464 FXUS61 KALY 072016 AFDALY AREA FORECAST DISCUSSION National Weather Service Albany NY 416 PM EDT Fri Oct 7 2022 .SYNOPSIS... Much cooler temperatures can be expected tonight as a result of the cold frontal passage from this afternoon. An isolated shower or two cannot be ruled out the remainder of the late afternoon into the evening, though the probability of occurrence decreases significantly after sunset. Dry, cool, and breezy conditions can be expected this weekend throughout much of the area, though some scattered lake effect showers in the western Adirondacks will persist late Saturday through Sunday. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... As of 415 PM EDT...The aforementioned, northeasterly progressing cold front continues to intrude further into the region, causing temperatures to drop in the Capital District and continue dropping in the Adirondacks. Scattered showers and gusty winds can be expected the rest of the afternoon/evening as the passage nears completion after sunset. Broad upper level troughing situated across southeast Canada and the Great Lakes region has deepened throughout the day today, forcing an upper level jet through the region with an influx of colder temperatures through much of the northeast. This new, cool airmass will bring mostly dry conditions tonight, though some scattered showers can be expected especially in the Adirondacks where influences from moisture advection off Lake Ontario could dominate. Gusty winds will aid in temperatures feeling fairly cool throughout the region this evening. Gust should begin to decrease after sunset, but will remain around 5-10+ mph throughout the night before increasing after sunrise tomorrow. Expected low temperatures look to range from the upper 30s to low 40s throughout the Hudson Valley while higher elevations can expect upper 20s to mid 30s. The winds, clouds and dry low-level environment should prevent frost formation where the growing season continues. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/... Tomorrow...A chilly air mass will open the weekend with the mid and upper level trough over the Great Lakes Region, Midwest Northeast and southeast Canada. H850 temps will be in the 0C to -5C range to start the day. The low to mid level flow veers to the northwest to start the day with light lake effect showers mainly west of the region over central NY. Though some lake effect clouds will persist south and west of the Capital Region in the cyclonic flow over the western Adirondacks, Mohawk Valley and eastern Catskills. Also, some mid and high clouds will be diminishing to the south and east with a weak wave passing near southeast New England that moved along the old front. Partly to mostly cloudy conditions will start the day but an increase partly to mostly sunny conditions especially from the Hudson River Valley eastward is expected for the afternoon with some upslope clouds possible along the western New England higher terrain. The west to northwest winds will continue at 10 to 15 mph with some gusts 20-25 mph in the northern Catskills/Greater Capital Region into the northern Taconics and Berkshires due to funneling and some downsloping. The low to mid-level flow veers more to the west to southwest late in the day as some lake effect showers may impact the western Adirondacks late in the afternoon. We kept some slight and low chance PoPs in north of Old Forge. Max temps were accepted close to GFS/NBM with highs about 5 to 10 degrees below normal with 40s over the mtns, and lower to mid 50s in the valleys with some upper 50s in the mid Hudson Valley. Saturday Night... High pressure will attempt to ridge in from the Ohio Valley/Mid Atlantic Region, as a cold front is slowly moving southeast with the amplifying mid and upper level trough east of Hudson Bay and over Quebec. Temps on the cool/chilly side for early October are expected again. The winds will likely go light and the skies will be clearer south and east of the Adirondacks. It is not an ideal radiational cooling environment but some patchy to localized areas of frost may form where the growing season continues outside the Mohawk and Hudson River Valleys over the higher terrain. We added patchy frost with a bit more coverage this forecast cycle. We may need a frost advisory if the winds go light to calm and the skies do stay clear/mostly clear. We will keep mention in the HWO. Meanwhile, a piece of short-wave associated with the broad long-wave trough will bring some lake effect showers into northern Herkimer and Hamilton Counties. A few wet snow flakes may mix Lake induced instability class looks conditional from the NAM. The low-level flow becomes west/southwest. Lows will be in the mid and upper 30s in many locations with pockets of lower 30s in the sheltered valleys/higher terrain. Sunday...A mid and upper level disturbance passes north of the forecast area with the cold front stalling over northern New England and northern NY. The mid level flow briefly becomes flatter or near zonal. The boundary layer flow will allow for occasional lake effect showers especially over the western and southern Adirondacks. Some of the light showers may spread into the Lake George Region. The air mass modifies slightly with 850 hPa temps warming back to 0C to +3C. Mostly cloudy/cloudy conditions will persist north of the I-90 corridor over the northern zones, and partly sunny/mostly sunny conditions south and east. Temps will only improve slightly and will still be a little below normal. Breezy west wind will continue. Highs will range from upper 50s to lower 60s in the valley areas and 40s to mid 50s over the hills and mtns. Sunday Night...Another weak short-wave impulse rotates around the