Area Forecast Discussion
Issued by NWS Albany, NY
Issued by NWS Albany, NY
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682 FXUS61 KALY 070708 AFDALY AREA FORECAST DISCUSSION National Weather Service Albany NY 308 AM EDT Fri Jun 7 2024 .SYNOPSIS... Morning sunshine fades behind increasing clouds as a closed low moves overhead resulting in additional areas of showers and perhaps a few thunderstorms. Even cooler, breezy, and mostly cloudy conditions return for Saturday with some enhanced lake effect and scattered diurnal driven rain showers. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... Isolated shower tracking into the western Mohawk Valley that will affect a small part of the southern Adirondacks through daybreak. Another shower in the mid Hudson Valley that will track into and through NW CT through daybreak. Otherwise, some areas of clearing outside of the showers and a zone of clouds in the Hudson Valley associated with one more stage of the gradual cold advection, moving east through daybreak. Some patchy fog is expected in areas that see some of the clearing. Lows in the 50s to around. && .SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY NIGHT/... For Friday, our closed low finally pushes eastward towards Eastern NY with the leading edge of the cold pool pushing into the area by 15 UTC or so. Morning sun will fade behind increasing clouds as the mid-level moisture spills overhead. Scattered showers develop along the leading edge of the intruding cold pool and mid-level moisture and sfc cold front by 15 - 18 UTC for areas mainly north and west of the Capital District. Forecast soundings show we will have a very shallow boundary layer under the cold pool with equilibrium levels only around 15kft or so. This will shrink our CAPE potential and lead to very shallow low-level convection. Thus, we do expect any severe weather but a few lightning strikes are likely as up to around 500 J/kg of CAPE develop. Some small hail is also not ruled out as wet-bulb zero heights drop under 10kft. Winds shift to the northwest behind the leading edge of the cold in the afternoon leading to slightly breezy conditions as wind becomes sustained 10-15kts and gusts up to 20-25kts. Scattered showers and possible storms spread south and east of Albany by 21 UTC and expand into western New England as the cold front shifts southeastward. Given the delayed onset of showers/storms, temperatures here will have a better chance of reaching into the low 80s. With dew points only in the 50s, it will feel much less humid as well. Areas north/west of the Capital District should be cooler only reaching into the low to mid 70s with 60s in the southern Adirondacks. Skies turn partly to mostly clear tomorrow night with areas south of I-90 becoming mainly clear. With overnight lows cooling into the low to mid 50s and dew points also dropping into the 50s, it will feel much more comfortable Friday night. The southern Adirondacks and southern Greens drop even cooler into the 40s. With a westerly wind fetch continuing off the lakes and cool air advection ongoing, some lake enhanced showers likely generate off Lake Ontario into the western Adirondacks. Maintained likely POPs in northern Herkimer County and high end chance in northern Hamilton given this potential. Some scattered lake enhanced showers may spill into the Upper Hudson Valley and southern VT. Our very broad upper level low remains straddled across southern Canada into the Great Lakes for Saturday. As the initial shortwave trough rotating around the low exits into the Canadian Maritimes, subsidence in its wake builds over much of the Northeast. While this reduces forcing for ascent aloft, the cold pool remains overhead and will support diurnally driven showers, especially north of I-90 closer to the cold pool. Westerly flow remains strong throughout the column which will support a continued fetch off the lakes and generate lake enhanced showers off Lake Ontario that extend into the Upper Hudson Valley at times. The cold pool will also support mostly cloudy skies and cooler temperatures that struggle to rise out of the low to mid 70s for much of the area. A tight pressure gradient in the wake of Friday`s cold front will also keep west to northwesterly winds rather breezy on Saturday. Sustained winds range 10 to 15kts and gusts up to 25-30kts, strongest winds will likely be down the Mohawk Valley, Capital District into western New England thanks to channeled flow. The breezy winds will make it feel even cooler on Saturday. The cold pool aloft will keep chance POPs in play (especially north of I -90) thanks to isolated to scattered diurnally driven showers