None.