Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 220545 AFDOKX Area Forecast Discussion National Weather Service New York NY 145 AM EDT Tue Oct 22 2019 .SYNOPSIS... A frontal system approaches today and passes across the region tonight. High pressure will build over the region through the middle of the week. A frontal system may impact the area late Friday into Saturday, with another possible by the end of the weekend. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... Clouds will continue to increase through the early morning hours. A northeast flow will begin to go more easterly closer to daybreak resulting in an increase in overall lower level moisture. It will remain dry with lows mainly at or slight above normal. Temperatures may level off towards daybreak as clouds thicken. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM WEDNESDAY/... A vertically stacked and occluded low pressure system over the Upper Midwest will lift northeast into Canada later Tuesday into Tuesday night. A complex frontal system to the east and southeast of the storm will approach during the day on Tuesday bringing extensive cloud cover in advance of a warm front. Despite good upper level amplitude, with an overall lack of blocking to the northeast I do expect the warm front to get through during Tuesday evening in most places, followed by the cold front for later Tuesday night, early Wednesday morning. As far as precip timing and intensity, with the dynamics going well north of the region we are not anticipating a significant rainfall event. There should be enough thermal forcing to result in a light rainfall event where precip amounts average around a half inch across the CWA, with some higher amounts closer to three quarters of an inch perhaps across northern and northwestern sections. The rain should be quite light during the day on Tuesday with the steadier rain approaching far western sections during the afternoon hours, say around 20z or so. There will be some drier air in the mid levels which will preclude any steadier rainfall until mainly the evening hours. The steadiest rainfall should fall between 1z and 6z across much of the forecast area. Towards daybreak Wednesday morning the last of any rain showers should be getting ready to exit far eastern sections. Temperatures on Tuesday will average near normal, and above normal Tuesday night. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... Rain will taper off from west to east on Wednesday as the frontal system pulls away. A westerly breeze can be expected, drying the area out by afternoon. The NBM was used for temperatures. Winds will lighten and skies clear Wednesday night. The CONSMOS was favored, allowing for better radiational cooling. Sunny with highs in the lower 60s on Thursday with high pressure centered southeast of the forecast area. The NBM was used for temperatures. A clipper type system is then progged for late Friday into Saturday. The ECMWF has consistent timing and placement with the 00Z and 12Z runs. The GFS is further north with the main low. A band of chilly moderate rain can be expected with an ECMWF solution, with a few showers possible under the GFS scenario. A blend of the model data was used for precipitation probabilities. The NBM was used for temperatures Friday through Saturday, with the CONSMOS used Saturday night. A chance of rain returns Sunday and Monday due to a southern stream upper low and Gulf of Mexico moisture. The ECMWF is the wet model with this, with the GFS now dry through the period. The NBM was used for temperatures. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... Low pressure system and a cold front approach today and move across the region tonight. A mainly VFR forecast through the first half of tonight becoming MVFR towards daybreak for all terminals lasting through the day and into Tuesday night. Isolated IFR conditions may be possible with some of the rain with the actual frontal passage. Expect light rain showers or drizzle to develop during the afternoon hours, becoming a more steady rain this evening and into the overnight. In addition, expect some lowered visibility. There is some uncertainty with the arrival time of lower conditions. NE-N winds averaging around 5-10kt. Winds veer more ENE late afternoon and evening. Southerly winds prior to the frontal passage will be possible in the late evening. Winds become northerly behind the cold front between 06-12z Wednesday. .OUTLOOK FOR 06Z WEDNESDAY THROUGH SATURDAY... .Tuesday night...MVFR/IFR rain at night. .Wednesday-Thursday...VFR. Chc W gusts 20-25kt on Weds. .Friday-Saturday...Chc MVFR and rain Fri PM into SAT AM. && .MARINE... Small Craft conditions are expected to continue on the ocean through at least the day on Wednesday. A dominant easterly swell will result in rough seas with a period of around 9 seconds, and with waves much of the time running at least 5 to 8 feet for the ocean waters. By Wednesday the winds are expected to increase to where gusts will approach 25 kts out on the ocean. Sub SCA conditions are expected for the non-ocean waters during this time frame, with marginal small craft advisory winds on the protected waters by Wednesday. Conditions improve Wednesday night through Friday. Small Craft Advisory conditions may be needed over the weekend depending on the strength and position of a frontal system. && .HYDROLOGY... No significant rainfall is anticipated through the forecast period. && .TIDES/COASTAL FLOODING... Water levels during this afternoons high tide along the south shore back bays will likely fall short of minor coastal flood benchmarks. No statements have been issued at this time based on the latest forecast water levels. && .EQUIPMENT... NYC NOAA Weather Radio Station KWO35 (162.55 MHz) remains off the air. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...Small Craft Advisory until 8 PM EDT Wednesday for ANZ350-353- 355. && $$ SYNOPSIS...JE NEAR TERM...DS SHORT TERM...JE LONG TERM...BC AVIATION...BC MARINE... HYDROLOGY...JE TIDES/COASTAL FLOODING... EQUIPMENT...

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