Area Forecast Discussion
Issued by NWS Albany, NY
Issued by NWS Albany, NY
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127 FXUS61 KALY 260606 AFDALY AREA FORECAST DISCUSSION National Weather Service Albany NY 206 AM EDT Wed Jun 26 2024 .SYNOPSIS... After a few light early showers mainly north of Albany, clouds give way to sunny, warm, and slightly breezy conditions today. A period of moderate to heavy rain and embedded thunderstorms overspread the region this evening along an incoming cold front. Storms south of Interstate 90 will be capable of producing gusty winds and heavy downpours that may result in localized flooding. Cooler and even breezier conditions arrive for Thursday as high pressure builds into the Northeast. && .NEAR TERM /THROUGH TODAY/... A mainly dry night is in store for eastern NY and western New England with mid-level clouds keeping temperatures mild in the 70s. Regional radar shows a small area of rain and a few storms tracking through Lake Ontario and high res guidance suggests these showers weaken as they cross into NY but some showers look to spill into the western Adirondacks by 09 - 12 UTC so maintained chance POPs there with even slight chance POPs extending into the Upper Hudson Valley to account for a few light sprinkles early this morning before all showers end. Then, early clouds give way to mainly sunny skies as zonal flow strengthens aloft in response to an incoming potent shortwave that will amplify as it swings into the Great Lakes. A pseudo warm front/dew point boundary settles just south of I-90 this afternoon with dew points north of this boundary across the Greater Capital District, southern VT, Upper Hudson Valley, and SW Adirondacks actually only rising into the upper 50s to low 60s as a pocket of dry air in the mid-levels tracks overhead and supports deep boundary layer mixing. Not only will the deep mixing result in temperatures warming into the mid to upper 80s but westerly winds should also turn a bit breezy with gusts reaching up to 20kts at times. South of this boundary temperatures will be a bit warmer reaching into the low to mid 90s and higher dew points in the low to mid 60s will make it feel even warmer. A few pockets of heat index values reaching 95 degrees likely in the mid-Hudson Valley but not enough coverage to warrant a heat advisory. Clouds increase late this afternoon from southwest to northeast as sfc winds back to the south and warm air and moisture advection increase ahead of an approaching cold front. Guidance remains in good agreement that the majority of the incoming rain and possible thunderstorms hold off until after 21 UTC but given the strong dynamics, forcing for ascent, and moisture fetch, rain may arrive a few hours earlier than high res guidance suggests so we still introduce likely POPs for the mid- Hudson Valley, the eastern Catskills, and Litchfield County by 21 - 00 UTC. && .SHORT TERM /TONIGHT THROUGH FRIDAY/... The most active part of the period is expected to be Wed evening into Wed night, as the aforementioned upper trough/cold front track eastward across the region. A warm/moist air mass will be in place just ahead of this system. Strong forcing and sufficient moisture (PWAT anomalies of +1 to +2 STDEV) are expected to lead to numerous showers and thunderstorms. With evening into early overnight timing, the magnitude of instability looks rather limited, with SBCAPE (< 500 J/KG) across much of the area. The best overlap of just enough instability and shear for severe storms looks to be across southern portions of Ulster and Dutchess counties where there is a small area of a Slight Risk (level 2 of 5) outlook. There looks to be enough shear (0-6 km bulk shear of 40-50 kt) across the entire area for storm organization, but really only enough buoyancy to maintain sustained updrafts across these far southern counties. The main threat looks to be damaging wind gusts. The severe threat should be non-existent across the northern 2/3 of the area. There is a Marginal Risk (level 1 of 5) from Albany and the Berkshires south, which has been trimmed south compared to prior outlooks. Due to high PWATs, there will be embedded downpours which could lead urban/poor drainage flooding and isolated flash flooding where persistent or repeated downpours occur. There is a Marginal Risk (level 1 of 4) of excessive rainfall across the entire area. Showers and storms should start to taper off by ~1 to 3 AM from