textproduct: New York

WHAT HAS CHANGED

Heat Advisory extended into Saturday for NE NJ, NYC metro, and Long Island

KEY MESSAGES

1. Very warm and very humid through Saturday. Continued very warm 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.

KEY MESSAGE 2

This aft/eve forcing and focus for scattered downpours/tstms is expected to be focused NW of NYC metro ahead of approaching weak surface trough in a highly unstable, very moist, weak to marginal deep layer shear environment. Weakening convection could possibly drifts east into the NYC metro and surrounding late this evening. This will present an isolated flash flood and wet microburst threat, primarily N&W of NYC into this evening.

Subtropical ridge breaks down Friday 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 Friday 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 Fri 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 an iso-sct pulse strong to severe threat in the high CAPE weak shear environment, particularly in late afternoon/evening with any more organized approaching convection.

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.

OUTLOOK FOR 18Z FRIDAY THROUGH TUESDAY

Friday Afternoon-Night: Showers and thunderstorms likely in the afternoon and evening, especially in the vicinity of NYC metros and N and W.

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 prolonged period of SW flow will feature gusts to around 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. At this point, no SCA due to marginal nature of threat.

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

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 thru Saturday. Potential for rip current risk to increase to high late afternoon and evening today and Friday 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 Friday for CTZ005>012. Air Quality Alert from 11 AM to 11 PM EDT Friday for CTZ007>012. Air Quality Alert until 11 PM EDT this evening for CTZ009-010. NY...Heat Advisory until 8 PM EDT Friday for NYZ067>071. 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.