Area Forecast Discussion
Issued by NWS Upton, NY

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581 FXUS61 KOKX 260957 AFDOKX Area Forecast Discussion National Weather Service New York NY 557 AM EDT Wed Sep 26 2018 .SYNOPSIS... A warm front will slowly move north of the area tonight, followed by a cold front Wednesday and Wednesday night. High pressure returns on Thursday and then builds to the north on Friday as a wave of low pressure passes to the south. A stronger high pressure builds from the west over the weekend and then offshore early next week. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... The main story today will be the potential for severe thunderstorms as a cold front approaches from the west. Prior to its approach, showers and thunderstorms will develop and move over the area, mainly across Long Island and Connecticut early this morning. The primary focus for these showers and thunderstorms is the warm front that is still in the vicinity. As the warm front lifts north, coverage should decrease until the cold front approaches later this afternoon. However, the chance for showers and thunderstorms remains until then. The cold front will approach this afternoon. Out ahead of the front, a line of showers and thunderstorms is forecast to develop. Some of these showers and thunderstorms will be strong, with gusty winds of 30-40 mph, and possibly severe, with damaging wind gusts of up to 60 mph. Lifted indices in the -4 to -6 range support the potential for severe, given the cold front as the primary lifting mechanism. There will be a decent amount of instability with MUCAPE values in the 1000-2000 J/kg range. Also associated with these storms will be brief, heavy rainfall. The rainfall is not expected to be nearly as high as yesterday. However, southern Connecticut has very low one hour flash flood guidance of 0.25"/hr or less thanks to the very heavy rain that fell yesterday. Despite the fact that the rainfall will be lower today as compared to yesterday, flash flooding will once again be possible, mainly for Connecticut. There is a high rip current risk for the Atlantic beaches today. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/... The threat for severe storms will continue through about midnight across the tri-state area, until the cold front pushes off the east coast. Also, the continued threat for flash flooding for Connecticut will continue. Thereafter, chances for showers and thunderstorms decreases as high pressure builds in from the northwest. The cold front will remain just to our south, and a slight chance for showers may continue across mainly Long Island for Thursday. A weak area of low pressure will develop along the frontal boundary, and unsettled weather will come back into the picture for Thursday night into Friday. There is a low rip current risk for the Atlantic beaches on Thursday. && .LONG TERM /FRIDAY THROUGH TUESDAY/... The low moves offshore into Friday night with a stronger high building into the region for the rest of the weekend. This high will likely move offshore early next week with the approach of the next frontal system. Temperatures should average near normal through the long term period with highs in the upper 60s and lower 70s and nighttime temperatures mainly in the lower and middle 50s. && .AVIATION /10Z WEDNESDAY THROUGH SUNDAY/... Warm front will lift north of the terminals this morning, followed by a cold front this evening and tonight. Heavy rain showers have re-developed east of NYC. These showers should linger through the early morning hours, mainly across KISP, KBDR and KGON. We should then see a break in the precipitation, before additional showers and thunderstorms return to the region this afternoon and evening as a cold front approaches and moves across the area. Some of these storms will be capable of gusty winds and heavy rain. Winds will continue to diminish overnight. Light and variable winds will be likely across the Lower Hudson Valley. S-SW winds of 10 to 15 kt expected today, then become NW behind the cold front after 00z tonight. NY Metro Enhanced Aviation Weather Support... Detailed information, including hourly TAF wind component forecasts, can be found at: http:/www.weather.gov/zny/n90 KJFK TAF Comments: Amendments possible this morning for changing flight categories. Showers and thunderstorms expected this afternoon/evening. The afternoon KJFK haze potential forecast is RED...which implies slant range visibility less than 4sm outside of cloud. KLGA TAF Comments: Amendments possible this morning for changing flight categories. Showers and thunderstorms expected this afternoon/evening. The afternoon KLGA haze potential forecast is YELLOW...which implies slant range visibility 4-6SM outside of cloud. KEWR TAF Comments: Amendments possible this morning for changing flight categories. Showers and thunderstorms expected this afternoon/evening. The afternoon KEWR haze potential forecast is GREEN...which implies slant range visibility 7SM or greater outside of cloud. KTEB TAF Comments: Amendments possible this morning for changing flight categories. Showers and thunderstorms expected this afternoon/evening. KHPN TAF Comments: Amendments possible this morning for changing flight categories. Showers and thunderstorms expected this afternoon/evening. KISP TAF Comments: Amendments possible this morning for changing flight categories. Showers and thunderstorms possible this evening. .OUTLOOK FOR 06Z THURSDAY THROUGH SUNDAY... .Wednesday night...Improvement to VFR. .Thursday...VFR. .Thursday night-Friday morning...MVFR possible, low chance of showers. .Friday afternoon-Sunday...VFR. && .MARINE... SCA remains for the ocean with sub-SCA conditions on other waters. The ocean seas will remain above 5 ft through tonight. Winds are likely to remain below SCA levels Thursday through the weekend on all area waters. Ocean seas on Thursday into Thursday night will remain elevated above 5 ft, but then should remain 3-4 ft from Friday into the weekend. && .HYDROLOGY... Despite rainfall forecast of 1/4 to 1/3 of an inch across the entire area, locally heavy rainfall with any thunderstorms today may lead to flash flooding for southern Connecticut due to low one hour flash flood guidance of 0.25" or less in areas that received very heavy rainfall yesterday. && .EQUIPMENT... NYC NOAA Weather Radio Station KWO-35 (162.55 MHz) remains off the air for an extended period of time. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...High Rip Current Risk through this evening for NYZ075-080-081- 178-179. NJ...None. MARINE...Small Craft Advisory until 6 PM EDT Thursday for ANZ350-353- 355. && $$ SYNOPSIS...JP NEAR TERM...JP SHORT TERM...JP LONG TERM...DS AVIATION...BC MARINE...JP HYDROLOGY...JP EQUIPMENT...

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