west to east as the disturbance and front move east. Cold advection begins late, which will result in low temperatures to drop to the mid 50s in the higher terrain to lower 60s in the Hudson Valley from around the Capital District south. Cooler/drier conditions in store for Thu, as high pressure builds eastward from the Great Lakes. There is just a low probability for a few morning showers across far northern areas. NW winds will gust to around 20-25 mph in favored areas, ushering in less humid conditions(dewpoints dropping into the 50s). High temperatures should be near normal ranging from upper 60s in the W. Adirondacks to lower 80s in the mid Hudson Valley. Thu night looks clear and cool with high pressure directly over the area. Clear skies, a dry air mass (PWAT anomalies of -1 to -2 STDEV) and light winds will lead to low temperatures below normal with 40s in the mountains to lower/mid 50s in the valleys. Dry/tranquil weather expected to persist Fri as high pressure shifts eastward into New England during the day. Highs may be a degree or two warmer than Thu, but overall temperatures will be near normal with continued low humidity levels. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... Active weather looks to return, as a warm front lifts northward across the region Fri night into early Sat, followed by a cold front passage Sat night into early Sun. Parameters lining up for potential strong to severe storms and localized flash flooding threat. GEFS already indicating anomalously strong SW winds and significant deep layer moisture (850mb v-component wind and PWAT anomalies of +2 to +3 STDEV) Sat to Sat night. Depending on timing of forcing from any pre-frontal surface trough and the cold front as well any significant disturbances aloft, will have to monitor trends for possible severe and/or flash flood hazards. Will continue mention of likely PoPs late Sat through Sat night, with scattered to numerous thunderstorms expected. The cold front should clear the area on Sun, with cooler/drier air starting to gradually filter in during the afternoon as winds become NW. With temperatures aloft still fairly warm, highs could reach well into the 80s across lower elevations although humidity levels should lower by later in the day. Will linger mention of chance PoPs into the day due to account for possible slower timing of the cold front passage and will refine further once the weekend gets closer. Good model consensus for a large area of high pressure building in early next week, with dry conditions, near normal temperatures and comfortable humidity levels. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... Through 06Z/Thu...VFR conditions are expected through daybreak, despite a few showers tracking southeast and affecting KGFL/KALB between 09Z-13Z/Wed as a warm front approaches. There could be borderline MVFR Cigs for a brief time between 13Z- 16Z/Wed at KALB and KPSF, otherwise mainly VFR conditions through at least mid afternoon. Later this afternoon, scattered showers/thunderstorms may develop at KPOU, with more widespread showers and thunderstorms expected after 00Z/Thu at KALB, KPOU and KPSF as a wave of low pressure tracks just south of the region. Occasional MVFR/IFR Vsbys/Cigs will be possible within any heavier showers/thunderstorms this evening. The best chance of thunderstorms will be at KPOU and KPSF, although some chance that thunderstorms reach as far north as KALB. South to southwest winds 5-10 KT with a few gusts of 15-20 KT through daybreak will then shift into the west by late morning at similar speeds/gusts. West to northwest winds will decrease to less than 5 KT toward and after sunset, although may become southeast at KPOU around 5 KT. Winds will be stronger, and variable in direction near and within any thunderstorms. Outlook... Wednesday Night: High Operational Impact. Definite SHRA...TSRA. Thursday: Low Operational Impact. Breezy. NO SIG WX. Thursday Night: No Operational Impact. NO SIG WX. Friday: No Operational Impact. NO SIG WX. Friday Night: No Operational Impact. NO SIG WX. Saturday: Moderate Operational Impact. Breezy. Likely SHRA...TSRA. Saturday Night: High Operational Impact. Likely SHRA...TSRA. Sunday: Moderate Operational Impact. Chance of SHRA...TSRA. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. MA...None. VT...None. && $$ SYNOPSIS...Speciale NEAR TERM...JPV/Rathbun/Speciale SHORT TERM...JPV LONG TERM...JPV AVIATION...Rathbun