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
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KOKX 191540 AFDOKX Area Forecast Discussion National Weather Service New York NY 1040 AM EST Fri Jan 19 2018 .SYNOPSIS...
-- Changed Discussion --
High pressure will build to the south through Saturday, while low pressure passes well to the north on Saturday. A back door cold front will pass through Sunday night, then return north as a warm front on Monday ahead of a strong frontal system for Monday night into Tuesday. High pressure will return for mid week.
-- End Changed Discussion --
&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --
High level clouds a bit more opaque than earlier anticipated due jet energy rounding a departing upper trough across New England. This may impact high temperatures slightly on the lower side of the guidance. Skies should become partly sunny this afternoon. Temps will be 5-10 degrees warmer than those of yesterday, with highs mostly in the upper 30s and lower 40s.
-- End Changed Discussion --
&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/... Zonal flow will prevail aloft between a flat trough passing to the north and ridging along the SE coast. After one more cold night inland with lows in the teens/20s, and lower 30s for NYC metro and most of Long Island, downslope flow/WAA will result in a mild day, with high temps in the upper 40s and lower 50s. It will however be brisk, as a tightening pressure gradient between low pressure passing E across Quebec and high pressure along the SE coast generates W to WSW winds gusting up to 35 mph in NYC and across Long Island, and 25-30 mph most elsewhere to the north/west. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... Zonal upper flow through the weekend, with confluence of Pacific and polar jet to the north of the region, and southern stream energy tracking through the deep south. Continued return flow around southern high pressure Sat Night into Sunday will allow for dry and unseasonably mild conditions under a Pacific air mass, with high temps in the lower and mid 40s on Sunday. A vigorous polar shortwave moving through southeastern Canada Sunday night will likely have a back door cold front pushing through the region, bringing in a more seasonable Canadian maritime air mass for Monday. Meanwhile, models in good agreement with the relatively tranquil pattern being interrupted early next week by the Pacific energy coming into the Western states today. This Pacific shortwave will amplify through the SW states, and eventually phase with subtropical jet energy. The resultant deep closed low is then expected to gradually track NE across the Central Plains and Mid Mississippi valley Sunday into Mon, before approaching the Northeast by Tuesday as it begins phasing with northern stream energy. There are still some timing/amplitude differences with this energy, which is manifesting in timing/track differences of a resultant frontal system as it tracks toward the region Monday Night into Tuesday. This model spread should decrease over the next 24 hrs as Pacific energy comes onshore, but subtle model differences may continue through Sunday until the subtropical and Pacific energy phase. Regardless, there has a been consistent model-to-model and run- to-run signal for a quick moving moderate to heavy rain event for Monday night into Tuesday, in response to strong deep layer lift (region under of nose of 65-70 kt LLJ and left front quad of a 100+ kt jet streak in difluent upper flow) of a subtropical moisture plume with PW +2 to + 3 standard deviations above normal over the region, focused ahead of the cold front and a surface wave. Before that, still appears there is potential for a light wintry mix N/NW of NYC metro Monday morning as a warm front moves north with increasing theta-e advection. The frontal system pushes through on Tuesday, with breezy conditions and CAA in its wake, returning dry and more seasonable temps for Wed/Thu. && .AVIATION /16Z FRIDAY THROUGH TUESDAY/... High pressure remains centered to the southwest of the region through tonight. VFR through the TAF period. Winds may briefly strengthen to 10-14 kt this afternoon with an occasional gust to 18 kt. Otherwise, W flow gradually backs to SW by this evening. ...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: Winds may be stronger than forecast this afternoon. The afternoon KJFK haze potential forecast is GREEN, which implies slant range visibility 7SM or greater outside of cloud. KLGA TAF Comments: Occasional gusts to 18 kt possible this afternoon. The afternoon KLGA haze potential forecast is GREEN, which implies slant range visibility 7SM or greater outside of cloud. KEWR TAF Comments: Occasional gusts to 18 kt possible this afternoon. The afternoon KEWR haze potential forecast is GREEN, which implies slant range visibility 7SM or greater outside of cloud. KTEB TAF Comments: Occasional gusts to 18 kt possible this afternoon. KHPN TAF Comments: Occasional gusts to 18 kt possible this afternoon. KISP TAF Comments: Occasional gusts to 18 kt possible this afternoon. .OUTLOOK FOR 12Z SATURDAY THROUGH TUESDAY... .Saturday...VFR. WSW winds G20-25KT. .Sunday...VFR. .Monday...Chance of MVFR or lower in -SHRA. S winds G20KT late day. .Tuesday...IFR in rain. LLWS. S winds G25KT morning, W winds G30- 35KT aftn. && .MARINE... Could see a stray gust or two up to 25 kt on the outer ocean waters today, but overall conditions should remain quiet today. Winds should ramp up tonight into Sat as the pressure gradient tightens between low pressure passing across Quebec, and high pressure along the SE coast, with lack of a sfc-based temperature inversion allowing for wind gusts to increase to SCA levels tonight, and to minimal gale force daytime Sat on the ocean waters E of Fire Island Inlet. These conditions should quickly abate Sat evening, with just some elevated seas lasting til midnight on the ern ocean waters. Sub SCA conditions expected Sunday and Monday. Winds and ocean seas expected to increase to SCA levels late Monday Night into Tuesday ahead of approaching cold front. SCA conditions likely continue on W/NW flow and caa flow Tuesday Night through Wednesday, with potential for a period of Gale conds. && .HYDROLOGY... A frontal system passing through late Monday night into Tuesday has the potential to bring around inch of rain. No significant hydrologic issues are anticipated at this time. && .EQUIPMENT... NYC NOAA Weather Radio Station KWO-35 (162.55 MHz) is off the air for an extended period of time. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...Small Craft Advisory from 6 PM this evening to 6 PM EST Saturday for ANZ355. Gale Watch from Saturday morning through Saturday afternoon for ANZ350-353. Small Craft Advisory from 6 PM this evening to 6 AM EST Saturday for ANZ350-353. && $$ SYNOPSIS...Goodman/NV NEAR TERM...Goodman/DW SHORT TERM...Goodman LONG TERM...NV AVIATION...MD/BC MARINE...Goodman/NV HYDROLOGY...Goodman/NV EQUIPMENT...//

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