Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 231620 AFDOKX Area Forecast Discussion National Weather Service New York NY 1220 PM EDT Thu Mar 23 2017 .SYNOPSIS... High pressure builds today and passes to the east tonight. A warm front moves across the region Friday. The warm front north of the region Friday night and Saturday will move back southwestward Saturday night into Sunday as a back door cold front. A weak low develops along the front and the low and front eventually move east of the region by Monday night and Tuesday of next week. Another cold front approaches for next Wednesday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... The forecast is still on track. Current high temperature forecast looks good considering 12z OKX sounding compared to forecast model output. Only slight adjustments were made to hourly temperatures and dewpoints to better match observed trends. The center of high pressure builds to our west, and passes to the south this afternoon. Upper trough tracks further to the east. A dry, chilly day is expected, with lighter NW winds than what was observed yesterday. A few gusts are possible in the NW flow, but winds will diminish this afternoon and back to the west as the high tracks south. Temperatures, after a cold start to the day, will rebound through the 30s, but will peak about 10 degrees below normal, upper 30s to lower 40s. Satellite confirms a clear sky for today. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/... Upper ridge to the west flattens tonight and Friday as closed low moves across the mid section of the country. Surface high pressure passes east of the area. A warm front then approaches Friday morning, with a weak shortwave riding along the top of the ridge, passing across the area Friday. Winds remain light tonight as they become variable or light S/SW. With cold airmass in place, temperatures will fall into the 20s and 30s as high clouds increase. Some locations may radiate into the teens. Still quite cold. Increasing moisture riding over the top of the flattening ridge will approach Friday morning. Light precip associated with warm air advection is anticipated. Expect a brief period of light precipitation to push through, with higher coverage NW zones, and less SE zones per model consensus. As for ptype, this could be problematic. Depending on when precip moves in, looks like shortly after 12Z, a wintry mix is possible. Snow, sleet and freezing rain is a good bet, especially away from the coast. Again, depending on precip onset. Temps near the coast should be warm enough for plain rain. QPF should be under a tenth of an inch, so this is not a big event. But, slick travel is possible as sfc/road temps may be cold enough for some light icing. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... Upper levels convey polar jet staying north of the region during the long term. Mid levels transition from zonal flow Friday night through Saturday night to ridging Sunday, which will be followed by an approaching shortwave on the back end of the ridge. The axis of this trough moves across on Monday. Behind this shortwave, more quasi-zonal flow will be established. There will be a larger shortwave approaching from the northwest for the middle of next week. At the surface, Friday night through Saturday will be when the region is in the warm sector. The warm front will be north of the region. Then, the front will start to shift southwestward, coming back through the region as a back door cold front Sunday. The front will stay west of the region and high pressure will stay well east of the region going through Sunday evening setting up easterly flow. For late Sunday night, the front will slide back east with weak low pressure developing along it. The weak low and front stay near the region Monday with more SE flow developing ahead of the low and finally these move east of the region Monday night and Tuesday. Another cold front approaches for the middle of next week. Overall, an unsettled weather pattern sets up leading to less diurnal temperature range as the airmass becomes more cool maritime from an increasing easterly flow with rounds of light to perhaps moderate rain at times. Temperatures are warmest on Saturday with area in the warm sector as highs are forecast to range from the low 50s to low 60s. Sunday looks to be the coolest day in the long term with a back door cold front moving in as highs that day range from the low to mid 40s. Otherwise the rest of the days feature highs in the upper 40s to low 50s for most locations. Lows at night through the long term are pretty consistent, in the upper 30s to low 40s for a majority of the area. && .AVIATION /16Z THURSDAY THROUGH MONDAY/... High pressure builds in from the west today, then slides offshore to the southeast into Friday morning. VFR through the TAF period. NW-WNW flow around 10 kt. Some terminals (KEWR/KTEB/KHPN/KISP) will see frequent gusts of around 15kt, while most will see infrequent gusts. Wind gusts should abate by mid-late afternoon throughout, with winds becoming light and variable at all terminals this evening. KJFK could see light SSW-S flow (just above 5 kt) establish itself by late in the TAF period. NY Metro Enhanced Aviation Weather Support... Detailed information, including hourly TAF wind component forecasts, can be found at: http:/ KJFK TAF Comments: Winds should be within +/- 20 degrees of 300 true/310 magnetic through the remainder of the afternoon. There is a low chance for isolated gusts up to 20 kt into this afternoon. KLGA TAF Comments: High confidence in winds to the right of 300 true/310 magnetic through 20z, then right around there for the remainder of the afternoon/early evening. There is a low chance for isolated gusts up to 20 kt into this afternoon. KEWR TAF Comments: High confidence in winds to the right of 300 true/310 magnetic through 18z, then right around there for the remainder of the afternoon/early evening. The afternoon KEWR haze potential forecast is GREEN...which implies slant range visibility 7SM or greater outside of cloud. KTEB TAF Comments: No unscheduled amendments are expected. KHPN TAF Comments: No unscheduled amendments are expected. KISP TAF Comments: No unscheduled amendments are expected. .OUTLOOK FOR 12Z FRIDAY THROUGH MONDAY... .Friday...MVFR possible. SW winds G25KT. .Saturday...Mainly VFR. Chance of mid-late afternoon MVFR. .Saturday night and Sunday...MVFR/IFR probable. E-SE winds G20-25KT. .Monday...MVFR possible. && .MARINE... Winds and seas are expected to remain below advisory criteria and continue to subside today as the center of high pressure moves closer from the west. The winds shift around to the west, then southwest tonight as the high moves east. As the pressure gradient tightens Friday, expect SW winds to increase, and SCA conditions are likely during the afternoon, with gusts 25 to 30 KT. Seas, per guidance, will build once again. SCA chances are higher Friday night as well as late Saturday night through Sunday night, mostly on the ocean. Otherwise sub SCA conditions on other waters and other time periods for the marine long term period covering Friday night through Monday. Ocean seas with wave heights are forecast to stay in SCA range Friday night into Saturday morning. Then the ocean seas are forecast to get below SCA criteria Saturday afternoon through Saturday evening before returning to SCA range late Saturday night through Sunday and perhaps even into early Monday. && .HYDROLOGY... Unsettled weather from this weekend through early next week may result in an inch or more of precipitation. However, this would occur over a prolonged period and would be intermittent, so no hydrologic concerns are anticipated. Snowpack melt in interior sections will continue at a slow rate through Thursday with most areas likely loosing any significant snowpack by Saturday as temperatures rise to above normal readings and lows even remain above freezing. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && $$ SYNOPSIS...JM/PW NEAR TERM...JC/PW SHORT TERM...PW LONG TERM...JM AVIATION...BC/Maloit MARINE...JC/PW HYDROLOGY...JM/PW is the U.S. government's official web portal to all federal, state and local government web resources and services.