Area Forecast Discussion
Issued by NWS Albany, NY

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000 FXUS61 KALY 211055 AFDALY Area Forecast Discussion National Weather Service Albany NY 655 AM EDT Wed Mar 21 2018 .SYNOPSIS... A coastal storm will brush far southeastern parts of the region with some snow for later today into tonight, otherwise, it will remain cold across the region with a partly to mostly cloudy sky. Aside from a passing flurry, mainly dry and continued chilly weather is expected for tomorrow through the weekend. && .NEAR TERM /THROUGH TONIGHT/... As of 643 AM EDT..A large closed off upper level low is moving out of the Ohio Valley and into the mid-Atlantic states. At the surface, low pressure is starting to organize just off the coast of the mid-Atlantic. IR satellite and water vapor imagery imagery shows a classic look for a developing coastal storm, with a large plume of cold and deep clouds moving northward towards eastern New York and New England. MRMS imagery shows the leading band of light precipitation lifting northward out of PA, NJ and the NYC area towards the mid-Hudson Valley and NW CT. There is a lot of dry air in place at low levels, with dewpoints still in the teens, so it will take a little while for the lower portion of the atmosphere to moisten up. The boundary layer and temps aloft are plenty cold, however, so any precip (once it does begin) will be in the form of snow. Light snow should begin across far southern areas within the next hour or two, as surface observations show light snow already as far north as White Plains and Teterboro, NJ. As the upper level low heads towards the coast, the surface low will continue to develop and slowly meander off the mid- Atlantic coast through the day today. Strong frontogenesis will start to take place along the coastal areas, which will be aided by strong easterly flow aloft, which provide plenty of Atlantic moisture into the storm. As the upper level low captures the surface low, it will become vertically stacked and only make slow progress northeastward today. The main forcing of both the surface low and upper level low will remain fairly far south of our area. As a result, only our far southern counties will be seeing snowfall from this storm. The 06z run of both the 3km HRRR and NAM suggest that precip through the mid to late afternoon hours today may only make it into Ulster, Dutchess and Litchfield Counties, and it may take until late in the day for precip to pick up in intensity, as the steadiest and heavier snowfall will remain further south across NJ and the NYC area. However, by late in the day and into the evening, heavier snowfall should be ongoing for the mid-Hudson Valley and NW CT, as the surface low gets a little closer and some heavier bands make it into the region. Light snow may even make it as far north as southern suburbs of the Capital Region and into the Taconics, Berkshires and southern VT too. With some mesoscale banding expected (as shown in the 00z HREF), some snow rates of 1 to 2 inches per hour will be possible across Dutchess and Litchfield Counties, which will make for difficult travel across this area. Further north, it will just remain mostly cloudy and chilly for the remainder of the area for today into tonight. Snow will be tapering off tonight from west to east, although it may linger across western New England for much of the overnight hours. Snowfall intensity will be greatest through about midnight, but then should be decreasing. As expected with a coastal storm like this, there will be a sharp north-to-south gradient of total snowfall amounts, especially across Dutchess/Litchfield Counties. These types of gradients make for tricky snowfall forecast, with big bust potential in/near the gradient area. Based on collab with WPC, neighboring offices and closely examining deterministic and ensemble output, we are forecasting amounts to range from 3-7 inches in northern parts of Dutchess/Litchfield Counties to 6-10 in southern areas. A few spots across southeastern Litchfield County near the New Haven County border will see around a foot of snowfall. The northern edge of the accumulating snowfall may be right across the Capital Region, where a coating to half inch can be expected, especially for those areas south/east of the city of Albany. High temps today will be in the upper 20s to mid 30s and overnight lows tonight will mainly be in the 20s. