Area Forecast Discussion
Issued by NWS Upton, NY

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KOKX 231036 AFDOKX Area Forecast Discussion National Weather Service New York NY 636 AM EDT Sun Jul 23 2017 .SYNOPSIS... A frontal boundary remains to our south today. Low then moves along the front, tracking off the mid-Atlantic coast Monday. High pressure builds over the northeast late Tuesday through Wednesday, then drifts off the coast Wednesday night. Another wave of low pressure follows for Wednesday night into Friday, with a cold front moving through Friday. High pressure returns Saturday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --
Initial shortwave passes to the east early this morning, with a wave of low pressure doing the same. High pressure, with weak ridging aloft, builds across New England. Other than an isolated shower, subsidence behind shortwave will likely keep the area dry today. Some sunshine will appear, particularly in southern CT. Temperatures today will be cooler, closer to seasonal norms of the lower to mid 80s. There is a moderate risk for the development of rip currents at ocean beaches today.
-- End Changed Discussion --
&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/... Weak ridge yields to approaching trough through this time frame. At the sfc, two areas of low pressure approach and pass. the area looks to remain on the north side of the frontal boundary as the coastal low passes juts south Monday. Ample forcing ahead of this system will result in increasing coverage for showers and possible thunderstorms tonight, from west to east. Best chance occurs from late evening and through the overnight hours. At this time, instability appears to be weak, so widespread thunder is not anticipated. On Monday, showers are possible, but the main area in the morning departs in the afternoon. For tonight, the rain and clouds will result in normal overnight low temps. However, cool temperatures are anticipated during the day Monday. With easterly flow, and plenty of clouds, leaned toward the lower end of the guidance, with a 2/3 and 1/2 blend followed. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... An upper level shortwave and accompanying wave of surface low pressure will be exiting to the east Monday night into early Tuesday. A few showers will be on-going at the beginning of the extended forecast period. CAPE values look meager. A weak ridge builds Tuesday and Wednesday. Then another shortwave amplifies into a significant trough into the eastern states Wednesday night into Thursday with a high amplitude trough, of 1 to 2 standard deviations above normal, digging all the way to northern Florida by Friday. The flow looked to be still progressive with a surface low moving through Thursday and Friday. However, there are hints that the upper low will close off again Friday into Saturday and remain along the northern coast into next weekend. At this time will keep with persistence and the more progressive flow and keep Friday night into Saturday dry as upper ridging builds to the north. Temperatures through the extended period will be near to slightly below seasonal normals. && .AVIATION /12Z SUNDAY THROUGH THURSDAY/... A frontal boundary will remain just south overnight as a wave of low pressure tracks along it, then sag farther south today after the low passes. Another low will then moves along the front tonight. Brief IFR vsby in heavier rain at KJFK has tapered off, leaving MVFR conditions in rain at KISP. Lingering MVFR conditions at KEWR/KTEB should improve overnight. Expect BKN VFR cigs through the day on Sunday, with NE flow turning SE in the afternoon. Played cigs more on the pessimistic side, but they could be higher than forecast if drier air works in from the NE, especially at the CT terminals. If the more optimistic scenario plays out, winds at coastal terminals could be more southerly then fcst as a sea breeze also develops. As the next low approaches, showers with MVFR conditions should make it to the NYC metro terminals after 02Z-03Z Mon. .OUTLOOK FOR 06Z MONDAY THROUGH THURSDAY... .Late Sunday night-Monday night...Showers likely. MVFR conds likely, IFR cigs possible. A rumble of thunder also possible late Sunday night. .Tuesday...Mainly VFR. .Tuesday night-Wednesday night...VFR. .Thursday...Chance of showers and possibly a tstm, with local MVFR or lower conds. && .MARINE... Increasing E-SE flow tonight and then E-NE flow on Monday ahead of an approaching low, with a warm front remaining to the south or only briefly entering the ocean waters, should eventually build ocean seas to minimal SCA criteria of 5 ft. This could happen in the NY Bight area as early as late tonight, but certainty in this is higher for daytime Monday. Wind gusts up to 25-30 kt are also possible on the eastern ocean/sound/bay waters daytime Monday. Ocean seas may also approach 5 ft Wed night-Thu as increasing S flow develops ahead of a cold front. Waves of low pressure passing through could also bring a chance of tstms on Thu. && .HYDROLOGY... An additional 1/2 to 1 inch of rainfall is likely from late tonight through Monday, with locally higher amounts possible. There is a small chance for minor flooding or urban and poor drainage areas, if any experience locally heavy rainfall. More rain is possible Thursday through Friday. Significant hydrologic impacts are not expected at this time. && .TIDES/COASTAL FLOODING... With the new moon phase today, tides are running high. Positive tidal departures of 1/2 to 1 ft are needed for minor flooding during the night time high tide. With east flow expected, and looking at what occurred earlier tonight, will issue a coastal flood advisory for western LI sound, the south shore bays of LI, and lower NY Harbor for the evening and night time high tides. A few locations could reach or slightly exceed moderate benchmarks across the south shore bays of Nassau and Queens. The threat for minor flooding could continue into Monday, with E/NE flow progged to continue. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...Coastal Flood Advisory from 11 PM this evening to 2 AM EDT Monday for CTZ009. NY...Coastal Flood Advisory from 11 PM this evening to 2 AM EDT Monday for NYZ071-073-176-177. Coastal Flood Advisory from 8 PM to 11 PM EDT this evening for NYZ074-075-178-179. NJ...None. MARINE...None. && $$ SYNOPSIS...PW NEAR TERM...PW SHORT TERM...PW LONG TERM...MET/PW AVIATION...Goodman MARINE...PW HYDROLOGY...PW TIDES/COASTAL FLOODING...PW is the U.S. government's official web portal to all federal, state and local government web resources and services.