Area Forecast Discussion
Issued by NWS Albany, NY

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000 FXUS61 KALY 151432 AFDALY Area Forecast Discussion National Weather Service Albany NY 932 AM EST Mon Jan 15 2018 .SYNOPSIS...
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High pressure will remain centered over eastern Quebec today, with a ridge extending southward through the northeast U.S. This will allow for dry and cold conditions to persist through today. A low pressure system will then approach from the Great Lakes tonight into Tuesday, bringing increasing chances for light snow. This system, combined with a developing coastal low pressure area, is expected to bring at a moderate snowfall to much of the region late Tuesday into Wednesday.
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As of 932 AM EST...Tranquil and cold conditions exist across the area this morning, courtesy of a strong area of high pressure over eastern Quebec, with ridging extending all the way southward through the mid Atlantic region. Temperatures remain in the single digits to low teens with a light northeast wind in place at the surface. Meanwhile, a southeast flow aloft has allowed some clouds to move into the region off the western Atlantic, especially across southeastern parts of the area. Dry conditions expected to persist through today under the influence of the ridging. High level clouds will move through and filter the sunshine, while low level stratus clouds gradually advect in from the south and east. Adjusted sky grids to reflect more pessimistic partly/mostly cloudy coverage based on trends in satellite imagery. It will be another cool day, with high only in the teens to mid 20s. Wind speeds will be relatively light though. Clouds will continue to increase and thicken tonight associated with a weak low pressure system moving eastward across the lower Great Lakes region. Some weak warm advection will eventually lead to some light snow developing. Will mention mainly chance pops for spotty light snow reaching the ground. The low levels will be quite dry to start, and available forcing/moisture with this system will be fairly limited to start, thus the reluctance to go with likely pops overnight.
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&& .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... Winter Storm Watch has been issued for the southern Green Mountains of Vermont and the Berkshires of Massachusetts from Tuesday afternoon through Wednesday morning... Light snow will become more likely spreading eastward through the Capital District Tuesday morning, as weak warm advection continues. The low levels are expected to become saturated by then, with confidence in some light snow accumulating. The light snow will spread to areas east of the Hudson Valley, including western New England Tuesday afternoon. Then, the weak area of low pressure is expected to stall along a strengthening baroclinic zone across western New England Tuesday night. At the same time, a secondary area of low pressure is forecast to emerge off the Delmarva and track northeast along the edge of the baroclinic zone. A positive tilt trough aloft will be advancing eastward across the lower Great Lakes and Ohio Valley region. This set up looks to be conducive for some mesoscale banding to develop, and resembles a potential quasi-stationary band pattern from noted CSTAR research. Deterministic and ensemble model QPF has also increased from previous runs, which lends more confidence to a moderate snowfall event, especially for much of the area from the foothills of the southern Adirondacks south and east. Due to the best forecast 850-700mb F-Gen across SE NY and the southern New England coast, the most likely area for potential mesoscale banding looks to be across the southern Green Mountains of Vermont and the Berkshires based on the CSTAR research. So we have issued a Winter Storm Watch for this area due to at least 50 percent confidence of greater than 6 inches of snow. Elsewhere, it appears an Advisory will eventually be needed with snowfall forecast of generally 3-6 inches outside of the Watch area, and lighter 1-3 amounts in the west-central Adirondacks. The snow from the coastal low should persist through much of Wednesday morning, especially for areas east of the Hudson Valley. This system will likely impact the morning commute for much of the area. Wednesday afternoon, lake effect snow showers will start to develop downwind of Lake Ontario as westerly wind align with conditional lake-induced instability developing. So scattered snow showers will move back into the western Adirondacks before dark with some light accumulations possible. Lake effect snow showers will continue into Wednesday night across the western Adirondacks, but will be light due to lowering inversion heights. Otherwise, it will be mainly dry with near normal temperatures for the rest of the area. && .LONG TERM /THURSDAY THROUGH SUNDAY/... The weather is expected to be quiet with a gradual warm up through the weekend. Upper energy exits Thursday with upper ridging building into our region through the weekend. There could be some isolated to scattered snow showers in the southern Adirondacks by Friday night and Saturday, with isolated rain showers Saturday as Isentropic lift and warm advection increase. By Sunday strong upper energy in the central U.S. will begin its move east and as it amplifies, the downstream upper ridging in our region will amplify, further strengthening the warm advection. Increasing clouds and slowly increasing coverage of showers is possible Sunday. Highs Thursday in the upper 20s to lower 30s but mid 20s northern areas. Highs Friday in the lower to mid 30s with mid to upper 20s northern areas. Highs Saturday around 40 to mid 40s but mid 30s northern areas. Highs Sunday in the 40s with some upper 40s southern areas and lower 40s northern areas. There could be some more snow melt and ice jam flood issues as the temperatures warm next weekend and some rain approaches by the end of the weekend and beginning of next week. && .AVIATION /15Z MONDAY THROUGH FRIDAY/... Some clouds have built west into the KPSF and KALB areas with broken ceilings at around 2000 feet at KPSF and 3500 feet at KALB. These clouds should tend to become intervals of scattered variable broken and rise above 3000 feet at KPSF. KPOU and KGFL may see some scattered clouds around 3500 feet as well this morning. High clouds will thicken and lower late this afternoon and evening but ceilings will continue well above 3000 feet. Winds through daybreak will be light northerly at 5 Kt or less to through mid morning, becoming northeasterly around 5 to 10 kt this morning and afternoon. Winds trend near calm this evening. Outlook... Monday Night: Moderate Operational Impact. Chance of SHSN. Tuesday: High Operational Impact. Likely SN. Tuesday Night: High Operational Impact. Likely SN. Wednesday: Moderate Operational Impact. Chance of SHSN...SN. Wednesday Night: No Operational Impact. NO SIG WX. Thursday: No Operational Impact. NO SIG WX. Thursday Night: No Operational Impact. NO SIG WX. Friday: No Operational Impact. NO SIG WX. && .HYDROLOGY... Ongoing flooding due to ice jams will continue to be addressed with areal flood warnings. There could still be some lingering issues as any existing ice jams may tend to become frozen in place due to the very cold temperatures expected over the next few days. Warmer weather is not expected until the weekend. In terms of precipitation, a moderate snowfall is expected for much of the area from Tuesday into Wednesday, with heavy snowfall possible in the southern Green Mountains and Berkshires. 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...None. NY...None. MA...Winter Storm Watch from Tuesday afternoon through Wednesday morning for MAZ001-025. VT...Winter Storm Watch from Tuesday afternoon through Wednesday morning for VTZ013-014. && $$ SYNOPSIS...JPV NEAR TERM...Frugis/JPV SHORT TERM...JPV LONG TERM...NAS AVIATION...NAS HYDROLOGY...11/JPV is the U.S. government's official web portal to all federal, state and local government web resources and services.