335 FXUS61 KALY 160553 AFDALY AREA FORECAST DISCUSSION National Weather Service Albany NY 153 AM EDT Sun Oct 16 2022 .SYNOPSIS... In the wake of a cold front, winds will remain a bit breezy tonight which will help keep temperatures a bit milder than previous nights. Then, dry and slightly cooler weather is expected on Sunday before another system brings clouds and showers for Monday. Much cooler weather arrives Tuesday and Wednesday. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... As of 153 AM EDT...Broad upper level trough extends all the way from the Upper Midwest eastward to the Northeastern US. The core of the upper level trough continues to be located just north of the Great Lakes over Ontario. At the surface, an occluded front is now located just east of the area, having crossed the area over the last few hours. While there wasn't any precip (or really many clouds) with the passage of the front, winds have been switching from the west-southwest to the west-northwest. With the light breeze continuing into the overnight hours, this has helped temps from falling too quickly and has been preventing radiational fog from forming so far. The one exception has been across the CT River Valley of southern VT, as this area has remained sheltered from the wind and some fog is already beginning to start to form in that area. Surface high pressure is just west of the area over western NY and will be building towards the area. This should allow winds to lighten up and become calm towards daybreak across much of the area. IR satellite imagery shows nearly clear skies over the entire area with only some patchy clouds over the Adirondacks and Mohawk Valley. As a result, there will be a brief window during the late night hours for some fog to develop just prior to sunrise (especially for western areas, where there will be the best chance of calm winds). Temps are currently in the mid 40s to low 50s but will start falling a little quicker once winds lighten up. Lows by daybreak should range from the mid 30s over the Adirondacks to the low to mid 40s in the Hudson Valley and NW CT. && .SHORT TERM /6 AM THIS MORNING THROUGH MONDAY NIGHT/... Sunday is shaping up to be a dry day as high pressure restrengthens across the region. 850 hPa temperatures will be lower (+3 to +6C) than on Saturday which will result in high temperatures only reaching the lower 50s to mid-60s. There will be some occasional mid and high clouds as well. The main upper-level trough will strengthen and dive southward and eastward across the Great Lakes Sunday night through Monday night. Southern stream energy will attempt to interact with this main trough increasing potential for upward vertical motion. The core of the upper-level low will slowly push eastward toward western New York by Monday night. At the surface, a new area of low pressure and associated cold front will develop across the Great Lakes with a secondary low attempting to develop with the southern stream energy off the mid-Atlantic coast or across New England. Most of Sunday night looks dry, then shower chances begin to increase toward daybreak Monday and continuing into the afternoon hours. There are indications a mid-level dry slot will work its way into the region Monday afternoon as the front lifts to the north and east. This should lead to a decrease in shower chances during Monday afternoon from south to north. Pops were adjusted to highlight this potential but there may need to be adjustments in timing in later updates. Otherwise, all areas should expect at least a period of rain at some point on Monday. With the clouds and showers, high temperatures will only reach the upper 40s to mid-50s across the higher elevations to the upper 50s to lower 60s in the valleys. A few showers may linger Monday night, especially across northern and eastern areas, but it will again depend on the strength and location of the mid-level dry slot. Otherwise, cooler air will begin to advect into the region. Low temperatures will drop into the 30s to lower 40s. && .LONG TERM /TUESDAY THROUGH SATURDAY/... Large-scale pattern change possible in the medium range. Driven by modest -NAO/negative North Atlantic Oscillation and +PNA/Positive Pacific North American Oscillation anomalies, the extended starts off with an amplified large-scale pattern featuring anomalous ridging over the western CONUS and anomalous troughing over the eastern CONUS. This will feature a warm West U.S. vs. a cool East U.S. setup. However, global computer models and ensembles (GEFS/ECE/CMC) are signaling at the potential for a major, large-scale pattern flip that will feature troughing over the western CONUS and ridging over the eastern CONUS (cool West US vs. mild/warm East US). What this means for us locally is a cool start with below normal temperatures moderating closer to normal levels by the end of the period. As far as precipitation, most of the forecast area will remain precipitation-free. The only real exception will be areas northwest of Albany, specifically Herkimer/Hamilton Counties that could be affected by lake effect rain/snow showers Tuesday night through Wednesday night. We start off the long-term period on Tuesday with an anomalously strong mid to upper low over the Great Lakes Region. The NAEFS Tuesday-Tuesday night are depicting H500 anomalies on the order of 3-4 STDEVs below