Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 281800 AFDOKX Area Forecast Discussion National Weather Service New York NY 200 PM EDT SAT MAY 28 2016 .SYNOPSIS... A westward extension of the Bermuda High will over the area through the weekend. A cold front approaches from the west on Monday, then crosses the Tri-state Monday night. High pressure builds down from Hudson Bay for the middle of the week. A cold front approaches from the west on Friday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Some minor adjustments were made to dewpoints and temperatures to better match observed trends. Temperatures were increased slightly towards NYC and locations to the northwest. Isolated to scattered convection north and west of NYC for this afternoon with differential heating along higher terrain acting as a trigger for convection with thermal trough setting up. Another day with a large temperature gradient between coastal and inland locations with the southerly flow. An unseasonably warm day is in store as deep ridging builds aloft and Bermuda high pressure remains over the area. Temperatures will be in the lower 90s across NE NJ and the interior Lower Hudson Valley. Southerly winds will increase this afternoon which will likely prevent temperatures in the city and interior southern CT from warming much above the middle 80s to near 90. Near the coast, highs will reach the upper 70s and lower 80s. Convection chances appear lower than on Friday as there is not much of a trigger with deeper ridging over the area. Instability will be largest away from the stronger sea breezes north and west of the city so this is where any widely scattered convection may develop late this afternoon. Best chance appears to lie across the NW interior which ends up closest to surface boundary to the north of the area. There is a moderate risk for the meteorological enhancement of rip current formation at Atlantic Beaches today. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/... Any convection that develops should dissipate with loss of daytime heating this evening. Backdoor cold front to the north will not make much progress south and will likely stall well to the north and east. Do not see much of a trigger or support for any shower/storms overnight so the forecast is dry after midnight. Low temperatures will be close to ten degrees above normal in the 60s. Ridging begins to break down aloft on Sunday as heights fall through the day with an approaching shortwave from the west. Forcing is weak during the day so will once again show best chances for any convection north and west of the city where better instability will reside. Moisture will be on the increase however as southerly flow off the western Atlantic strengthens. Highs should end up a few degrees cooler than Saturday with the stronger southerly flow and a few more clouds in the afternoon. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... The main focus of the long term is Sunday night into Monday as the ridge continues to break down and shift east. A shortwave approaches from the west Sunday night in combination with an increasing southerly flow which will advect tropical moisture from remnants of tropical system off the Carolinas. Precipitable waters are progged to be near 2 inches and these values are close to the maximum observed precipitable water for May 30 per SPC Sounding Climatology. The region will also lie in the favorable right entrance region of a 80-100 kt upper level jet and low level winds will also increase. Pattern recognition with all of these ingredients shows the potential for a predecessor rain event during this time frame with locally heavy rainfall. The biggest uncertainty lies in where heaviest bands of rain will set up. Even with this uncertainty, have increased pops to categorical late Sunday night into Monday as all of the aforementioned ingredients come together. Have also included mention of thunder, although instability will likely be on the low side. See hydro section for more details. The shortwave axis moves across the area late Monday into Monday night which will push the deep moisture plume to the east ending the rain. Cold front will likely be slower to move through the area and may not completely clear the area until Tuesday. Deep ridging builds over the northeast Wednesday and Thursday. Surface high pressure should move across New England on Wednesday and then set up over the Canadian Maritimes on Thursday. A cold front approaches from the west in conjunction with a shortwave trough. The trend in temperatures should be closer to seasonal norms for the middle and end of next week. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... High pressure will remain nearly stationary across the western Atlantic through Sunday with a thermal trough across the interior each afternoon. Another afternoon of S/SW flow with local seabreeze enhancements. Similar to Friday afternoon, expect the development of a coastal seabreeze jet around 20Z that will impact KJFK and kLGA. Gusts up to 30 kt possible at KJFK. This may translate east and impact KISP during the evening hours. SW winds diminish to less than 10 kt this evening. Isolated to scattered convection this afternoon and early evening primarily north and west of the NYC terminals. Have maintained VCSH at KSWF through 00Z. MVFR fog is possible late tonight at KSWF, with a low chance across the remainder of the non-NYC terminals. .OUTLOOK FOR 18Z Sunday through Thursday... .Sunday Afternoon...Mainly VFR with afternoon seabreezes. Chance of MVFR or lower in any isolated to scattered afternoon showers/thunderstorms mainly for Lower Hudson Valley/interior S CT terminals. .Sunday night-Monday...MVFR or lower likely. Showers/thunderstorms could produce locally heavy rainfall. .Monday night-Tuesday night...Becoming VFR Monday Night. .Wednesday and Thursday...VFR. && .MARINE... The marine forecast remains on track. A weak to moderate pressure gradient over the region through Wednesday will keep sustained winds to 15 kt or less over the waters around Long Island. With no significant swells currently forecast during this time frame, seas should remain below Small Craft levels as well. && .HYDROLOGY... No significant widespread precipitation is expected through Sunday. Rainfall amounts around one to one and a half inches are possible Sunday night into Monday with locally higher amounts. Minor urban or poor drainage flooding is possible from the heaviest rainfall. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && $$ SYNOPSIS...DS NEAR TERM...Maloit/JM/DS SHORT TERM...DS LONG TERM...DS AVIATION...DW MARINE...Maloit/JM HYDROLOGY...DS

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