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... Mainly dry and quiet weather is expected through the short term period. The departing storm on Thursday will continue to allow for brisk conditions, thanks to the strong pressure gradient in place. However, it should be dry, but cold for late March, with temps stuck in the 30s. Overnight lows on Thursday night will be in the 20s with partly cloudy conditions and still a little breezy. During the day on Friday, there could be a few light showers or flurries, especially for the higher elevations, as a fast moving upper level low slides by to the southwest. This upper level low will be swinging around the broad trough in place over the Northeast behind the departing storm. However, moisture will be very limited, so little snowfall is expected. A dusting is possible for high terrain areas, but precip looks fairly light and spotty. Highs will be in the 30s once again. Dry and quiet weather is expected for Friday night with lows in the teens and 20s. && .LONG TERM /SATURDAY THROUGH TUESDAY/... Overall guidance is in agreement regarding the longwave pattern with a lingering trough over the Northeast for the weekend with ridging building in early in the week. While at the surface, cold Canadian high pressure from over Hudson`s Bay is expected to shift southward through the period dominating our weather. Mainly fair weather is expected for the period; there could be a few showers Saturday night and/or snow as the upper level swings through. The southern stream system originating from the Plains is expected to weaken as it moves eastward across the Southeastern United States over the weekend and encounters the strong ridge. Below normal temperatures will continue through the weekend, however early next week with abundant sunshine temperatures are expected to warm seasonable levels for late March/early Spring with highs mainly in the 40s by Tuesday. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
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The high continueS to retreat as the coastal low further develops along the southeast and mid Atlantic coast. The storm will move gradually north-northeastward through the TAF period, 12Z/Thursday, passing well south of Cape Cod late tonight. Clouds will continue to thicken and lower across the area however airmass very dry and will take time to moisten up. Steady snow is expected to reach KPOU by late morning with IFR conditions developing however snow is not expected to start at KPSF until late in the afternoon. While at KALB only some flurries are possible this evening with MVFR conditions and at KGFL only VFR conditions are expected. Northeasterly winds will increase and have already become gusty at KPOU. Winds will be the strongest at KPOU and KPSF. Overall winds will to the north then northwest tonight. Outlook... Thursday Night: No Operational Impact. NO SIG WX. Friday: Low Operational Impact. Slight Chance of SHSN. Friday Night: No Operational Impact. NO SIG WX. Saturday: No Operational Impact. NO SIG WX. Saturday Night: Low Operational Impact. Slight Chance of SHSN. Sunday: Low Operational Impact. Slight Chance of SHRA...SHSN. Sunday Night: No Operational Impact. NO SIG WX. Monday: No Operational Impact. NO SIG WX.
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&& .FIRE WEATHER... The Fire Weather season has officially begun across eastern New York and western New England. Despite this, snow cover is in place across much of the region, which will mitigate any potential fire weather hazards for the time being. Additional snowfall is expected today into tonight for southeastern parts of the area which will continue to prevent issues in the near future as well. A coastal storm will brush far southeastern parts of the region with some snow for later today into tonight, otherwise, it will remain cold across the region with a partly to mostly cloudy sky. Aside from a passing flurry, mainly dry and continued chilly weather is expected for tomorrow through the weekend. && .HYDROLOGY... No hydrologic issues are anticipated through the week. Although northern areas will stay dry today into tonight, areas south and east of the Capital Region will see some snow for today into tonight, with the heaviest amounts across Dutchess and Litchfield counties. Total liquid equivalent in these areas will be up to nine tenths of an inch, although areas outside Dutchess and Litchfield Counties will generally see less than a third of an inch. This snowfall won`t have any immediate impact on area rivers and streams. Behind this storm system, mainly dry weather is then expected for the remainder of the week and into the weekend. There could be a few passing snow showers or flurries for Friday through Sunday, but this will produce little to no measurable precipitation. A slow diurnal snowmelt is expected over the next several days, with temperatures above freezing during the day, and below freezing at night. There will be little impact on the waterways with minimal, if any, rises. For details on specific area rivers and lakes, including observed and forecast river stages and lake elevations, please visit the Advanced Hydrologic Prediction Service /AHPS/ graphs on our website. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...Winter Storm Warning until 8 AM EDT Thursday for CTZ001-013. NY...Winter Weather Advisory until 8 AM EDT Thursday for NYZ061-063- 064. Winter Storm Warning until 8 AM EDT Thursday for NYZ065-066. MA...Winter Weather Advisory until 8 AM EDT Thursday for MAZ025. VT...None. && $$ SYNOPSIS...Frugis NEAR TERM...Frugis/Wasula SHORT TERM...Frugis LONG TERM...IAA AVIATION...IAA FIRE WEATHER...Frugis HYDROLOGY...Frugis is the U.S. government's official web portal to all federal, state and local government web resources and services.