Area Forecast Discussion
Issued by NWS Albany, NY

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000 FXUS61 KALY 190917 AFDALY AREA FORECAST DISCUSSION National Weather Service Albany NY 417 AM EST Tue Feb 19 2019 .SYNOPSIS... It will remain cold today through Wednesday morning with mainly dry weather. Another system will bring snow transitioning to a wintry mix late Wednesday into Wednesday night, with milder air returning by Thursday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... As of 4 AM EST, areas with clear skies, calm winds along with the fresh snowpack in place have had temperatures plummet to between zero and 10 below. Most of these locations were located within the southern Adirondacks and the Lake George region. Elsewhere, occasional clouds and some wind has kept temps somewhat milder, generally between 5 above and 15 above. We still could see temperatures fall another 3-5 degrees through daybreak, perhaps locally more where temps remain in the teens. So, expect widespread single digits above and below zero outside of the southern Adirondacks, where temps around sunrise may be as low at -15 to -20 F. After the cold start, expect mostly sunny skies through today which should allow temps to reach the lower/mid 20s for lower elevations, and teens across higher elevations. Temps may reach the lower 30s across portions of the mid Hudson Valley. Brisk west/northwest winds will later this morning, with some gusts up to 20-25 mph possible. Later this afternoon, as low level winds back into a more westerly direction, some low level moisture from the Great Lakes may extend into portions of the westernmost Mohawk Valley and southwest Adirondacks with some clouds and flurries possible toward sunset. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/... Tonight will be mainly clear with nearly calm winds, so expect temps to drop off once again to between 5 below and 15 above for many areas, with some sheltered areas of the southern Adirondacks possibly dropping back to around 15 below. Some high clouds will increase from southwest to northeast toward daybreak. Also, some Lake Effect clouds and light snow showers/flurries could extend into portions of central and northern Herkimer County at times. Wednesday-Wednesday night, the next storm system tracks into the Great Lakes region during this time period, with a warm front extending from the low into the mid Atlantic region. As the warm front tracks northeast, strengthening isentropic lift along the 290-295 K surfaces should allow clouds to rapidly increase Wednesday afternoon, with snow developing from southwest to northeast late in the afternoon. It appears that the snow should reach the I-90/I-88 corridors and points south/west by sunset, and a few hours thereafter across the southern Adirondacks extending into southern VT. This could lead to a slippery evening commute, with snowfall accumulations up to an inch for these aforementioned areas. The snow, light to moderate in intensity, may become somewhat patchy as it tracks northeast, as the deepest moisture begins to shunt eastward across the northern mid Atlantic states and off the NJ coast Wednesday evening, where a weak secondary surface wave may develop along the impinging low level warm front. In fact, models also suggest a fairly deep wedge of dry air within the H700-500 layer translates northeast into the region by late Wednesday evening. Eventually, a warm nose aloft will track northward Wednesday evening, changing snow to a sleet/freezing rain mix, with mainly freezing rain/freezing drizzle in many areas after midnight as the elevated warm nose coincides with the lack of ice nuclei within the impinging mid level dry layer. So, after a period of snow with generally 1-2 inches of accumulation (perhaps locally higher across higher terrain of the southern Greens, northern Berkshires, and SW Adirondacks), expect mainly light sleet and freezing rain to occur, with ice accretion of a light glaze to up to one tenth of an inch to occur. Given prospects for some freezing rain, it is likely that Winter Weather Advisories will be issued for at least portions of the region for Wednesday night. Thursday, lingering freezing rain/freezing drizzle may persist Thursday morning, especially for areas near and north of I-90. As the weakening system`s occluded front tracks east across the region later Thursday morning, increased mixing should allow temps to spike into the 40s for many areas, with even some 50s possible across lower elevations within the mid Hudson Valley and NW CT. Temps across higher terrain areas may then start to fall later in the day back into the 30s. It will become windy by afternoon, with west/northwest winds potentially gusting to 25-35+ mph. Thursday night, increasing cold air advection and a west/northwest cyclonic flow should allow for mostly cloudy skies with spotty snow showers/flurries possible across the Mohawk Valley and southwest Adirondacks. Otherwise, temps will slowly fall back through the 30s with some 20s possible by daybreak Friday. && .LONG TERM /FRIDAY THROUGH MONDAY/... Flat upper ridging in eastern North America will keep temperatures at or a little above normal through the period. Strong upper energy in the western and central U.S. will continue to weaken as it tracks within the northern periphery of the upper ridging and broadly confluent upper flow. Dry weather is expected Friday and Saturday, although, Saturday there will be increasing clouds with the leading edge of some patchy light precipitation possibly approaching southern areas. Highs Friday in the upper 30s to lower 40s but lower 30s northern areas. Highs Saturday in the lower 40s with mid 30s northern areas. Upper energy and increasing low level moisture and forcing track toward our region Saturday night and through our region Sunday. Mixed precipitation Saturday night will become rain Sunday. There are questions as to the timing of the onset and exit of precipitation in the fast west southwest upper flow and adjustments will be made as we get closer to next weekend. Showers could linger into Sunday night. Highs Sunday in the lower to mid 40s but a few upper 40s southern areas and around 40 northern areas. Any precipitation ends Sunday night, except for some possible lake effect snow shower activity that could extend into the southern Adirondacks and western Mohawk Valley. Highs Monday in the upper 30s to lower 40s but lower 30s southern Adirondacks. && .AVIATION /09Z TUESDAY THROUGH SATURDAY/... Mostly clear sky overnight through this afternoon and evening with high pressure in control of the weather. VFR conditions expected through this evening. Northwest winds at 6 Kt or less through daybreak will increase to 10 to 15 Kt with gusts to near 20 Kt late this morning and afternoon. Northwest winds diminish to 6 Kt or less this evening. Outlook... Wednesday Night: High Operational Impact. Definite SN...FZRA...SLEET. Thursday: Moderate Operational Impact. Windy With Gusts To 30.0 Chance of SHRA...RA. Thursday Night: Low Operational Impact. Breezy NO SIG WX. Friday: No Operational Impact. NO SIG WX. Friday Night: No Operational Impact. NO SIG WX. Saturday: No Operational Impact. NO SIG WX. && .HYDROLOGY... Hydrological impacts are not expected through at least this week. Seasonably cold weather is expected through Wednesday, promoting ice expansion on area waterways. The next system arrives late Wednesday into Thursday morning with snow transitioning to a wintry mix. Precipitation amounts of generally a quarter to a half an inch are expected. Temperatures are expected to run a bit above normal Thursday into the weekend. Another period of rain or mixed precipitation is possible Sunday. 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...None. VT...None. && $$ SYNOPSIS...IAA/KL/Thompson NEAR TERM...KL SHORT TERM...KL LONG TERM...NAS AVIATION...NAS HYDROLOGY...KL/Thompson

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