Marine Weather and Tide Forecast for Stony Brook, NY

KEY MESSAGES
1) A marginal risk of severe thunderstorms and a marginal risk of flash flooding with thunderstorms this afternoon into this evening across western portions of the region.

2) Heat advisory for much of the region Thursday through Friday with hot and humid conditions expected.

3) A marginal to slight risk of severe thunderstorms and a marginal risk of flash flooding for the entire region Thursday into Thursday evening.

4) More showers and thunderstorms possible Friday into Friday night.
Still marginal to slight risk for severe thunderstorms as well as localized flash flooding.

5) Still hot but not as humid for the weekend, temperatures cool off more early next week. Multiple chances of showers and possible thunderstorms.

DISCUSSION

KEY MESSAGE 1
Mid level trough pushes southeast into area through this evening.
The trough then shifts east, halting the height falls with some slight height rises towards early Thursday. At surface, a warm front develops north and west of the area. This front will eventually pass to the north and northeast later today into tonight.

Basically, the highest instability relatively will be NYC vicinity and locations to the north and west. This is where there will be higher chances of thunderstorms. Bulk shear 0-6 km AGL appears limited to 20-25 kt making for a marginal severe risk with main threat being damaging winds. Also, PWATs increase to near 2 inches, making for torrential downpours with thunderstorms that develop.
With some steering flow, thunderstorms in their complexes will have sufficient speed to limit flood threat to marginal.

CAPE generated today will be limited by the insolation which is expected to be lessened by the abundance in clouds with lower temperatures as a result. However, airmass will be getting more humid as dewpoints will eventually rise well into the 60s to near 70.

KEY MESSAGE 2
The main hot and humid airmass encompasses the region Thursday through Friday with 850mb temperatures increasing to near 20 degrees C.

The region synoptically will be within the warm sector of an approaching low pressure system. The aforementioned warm front will be well to the northeast of the region. The associated cold front will be well to the west. Dewpoints will be near 70. Surface temperatures rise each day into the upper 80s to lower 90s for much of the region, except coastal SE CT and Eastern Long Island. The majority of the region except for SE CT and Eastern Long Island is in a heat advisory which starts 12PM Thursday and goes until 8PM Friday. There will be some localized spots which have temperatures reach into mid 90s. Heat advisory area have max heat indices range from mid 90s to lower 100s.

One caveat is the possibility of a back door cold front on Friday.
This is shown more from the GFS but not as evident in other models.
Still a MAV and MET MOS blend showed much of the area getting heat indices in mid 90s to near 100.


KEY MESSAGE 3
With the greater heat and increased humidity Thursday, this will allow for more CAPE, up to several thousand J/kg with some models.
With smaller positive vorticity maxima overriding the mid level ridge, there will be forcing and a greater chance of thunderstorms.
Greater shear present as well with 0-6 km AGL shear getting to near 35-40 kt. There is a slight risk of severe thunderstorms for much of the area, more marginal for extreme eastern parts of the region where CAPE will be less. Along with this, the airmass PWATs remain near 2 inches, so there will be a marginal flash flood risk.

KEY MESSAGE 4
Friday, still hot and humid airmass but bulk shear decreases during day. Depending on the cold front timing though, there will be potential still for thunderstorms and there is still a chance of some of them to be severe. The cold front looks to approach late in the day and move across at night. This timing could change with subsequent forecast updates.

KEY MESSAGE 5
Still hot for the weekend with quite a few locations reaching highs in the lower 90s but post cold front, dewpoints will be lower.
Airmass will become less humid. Heat indices max values stay near 90 or less. Unsettled weather pattern establishes itself, nearly zonal mid level flow. Periodic low pressure disturbances with periodic chances of showers heading into early next week.

AVIATION /15Z WEDNESDAY THROUGH SUNDAY/
A weak warm front pushes through this afternoon, along with weak disturbances tonight and once again late Thursday.

VFR for much of this afternoon. MVFR then possible with cigs around 3kft into the tail end of the afternoon and evening. Widely scattered showers are going to be around throughout the day, but the relatively higher chances for showers will be in the late afternoon and evening. An isolated thunderstorm will be possible as well, with the best chance 22-03z. Cigs continue to lower tonight becoming widespread MVFR and possibly IFR for most terminals between 00-06Z.
Some improvements in cigs possible toward 12Z with VFR returning at some point Thursday morning.

Southerly flow increases to 10-15kt this afternoon. Winds again subside tonight to around 10kt or less, becoming more SW by Thursday morning.

...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...

Amendments likely to fine tune the timing of any more persistent SHRA/TSRA as well as the timing of category changes into the late afternoon and evening.


OUTLOOK FOR 12Z THURSDAY THROUGH SUNDAY

Thursday-Friday: MVFR or lower possible at times with chances of showers and thunderstorms in the late afternoon and evening.

Saturday-Sunday: VFR.

Detailed information, including hourly TAF wind component forecasts, can be found at: https:/ www.weather.gov/zny/n90

MARINE
Marginal SCA conditions for ocean late this afternoon into this evening. Otherwise mainly sub-SCA much of the remainder of the forecast. There could be some potential SCA conditions returning to some of the waters towards the end of the weekend.

Rip Currents...

For today, there is a moderate rip current risk with S-SSW winds 10-15 kt and waves around 3-4 ft.

For Thursday, there is a moderate rip current risk with SW winds around 10 kt and waves around 3-4 ft.

OKX WATCHES/WARNINGS/ADVISORIES
CT...Heat Advisory from noon Thursday to 8 PM EDT Friday for CTZ005>010.
NY...Heat Advisory from noon Thursday to 8 PM EDT Friday for NYZ067>075-078-080-176>179.
NJ...Heat Advisory from noon Thursday to 8 PM EDT Friday for NJZ002- 004-006-103>108.
MARINE...None.