Area Forecast Discussion
Issued by NWS Albany, NY

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939 FXUS61 KALY 180628 AFDALY Area Forecast Discussion National Weather Service Albany NY 128 AM EST Thu Jan 18 2018 .SYNOPSIS... A low pressure system will move into the Canadian Maritimes tonight, with snow showers ending across our area. Seasonably cold and mainly dry weather is expected tonight through Thursday, except for some lake effect snow showers across the western Adirondacks. An upper level disturbance may trigger additional snow showers for Thursday night into early Friday. Fair weather, with a gradual warming trend is expected for this upcoming weekend. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... As of 1226 AM EST...Made some minor adjustments to temperatures and sky cover based on latest observations and trends. A micro ridge has set over upstate NY and PA, and the skies have cleared across the majority of the forecast area based on GOES-16 10.3-3.9 micron scan except for lake enhanced clouds coming off Lake Ontario moving over the western Adirondacks. Temps have dropped off close to the mins forecasted in some spots with the clear skies, and light to calm winds coupled with the fresh snow pack. We have adjusted mins down a few degrees further into the the single digits and lower teens. The KTYX radar and some of the CAMS continue to show lake enhanced/effect snow showers forming that may lead to a quick 1-3 inches across portions of the western Adirondacks, esp north of Route 28 and Old Forge overnight into the morning. Some high clouds ahead of the next shortwave may move into the region towards daybreak. Overall, expecting the ideal radiational cooling conditions to last into the early to mid morning hours. Please see our Public Information Statement product with the latest snow totals. && .SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY/... Thursday, a mix of sun and clouds, with chilly temperatures, mainly in the 20s for lower elevations, and teens across higher terrain. Some additional Lake Effect snow showers could lead to an inch or two across far northern Herkimer CO. For Thursday night, a potent upper level shortwave, currently noted on WV satellite imagery across south central Canada, is expected to track across the region. With some added lake moisture, and mid level warm advection combined with strengthening cyclonic vorticity advection, a burst of snow showers may occur, especially for areas near and north of the I-90 corridor. Minor accumulations of up to an inch could occur, except locally higher across portions of the western Adirondacks, and perhaps higher elevations of southern VT. Lows should mainly be in the teens. Friday-Saturday, after any residual snow showers Friday morning, expect a clearing trend for later Friday into Saturday, although snow showers could linger across the western Adirondacks. Friday highs should mainly reach the 20s to lower 30s, with Friday night lows in the teens/20s. Milder for Saturday, with highs reaching the lower/mid 30s across higher terrain, to near or over 40 in valley areas, warmest across the mid Hudson Valley region. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... Temperatures will close the weekend above normal, as high pressure will be ridging in from the Southeast and lower Mid Atlantic States. The mid and upper level flow will be zonal closing the weekend, as a cold front will be near the St Lawrence River Valley, and northern New England. Lows temps Sat night fall back into mid and upper 20s, and highs on Sunday will be about 10 degrees above normal with upper 30s to mid 40s in the valley areas and hills, and 30s over the mtns. A few rain or snow showers may graze the western Adirondacks with the front nearby and weak disturbances in the fast flow through Sunday. Sunday night through Monday...An upper level trough moves in the central Plains, and closes off. Diffluent flow sets-up upstream over the Midwest and Great Lakes Region. A warm front moves towards NY and PA with a slight to very low chance of snow showers Sunday night, though there are timing difference with the latest 12Z GFS/ECMWF/CAN GGEM and GEFS, and much of the night time period may be dry. A lead mid-level short-wave coupled with the warm front may produce spotty light pcpn into Monday, as the synoptic forcing looks rather weak, but some light rain or snow showers looks possible. The H500 low cuts off over the Midwest and western Great Lakes Region on Monday. Lows Sunday night should fall back into the mid 20s to around 30F before the clouds increase with the spotty light pcpn, and highs in the warm advection regime will be in the mid 30s to lower 40s. Monday night through Tuesday...The low to mid-level southerly flow increases ahead of the cutoff cyclone and its cold front, as the latest 12Z GEFS has +v-component wind anomalies /southerlies/ increase +2 to +3 standard deviations /STD DEVs/ above normal with PWATS increasing to 1 to 2 STD DEVS above normal. Some snow melt, and ice break is possible, as low temps will likely be above normal with mid and upper 30s in the valleys, and upper 20s to mid 30s over the higher terrain. The cutoff cyclone moves northeast into southeast Ontario with some Gulf and Atlantic moisture moving into the forecast area ahead of the cold or occluded front with a potential weak wave moving along it. The ptype could be messy with rain mixed with sleet, then rain, and finally transitioning to snow late in the day depending on the frontal passage. We will have to monitor for any hydro issues especially with the present ice jams, as highs will be in the mid and upper 30s north and west of the Capital Region, and lower to mid 40s south and east. Total QPF may be in the half an inch to inch plus range Mon night into Tuesday. Tuesday night into Wednesday...The cold or occluded front moves through with the pcpn ending as snow showers, as colder air filter in. In the strong cold advection, lows fall back into the teens to mid 20s. The threat for isolated to scattered snow showers continues in the cyclonic flow, especially along the favored westerly upslope areas of the western Adirondacks/southern Greens. High temps will be near normal for the mid week. && .AVIATION /06Z THURSDAY THROUGH MONDAY/... The coastal low which has developed off the southeast coast will deepen and move northeastward out to sea through the TAF period. In the meantime, high pressure will continue to build in from the south and west at the surface. While aloft an upper level disturbance will move over the region late tonight which may result in some snow showers mainly north and west of the Hudson River Valley after 06Z/Friday. Mainly VFR conditions will dominate. Mainly clear skies overnight with some lower level stratocumulus around 3-3.5 kft AGL expected to impact KALB/KPSF/KGFL later this morning. Cirrus clouds will stream in this evening. Light to calm winds overnight with a westerly flow developing Thursday and increasing to 9-13 knots with gusts mainly in the teens at KALB and KPSF during the day. Outlook... Thursday Night to Saturday: No Operational Impact. NO SIG WX. Saturday Night: Low Operational Impact. Slight Chance of SHRA...SHSN. Sunday: Moderate Operational Impact. Chance of SHRA...SHSN...RA. Sunday Night: High Operational Impact. Likely RA. Monday: High Operational Impact. Likely RA. && .HYDROLOGY... Ongoing flooding due to ice jams will continue to be addressed with areal flood warnings, as some lingering issues continue due to existing ice jams which have become frozen in place. A gradual warming trend is expected to occur beginning this weekend. In terms of precipitation, only some snow showers are expected through Friday, with generally dry conditions expected over the upcoming weekend. 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...KL/JPV/Wasula NEAR TERM...KL/JPV/Wasula SHORT TERM...KL LONG TERM...Wasula AVIATION...IAA/Wasula HYDROLOGY...KL/JPV

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