normal. During this time period, near the surface, the forecast area will be placed within the cold sector and dry slot of this storm system with the cold front and primary precipitation shield/axis displaced to our east, and a vertically-stacked, cut-off low positioned to our west/northwest over southeastern Ontario. That said, Tuesday should feature mainly dry conditions across the area. Tuesday night and especially on Wednesday, backing winds will continue out of the west-southwest with continued cold air advection (CAA). Backing winds along the long axis of the eastern Great Lakes (i.e. Erie and Ontario) coupled with cold air aloft with H850 temps between -2C to -5C over surface lake waters around 15C will result in a lake effect response in the form of lake effect rain/snow showers as the aforementioned cut-low spins over the eastern Great Lakes. The greatest confidence in lake effect rain/snow showers is northwest of Albany, specifically Herkimer/Hamilton Counties Tuesday night through Wednesday. The remainder of the area should remain dry thanks to a building surface high to our south. Wednesday night into Thursday, lake effect rain/snow showers will wane over our northwestern sections (Herkimer/Hamilton Counties) as the aforementioned cut-off/vertically stacked low retreats to the north into Canada and weakens. Dry conditions should continue during this time period with the area on the northern flank of an elongated surface high pressure system. Tuesday into Thursday, given the synoptic setup, there will be a cloud coverage gradient over the area with cloudy to mostly cloudy skies northwest of the Capital Region and mostly sunny skies southeast of the Capital Region. Thursday night into the weekend or through the remainder of the extended, conditions will remain quiescent with the surface high pressure system taking a stronger hold over the region. Overall, temperature anomalies will be Autumn-like starting off below normal before trending closer to normal levels by the end of the period. High temperatures will be in the low to mid 50s along the river valleys Tuesday through Thursday (40s higher elevations with pockets of mid to upper 30s over the highest peaks of the Adirondacks). Temperatures will then moderate some with highs projected in the upper 50s to lower 60s Friday along the river valleys (50s and pockets of 40s higher elevations) and lower 60s Saturday along the river valleys (50s higher elevations). Overnight low temperatures are expected to start off in the 30s most areas with pockets of 20s higher elevations Tuesday night through Thursday night before moderating to the lower 40s along the river valleys and mid to upper 30s higher elevations. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... Through 06z Monday...As of AM, all terminals are experiencing VFR conditions with limited cloud cover and light westerly winds of magnitudes less than 10 kt. VFR conditions are expected to be maintained throughout the TAF period until 06z Monday, though KGFL could enter into IFR conditions for a short time should cloud cover remain clear to relatively low and winds reduce to calm or near calm. A cold front has passed through the region over the last couple of hours, causing winds to shift to out of the west. Some mid and low clouds have and are continuing to develop as a result of the front, but cloud cover is expected to remain on the order of FEW-BKN throughout the course of the morning until after sunrise. There is a bit of uncertainty surrounding cloud cover during this TAF cycle. Models seem to be divided in their guidance for cloud cover with the GFS being a bit more aggressive than the NAM and NAM 3km. However, the trend at KGFL/KALB/KPSF seems to be an increase in cloud cover until after around 20z when a decrease can start to be seen. KPOU on the other hand is expected to observe an increase in cloud cover from FEW to BKN and then maintaining that coverage for much of the TAF period. KPSF looks to get the cloudiest, having a period of OVC between 16z and 21z. At the time of TAF issuance, KGFL is showing an observation of SKC for cloud cover. Because there is some uncertainty surrounding when clouds are expected to increase, there is a possibility that KGFL could experience a brief reduction in visibility due to fog. This will be especially possible should winds reduce in magnitude as they are predicted to at this time. To account for this possibility, a TEMPO group has been added to the KGFL TAF between 11z and 14z when fog is most probable to be seen should the aforementioned conditions be fulfilled. Winds are expected to be light and variable and light and out of the west/northwest through 06z Monday. Wind magnitude is not expected to exceed 5kt. Outlook... Sunday Night: Moderate Operational Impact. Chance of SHRA. Monday: High Operational Impact. Likely SHRA. Monday Night: Moderate Operational Impact. Chance of SHRA. Tuesday: Low Operational Impact. Slight Chance of SHRA. Tuesday Night: No Operational Impact. NO SIG WX. Wednesday: Low Operational Impact. Slight Chance of SHRA. Wednesday Night: No Operational Impact. NO SIG WX. Thursday: No Operational Impact. NO SIG WX. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. MA...None. VT...None. && $$ SYNOPSIS...Rathbun/Speciale NEAR TERM...Frugis SHORT TERM...Rathbun LONG TERM...Evbuoma AVIATION...Gant