Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 281956 AFDOKX Area Forecast Discussion National Weather Service New York NY 356 PM EDT Wed Sep 28 2016 .SYNOPSIS...
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High pressure over southern Quebec keeps us in a moist easterly flow off the Atlantic into the weekend as low pressure spins over the Ohio Valley. The high departs as a frontal boundary moves through this weekend. Another area of high pressure builds early next week.
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&& .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
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The only real uncertainty for the overnight is the extent of light pcpn and will is measure? There also is some higher level moisture coming up from the south as seen on RADAR. Have played this as drizzle from the stratus and chance POPs (West) from the moisture coming up from the south, though with QPF being less than a few hundreds. Temps fall to 55-60 range - above normal as ENE flow persists off the Atlantic.
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&& .SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
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Overall, expecting persistence with low clouds and light precipitation and a small diurnal range in temps. Chance for measurable QPF increases to categorical Thursday night as frontal boundary starts moving north and over-running is enhanced. Temps only top out in the Mid 60s - about 5 degrees or so below normal.
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&& .LONG TERM /FRIDAY THROUGH WEDNESDAY/...
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Blocked upper level pattern noted for much of the period, with large western Atlantic ridge holding Friday as cutoff upper low over the Ohio Valley remains nearly stationary through Friday night. Kicker upstream finally allows this cutoff to weaken and lift in time this weekend. By early next week, the Atlantic ridge gets pushed southeast as trough to the north lower heights across eastern Canada. Meanwhile, cutoff as already mentioned weakens as it moves east. However, differences arise by Tuesday as some solutions weaken this trough much more than other forms of guidance. Ridge builds east of the Mississippi by Wednesday. At the surface, high pressure to the north remains nearly stationary through Saturday as you would expect. Meanwhile, low pressure underneath cutoff remains well to the west, with frontal boundary located to our south. This front and triple point low lifts in time this weekend with the changing upper level pattern, and will be replaced by high pressure into early next week. Deep southerly flow between the offshore high, and the low to the west will lift over the warm front resulting in rain Friday and Friday night. With ample lift, moisture and presence of upper trough, expect rain chances to continue through the weekend. The weather may be more showery in nature for the latter portion of the weekend. Elevated weak instability could result in some thunder at times as well. Then mainly dry weather returns for the early to middle portion of the upcoming week. Below normal daytime temperatures Friday and Saturday are expected, due to the clouds, rain and easterly flow. Nighttime lows however remains slightly above normal. These daily temperatures will warm closer to normal early next week. Developing east flow maintains this near normal temperatures into the mid week period.
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&& .AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
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The main theme of the forecast will be MVFR stratus with some patchy drizzle that will become more widespread into this evening. Rain chances increase late tonight into Thursday from west to east but this will be primarily light. There is uncertainty with the forecast and some IFR will be possible at times. Timing of any IFR is of low confidence but a relatively higher chance for IFR stratus overnight into early Thursday morning. NE winds 10-15 kt with gusts in the 20-25 kt range will be in place through much of the TAF period. Some locally higher gusts to near 30 kt will be possible at times. 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: Wind gusts could be a few kts higher than forecast. There could be fluctuation between MVFR and IFR tonight into Thursday. KLGA TAF Comments: Wind gusts could be a few kts higher than forecast. There could be fluctuation between MVFR and IFR tonight into Thursday. KEWR TAF Comments: Wind gusts could be a few kts higher than forecast. There could be fluctuation between MVFR and IFR tonight into Thursday. KTEB TAF Comments: Wind gusts could be a few kts higher than forecast. There could be fluctuation between MVFR and IFR tonight into Thursday. KHPN TAF Comments: Wind gusts could be a few kts higher than forecast. MVFR could lower to IFR at times. KISP TAF Comments: Wind gusts could reach 25-30 kt at times this afternoon. IFR will be possible at times and there could be fluctuation between MVFR and IFR. .Outlook for 18Z Thursday through Monday... .Thu-Sat Night...IFR/MVFR in rain. NE winds 15-20 kt with gusts near 25 kt Thu-Fri Night. Gusts to 30 kt possible Thu-Fri Night. NW winds 10-15 kt with gusts near 20 kt Sat-Sat Night. .Sun-Mon...VFR. MVFR possible with showers Sunday.
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&& .MARINE...
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SCA conds occurring on all waters and will do so overnight. Expect winds to increase slightly on Thursday. Expect minimal gales on the Ocean by late morning. Seas build to around 5 ft on the open portions of the Sound and 10 ft on the Ocean. Rough conditions continue Friday with high pressure to the north and a warm front just south, resulting in gusty easterly winds. Conditions will improve as the front lifts north this weekend, and the pressure gradient weakens. High pressure will eventually build behind this frontal system early next week.
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&& .HYDROLOGY...
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The more significant rainfall is expect to not arrive until Thursday overnight and continue into the weekend. Totals are expected to average around 1". The prolonged nature of the rain event should preclude any hydrologic issues.
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&& .TIDES/COASTAL FLOODING...
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A persistent moderate easterly flow though the week will elevate water levels with an increase in astronomical high tides. Minor coastal flooding is expected on Thursday in the most vulnerable areas of the western Great South Bay. The region for minor flooding will likely expend for Friday`s high tides. Moderate levels of coastal flooding does not appear likely at this time except for the most vulnerable regions of southern Nassau.
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&& .OKX WATCHES/WARNINGS/ADVISORIES...
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CT...None. NY...Coastal Flood Advisory from 6 AM to 10 AM EDT Thursday for NYZ179. Coastal Flood Advisory from 6 PM to 10 PM EDT Thursday for NYZ179. NJ...None. MARINE...Small Craft Advisory until 6 PM EDT Friday for ANZ330-335-338- 340-345. Gale Warning from 6 AM Thursday to 6 PM EDT Friday for ANZ350- 353-355.
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&& $$ SYNOPSIS...Tongue NEAR TERM...Tongue SHORT TERM...Tongue LONG TERM...PW AVIATION...JM MARINE...Tongue/PW HYDROLOGY...Tongue/PW TIDES/COASTAL FLOODING...

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