mid and upper level trough and will bring some clouds and few showers to the Adirondacks, western Mohawk Valley and the Lake George Region. The old cold front may be near the Adirondacks and central VT. The low-level moisture is not that impressive. The skies will be partly cloudy and mainly dry conditions are expected from the Greater Capital Region south and east. Lows will be in the mid 30s to lower 40s. Some patchy frost may occur in the higher terrain if the winds decouple and the skies stay clear in a few spots. && .LONG TERM /MONDAY THROUGH FRIDAY/... After a warming trend Tuesday through Thursday of the upcoming work week, a full latitude trough develops over the Central CONUS and closes off before gradually sliding eastward towards the Northeast. This feature will be the focus of the long term period. The latest 12 UTC guidance has slowed down the time of arrival of the associated surface cold front in comparison to previous model runs so the main update to this forecast is to delay chance and likely POPs to Thursday afternoon into Thursday night. Read on for details. We start off the period on Monday (Columbus/Indigenous Peoples' Day) with a thermal gradient stalled over the region and a weak shortwave pushing through the Northeast. As a vort max at the bottom of the trough swings through during the day, westerly flow and cool air advection down the long fetch of Lake Ontario looks to result in enough of a delta-T gradient to produce some lake effect showers. Guidance suggests this combined with enhance lift from cyclonic vorticity advection ahead of the incoming shortwave could allow the showers to extend inland enough to reach into our southern Adirondack and western Mohawk Valley areas. Maintained slight chance POPs into these areas. Kept the rest of the region dry. Otherwise, expecting partly to mostly cloudy skies for the Monday holiday due to some enhanced lake moisture with seasonable temperatures in the upper 50s to low 60s. The stalled boundary from Monday lifts northward as a warm front Tuesday into Wednesday once the upstream ridge axis pushes through. This will allow a much warm air mass to advect into the Northeast. Expect a warming trend through the middle part of the week with temperatures climbing well into the 60s to potentially even touching the 70 degree by Thursday. While radiational cooling Monday night will lead to a seasonably cool night with lows in the 30s to low 40s, overnight lows will also trend milder through the week with lows only in the 40s for much of the region with the valley possibly only dropping into the low 50s Wed night. Thursday into Friday will feature the main forecast challenge of the upcoming long term as a full latitude trough develops in the Central Plains and closes off before very gradually tracking eastward. The latest 12 UTC has trended much slower compared to 00 UTC guidance which is likely due to the fact that there is good model consensus for the trough to close off. In fact, the 12 UTC ECWMF has trended nearly 24 hours slower with the time of arrival of the cold front compared to the 00 UTC run. Due to the trough closing off, the downstream ridging over the Northeast amplifies further with the sfc high pressure off the New England coast building to ~1025-1030hPa in response. As a result, the pressure gradient between these two features tightens over the Northeast which will likely lead to strong southerly winds for Thursday. We increased sustained winds and wind gusts compared to the NBM output and also increased high temperatures (closer to the NBM 75th percentile guidance) as more of Thursday appears dry which enhances the amount of time we will stay in the warm sector. Given the anomalously warm temperatures ahead of the boundary and very impressive dynamics, SPC's Day 4-8 discussion has mentioned the potential for thunderstorms over the region for Thursday. Still uncertainty on the exact timing and track of the sfc cold front but we will keep an eye on trends and potential for any instability to develop. Behind the cold front and trough axis, a much colder air mas will track into the Northeast just in time for the weekend. Depending on the wind orientation, some lake effect showers could form. && .AVIATION /19Z FRIDAY THROUGH WEDNESDAY/... A cold front will track southeast across the TAF sites through this afternoon, with a brisk northwest wind and some lake effect clouds developing in its wake. The cold front should track through KGFL, KALB and KPSF by 20Z, and KPOU by 21Z/Fri. A period of MVFR Cigs, and some light showers will be possible with and just behind the front at KGFL, KALB and KPSF. In the wake of the front, mainly VFR Cigs are expected tonight, however occasional MVFR Cigs could occur, especially at KPSF where a period of low MVFR Cigs is possible. Any MVFR Cigs should lift to VFR between 13Z-15Z/Sat, with mainly VFR conditions expected thereafter. Winds will become west to northwest this afternoon, and increase to 8-15 KT, with some gusts up to 25 KT possible, especially at KALB and KPSF. Winds will become northwest to north tonight at 8-12 KT, with similar winds expected through midday Saturday. Outlook... Saturday Night: No Operational Impact. NO SIG WX. Sunday: No Operational Impact. NO SIG WX. Sunday Night: No Operational Impact. NO SIG WX. Columbus Day: No Operational Impact. NO SIG WX. Monday Night: No Operational Impact. NO SIG WX. Tuesday: No Operational Impact. NO SIG WX. Tuesday Night: No Operational Impact. NO SIG WX. Wednesday: No Operational Impact. NO SIG WX. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. MA...None. VT...None. && $$ SYNOPSIS...Gant/Wasula NEAR TERM...Gant/Wasula SHORT TERM...Wasula LONG TERM...Speciale AVIATION...KL