Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 180143 AFDOKX Area Forecast Discussion National Weather Service New York NY 843 PM EST Fri Feb 17 2017 .SYNOPSIS... High pressure moves through the area tonight, with a warm front moving across the northeast by Saturday morning as the high moves east. A weak surface trough moves through the area Saturday night, followed by a cold front Sunday night. High pressure builds Monday through Tuesday. A warm front will approach Tuesday night followed by a weak cold front becoming nearly stationary just south of the area Wednesday through Friday. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
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Thick jet cirrus is currently bisecting the forecast area. As a result, the forecast has been updated to increase cloud cover accordingly. Otherwise, as high pressure builds across the region tonight and the pressure gradient begins to relax, gusts will gradually subside. West-northwest flow along with increasing subsidence has led to slightly warmer temperatures than originally forecast, but overall highs today are seasonable. Overnight, an upper jet streak will move through the area, with associated mid and upper-level high clouds briefly increasing. Potential cloud cover and a return to southerly flow and weak warm advection should lead to slightly warmer temperatures than last night. Overnight temperatures will be a few degrees above climatological normals. After examining verification for the previous 7 days, have edged on the warmer side of guidance for minimum temperatures tonight.
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&& .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... Temperatures will be mild following a weak warm frontal passage in the morning as southerly/southwesterly flow continues. Expect highs to be 10-15 degrees above climatological normals, with any morning cloud cover quickly moving east and clearing out by afternoon. A weak surface trough moves through Saturday afternoon/evening with no real appreciable change in conditions other than a slight wind shift to a more westerly direction. Winds should remain elevated overnight, maintaining mixing and along with subsidence on the back side of the trough will act to keep minimum temperatures well above climatological normals. Despite lingering moisture, have discounted deterministic model solutions chance of stratus beneath the inversion overnight, as any subsidence and a return to offshore/downslope winds should hinder significant cloud development. && .LONG TERM /SUNDAY THROUGH FRIDAY/... Sunday...As a weak northern stream short wave moves east of the area a higher amplitude short wave will move off the southeast coast, taking the rain with it. WNW downsloping winds and full sun will cause temps to rise between 50 and 60 degrees, about 15 degrees above normal. Sunday Night thru Tuesday...A canadian high pressure system will move southeast down a high amplitude upstream ridge causing cooler temps with highs in the 40s Monday and Tuesday and lows in the 20s and low 30s Monday Night. Tuesday Night thru the day Wednesday...will bring our next chc for a light "mainly" rain event between the retreating high and approaching short wave trough. Most likely rainfall amounts one tenth to one quarter inch. Areas of light freezing rain possible for a few hours across the far northern zones, including interior southern CT. Thursday and Friday...with more sun on Thu, temps once again are forecast between 50 and 60 degrees, near 15 degrees above normal on a light W flow. As low pressure approaches friday with more cloud cover and a light onshore flow, temps are fcst mainly in the upper 40s and low 50s, still above normal values. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/... High pressure slides southeast of the region as a warm front approaches, eventually moving across early Saturday. VFR conditions are expected through the TAF period although there will be a low chance of MVFR stratus moving in from the north late tonight. Not enough confidence to insert in TAFs. NW flow with true direction 290-300 will weaken this evening with any gusts subsiding. The flow will become light and variable late this evening and then increase from the SW Saturday with gusts developing in the late morning and afternoon. Timing of gusts could be 1-3 hours off. A low level jet develops by early Saturday night of near 40kt at 2kft. ...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: An occasional gust to 15-20 kt possible before 02Z. Timing of gusts Saturday could be 1-3 hours off. Also gusts may be more occasional Saturday. KLGA TAF Comments: An occasional gust to 15-20 kt possible before 02Z. Timing of gusts Saturday could be 1-3 hours off. Also gusts may be more occasional Saturday. KEWR TAF Comments: Timing of gusts Saturday could be 1-3 hours off. Also gusts may be more occasional Saturday. KTEB TAF Comments: Timing of gusts Saturday could be 1-3 hours off. Also gusts may be more occasional Saturday. KHPN TAF Comments: Timing of gusts Saturday could be 1-3 hours off. Also gusts may be more occasional Saturday. KISP TAF Comments: Timing of gusts Saturday could be 1-3 hours off. Also gusts may be more occasional Saturday. .OUTLOOK FOR 00Z SUNDAY THROUGH WEDNESDAY... .Saturday night-Sunday afternoon...VFR. LLWS decreases late Saturday evening. .Sunday night-Monday...VFR. NW winds near to right of 310 mag 10kt with gusts near 15-20kt during the daytime. .Monday night through Tuesday evening...VFR. .Late Tuesday night-Wednesday...MVFR possible in rain. && .MARINE... Sub-Small Craft Advisory conditions prevail through Saturday with a high pressure ridge and weak pressure gradient shifting through. Winds then pick up again Saturday night into Sunday with the approach and passage of a cold front, but with winds and seas likely remaining below advisory criteria. Following the cold frontal passage and as canadian high pressure builds southeast across the area, a Small Craft Advisory/SCA is possible across the Atlantic Ocean coastal waters south of Long Island Sunday night and Monday as NW winds range from 15-20 kt with occasional gusts near 25 kt and seas build to around 4 feet. && .HYDROLOGY... No hydrologic impacts are anticipated through the next 7 days as any snow melt will be gradual. The next light "mainly" rainfall between one tenth and 1/4 inch is forecast between a retreating high pressure system and an approaching low Tuesday night and Wednesday. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && $$ SYNOPSIS...GC NEAR TERM...12/MD SHORT TERM...MD LONG TERM...GC AVIATION...JM MARINE...12/GC/MD HYDROLOGY...MD

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