Marine Weather and Tide Forecast for Elmont, NY

KEY MESSAGES
1. Hot and humid conditions persist through at least Saturday.
Continued heat but likely with lower humidity Sunday and Monday, possibly lingering into early next week.

2. Potential for scattered afternoon/evening heavy downpours and thunderstorms through Saturday, presenting a threat for isolated to scattered instances of flash flooding and strong to severe thunderstorm winds, particularly for NYC and points N&W.

DISCUSSION

KEY MESSAGE 1
An anomalously strong subtropical ridge will gradually break down into the weekend as the westerlies once again drop back into the area.

Deep SSW flow from Gulf/Sub-tropic origin will continue a very warm and more notably a very humid airmass across the region through at least Saturday.

Daytime highs will run 3 to 7 degrees above normal, well below records, but the high humidity (mid to upper 70s Tds) will make it feel quite uncomfortable. Heat index values today will get solidly into heat advisory criteria. Max heat index values today in the upper 90s to 104 across much of the area, except mid 90s across the immediate southern and eastern coasts.

With approaching shortwave on Saturday, perhaps more in the way of convective debris, and some subtle indication of Tds being slightly lower (lower to mid 70s). This appears to have heat indices slightly lower in the mid 90s to lower 100s for NYC, NJ metro, and LI, with lower to mid 90s interior. Enough confidence in another day of mid 90 heat indices to extend the heat advisory into NYC, NE NJ, and LI at this point. The heat advisory may need to be extended into Saturday for interior areas as well if confidence in higher heat indices persists.

Better signal for lowering TDs (upper 60s/lower 70s) for Sunday into Monday in wake of a weak cold front. So although temps will likely remain very warm in the upper 80s/lower 90s, HI's will likely fall back into the lower 90s to 95. Heat advisories may need to be extended for NE NJ and NYC Metro, but marginal at this point.

Heat indices may perk back up into the mid to upper 90s on Tuesday ahead of next approaching series of northern stream shortwaves and cold front, before a general signal for a cool down to more seasonable temps for middle of next week.

KEY MESSAGE 2

The subtropical ridge breaks down today into Saturday, as a series of shortwaves approach and then cross the region around large central Canada closed low.

These shortwave will provide better forcing for more widespread aft/eve convection today and possibly Saturday in a similar highly unstable, very moist, weak to marginal deep layer shear environment. Good signal on the CAMs for iso-sct convective initiation by early afternoon along coastal seabreeze, with perhaps a more organized line developing across central/eastern PA/NY working into the region late afternoon/evening. With low mbE vectors magnitudes and high PWATS, potential for 2+" rainfall rates and iso-sct flash flooding exists. In addition, despite generally weak shear over the area, high instability given the heat and humidity will provide for a potential for any pulse-like convection to produce localized downbursts. The threat for strong to damaging winds is slightly increased if convection is able to organize. As a result, SPC has expanded and increased the threat for severe thunderstorms this afternoon and evening, with NYC, NE NJ, and the Lower Hudson Valley now in a slight risk for severe thunderstorm development and a marginal risk expanded about 1 county eastward through the CWA, generally through western CT and central LI.

A similar threat is possible for Saturday aft/eve, although some uncertainty on exact timing of shortwave energy and cold front with peak diurnal instability. This will be refined the next 24 hours with high-res model trends.

Threat for convection looks limited on Sunday in wake of weak cold frontal passage bringing in a drier and weakly unstable airmass.

AVIATION /15Z FRIDAY THROUGH TUESDAY/
A trough of low pressure will remain nearly stationary across the region into Saturday.

Mainly VFR. Showers and thunderstorms are possible this afternoon and evening. The highest chances are for the terminals in the vicinity of the NYC metro on NW. Current timing looks to be from 19z through 02z. MVFR or lower possible in this activity and there may also be a brief wind shift to the W or NW and gusts in excess of 35 kt in the strongest storms.

Conditions should remain VFR tonight although there is a chance for some MVFR at some outlying terminals overnight. Confidence is not high enough to include in the TAF at this time.

Light winds to start will become W-SW into the early afternoon.
Coastal terminals will become S with afternoon sea breeze enhancement. Wind speeds around 10 kt are expected this afternoon.
Winds will weaken outside of showers/storms this evening, shifting to the SW and then likely VRB overnight. SW winds increase on Saturday.

...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Amendments possible for TSRA timing this afternoon and evening.
There is a chance for a popup shower/storm an hour or two before the TEMPO indicated in TAF.

PROB30 for TSRA 00-02z could end up just SHRA.

OUTLOOK FOR 12Z SATURDAY THROUGH TUESDAY

Saturday: Mainly VFR. Low probability for showers thunderstorms in the afternoon and evening. SW gusts 15-20 kt possible.

Sunday: VFR.

Monday-Tuesday: Mainly VFR. Low probability for showers and thunderstorms in the afternoon and evening N and W of NYC terminals.

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

MARINE
A persistent SW flow of 10 to 15 kt with gusts up 20 kt on the ocean waters each late afternoon and evening through Sat.
Occasional gusts to 25 kt possible near entrance to NY Harbor with coastal jet formation each late afternoon/evening, which could have ocean seas building to 3-5 ft during these times.

Rip Currents: Persistent SW flow and associated wind waves will lead to a moderate rip current risk today and Saturday.
Potential for rip current risk to increase to high late afternoon and evening today with coastal jet development and increase in breaking waves to 3 to 4 ft, particularly for NYC and western LI beaches.

OKX WATCHES/WARNINGS/ADVISORIES
CT...Heat Advisory until 8 PM EDT this evening for CTZ005>012.
Air Quality Alert until 11 PM EDT this evening for CTZ007>012.
NY...Heat Advisory until 8 PM EDT this evening for NYZ067>071.
Air Quality Alert until 11 PM EDT this evening for NYZ069>075- 078>081-176>179.
Heat Advisory until 8 PM EDT Saturday for NYZ072>075-078>081- 176>179.
NJ...Heat Advisory until 8 PM EDT Saturday for NJZ002-004-006- 103>108.
MARINE...None.