FXUS61 KALY 221754 AFDALY Area Forecast Discussion National Weather Service Albany NY 154 PM EDT Sat Aug 22 2026 .WHAT HAS CHANGED... SPC expanded the Marginal Risk for isolated severe weather (level 1 of 5) on Sunday to now cover most of eastern NY and western New England. WPC removed the marginal risk for excessive rainfall (level 1 of 4) for Saturday. && .KEY MESSAGES... 1) After a dry Saturday, areas of showers and thunderstorms arrive late tonight into Sunday A.M with showers and storms returning Sunday P.M. There is a marginal risk (level 1 of 5) for isolated severe thunderstorms across much of eastern NY and western New England Sunday P.M. 2) Isolated to scattered showers and thunderstorms continue Monday and Tuesday, especially near and north of I-90, with temperatures remaining slightly cooler than normal. && .DISCUSSION... KEY MESSAGE 1... Broad troughing continues developing over the Upper Great Plains into the Great Lakes today while the Northeast remains on the west side of large scale ridging over the western Atlantic. While height falls creep into western NY today, eastern NY and western New England remains under the influence of weak subsidence, keeping us dry. Tonight, our upstream trough over the Great Lakes amplifies and digs into the Ohio Valley as two shortwaves phase together with the parent cyclone taking on a negative tilt. This results in strengthening upper level diffluence over the mid-Atlantic as a warm front lifts northward with a weak sfc low developing along the boundary. Meanwhile, strengthening southwest flow aloft will also allow moisture to advect into the Northeast with PWATs rising over 1.50". Chances for showers and even a slight chance for thunderstorms increases from southwest to northeast 06 - 12 UTC Sunday as the front approaches. Guidance continues to hint that the weak sfc low will aid in a more organized area of rain/embedded storms. As mentioned in the previous discussion, the latest probabilistic guidance from the HREF continues to show potential for moderate to heavy rain late tonight into Sunday morning with a 50 - 75% chance for over 0.50" of rain 09 to 15 UTC Sun and even a 25-50% chance for over 1" of rain. However, our recent dry stretch will likely limit flooding and WPC removed the marginal risk for excessive rainfall. After this initial A.M period of rain/storms, we should have a brief break before an occluded front and stronger height falls from the closed parent low over the eastern Great lakes arrive. There remain uncertainties regarding how much instability can develop. While there will be plenty of low- level moisture, morning clouds may struggle to break for sun during the small window before the occluded front arrives Sun P.M. Even still, mid-level dry air and cooler temperatures aloft wrap eastward as the parent cyclone matures, helping to steepen lapse rates with forecast soundings showing "tall- skinny" CAPE developing. Given the high humidity, even limited insolation will contribute to sufficient instability and help generate low- topped convection. While 0-6km shear is rather impressive ranging 40-50kts, 0-3km shear only ranges 20-30kts. Should weak instability keep convection low-topped, storms will not tap into the stronger deep layer shear, decreasing the severe weather potential. SPC expanded the marginal risk (level 1 of 5) for isolated severe weather to now cover much of eastern NY and western New England given persistent forcing ahead of the parent cyclone; however, weak instability/shear are listed as reasons will severe weather may be limited. Main concerns are damaging winds from any severe weather with a linear storm mode favored as shear vectors remain parallel to the boundary. KEY MESSAGE 2... The vertically stack closed low and associated cold pool in the eastern Great Lakes slowly advances eastward Monday into Tuesday supporting slightly cooler than normal temperatures and continued moist cyclonic flow aloft. Coverage of showers and even low- topped convection increases Monday afternoon, especially near/north of I-90, as additional shortwaves rotate around the base of the closed low. Given the cool pool aloft, it likely will not take much upscale growth before lightning occurs with even small hail possible from any taller storms. As winds aloft becoming westerly, a weak lake effect signal looks to develop downstream of Lake Ontario, supporting steadier periods of rain directed into the western Adirondacks and Mohawk Valley Monday P.M into Monday night. Unsettled conditions continue into Tuesday with additional diurnally driven showers again mainly near/north of I-90 but shower coverage should be lower than Monday as the parent cyclone slowly exits into New England. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... Through 18z/Sunday...VFR conditions remain through the afternoon across the terminals before ceilings begin to lower to MVFR this evening due to an approaching frontal system. MVFR ceilings will continue overnight at all of the terminals along with the possibility of fog/mist developing at KGFL and KPSF near sunrise. CAMs also suggest rain showers arriving between about 08z to 13z from the west lowering ceilings and visibilities to MVFR. After sunrise, model soundings continue to show low stratus persisting into the late morning maintaining MVFR ceilings and even lowering to IFR/LIFR for periods through the end of the TAF period. Additional chances of steadier rain showers and isolated thunderstorms through the end of the TAF period could lower flight conditions to MVFR/IFR, but confidence will increase with following TAF cycles. Winds through the TAF period will prevail out of the southeast with speeds this afternoon 5-10 kt becoming 5 kt or less overnight. Winds tomorrow generally range 5-10 kt, however stronger gusts around 25 kt could accompany any thunderstorms that develops. Outlook... Sunday Night: Low Operational Impact. Slight Chance of SHRA...FG. Monday: Moderate Operational Impact. Chance of SHRA...TSRA. Monday Night: No Operational Impact. NO SIG WX. Tuesday: Low Operational Impact. Breezy. Slight Chance of SHRA...TSRA. Tuesday Night: No Operational Impact. NO SIG WX. Wednesday: No Operational Impact. NO SIG WX. Wednesday Night: No Operational Impact. NO SIG WX. Thursday: Moderate Operational Impact. Chance of SHRA...TSRA. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. MA...None. VT...None. && $$ DISCUSSION...24/31 AVIATION...53