Marine Weather and Tide Forecast for Greenport, NY

KEY MESSAGES
1) A Heat Advisory remains in effect for NYC and northeast New Jersey as hot weather continues through this afternoon.

2) Scattered strong to severe thunderstorms are possible this afternoon and evening, followed by lingering showers tonight into early Thursday.

3) Unsettled with periods of showers expected for the upcoming holiday weekend along with a much cooler airmass over the region.

4) Cold water safety concerns continue today with good boating weather early in the day, and water temperatures still in the 50s.s.

DISCUSSION

KEY MESSAGE 1
No changes were made to the heat advisory for the NYC metro and NE NJ which remains in effect until 8pm.

One last hot day is expected today as the region remains on the NW periphery of western Atlantic ridging. Temperatures should end up a few degrees lower compared to Tuesday in the warmest spots, but still will reach the low to potentially mid 90s in NE NJ and portions of the NYC metro away from the Atlantic coast.
Elsewhere, highs will reach the mid to upper 80s except for 70s to low 80s closest to the coast. Followed the same trend as recent days and blended in some of MAV/MET guidance along with the 10th percentile of the NBM, since the NBM deterministic continues to run too hot. This is especially true for locations more impacted by a bit more onshore flow.

Max heat indices will reach the mid 90s in the Advisory area and generally the upper 80s to low 90s for other locations away from the immediate coast.

Temperatures and heat indices may drop significantly in the mid to late afternoon if showers and thunderstorms develop. There is a chance the Advisory will be cancelled sooner than 8pm if this scenario were to occur.


KEY MESSAGE 2
A cold front will move across the region this afternoon and evening. The front will serve as a mechanism to develop showers along with scattered thunderstorms in the afternoon and evening. SPC has continued to outline a marginal risk for severe thunderstorms across the southern two-thirds of the region. A few of the storms may become severe with damaging wind gusts the main threat. Timing for the severe thunderstorm potential continues to be from 2pm-8pm.

The latest CAMs are still offering varying coverage of convective development with some just showing isolated coverage with others scattered to a bit more numerous. The cold front will provide convergence along with falling heights aloft. Strong heating today should provide enough instability to promote convective development, first early this afternoon for the interior and then the rest of the area by mid to late afternoon. Lingering convection may still impact portions of the coast this evening as the front sags south across the area.

While brief heavy downpours are possible in any shower or thunderstorm, quick storm motion will mitigate the potential for anything more than nuisance flooding.

Showers will likely linger the first half of the night near the coast as the front works offshore. There may also be some redevelopment of showers late tonight into early Thursday morning as a weak wave of low pressure develops along the front. The low pressure is tied to a passing jet streak to our north, associated with a broad trough over Northern New England and southeast Canada. There is still some uncertainty with this feature as some of the model guidance keeps the showers just south of Long Island.

Conditions should dry out Thursday afternoon, but lingering cloud cover may persist through much of the day. Best chance for some clearing looks to be well northwest of the NYC metro.

Daytime temperatures on Thursday will only be in the 60s, 20-30 degrees cooler than Wednesday.


KEY MESSAGE 3
The end of the week will remain dry and much cooler. The dry period will be short-lived as unsettled weather with periods of showers looks likely for the upcoming holiday weekend. The frontal boundary that moves through today/Wednesday will remain to our south with multiple disturbances/waves of low pressure moving along it through the weekend. Moisture from these systems will overrun high pressure to our north and east.

The main challenge for this period is timing when the most widespread shower activity will occur. The highest probabilities currently are from late Friday through early Sunday. However, there is still some uncertainty, especially if the surface ridging from the high is stronger. This would help suppress the showers a bit further south, with at least the northern half of the region seeing less rainfall. Chances for showers continue late Sunday into Memorial Day as additional energy may pass to west or northwest.

