105 FXUS61 KALY 020250 AFDALY AREA FORECAST DISCUSSION National Weather Service Albany NY 950 PM EST Fri Jan 1 2021 .SYNOPSIS... A storm system will bring snow, sleet, freezing rain and rain to the area tonight into Saturday. Another storm will quickly follow bringing a light to moderate snowfall to the area Sunday and Sunday night. && .NEAR TERM /THROUGH SATURDAY NIGHT/... Winter Weather Advisory remains in effect for the entire area for mixed precipitation beginning at 7 pm continuing into early Saturday... As of 940 PM EST, band of moderate to locally heavy snow is now occurring close to and immediately north of I-90 in NY and into northern Berkshire Co MA. Latest KENX dual-pol radar correlation coefficient suggests mixed hydrometeors across central/southern Schoharie County into southern Albany County and central/southern Berkshire County, where some reports of sleet/freezing rain are now occurring. Expect this band of moderate snow close to and north of I-90 to continue shifting northward over the next 1-2 hours, with a changeover to sleet/freezing rain slowly progressing from south to north. A quick 1-2 inches of snow is expected over the next 2 hours within this band, especially north of I-90, where mainly snow is expected, while slightly less is expected just south of I-90 a transition to sleet is expected over the next hour. Still expect total snow/sleet amounts of 2-4 inches for most areas north of I-90, and generally 1-2 inches within the Capital Region and northern Schoharie County east through northern/central Berkshire County, and only a coating to less than an inch farther south and east. Meanwhile, mainly freezing rain has been occurring across the far SE Catskills, mid Hudson Valley and NW CT. A few pockets of plain rain may be occurring within some valley areas, although with dewpoints still hovering around 30 degrees, some icing may still occur on exposed and/or untreated surfaces. Previous discussion follows... High pressure will continue to weaken and shift eastward off the New England into this evening. A strengthen low will track into the Ohio Valley/eastern Great Lakes Region tonight with a secondary low beginning to develop over the mid-Atlantic Region as the potent short wave approaches. The secondary low will become the dominate low but not until Saturday which means the warm nose aloft from the primary with move across the local area tonight into Saturday resulting mixed precipitation. No big changes to the forecast with light to moderate snowfall along and north of I-90 with lesser amounts to the south. Strong isentropic lift will occur overspreading precipitation across the region. The HREF continues to signal good potential for greater than 1 inch/hour snowfall rates this evening across parts of the Mohawk Valley, southern Adirondacks and even into the Saratoga region. The pattern resembles a Laterally Translating Mesoscale Band setup from CSTAR research, given a primary cyclone to our west with a potent 700 mb short wave and strong warm advection downstream of the cyclone. Snow overspreads the area this evening with warming aloft causing a changeover to sleet and freezing rain into the southwest portion of the area early in the evening gradually moving northward overnight. Low level cold air will hold on due northeast ageostrophic flow resulting in more snow across northern areas and hours of freezing rain across the entire area. A changeover to plain rain is expected to begin during the early morning hours in the mid-Hudson Valley spreading northward up the valley initially then spreading to the higher terrain. Ice accumulations of glaze to to two tenths of an inch are expected with the greatest accretions above 1000 feet elevation. Thermal profiles indicate the Adirondacks and portions of southern Vermont will not changeover to all rain before colder air moves back in on the backside of the system as the secondary low become primary. As temperatures aloft cool the steady precipitation will taper off to scattered rain/snow showers by early Saturday afternoon. Brisk and gusty conditions develop by Saturday afternoon, as the cyclone consolidates and strengthens in the Gulf of Maine. Northwest winds will likely gust between 25-35 mph. Temperatures will rise above freezing in most areas with 40s in the mid-Hudson Valley northward into the southern reaches of the Capital District and across northwestern Connecticut into the southern Berkshires with 30s across the rest of the area. Tranquil conditions and seasonable temperatures expected for Saturday night, as high pressure quickly builds into the region. Winds will diminish as well. && .SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/... After high pressure briefly takes control of the Northeast, a second low pressure system develops for Sunday in response to a shortwave trough progressing from the MS Valley to the Ohio Valley. Guidance shows it forming along the lingering cold front from our first storm initially in the Gulf Coast states and then tracking northeastward strengthening off the mid-Atlantic coast and remaining mainly south of Long Island Sunday afternoon into Sunday night. While the center of the system stays to our south, its northwest quadrant and the region with enhanced mid-level FGEN brushes our southern zones, mainly the eastern Catskills, NW CT and the mid-Hudson. Some additional light QPF amounts extend northward into the Capital District and even north of I-90 but the GFS, NAM and ECMWF all suggest that the highest QPF amounts ranging 0.15 - 0.30" remain mainly south of I-90 which will be in closer proximity to the low. The CMC tracks the low further north and thus shows high QPF amounts for the entire region but this was considered a northward outlier. Thermal profiles support a mainly snow sounding given that we remain north of the low. Daytime highs look to reach into the low to mid 30s but once precipitation begins in