Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 231939 AFDOKX Area Forecast Discussion National Weather Service New York NY 239 PM EST Wed Jan 23 2019 .SYNOPSIS... A frontal system will approach today into tonight with a wave of low pressure riding along it to our north Thursday morning. The low will drag a cold front across the region Thursday afternoon. High pressure will then build into the region Thursday night and remain nearby through Saturday. A cold front will approach and move across the area on Sunday. Another cold front and low pressure system will move across the area early next week. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Spotty radar returns have developed over western/northern zones, however so far have yet to see any evidence of precipitation being reported at the various ASOS they have passed over. However, cannot have 100% confidence that no precipitation is reaching the ground, so have increased pops to slight chance early this afternoon and issued an SPS for patchy freezing rain for Orange County where there are areas with temperatures still at or below freezing. Given the T-Td spread, could also see some spotty reports of sleet with these returns. Highs this afternoon should range from the mid-upper 30s across the NW zones to the lower 40s for coastal zones. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
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Light rain spreads across the area tonight, and at the same time, temperatures continue to rise on a S-SW wind flow. There`s still some concern that parts of the far NW zones could have surface temps supportive of freezing rain at the time when rain becomes likely, so will need to keep close watch on this potential. Rain becomes more moderate early Thursday morning, and could be heavy at times by mid-morning with strong isentropic lift and an impressive llj. Approaching shortwave energy should enhance forced ascent and also create weak destabilization aloft, increasing the chances of heavier downpours. After collaboration with the surrounding office, have issued a flash flood watch for Thursday. Smaller stream and urban/poor drainage flooding would be the main threat. Timing of the greatest flood threat looks like morning to midday. A cold front passes through during the afternoon with rain probably coming to an end not too long after the passage, however a strong upper jet streak shifts in with enhanced lift, continuing at least chances of additional PCPN. Could be cold enough for a mix of rain and snow for far NW areas late- day. It should also become breezy, especially near the coast. Strong winds with the llj will be not too far above the surface, however with such a strong inversion, thinking is that none of the area would likely see advisory-level gusts.
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&& .LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/... High pressure builds into the area behind a departing cold front Thursday night and remain in place through Saturday. This will result in dry and cold conditions. Highs on Friday will climb into the lower and middle 30s, while highs will struggle to get out of the 20s on Saturday. The high moves offshore Saturday night, allowing a an upper level shortwave and associated surface cold front to move across the area on Sunday. This could result in a few snow showers, will keep POPs at chance or slight chance for now. No accumulations at this time are expected with any of the snow showers. A stronger shortwave and associated frontal system will move across the area early next week, bringing yet another chance of precipitation to the region. There are differences with the exact track and placement with this next system, so details remain somewhat sketchy. Temperatures on Sunday through Tuesday will climb 30s and lower 40s. light rain has developed over far western zones && .AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
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A frontal system will slowly approach the area through tonight, then move through Thursday afternoon to evening. Ceilings generally 025-035 should persist into the evening, with the lowest ceilings expected across KSWF, KHPN, KEWR and KTEB. MVFR ceilings will gradually move into the remainder of the terminals late this evening. Thereafter, IFR or lower develops overnight in steadier light rain, becoming increasingly prevailing as rain intensity increases towards the morning push. At least initially, a wintry mix is possible at KSWF through around 21Z today. S/SW winds 10 kt will increase to 10-15 kt and with occasional gusts to near 20 kt possible for south coastal terminals. S/SW winds increase to 15 to 25 kt towards the Thursday morning push. More significantly, LLWS from SW winds of 50-60kt@ 2 KFT develop for coastal terminals by this evening, strengthening to near 60-70kt, especially from KJFK eastward by the morning push. LLWS may approach 80 kt for KISP and KGON Thursday morning. Winds then shift to WNW and remain strong following the frontal passage Thursday, which is expected to occur from west to east between 17-20Z. Gusty winds to near 45kt may be possible with the frontal passage, along with heavy rain and low visibilities. Conditions will gradually improve to MVFR to VFR following the passage. KSWF may experience a brief -RASN mix following the frontal passage. 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 MVFR development may be 1 to 3 hours later than forecast. Occasional gusts to 20 kt possible. KLGA TAF Comments: Timing of MVFR development may be 1 to 3 hours later than forecast. Occasional gusts to 20 kt possible. KEWR TAF Comments: Timing of MVFR development may be 1 to 3 hours later than forecast. Occasional gusts to 20 kt possible. KTEB TAF Comments: Timing of MVFR development may be 1 to 3 hours later than forecast. Occasional gusts to 20 kt possible. KHPN TAF Comments: MVFR may be periodic this afternoon. Occasional gusts to 20 kt possible. KISP TAF Comments: Timing of MVFR development may be 1 to 3 hours later than forecast. Occasional gusts to 20 kt possible. .OUTLOOK FOR 18Z THURSDAY THROUGH MONDAY... .Thursday-Thursday night...IFR or lower likely in rain becoming VFR late in the day and Thursday night. Gusts to 45 kt and reduced visibility possible with frontal passage. Winds becoming N-NW G25-35KT Thursday aft/eve. .Friday-Friday night...VFR. W wind gusts near 20 KT Friday. .Saturday...Mainly VFR. .Sunday...Chance of snow showers. MVFR or lower possible. .Monday...VFR.