Otherwise, will remain mostly cloudy through the weekend with temperatures likely running below normal for late May in the low to mid 60s. Nighttime temperatures should be in the 50s. The frontal boundary may get pushed further south by next Tuesday, which could help lower any chance for showers.


KEY MESSAGE 4
One last day of cold water safety concerns due to another day of hot air temperatures. The cold water temperatures can quickly cause hypothermia and physical incapacitation to anyone suddenly immersed in the water. Anyone going out on small boats, canoes or kayaks should plan accordingly and use extreme caution to avoid this threat.

AVIATION /06Z WEDNESDAY THROUGH SUNDAY/
A cold frontal passage occurs this aftn and eve. High pres builds N of the area on Thu.

Mainly VFR conditions are expected through 18Z. Scattered showers with embedded thunderstorms are expected to develop after 18Z, with the best chance from 21-00Z. Kept TSRA chances in a PROB30 at this time as confidence in the coverage of TSRA remains uncertain. If a thunderstorm does occur, it could be strong to severe with brief strong gusty winds up to possibly 40 to 50 kt. MVFR or lower conditions possible in any TSRA.

Aft the fropa, CIGS lower to around 4000ft overnight with the potential for additional shwrs. Confidence in shwrs is low so they have not been included in the TAFs.

WSW winds this mrng, becoming NW this afternoon and evening aft the fropa. The flow veers further to the NE aft 8-9Z Thu. Wind speeds generally around 10-15 kt much of the TAF period with gusts to near 20 kt this afternoon.

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

Amendments possible to refine timing of showers and thunderstorms today.

MVFR CIGS possible aft 00Z Thu, but the probability was too low to include in the TAFs attm.


OUTLOOK FOR 06Z THURSDAY THROUGH SUNDAY

Late Tonight: Mainly VFR with NW winds veering to the NE.

Thursday: MVFR or lower conditions possible early for coastal terminals and NYC terminals at times with a chance of showers.
Mainly VFR thereafter.

Friday: Possible showers and MVFR conditions. Chances of showers increase late day into night. Showers become likely at night.

Saturday: MVFR or lower with showers. E-NE wind gusts 15-20 kt.

Sunday: MVFR or lower with chances of showers. NE wind gusts 15-20 kt during the day.

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

MARINE
A Small Craft Advisory remains in effect on the ocean waters through early this evening. Winds will likely be marginal and overall below 25 kt, but there still may be a few gusts nearshore around 25 kt. Seas should build to 5-6 ft, especially east of Fire Island Inlet. 5 ft seas could linger east of Moriches Inlet into the evening, so have extended the SCA for these waters until 11 pm.

In addition to the elevated seas and marginally gusty winds, a cold frontal passage late Wednesday afternoon into Wednesday evening will bring with it the potential for strong to severe thunderstorms with gusts in excess of 35 kt.

Conditions tonight through Friday are expected to remain below SCA levels with a cold front south of the waters. The next chance for SCA conditions will be this weekend as several waves of low pressure pass along the cold front to our south.

One last day of cold water safety concerns due to another day of hot air temperatures. The cold water temperatures can quickly cause hypothermia and physical incapacitation to anyone suddenly immersed in the water. Anyone going out on small boats, canoes or kayaks should plan accordingly and use extreme caution to avoid this threat.

CLIMATE

Record High Minimum Temperatures:

May 20: KEWR: 72/1996 KBDR: 61/2019 KNYC: 74/1996 KLGA: 77/1996 KJFK: 63/1996 KISP: 62/1996

OKX WATCHES/WARNINGS/ADVISORIES
CT...None.
NY...Heat Advisory until 8 PM EDT this evening for NYZ072>075-176- 178.
NJ...Heat Advisory until 8 PM EDT this evening for NJZ002-004-006- 103>108.
MARINE...Small Craft Advisory until 11 PM EDT this evening for ANZ350.
Small Craft Advisory until 6 PM EDT this evening for ANZ353- 355.