Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 170001 AFDOKX Area Forecast Discussion National Weather Service New York NY 801 PM EDT Wed Aug 16 2017 .SYNOPSIS... An area of high pressure will build into the region through tonight, then slowly shift offshore Thursday. A warm front will approach Thursday night. A cold front slowly approaches from the west on Friday, moving across the region on Saturday. High pressure returns on Sunday into Monday before the next cold front approaches from the west on Tuesday. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... Only minor updates needed to the forecast this evening to reflect current temperature and dew point trends. Dry conditions tonight and into tomorrow as high pressure continues to move eastward then offshore by Thursday. Temperatures tonight will be in the lower to mid 60s along the coast and mid 50s inland. Patchy fog possible late tonight and through early Thursday morning. A high rip current risk will continue this evening for the ocean beaches as the largest swells from distant Hurricane Gert arrive. For details on Gert, please refer to National Hurricane Center products. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/... Mostly sunny conditions expected on Thursday as high pressure begins to shift offshore Thursday allowing for the return of a southerly flow. As a low pressure system lifts through the Great Lakes, a warm front will lift northward towards the area late Thursday afternoon. Showers and possible thunderstorms will start to develop north and along the warm front late Thursday afternoon then spread across the region Thursday night. Temperatures on Thursday will be in the upper 70s to lower 80s with nighttime temperatures in the upper 60s to lower 70s. There will be a moderate risk of rip currents at ocean beaches for Thursday. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... Main concern in the long term period surrounds a frontal system progged to affect the area Friday into the first portion of Saturday. The parent low pressure system will be spinning across the northern Great Lakes Friday morning, with its warm front draped near the region. Low level warm advection near the warm front is the main source for lift with the expectation that showers will grow in coverage through the morning. The warm front should lift to the north in the afternoon, but abundant cloud cover should preclude any significant instability. Will continue to mention chance of thunder, with showers becoming likely through the morning and afternoon. The new 12z suite of models and ensembles are in good agreement that the main cold front will still be off to the west across upstate NY and PA Friday evening. With the main upper trough still located well to the west, do not think there will be any severe weather, with the latest Day 3 SPC outlook confining a marginal risk closer to the cold front. The front will gradually move to the east Friday night into Saturday morning, but will not completely move offshore until Saturday night. Showers with possible thunder will continue Friday night before tapering off Saturday morning out east. Locally heavy rain is possible anywhere Friday into early Saturday, but difficult to pinpoint since convection will throw off QPF on models, especially at this time range. Three quarters to one inch of rainfall is possible on average Friday through Friday night. The main moisture feed and lifting mechanism will then be offshore Saturday afternoon, with just a slight chance for a shower or storm as the cold front moves through. The upper trough is still expected to lag behind the front Saturday night, but have elected to remove PoPs due to cold advection behind the front and much drier air moving in. The upper trough should be offshore Sunday morning, with rising heights aloft expected through early next week as ridging takes shape across the southeastern US. This should bring a brief warming trend, with higher humidity levels and temperatures warmer than normal for this time of year in the middle and upper 80s. However, we still lie near the main belt of the westerlies to our north and m models signal a longwave trough developing over the eastern states late Tuesday into Wednesday along with the next cold front. && .AVIATION /00Z THURSDAY THROUGH MONDAY/... High pressure builds into the area tonight and slides offshore on Thu as a warm front approaches from the SW. VFR through the TAF period outside any overnight patchy fog. Dewpoints are forecast to drop overnight, so fog development is expected to be less widespread compared to last night. Northerly winds 5kt or less prevail tonight. Flow has weakened enough for the seabreeze to finally make it into KJFK, but this S flow should only last an hour or two before shifting back around. Boundary has now become so diffuse and with TJFK down it has been tough to see on radar. As the high shifts offshore on Thu winds will veer to the SE-S with seabreeze enhancement possible in the aftn. NY Metro Enhanced Aviation Weather Support... Detailed information, including hourly TAF wind component forecasts, can be found at: http:/ KJFK TAF Comments: Winds may be slightly higher and 20 degrees further to the left than forecast aft 18z. KLGA TAF Comments: Winds may be slightly higher and 20 degrees further to the left than forecast aft 20z. KEWR TAF Comments: Winds may be slightly higher aft 20z. KTEB TAF Comments: Winds may be slightly higher aft 20z. KISP TAF Comments: Winds may be slightly higher and 20-30 degrees further to the left than forecast aft 19z. .OUTLOOK FOR 00Z FRIDAY THROUGH MONDAY... .Thursday night through Saturday night...MVFR or lower flight cat possible in showers/tstms. .Sunday And Monday...VFR. && .MARINE... Long period southerly swells from Hurricane Gert should slowly subside tonight into Thursday as the hurricane moves farther out to sea. Thursday night winds and seas will remain below advisory levels as a cold front approaches from the west. Increasing southerly flow on Friday ahead of a cold front will bring the chance for some gusts close to SCA levels on the ocean waters west of Fire Island inlet, with gusts closer to 20 kt elsewhere on the ocean. Ocean seas could build near 5 ft as well late Friday into Friday night. The front should cross the waters through the day on Saturday with subsiding seas and winds remaining below SCA levels. Sub-SCA conditions are forecast Sunday and Monday. && .HYDROLOGY... Locally heavy rainfall is possible Friday into early Saturday. An average of 3/4 to 1 inch of rainfall is forecast. However, it is difficult to pinpoint where heavier showers/storms will develop at this time. No significant hydrologic impacts are expected, but some minor urban flooding is possible. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...High Rip Current Risk until 9 PM EDT this evening for NYZ075- 080-081-178-179. NJ...None. MARINE...Small Craft Advisory for hazardous seas until 2 AM EDT Thursday for ANZ353-355. Small Craft Advisory for hazardous seas until 8 AM EDT Thursday for ANZ350. && $$ is the U.S. government's official web portal to all federal, state and local government web resources and services.