Marine Weather and Tide Forecast for Niagara Falls, NY

KEY MESSAGES
1) Strong to severe thunderstorms are possible today, with damaging winds as the main hazard.

2) Another round of widespread showers expected with a few possible thunderstorms Saturday into Saturday night.

3) The very warm pattern continues through Saturday before much colder air arrives by early next week.

DISCUSSION
KEY MESSAGE 1...Strong to severe thunderstorms are possible today, with damaging winds as the main hazard.

GOES water vapor shows an upper level ridge across the eastern CONUS with moisture streaming across the Great Lakes and Northeastern states early this morning. Satellite derived moisture fields show a broad area of PWATS over 1.25" and percent of normal at 200%. Large scale forcing has moved east of the region early this morning, with lingering scattered showers across the eastern Lake Ontario region.

Attention turns upstream as a shortwave trough digs into the Mid- western states. An area of low pressure from southern Wisconsin to central Michigan will move northeast today. Initially, an uptick in winds and warm air advection across the northern Ohio valley will support showers and isolated thunderstorms across far western NY this morning. As the surface low moves northwest of the forecast area, a cold front will approach the region today. A very moist airmass and daytime heating will result in destabilization across the region. Guidance remains uncertain regarding the magnitude of instability across interior western and north-central NY today, with the HRRR more favorable for moderate instability and the REFS more subdued. Earlier showers and cloud cover especially across far western NY may lead to more inhibition. Forecast 0-6km shear is around 40kts this afternoon and the combination of moderate shear and instability will support the development of strong to severe multicell, possibly supercells. The primary threat will be damaging winds, however large hail and an isolated tornado can't be ruled out. In fact, HRRR guidance depicts a differential heating boundary along the southern shore of Lake Ontario into the eastern Lake Ontario region that could be a zone for severe thunderstorms. The SPC Day 1 outlook has Marginal and Slight risk areas across the forecast area. Thunderstorms are likely to develop along the Lake Erie lake breeze early this afternoon and move eastward while tapping into a favorable environment for strong thunderstorms. Due to the moist airmass, thunderstorms will be capable of heavy downpours, however quick moving storms should limit any hydro concerns.

The area of low pressure will move northeast of the region with the cold front moving into the forecast area and stalling overnight. The potential for strong thunderstorms will exit to the east this evening, but scattered showers will be possible overnight. Also, patchy fog is possible.

KEY MESSAGE 2...Another round of widespread showers expected with a few possible thunderstorms Saturday into Saturday night.

A deep closed low trudging across the southern Canadian Prairies Friday night through Saturday night will lift northeast across Hudson Bay and further strengthen by Sunday. This will send a powerful cold front through the eastern Great Lakes Saturday afternoon into Saturday night. A strong southwesterly LLJ immediately ahead of the front transporting a plume of Gulf-based moisture across the Mississippi Valley will support another round of widespread rain showers.

Diurnal timing of the front looks favorable for enough instability to grow within the warm sector to potentially bring a few thunderstorms as well. Uncertainty remains moderate to high in the severe potential as models advertise the LLJ weakening over the region as the precip moves in Saturday afternoon. While the greatest threat thus appears to be upstream across the Ohio Valley, could see a lower-end threat extending northeast into WNY where the stronger jet energy and building instability have the most favorable overlap in our forecast area. The strong, unidirectional mid/upper level flow may support a linear convective mode with a few localized strong wind gusts.

The heaviest, steadiest precipitation should lie east of the forecast area by early Sunday morning. Mid to long range guidance suggests a secondary wave developing along the front in the Mid- Atlantic region Saturday night which may slow its overall progression, while the main trough axis will not move through until Sunday night. This will continue to support lower-end chances for showers, though the colder, more stable post-frontal environment will be highly unfavorable for thunderstorms.

KEY MESSAGE 3...The very warm pattern continues through Saturday before much colder air arrives by early next week.

While temps will cool off a few degrees for Friday as the quasi- stationary boundary hanging over the region is firmly shoved to the southeast, above average temperatures will persist through Saturday.

The more substantial pattern change will come behind the cold front described in Key Message (2) as deep upper level troughing crosses the Northeast. 850mb temps around +15C Saturday afternoon will tumble to either side of -6C by Sunday morning, then bottom out around -12C Monday morning. This will translate to sfc high temperatures averaging 10-15 degrees (F) below normal Sunday through Monday night. Overnight lows will be similarly cold, with areawide temps dipping below freezing and potentially even into the teens across the higher terrain areas, depending on the amount of clearing that takes place.

The trough axis moving through the region combined with some minor lake enhancement and upslope effects may even support a few snow showers or flurries at times early next week. Impactful accumulations appear very unlikely at this range.

High pressure at all levels cresting over and east of the region should cause a southerly flow to develop by Tuesday, with temperatures recovering to near climatological averages through midweek.

AVIATION /06Z THURSDAY THROUGH MONDAY/
Regional radar shows scattered showers in vicinity of Lake Ontario with the heaviest rain and thunderstorms east of the region early this morning. A warm, humid airmass resides across the region. An area of low stratus and fog are located northeast of Lake Erie and east-northeast of Lake Ontario and LIFR conditions will continue at BUF/IAG through 10z and ART through 13z. A brief period of MVFR/IFR is expected at KROC early this morning, before improving to VFR by 12z. Showers are likely east of Lake Ontario through this morning and may disrupt/improve flight conditions before falling back down.
An area of scattered showers with a slight chance of a thunderstorm are possible across far western NY through the morning hours.

Another round of showers and thunderstorms is expected across the region today, with the potential for isolated to scattered strong thunderstorms this afternoon. Thunderstorms may produce gusty winds, small hail, and heavy downpours.

A weak cold front will move into the region tonight. Scattered showers and patchy fog are expected with flight conditions lowering to IFR or below across the region overnight.

Outlook...

Friday...VFR/MVFR with showers possible.

Saturday...Mainly VFR with a chance for showers later in the afternoon.

Sunday...A mixture of MVFR/IFR with rain showers mixing with and changing over to snow throughout the day.

Monday...Improving to VFR/MVFR. Lingering lake enhanced snow showers and clouds gradually dissipate.

MARINE
A warm, humid airmass will reside across the eastern Great Lakes through Saturday. Multiple rounds of showers and thunderstorms will cross the lakes today, a few of which may produce strong surface wind gusts and locally higher waves. Otherwise the warmer airmass and relatively cold lake temperatures will result in limited mixing of synoptic winds...thereby precluding any real risk of advisory- level conditions.

Relatively light winds and minimal wave action are then expected later tonight and Friday as high pressure builds across the Lower Great Lakes...before winds increase out of the south/southwest Saturday/Saturday night in association with the approach/passage of a strong cold front. This may result in the next round of SCA conditions with the frontal passage also accompanied by another round of showers and storms...some of which could produce locally stronger winds and higher waves.

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