Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 192329 AFDOKX Area Forecast Discussion National Weather Service New York NY 629 PM EST Sun Feb 19 2017 .SYNOPSIS... Low pressure near the Canadian Maritimes moves east tonight as a cold front passes through the region late tonight into early Monday morning. Meanwhile high pressure builds in from the north through Monday night. The high pressure shifts offshore on Tuesday ahead of a warm front that moves across Tuesday night into early Wednesday. A weak cold front then follows later on Wednesday, and then remains nearby into Thursday. The front lingers near the region on Friday before lifting north as a warm front Friday night into Saturday. Another cold front may move across late Saturday or Saturday night. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
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Forecast on track this evening. Just made minor adjustments to hourly temperatures and dewpoints to reflect latest observations. Deep cyclonic flow will remain across the region with upper low pressure across eastern Canada that will be shifting east tonight. A weak shortwave rotates through the upper low, with the energy remaining well to the north. A weak cold front is expected to pass through the region late tonight as heights build to the west after 09Z. Cold advection will be weak. And decoupling is not expected, possible occurring just before 12Z. Overnight temperatures will remain above seasonal averages. Moisture will be very limited with the front, with a dry frontal passage and minimal cloud cover.
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&& .SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/... A deep northwest flow will remain across the region Monday into Monday night as heights slowly rise through the period. A upper ridge axis will be just west of the CWA by 12Z Tuesday. A cooler airmass will be across the region Monday, however, high temperatures will still be above seasonal normals, with temperatures fairly uniform across the region. Monday night winds are expected to decouple with nearly clear conditions as the ridge nears the region, and a wide range of temperatures is forecast, with lows closer to normal. && .LONG TERM /TUESDAY THROUGH SUNDAY/... The main story of the long term period is well above normal temperatures. Models are in general agreement on the overall pattern through next weekend, with differences increasing by the end of the week into early next week. The coolest day in the period is likely to be on Tuesday surface high pressure and mid and upper level ridging dominate. Forecast highs will be near seasonable normals in the lower and middle 40s. The ridge axis and surface high move offshore late Tuesday as a warm front approaches from the west associated with low pressure traversing across southeast Canada. A subtle shortwave moves across Tuesday night as well. This system is going to run into ridging over the east with best jet dynamics remaining well to the north and west. Chance pops continue to look good with the main change with this forecast package is to remove sleet across the interior. Thermal profiles are too warm to support anything other than liquid. Increasing southerly flow and cloud cover Tuesday evening should prevent temperatures from falling below freezing across the interior so forecast shows plain rain everywhere. Lows Tuesday night are in the middle and upper 30s. Heights rise behind the departing shortwave and the warm front passage on Wednesday. A weak cold front gradually approaches with high pressure off the southeast coast. Flow around the high and ahead of the cold front will transport spring-like temperatures back to the region. Highs on Wednesday are forecast in the upper 50s and lower 60s. These highs fall short of record highs for Feb 22. The cold front may stall near or just west of the area Wednesday night into Thursday. This means unseasonably warm conditions will continue. Westerly flow in the middle and upper levels with core of jet to our north continues to pump warm air into the region from the west. MOS and model consensus blends are likely several degrees too cool for Thursday. Have raised highs for Thursday with forecast readings approaching 70 degrees in the NYC metro and NE NJ and lower to middle 60s across the Lower Hudson Valley and interior CT. See climate section below for Feb 23 record highs. Coastal CT and Long Island may end up closer to 60 due to an onshore component of the wind. Dry conditions continue Thursday night as cold front attempts to move across. A new wave of low pressure develops across the central states on Friday and then tracks through the Great Lakes Friday night and into SE Canada on Saturday. Unseasonably warm temperatures continue, but should be more in the 50s to near 60 due to increased cover. Timing of associated frontal passages differ among the deterministic and ensemble guidance. Chances for showers increase however Friday night into Saturday. Since this is a day 6/7 forecast, have capped pops at high chance. If the cold front does move through by Sunday morning, a return to more seasonable temps are expected. && .AVIATION /00Z MONDAY THROUGH FRIDAY/...
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High pressure builds tonight and Monday from the west. NW winds remain 10 kts or less tonight. Then, an increase to 10 to 15 kt is expected after 13-15Z Monday. A few gusts to 20 kt are possible. Winds remain NW, then turn toward the N late in the day and lighten. Anticipate VFR conditions through the TAF period with little cloud cover. .OUTLOOK FOR 00Z TUESDAY THROUGH FRIDAY... .Monday night-Tuesday evening...VFR. .Tuesday night...MVFR possible in rain. .Wednesday-Thursday night...VFR. .Friday...Sub-VFR in showers possible.
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&& .MARINE... Low pressure well north and east of the forecast waters will continue to track east of the Canadian Maritimes tonight into Monday morning with a cold front expected to pass through the waters late tonight into early Monday morning. Meanwhile high pressure will be building in from the north. A cyclonic flow will remain across the waters with winds and seas below small craft advisory levels. With the cold frontal passage weak cold advection increases along with the pressure gradient force. There may be occasional gusts right around 25 KT for a couple of hours, especially across the eastern forecast waters. However, with the uncertainty and brief nature of the gusts, will not issue an advisory at this time. With high pressure building over the waters Monday and Monday night winds and seas will remain below small craft advisory levels. High pressure slides offshore on Tuesday ahead of an approaching warm front. This front moves across Tuesday night and will be followed by the approach of a cold front. This cold front likely remains near the waters through the end of the week. The pressure gradient will remain relatively weak with winds and seas below SCA levels. The next chance for SCA conditions will be Friday night into Saturday as the next low pressure and associated frontal system approaches. && .HYDROLOGY... No hydrologic impacts are anticipated through the next 7 days. && .CLIMATE... The following are record high temperatures for Thursday February 23, 2017 Central Park........70 (1985) LaGuardia...........66 (1985) Kennedy.............62 (1990) Islip...............61 (2012) Newark..............68 (1985) Bridgeport..........60 (2012) && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && $$ SYNOPSIS...DS/MET NEAR TERM...DS/MET SHORT TERM...MET LONG TERM...DS AVIATION...PW MARINE...DS/MET HYDROLOGY...DS/MET CLIMATE... is the U.S. government's official web portal to all federal, state and local government web resources and services.