Area Forecast Discussion

WHAT HAS CHANGED

Small Craft advisory has been cancelled. Otherwise, no significant changes with the forecast.

KEY MESSAGES

1) Heat advisory remains in effect for much of the region Thursday through Friday with hot and humid conditions expected.

2) There is a risk for isolated to scattered severe thunderstorms and localized flash flooding during the late afternoon and evening hours Thursday and Friday.

3) 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...

An upper ridge will briefly re-establish itself over the region on Thursday and again on Friday behind any storms that move through on Thursday evening. This will be ahead of an upper level trough, which will support a surface low pressure system that will move through the region on Friday night. In the warm sector of this system, 850 mb temperatures will surge toward the 20 C mark, translating to surface temperatures in the upper 80s to lower 90s. Meanwhile, there will be an increase in surface moisture across the region with dew points in the upper 60s to lower 70s. Together, this will allow for Heat Index values to be in the mid 90s to lower 100s for Thursday and Friday with the Heat Advisory remaining in effect for much of the area. Temperatures and heat index values will remain muted in the lower to mid 80s for coastal SE CT and Eastern Long Island, and these areas will remain out of the Heat Advisory.

.KEY MESSAGE 2...

The airmass over the region is expected to become much more unstable on today with high heat and humidity (dew points around 70). Confidence is increasing for a complex of showers and thunderstorms to move in from the NW during the late afternoon and evening hours. A high CAPE environment with mid level lapse rates around 6.5C will be sufficient enough to support deep convection. Shear is marginal but may be just enough to support cold pool maintenance. Isolated pulse severe is the main threat with some small bowing segments possible. While temperatures are warm aloft, deep convection will warrant a large hail threat in addition to damaging wind gusts. SPC has a slight risk with isolated to scattered coverage. WPC has included the area in a marginal risk for excessive rainfall, which is localized flash flood threat. High PW values around 2" along with deep convection favor high rainfall rates. Max hourly rainfall rate look to be about 2 inches.

Friday will feature another high CAPE, weak shear day with evening showers and thunderstorms likely along and ahead of an approaching cold front. Expect isolated to scattered severe thunderstorms with the main threat being damaging wind gusts. SPC once again has much of the area in a slight risk for severs storms, though a more prominent threat of damaging wind gusts, especially for western areas. Flash flood threat looks isolated at this time.

.KEY MESSAGE 3... Still hot for the weekend with quite a few locations reaching highs in the lower 90s but lower dew points will limit the extent of the heat index values as the 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 /12Z THURSDAY THROUGH MONDAY/

Weak low pressure resides near the region through the TAF period. A cold front approaches from the west Friday.

Mainly VFR into the morning hours. A higher likelihood of MVFR to IFR conditions at KISP with sub-IFR at KGON in stratus/fog initially this morning. By late morning and through remainder of TAF period, mainly VFR but MVFR or lower possible within showers and thunderstorms. The window for these generally in the 21-03Z timeframe. There is the possibility that some thunderstorms could become severe with brief strong wind gusts up to 50 kt being the main threat. Showers and thunderstorms taper off late this evening into the overnight.

Regarding winds, they will increase out of a general SW to WNW direction to near 10 kts. Flow generally westerly tonight into Friday also near 10 kts. Some locations will have gusts up to 20 kt late afternoon into early evening.

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

Timing of showers and thunderstorms could be 1 to 3 hours off from TAF.

.OUTLOOK FOR 12Z FRIDAY THROUGH MONDAY...

Friday: VFR initially. Then MVFR or lower possible at times with chances for showers and thunderstorms late afternoon into the night. Again, potential for some thunderstorms to be severe with main threat being damaging winds.

Saturday: VFR.

Sunday: VFR early day, then slight chance of a shower or thunderstorm with brief MVFR or lower possible. Showers likely at night with MVFR or lower possible and a slight chance of a thunderstorm. Southerly wind gusts 15-20 kt afternoon and evening.

Monday: Mainly VFR. Slight chance of a shower with MVFR possible.

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

MARINE

SCA conditions have largely come to an end so the advisories have been cancelled.

Sub-SCA conditions are expected through much of the forecast period with near SCA conditions possible once again for the ocean waters Sunday afternoon through Monday morning.

Rip Currents...

For today, there is a moderate rip current risk with SW winds around 10 kt and surf around 3 ft.

For Friday, the risk is low with with SW-S winds around 10 kt and surf heights around 2 ft

CLIMATE

Record High Temperatures:

June 11: KEWR: 96/2000 KBDR: 93/1984 KNYC: 95/1973 KLGA: 96/1984 KJFK: 93/1984 KISP: 93/1973

June 12: KEWR: 97/2017 KBDR: 93/2017 KNYC: 93/2017 KLGA: 96/2017 KJFK: 92/2017 KISP: 91/2017

Record High Minimum Temperatures:

June 11: KEWR: 77/1984 KBDR: 71/2008 KNYC: 78/1984 KLGA: 76/1973 KJFK: 76/1984 KISP: 71/1984

June 12: KEWR: 74/1973 KBDR: 69/1973 KNYC: 76/2017 KLGA: 76/2017 KJFK: 73/1970 KISP: 70/1973

June 13: KEWR: 74/2005 KBDR: 71/2017 KNYC: 77/2017 KLGA: 80/2017 KJFK: 72/2017 KISP: 70/1969

OKX WATCHES / WARNINGS / ADVISORIES

CT...Heat Advisory from noon today to 8 PM EDT Friday for CTZ005>010. Air Quality Alert from 11 AM this morning to 11 PM EDT this evening for CTZ009>012. NY...Heat Advisory from noon today to 8 PM EDT Friday for NYZ067>075-078-080-176>179. Air Quality Alert from 11 AM this morning to 11 PM EDT this evening for NYZ071>075-078>081-176>179. NJ...Heat Advisory from noon today to 8 PM EDT Friday for NJZ002- 004-006-103>108. MARINE...None.