Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 261825 AFDOKX Area Forecast Discussion National Weather Service New York NY 225 PM EDT THU MAY 26 2016 .SYNOPSIS... The region will be under the influence of a westward extension of the Bermuda High through the weekend. A cold front approaches from the west Monday, then pushes through the area Monday night. This front then stalls out near or just to the south of the area through Wednesday as high pressure builds to the north. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Weak shortwave moving into the upper ridge was producing mainly cloudiness. Heights remain steady or rise slowly through this afternoon. Best instability will be inland. Convection will be diurnal and confined to inland locations. Updated pops to reflect changes and converted to areal coverage wording. There is a moderate risk of rip current development at the Atlantic beaches today into this evening. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/... 500 mb shortwave enters tonight, but weakens as the shortwave moves into the upper ridge, and moves across the region. Loss of instability will help keep any showers/storms isolated to scattered in nature, and confined to inland. In addition, convection will be weakening with loss of heating. Updated pops to have convection during the afternoon and evening periods, and to use areal wording. 850-700 mb shortwave slowly moves through the CWA during Friday. Moisture depth and lift will be greater during the morning, but CAPES will be higher in the afternoon. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... A westward extension of the Mid-Atlantic Ocean based sub-tropical ridge builds in Friday night-Saturday, then retreats back to the southeast Saturday night and Sunday. The result will be continued very warm and humid conditions across the region. There will also be some mainly diurnal isolated-scattered showers and thunderstorms from Friday evening through Sunday as well. Temperatures during this time frame were based on a blend of all available guidance, with NAM 2-meter temperatures blended in Friday night-Saturday night, and a mix down from 975-850 hPa, per BUFKIT soundings, blended in for highs on Saturday. Lows will run around 10 degrees above normal both Friday and Saturday night. Highs Saturday and Sunday should run around 10-15 degrees above normal. The forecast for Sunday night-Wednesday is very much dependent on the interaction between a northern stream shortwave that is forecast to move across the Great Lakes and a possible closed low near the mid-Atlantic Coast. There is quite a spread in model solutions, with the GFS showing the most interaction between these two systems and the ECMWF the least. The CMC-Global is somewhat in between these two solutions, but trends closer to the ECMWF with time. It should be noted that the ECMWF and GFS basically flipped solutions from the 12z to the 00z runs. The result is a low confidence forecast from Sunday night-Wednesday. For now will run with pops increasing to chance throughout Sunday night for showers and thunderstorms, continuing on Monday, then tapering off Monday night. Given uncertainties in how quickly the airmass changes on Tuesday, have included some diurnal convection then, however, if the ECMWF/CMC are correct, Tuesday could end up dry. Given the overall uncertainty then maintain mainly slight chance pops for Tuesday night and Wednesday. For temperatures Sunday night-Wednesday, the Superblend was used, with above normal temperatures forecast, but not quite as warm as this weekend. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/...
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Persistence forecast the next 24 hours with high pressure over the Western Atlantic and a thermal trough inland each afternoon. This will result in mainly VFR conditions and a southerly flow with local seabreeze enhancements. An isolated thunderstorm is possible each afternoon/evening, but primarily north and west of the NYC terminals. Chances remain too low to mention in TAFs. NY Metro Enhanced Aviation Weather Support... Detailed information...including hourly TAF wind component fcsts can be found at: http:/www.weather.gov/zny/n90 KJFK TAF Comments: No unscheduled amendments expected. KLGA TAF Comments: No unscheduled amendments expected. KEWR TAF Comments: No unscheduled amendments expected. KTEB TAF Comments: No unscheduled amendments expected. KHPN TAF Comments: No unscheduled amendments expected. KISP TAF Comments: No unscheduled amendments expected. .OUTLOOK FOR 18Z Friday through Tuesday... .Friday afternoon-Sunday...Mainly VFR, but sub-VFR possible in mainly isolated showers and evening thunderstorms. .Monday and Tuesday...Sub-VFR possible in showers and thunderstorms.
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&& .MARINE... Updated pops and weather over the waters this afternoon through Friday. Otherwise, no changes to winds and seas. A weak to moderate pressure gradient over the region through Monday will keep winds to 15 kt or less over the waters around Long Island. With no significant swells forecast during this time frame, seas will remain below Small Craft levels as well. && .HYDROLOGY... No significant widespread precipitation expected through Friday night. There is the potential for locally heavy rainfall, for areas mainly N/W of NYC Saturday and Sunday, with a higher chance of a more widespread moderate to heavy rainfall from Sunday night into Monday, and possibly lingering farther into next week. For this weekend, the main threat is ponding of water on roadways, with a low risk of minor flooding of urban and poor drainage areas (once again the main threat this weekend will be to the N/W of NYC). At this time, there is too much uncertainty to specify any threat for early next week, other than to note the situation bears watching. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && $$ SYNOPSIS...JC/Maloit NEAR TERM...MET SHORT TERM...JC LONG TERM...Maloit AVIATION...DW MARINE...MET HYDROLOGY...JC/Maloit

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