Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 210605 AFDOKX Area Forecast Discussion National Weather Service New York NY 105 AM EST Tue Nov 21 2017 .SYNOPSIS... High pressure slides farther of the Mid-Atlantic coast today. A cold front approaches front he west tonight, then passes through early Wednesday followed by high pressure. A warm front moves north Saturday followed by a cold front Saturday night. High pressure builds to the west Sunday and Monday. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... Temperatures, dewpoints, and cloud coverage were adjusted to better match observed trends. Temperatures were holding nearly steady along the coast this evening with the westerly breeze continuing. The region will be in between the polar jet and subtropical jet with some slight mid level ridging taking place. At the surface, high pressure will be moving off the Carolina Coastline and into the Western Atlantic Ocean. Thin cirrus early this morning, so will go with a mostly clear sky forecast. Winds are becoming lighter as well, making for more radiational cooling, more for the inland locations. The coast will have more of a breeze, making for less radiational cooling there. MAV/MET guidance in fairly good agreement for morning lows. This combination was used for lows overnight but with some slight manual adjustments. Min temperatures along coast were made slightly higher. Temperatures fall into upper 20s and 30s, for much of the region. NYC will remain in the upper 30s to lower 40s. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TUESDAY/... Gusty SSW flow returns today as the cold front approaches from the west. Gusts to around 25 mph will be likely across the coastal locations. It will be a mostly sunny day, with temperatures climbing into the middle and upper 50s. Southerly flow across the area tonight will result temperatures remaining nearly steady overnight. Low pressure will develop over the SE coast and gradually lift up the eastern seaboard as a cold front approaches from the west. Rain expected to move in late tonight although there is some uncertainty in the westward extent of the precipitation shield. For now, will keep just chance pops in for the eastern half of the CWA. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... Good agreement with most of the guidance and the previous forecast as regards the passage of a cold front late tonight/early Wednesday, as a southern stream wave of low pressure passes to the east of Long Island. The northern stream wave passes well to the north as a weakening cold front moves through. There is a chance that the northwestern zones of the forecast area remain dry, and have only slight chance probabilities there. The ECMWF is a little slower with the frontal passage and low, keeping precipitation into later in the afternoon. Have sided with continuity and end precipitation early Wednesday afternoon, keeping probabilities in the likely category east. Also, the ECMWF was more than double with the QPF and again stayed with continuity. A very active flow will remain across the region as a full latitude trough remains across the eastern United States into the beginning of next week. Surface high pressure will remain late Wednesday into Friday. However, another shortwave moves through the trough Thursday night into Friday, and at this time passes to the north. There is a chance that the wave digs farther to the south, weakening the mid and low level ridge, with the possibility of precipitation inland. Again, kept with continuity and will remain dry into Friday night. Yet another shortwave rotates through the eastern trough Saturday, with a surface low, a clipper type system, passing through the Great Lakes region. A weak warm front develops Friday night and passes through Saturday, followed quickly by the cold front. At this time only the well inland areas may see a period of light snow, slight chance, as the cold air moves in behind the front Saturday night. Otherwise all rain is expected. Will leave Sunday and Monday dry, however, a weak tough or re- enforcing cold front, moves through Sunday with maybe a few flurries. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... High pressure slides further of the Mid-Atlantic Coast today. A cold front approaches from the west this evening. VFR through the TAF period. WSW-SW winds diminish early this morning, and back to the SSW- SW. Winds increase after daybreak, becoming gusty by late this morning, with gusts up to around 25KT likely. Isolated peak gusts to around 30KT are possible at eastern terminals. Gusts abate late this afternoon/early this evening. .OUTLOOK FOR 06Z WEDNESDAY THROUGH SATURDAY... .Late tonight-Wednesday...MVFR possible with showers, mainly east of the city terminals. NW winds G20-25KT possible late morning/afternoon. .Wednesday night-Saturday...VFR. NW-N winds G15-25KT possible Wednesday night. W-NW winds G15-20KT possible Thursday night at mainly eastern terminals. SW winds G15-20KT possible Saturday. && .MARINE... Winds briefly subside early this morning, but increase again towards midday from the SSW as a cold front approaches for the west. SCA remains in effect for all waters through this evening, except for the ocean waters which continues through tonight. A few gusts may approach gale force today, however, thinking that gusts remain just below criteria. Ocean seas build to 5-8 ft during the day, and start to subside late tonight. A cold front will be moving east of the forecast waters early Wednesday as high pressure builds to the west, and then over the waters Thursday into Friday. Winds are expected to remain below small craft advisory levels across all the forecast waters Wednesday into Friday. However, ocean seas likely remain at small craft levels into Friday. As a warm front approaches from the south Friday night and moves north Saturday, as a cold front approaches Saturday, southwesterly winds will increase and ocean gusts may be around small craft levels Friday night and Saturday. Also, ocean seas likely build to small craft levels. Winds and gusts may fall below small craft levels for several hours late Saturday into Saturday night, then Sunday increase again in the cold air behind the cold front. Ocean seas remain at small craft levels into Sunday night. && .HYDROLOGY... No hydrologic problems are anticipated the next 7 days. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...Small Craft Advisory until midnight EST tonight for ANZ330-335- 338-340-345. Small Craft Advisory until 6 AM EST Wednesday for ANZ350-353- 355. && $$ SYNOPSIS...BC/19 NEAR TERM...JM/BC SHORT TERM...BC LONG TERM...19 AVIATION...Maloit/JC MARINE...JM/BC/19 HYDROLOGY...BC/19

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