response to enhanced overrunning Sunday afternoon, wet-bulbing effect should allow mainly snow. Due to potential for some enhanced mid-level FGEN and southeasterly flow upsloping the eastern Catskills, Litchfield Hills and even the Berkshires, some periods of moderate snow are possible. BUFKIT soundings also show omega extending through the DGZ in this region which also would support moderate/steady snow mainly Sunday afternoon into Sunday evening. The storm then exits into New England early Monday morning. Total snowfall amounts at this point range 1 to 3 inches with locally higher amounts up to 3-5 inches in the aforementioned higher terrain areas. Snowfall amounts should decrease heading into the southern Adirondacks and Upper Hudson Valley with amounts mainly under 2 inches since these areas will be farther removed from the low. Current snowfall amounts would support a winter weather advisory in NW CT and potentially the southern Berkshires where advisory criteria stands at 3 inches. The eastern Catskills including Schoharie County and the Helderbergs will be close to advisory criteria but current forecast shows amounts across 50 percent of the zones just shy of the 4 inch threshold. If confidence in mesoscale banding increases, we may need to issue an advisory. && .LONG TERM /MONDAY THROUGH FRIDAY/... Upper level flow becomes somewhat blocky across eastern North America downstream into the North Atlantic Ocean during this period, with occasionally unsettled conditions possible. Lingering snow/snow showers will be possible Monday, depending on the eventual track and speed of storm system along/east of the New England coast. Best chances for snow look to be mainly east of the Hudson River, especially in the morning hours. Otherwise, max temps mainly in the 30s. Additional upper level energy looks to approach from east central Canada into the Great Lakes region and northern mid Atlantic states Tuesday-Wednesday. Expect some snow showers as this energy passes through, with some possibility of more frequent snow showers or periods of snow across upslope areas of western New England, as some additional moisture potentially backs west/southwest from the offshore storm system and interacts with the passing upper level energy. Fair weather looks possible for Wednesday night-Thursday, before additional upper level energy potentially approaches from the Great Lakes/Ohio Valley region by Friday/Friday night. Depending on how far north deeper moisture/energy reach, there could be some snow or snow showers across portions of the region by next Friday night, however confidence in this is very low at this time range. For now, have some slight chance PoPs Friday night for far eastern areas, while remaining dry across the remainder of the region. Temperatures look to be slightly above seasonal level through the week, with daytime highs mainly in the 30s for valleys, and mid 20s/lower 30s for higher elevations. Overnight lows mainly in the 20s, with some teens across higher terrain for Thu-Sat mornings. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... Low pressure will approach from the southwest tonight, and will pass across the TAF sites Saturday morning. Band of mixed precipitation is about to reach KALB/KPSF, with a sleet/freezing rain/snow mix initially, before changing over to more snow/sleet through 04Z/Sat. A period of moderate snow may occur at KGFL between 02Z-05Z/Sat, with sleet/freezing rain becoming mainly freezing rain at KPOU by 02Z/Sat. Warmer air aloft should change precipitation to mainly freezing rain after midnight at the TAF sites, with perhaps some sleet occasionally mixed in. Precipitation should change to plain rain from south to north between 08Z/Sat-13Z/Sat. Rain or rain showers could briefly mix back with some snow or sleet at KGFL before ending around midday. Flight categories will deteriorate to MVFR, then IFR, especially for Cigs overnight through Saturday morning. Vsbys should vary between MVFR and IFR, with lowest visibilities occurring in areas where P-type is all snow. Cigs should improve to MVFR, then VFR during Saturday afternoon. Winds overnight will be mainly northeast through southeast at 5-10 KT. Winds will shift into the west to northwest around midday Saturday, and increase to 10-15 KT with gusts of 25-30 KT expected, strongest at KALB and KPSF. Low level wind shear is possible late tonight at KPOU and possibly KPSF, especially between 08Z-12Z/Sat. Outlook... Saturday Night: Low Operational Impact. NO SIG WX. Sunday: Moderate Operational Impact. Chance of SN. Sunday Night: High Operational Impact. Likely SN. Monday: Moderate Operational Impact. Chance of SN. Monday Night: Low Operational Impact. NO SIG WX. Tuesday: Moderate Operational Impact. Chance of SHSN. Tuesday Night: Low Operational Impact. Slight Chance of SHSN. Wednesday: No Operational Impact. NO SIG WX. && .HYDROLOGY... Hydrological concerns are not anticipated through the next week. A storm will bring snow, sleet, freezing rain and rain to the area tonight into Saturday. QPF amounts of 1/2 to 1 inch are expected with some enhanced areas just over an inch in portions of the southern Adirondacks and southern Green Mountains. Some minor river rises are expected across the southern half of the area, but will not be significant. Another storm will bring a light to moderate snowfall to the area Sunday and Sunday night. 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 Weather Advisory until 7 AM EST Saturday for CTZ001-013. NY...Winter Weather Advisory until 7 AM EST Saturday for NYZ047>053- 058>061-063>066. Winter Weather Advisory until 11 AM EST Saturday for NYZ032- 033-038>043-054-082>084. MA...Winter Weather Advisory until 11 AM EST Saturday for MAZ001- 025. VT...Winter Weather Advisory until 11 AM EST Saturday for VTZ013>015. && $$ SYNOPSIS...IAA NEAR TERM...IAA/KL SHORT TERM...Speciale LONG TERM...KL AVIATION...KL/Speciale HYDROLOGY...IAA