Area Forecast Discussion
Issued by NWS Upton, NY

Current Version | Previous Version | Graphics & Text | 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 281615 AFDOKX Area Forecast Discussion National Weather Service New York NY 1215 PM EDT Tue Mar 28 2017 .SYNOPSIS... A stationary front front will remain to the south today. Low pressure will pass to the south tonight. High pressure will build in on Wednesday and Thursday, then pass east Thursday night. Low pressure approaching from the Central states will impact the region Thursday night into Saturday. High pressure will build in on Sunday and Monday. && .NEAR TERM /THROUGH TONIGHT/... Adjusted coverage of showers/tstms based on ongoing and upstream activity, which was fairly well represented in high-res guidance. Elevated instability is best correlated with 12Z NAM TT indices and indicates that a second round of showers/tstms after the first moving across Long Island, over southern NJ and SE PA, and located NE of the sfc low centered between Washington DC and Baltimore, should hold together and move into NYC metro and Long Island from late afternoon into the early evening as the low moves ENE toward or just south of the area, Fog limited attm mainly to the higher elevations and also in the valleys well NW of NYC per sfc obs. The models were in good agreement so a blend was used for temperatures through tonight. && .SHORT TERM /WEDNESDAY/... Dry weather with a northwesterly breeze. Despite a cooler airmass in place, temperatures will actually be warmer than Tuesday because of deep mixing. Mostly sunny skies are progged, although some fair weather convective clouds will be possible if they are able to overcome the subsidence. A blend of the guidance was used for temperatures. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... The extended period will feature a split flow across the continental United States with systems moving through active northern and southern streams. As a result, even through there are similarities in the longwave and overall solutions, the details of the forecast have become more uncertain, and inconsistencies from run to run have increased. Currently there is now little to no phasing of systems impacting the east, and in particular the region, Thursday night into Saturday, and yet another system Monday night into Tuesday. There are now more uncertainties as to the depth of the lows, timing, and tracks. For late Thursday night through Saturday night have long period of probabilities, and even likely probabilities from Friday into Saturday. This is likely too long a period however, with the uncertainties wanted to maintain some consistency with prior forecasts. Both the ECMWF and GFS have some lingering cold air across the northern portions of the CWA Thursday night before warm advection increases. So have kept a mix of snow and rain inland. Canadian high pressure builds in for late Saturday night into Monday, and possibly Tuesday if ridging remains as per the GFS. The ECMWF is quicker to weaken and shift the ridge off shore Tuesday. Have introduced a low chance of precipitation for Tuesday. && .AVIATION /16Z TUESDAY THROUGH SATURDAY/... A front remains just south of the terminals and attempts to push back north as a warm front today. Light ENE winds this morning with areas of rain and low ceilings. LIFR conditions at times this morning, otherwise areas of rain this morning will result in IFR conditions at times, and then back down to LIFR when the rain lightens or stops. Some thunder will be possible along the southern terminals (KEWR, KJFK, KISP) this morning between 14z-16z Another area of rainfall will arrive later in the day and for the evening. There is a thunderstorm chance with this next area of rainfall for the city terminals, but not confident enough to put in TAFS at this time. IFR to LIFR conditions are expected to prevail until about 6z late tonight, with improving conditions thereafter from west to east. 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: Timing of next area of rain may be off by +/- 2 hours this afternoon. There is a thunderstorm chance late today but confidence is low. KLGA TAF Comments: Timing of next area of rain may be off by +/- 2 hours this afternoon. There is a thunderstorm chance late today but confidence is low. KEWR TAF Comments: Timing of next area of rain may be off by +/- 2 hours this afternoon. There is a thunderstorm chance late today but confidence is low. The afternoon KEWR haze potential forecast is YELLOW...which implies slant range visibility 4-6SM outside of cloud. KTEB TAF Comments: Timing of next area of rain may be off by +/- 2 hours this afternoon. There is a thunderstorm chance late today but confidence is low. KHPN TAF Comments: Timing of next area of rain may be off by +/- 2 hours this afternoon. There is a thunderstorm chance late today but confidence is low. KISP TAF Comments: Timing of next area of rain may be off by +/- 2 hours this afternoon. There is a thunderstorm chance late today but confidence is low. .OUTLOOK FOR 12Z WEDNESDAY THROUGH SATURDAY... .Wednesday...VFR. N-NW gusts 15-20KT. .Thursday...VFR. .Friday...A wintry mix possible early north and west with IFR conditions possible before a change to rain, otherwise sub VFR conditions with rain elsewhere. .Friday night and Saturday...Chance of rain with MVFR or lower conditions. E winds G20-25KT at coastal terminals for Saturday. && .MARINE... Winds and seas will remain below advy levels through tonight, but could briefly come close on the ocean tonight as NE winds increase on the back side of departing low pressure. Patchy fog may limit visibilities to 1 NM or less at times into the first half of tonight, but it should no longer be widespread. Advy level winds are also possible on Wed, and are more likely on the ocean Wednesday night into Thursday, with strong and gusty northwest winds and seas approaching 5 ft, as high pressure builds in. Occasional gusts to 25 kt also possible Wed night on the eastern Sound and bays. The next chance of advy conditions will be late Friday through Saturday night as southerly winds increase ahead of low pressure. && .HYDROLOGY... Basin average rainfall of a half inch or less can be expected through tonight. Locally heavier amounts just over an inch plus local nuisance poor drainage flooding are possible with any heavier thunderstorms. Additional rainfall of 1/2 inch to 1 inch is possible Thursday night through Saturday. No hydrologic concerns are anticipated. && .TIDES/COASTAL FLOODING... Astronomical tides remain high due to a recent new moon. Water levels may approach minor flood thresholds during the high tide cycles Thursday night, with minor flooding possible Friday night as a low pressure system approaches. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && $$ SYNOPSIS...12/MET NEAR TERM...12/Goodman/MET SHORT TERM...12 LONG TERM...MET AVIATION...BC/JE MARINE...12/Goodman/MET HYDROLOGY...12/MET/Goodman TIDES/COASTAL FLOODING...

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.