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&& .MARINE... Made minor changes with this update to reflect the latest trends of observations and guidance. The forecast appears on track. SCA conds on the ocean this afternoon with a strengthening southerly flow. The rest of the waters are expected to have advisory-level gusts tonight as winds further increase. A strong low level jet then shifts into the waters for Thursday. A gale watch remains in effect for the ocean on Thursday, and have added the south shore bays, eastern bays, and eastern LI Sound to the watch. A strong low level inversion should prevent anything stronger than gales here. SCA otherwise for NY Harbor and western LI Sound on Thursday. Small craft conditions will continue Thursday night and Friday as gusty northwest winds prevail. Seas will remain above 5 ft on the ocean. Winds and seas diminish Saturday as the pressure gradient relaxes and winds shift to the W-NW. SCA conditions may return on Sunday as seas could increase back to 5 ft. && .HYDROLOGY... 1.25 to 2.25 inches of rain is forecast for tonight through Thursday, however most of this will probably fall during Thursday morning into early afternoon. Urban and poor drainage flooding is therefore possible for Thursday, as well as small stream and flashy river flooding. Larger streams and main stem rivers should remain below flood stage. && .TIDES/COASTAL FLOODING... Some minor flooding may be possible with the high tide cycle Thu morning along the south shore bays of western Long Island via strengthening onshore flow and lingering high astronomical tides after the recent full moon. && .EQUIPMENT... NYC Central Park winds are out of service until further notice. Loss of data is due to a severed cable. Parts are on order. NYC NOAA Weather Radio Station KWO35 (162.55 MHz) will remain off the air for an extended period of time. && .OKX WATCHES/WARNINGS/ADVISORIES...
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CT...Flash Flood Watch from Thursday morning through Thursday afternoon for CTZ005>012. Coastal Flood Advisory from noon to 3 PM EST Thursday for CTZ009>012. NY...Flash Flood Watch from Thursday morning through Thursday afternoon for NYZ067>075-078>081-176>179. Coastal Flood Advisory from noon to 3 PM EST Thursday for NYZ071. Coastal Flood Advisory from 9 AM to 2 PM EST Thursday for NYZ178-179. NJ...Flash Flood Watch from Thursday morning through Thursday afternoon for NJZ002-004-006-103>108. MARINE...Gale Watch from Thursday morning through Thursday afternoon for ANZ330-340-345-350-353-355. Small Craft Advisory from 6 PM this evening to 6 AM EST Thursday for ANZ330-340-345. Small Craft Advisory from 6 PM this evening to 6 PM EST Thursday for ANZ335-338. Small Craft Advisory until 6 AM EST Thursday for ANZ350-353- 355.
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&& $$ SYNOPSIS...BC/JC NEAR TERM...JC/Maloit SHORT TERM...JC LONG TERM...BC AVIATION...MD/PW MARINE...BC/JC/Maloit HYDROLOGY...BC/JC TIDES/COASTAL FLOODING... EQUIPMENT...

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