developing. Areas south of the interstate should have drier conditions with the mid-Hudson Valley and NW CT mainly dry. Thunderstorms appear unlikely. The first half of Saturday night starts dry as we lose daytime heating with temperatures cooling into the 50s once again. Clouds quickly increase after Midnight as a potent shortwave trough rotating around our parent closed low and attendant sfc cold front tracks south and eastward through eastern NY towards western New England. Another area of rain likely develops in Western and Central NY and overspreads into areas west of the Hudson River before sunrise. Given ongoing uncertainty on exact timing and coverage, we have widespread chance POPS throughout the region from 06 - 12 UTC Sunday but may trim it back to focus on western areas in future updates. && .LONG TERM /SUNDAY THROUGH THURSDAY/... Long term period begins at 12z Sunday with the broad upper low located in southeastern Canada. An upper shortwave will rotate around the periphery of the upper low Sunday, bringing increased chances for showers and perhaps a few rumbles of thunder, especially in the afternoon. An associated weak cold frontal boundary will also help to increase coverage of showers during the afternoon. Coverage of showers should diminish overnight with the loss of daytime heating. Highs will be mainly in the 60s (high terrain) to 70s (valleys) with overnight lows in the 40s (terrain) to 50s (valleys). Monday, the upper low pulls away further to the east, although a piece of the upper low will break off and linger over our region as an upper trough. This will result in continued chances for a few afternoon showers and perhaps a rumble of thunder, although coverage of showers and storms will be less than on Sunday. Temperatures will be similar to those on Sunday for both daytime highs and overnight lows. Tuesday through Thursday...Upper ridging builds overhead Tuesday as the upper low finally departs from our region. This should result in a much drier day Tuesday, although a rogue afternoon showers till can`t completely be ruled out especially if the upper low is a little slower to depart than currently expected. Forecast confidence decreases for the Wednesday into Thursday timeframe, as most sources of guidance keeps us dry through Wednesday, although upper troughing will be approaching from the west and could bring increased chances for showers Wednesday night or Thursday. We will continue to refine the forecast in the coming days as we get a better handle on the timing and evolution of this approaching trough. Temperatures Tuesday will be a couple degrees warmer than on Monday. Wednesday, temperatures may climb to around 80 for valley areas, with mid 80s possible Thursday. Overnight lows also trend warmer, from 40s to 50s Tuesday night to 50s to around 60s for Wednesday and Thursday nights. && .AVIATION /07Z FRIDAY THROUGH TUESDAY/... As of 145 AM EDT, small cluster of heavy showers will be crossing KPOU over the next 20-40 minutes. Brief period of MVFR/IFR Vsbys possible with heavy rain. Otherwise, ground fog will be main issue through sunrise at KGFL, KPSF and KPOU. Periods of IFR/LIFR are expected through 11Z at these locations, though there could be a few brief improvements through 08Z/Fri. At KALB, although overall chances for fog are slightly less, can not rule out a brief period of MVFR/IFR Vsbys/Cigs around 10Z/Fri. Any low clouds/fog should lift between 10Z-12Z/Fri, with VFR conditions then prevailing. Isolated to scattered rain showers will develop this afternoon, and could result in brief periods of MVFR Vsbys, perhaps even a few minutes of IFR. A few rumbles of thunder could accompany any heavier showers. Showers should taper off between 22Z/Fri-02Z/Sat, with clouds persisting with Cigs of 5000-7000 FT AGL. Light/variable to calm winds through daybreak will become southwest at 4-8 KT by mid morning, then west to southwest at 5-10 KT this afternoon and evening. Winds will be stronger, and variable in direction in and near any heavier showers. Outlook... Friday Night: Low Operational Impact. Slight Chance of SHRA...TSRA. Saturday: Low Operational Impact. Breezy. Isolated SHRA. Saturday Night: Moderate Operational Impact. Scattered SHRA. Sunday: Moderate Operational Impact. Breezy. Chance of SHRA...TSRA. Sunday Night: No Operational Impact. NO SIG WX. Monday: Moderate Operational Impact. Chance of SHRA. Monday Night: No Operational Impact. NO SIG WX. Tuesday: Low Operational Impact. Slight Chance of SHRA. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. MA...None. VT...None. && $$ SYNOPSIS...NAS NEAR TERM...NAS/Wasula SHORT TERM...Speciale LONG TERM...Main AVIATION...KL