Area Forecast Discussion
Issued by NWS Albany, NY

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000 FXUS61 KALY 180559 AFDALY Area Forecast Discussion National Weather Service Albany NY 1259 AM EST Sat Nov 18 2017 .SYNOPSIS... High pressure will slide across the region tonight. A warm front approaches Saturday with clouds and the increase chance for wet conditions later in the day into Saturday night. A strong cold front pushes through by Sunday morning with rain showers mixing with snow along with increasing winds. Strong gusty winds and colder temperatures will occur through Sunday night. Then lake effect snow will develop Sunday night into Monday. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... As of 1240 am, seeing mid/high level clouds continuing to increase from west to east across the region. Temps have begun to stabilize across areas along the Hudson Valley and points west, so suspect we have reached our overnight lows in these locales. Previous discussion...Earlier mid level cloud deck across central NYS eroded upon tracking east. Latest 00Z/18 upper air soundings across the northeast suggest the mid level ridge axis was still located across west/central NYS, favoring the erosion of mid level clouds as they enter our region. However, as this ridge axis shifts farther east after midnight, there should be a better tendency for mid level clouds to extend/advect into our region. So, mainly clear through at least midnight, with a gradual increase in mid level clouds from NW to SE after midnight. As for low temps, with some mid teens across portions of the western Adirondacks already, have lowered min temps in this region, as some single digits/lower teens could occur shortly after midnight, before temps gradually rise in this region before daybreak as clouds increase, and a light southeast wind develops. Elsewhere, expect mid teens to lower 20s by daybreak. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SUNDAY/... Strong to potentially damaging winds possible behind a cold front Sunday... Surface ridge axis slides east of the region Saturday morning as moisture profiles remain quite dry per the average moisture profiles. Even the latest 18Z NAM is even drier as we will delay PoPs/Wx a bit longer through Saturday morning. Then strong isentropic lift and warm advection will occur Saturday afternoon as low level jet magnitudes climb toward or higher than 50kts. Periods of rain/drizzle will evolve and some of the onset wet bulb processes may bring a wintry mix into portions of the region. However, this should be rather short lived as strong warm advection will continue to warm the column for mainly rain. This continues into Saturday night as surface low and strong upper level impulse approaches as surface low tracks across upstate NY. Then strong cold advection with the passage of the cold front by Sunday morning sunrise west of the Hudson. This is where a transition toward rain/snow to snow showers and possible squalls will occur as H850 temperatures drop back below 0C across the entire region. The main story of the day will be the increasing winds. Forecast BUFKIT profiles suggest mixing layer heights climb toward 5K feet where 50+kts reside. Furthermore, per the forecast trajectories, some funneling down the Mohawk into the Capital District, Taconics and Berkshires could enhance the wind magnitudes. At this time, we will continue to highlight into the HWO as future guidance may warrant headlines. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... Sunday night through Monday...The extended forecast opens with Lake Effect snowfall impacting locations west of the Hudson River Valley. There is still some disagreement with the guidance on the orientation of the bands and the favored low-level trajectory. Our forecast remains close to the latest NAM/GFS with west to northwest flow, and the Schoharie Valley and west-central Mohawk Valley being overspread with snow showers late Sunday through early Monday, and then the band/bands lifting northward into the western Adirondacks, as the low to mid level flow backs to the west with high pressure building in from the Carolinas. Some of the lake effect snow showers may extends into the Capital Region, northern and central Taconics, and the Berkshires with light accums. Locations further to the west may receive light to localized moderate amounts of snow. Lake effect snow showers should end by late Monday night as the ridging extends northward into our region. Highs Monday will mainly be in the upper 20s to mid 30s in most locations, the exception will be the Capital District, Mid Hudson Valley, and southern Litchfield CTY where some upper 30s to around 40F readings are possible. Lows Monday night will be mainly in the 20s. Tuesday...Mild, dry, and mostly clear conditions will be present with high pressure building in from the south. Highs for Tuesday will be about 5 degrees above normal in the upper 40s to low 50s. Wednesday through Friday...High pressure will try to stay in place to our south with a couple quick bursts of energy dropping down from Canada through the Northeast US. Going with slight chance PoPs north of the Capital region for now as there is considerable uncertainty between global models at this point. Highs look to be slightly below normal in the 30s/40s with lows generally in the upper 20s. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... As the ridge axis across the region weakens and shifts eastward overnight into Saturday high and mid level clouds will stream in. Clouds will thicken and quickly lower late in the day into the evening as a strong low pressure system approaches from the west and rain moves into and develops over the local area. Expecting widespread MVFR by 00Z and IFR developing by late evening as clouds lower further and rain becomes steadier and heavier which will continue through the overnight hours. Winds will remain very light to calm overnight with a southerly flow developing Saturday morning. Southerly winds will increase to 6 to 10 knots by late morning/early afternoon with gusts into the teens at KALB as flow funnels up the Hudson River Valley. Winds will remain southerly with a bit of a shift to the southwest and will increase some in speed and gusts at KALB and KPSF buy evening. Outlook... Sunday: Moderate Operational Impact. Windy. Scattered SHRA. Sunday Night: Moderate Operational Impact. Breezy. Chance of SHRA...SHSN. Monday: Moderate Operational Impact. Breezy. Chance of SHRA...SHSN. Monday Night - Tuesday: No Operational Impact. NO SIG WX. Tuesday Night: Low Operational Impact. Slight Chance of SHRA...SHSN. Wednesday: Low Operational Impact. Slight Chance of SHRA. && .FIRE WEATHER... Cold and dry conditions in store for tonight, as high pressure builds eastward across the region. A low pressure system will approach from the lower Great Lakes on Saturday, bringing the next chance for widespread precipitation. The storm system will intensify Saturday night as it tracks northeast through the Saint Lawrence River Valley, and will drag a cold front across our region by Sunday morning. Increasing wind magnitudes and colder air will filter in by Sunday night, with lake effect snow developing downwind of Lake Ontario. && .HYDROLOGY... No hydrologic problems are expected on the main stem rivers through the next week. High pressure will briefly build in today before a strong low pressure system approaches from the Great Lakes Region on Saturday. Widespread rain may begin as a mix with snow in the western Mohawk Valley and southern Adirondacks but then quickly change to to all rain that will continue through Saturday night. A cold front will sweep through Sunday morning with additional rain changing to snow over the higher terrain. At this time, total QPF from this system looks to range from a half inch to near an inch. A colder air mass will then build in Sunday night through early next week, with some lake effect snow downwind of Lake Ontario affecting the western Adirondacks and Mohawk/Schoharie Valleys. 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...BGM NEAR TERM...KL/BGM/Thompson SHORT TERM...BGM LONG TERM...Cebulko AVIATION...IAA FIRE WEATHER...BGM/JPV HYDROLOGY...BGM/JPV

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