Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 190737 AFDOKX Area Forecast Discussion National Weather Service New York NY 337 AM EDT Thu Oct 19 2017 .SYNOPSIS... A weak frontal passage will occur tonight. High pressure will dominate from Friday night through Monday. A slow moving frontal system will then move across during the middle of next week. && .NEAR TERM /THROUGH TONIGHT/... A upper level system over northern Ontario will track across Hudson Bay today and into northern Quebec tonight. This will drag a boundary through the forecast area late tonight. It is difficult to call it a cold front because temperatures behind it on Friday will be virtually the same, but the temperature structure aloft does indicate that it is indeed a cold front. Regardless, there is very little moisture to work with so the frontal passage will be dry. Winds ahead of the front today will ramp up out of the southwest. A solid breeze can be expected along the south coasts by late afternoon, particularly across eastern Long Island. Temperatures will remain way above normal again with most spots at least 70 for highs. Slightly milder temperatures are likely tonight as winds likely stay up, at least a little, in most areas. A blend of guidance was used. && .SHORT TERM /FRIDAY/... Northwest winds and continued dry. 850 flow in the 35-40kt range, and with subsidence and a dry airmass, there is a good chance mixing overperforms the model data. Because of this, winds were bumped up significantly from the model blend. The deep mixing flow is also the reason temperatures will be near 70 or above once again. Temperatures were raised above guidance, but if mixing to 850 is realized, 80 degrees highs will be realized. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... Ridging at the sfc and aloft will dominate into Monday ahead of an upper trough in the Western states. As this trough reaches the Plains states, its southern extension will likely cut off over the South and tap into Gulf moisture before phasing with another trough digging into the northern Plains. Wx should be dry and unseasonably warm until at least Monday, with high temps in the 70s, and possibly nearing 80 in NE NJ on Sat. NWP guidance continues to trend toward a later timing of the approaching frontal system for mid next week. There could be some sct showers and/or patchy of light rain/drizzle via low level warm/moisture advection well ahead of the approaching front as early as Mon night-Tue. More significant rainfall with the front now looks to hold off until at least Tue night and possibly until Wed, and the slow moving front, with attendant warm/moist conveyor belt, low level jet, and multiple tropical connections, one out of the Gulf of Mexico and another developing out of the subtropical western Atlantic, could become a heavy rain producer during this time. && .AVIATION /08Z THURSDAY THROUGH MONDAY/... A weak cold front approaches from the northwest today, then begins to cross the area into tonight. VFR through the TAF period. Winds become SW at less than 10KT at all terminals by mid morning. By early afternoon winds back to the SSW and increase to around 10KT with gusts up to around 20KT at all but KISP, where infrequent gusts up to around 20KT are possible. Wind gusts should abate during the evening, with winds veering to the SW-WSW. .OUTLOOK FOR 06Z FRIDAY THROUGH MONDAY... .Late tonight-Friday night...VFR. NW-N winds G15-20KT possible Friday and Friday evening. .Saturday-Monday...VFR. SW winds G15-20KT possible Sunday and Monday in the afternoon/evening. && .MARINE... A quick round of marginal small craft advisory level winds and seas are still expected this afternoon and evening on the eastern ocean. Elsewhere, winds and seas will generally be below small craft advisory levels through Friday. There could be some nearshore gusts approaching 25 kt Friday afternoon on northwest flow. Quiet conditions expected this weekend into early next week as high pressure dominates. Any SCA conditions with a slow moving frontal system would occur beyond the end of the fcst period. && .HYDROLOGY... Rainfall of 1-2 inches with locally higher amounts is possible during the middle of next week. Timing is a little uncertain as NWP guidance continues to trend toward a later timing, occurring either Tue night into Wed night or Wed into thu Thu morning. The most likely impact at this early juncture appears to be urban/poor drainage flooding. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...Small Craft Advisory from 4 PM this afternoon to 6 AM EDT Friday for ANZ350-353. && $$ SYNOPSIS...12/Goodman NEAR TERM...12 SHORT TERM...12 LONG TERM...Goodman AVIATION...Maloit MARINE...12/Goodman HYDROLOGY...Goodman

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