Weather Alerts For Rensselaerville, NY

There is a Slight Severe Storm Risk for your location. Continue reading for today's outlook from the National Weather Service's Storm Prediction Center. -------------------- National Severe Storm Outlook THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE MIDWEST/SOUTHERN GREAT LAKES AND SOUTHERN/CENTRAL PLAINS THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHEAST SUMMARY Severe thunderstorms are expected this afternoon through tonight from the southern Plains into the Midwest. Large to giant hail, several tornadoes (some strong), and swaths of severe/damaging gusts are all likely, particularly from Iowa into the southern Great Lakes. Synopsis An active severe weather day is anticipated for much of the southern/central Plains into the Midwest/Great Lakes and parts of the Northeast. The primary upper trough centered over the Four Corners late this morning will eject east-northeastward towards the southern/central Plains by this evening, while a separate mid-level shortwave trough over the northern Plains/Upper Midwest will also move east-northeastward across the Upper Great Lakes into Ontario. Another convectively enhanced low-amplitude shortwave trough will also develop eastward across the Lower Great Lakes into the Northeast. Recent surface analysis indicates multiple surface lows, with one over southern Ontario and another over southeast NE/northeast KS. A seasonably rich/moist low-level airmass exists to the south of a front extending between these two lows, with surface dewpoints already in the low to mid 60s across much of the southern/central Plains to the east of a dryline. Both the dryline in the southern/central Plains and developing warm front in the Midwest/southern Great Lakes will likely serve as foci for intense thunderstorms this afternoon and evening, including the potential for several supercells. Midwest/Ohio Valley/Great Lakes A complex scenario for severe thunderstorms remains apparent across the Midwest/OH Valley into the southern Great Lakes today, with multiple outflow boundaries from earlier convection rendering greater than usual uncertainty with the southward extent of possible thunderstorm development in IL/IN/OH. In general, continued low-level warm advection from the central Plains into the Midwest/OH Valley will support a moistening/destabilizing airmass through the afternoon as a northern-stream shortwave trough moves eastward across the Upper Midwest. A surface warm front will extend northeastward from a weak surface low in IA across southern WI and Lower MI. It still appears likely that multiple intense supercells will develop by 20-21Z along/near this boundary in IA/southern WI/northern IL in a very favorable airmass for significant severe hail given strong deep-layer shear and the presence of steep mid-level lapse rates. Low-level shear is expected to gradually strengthen through the evening in tandem with a modestly increasing south-southwesterly low-level jet. Any supercells than can remain on the warm/south side of the front will be capable of producing tornadoes, a few of which could be strong (EF-2/3). Some consideration was given to including greater tornado probabilities and a Moderate Risk (level 4 of 5) focused across southern WI/far northern IL. But, convection may have a tendency to grow upscale fairly quickly this evening, so confidence was not high enough for a categorical upgrade at this time. Regardless, very large to giant hail (potentially up to 3-4 inches in diameter) will be a threat with sustained supercells, and a swath of severe/damaging winds appears likely with a convective cluster spreading eastward across southern Lower MI this evening into tonight. A somewhat separate area of severe potential should also exist farther south across central IL into IN/OH this afternoon and evening. Greater low-level moisture and related instability are expected to exist across these areas compared to locations farther north. While large-scale forcing should remain fairly weak/nebulous across this region, a remnant outflow boundary may provide a focus for supercell development across central IL into IN by 20-21Z. Have expanded the Slight Risk for large hail, damaging winds, and perhaps a few tornadoes southward across these areas to account for this still somewhat uncertain potential. Southern/Central Plains 12Z observed soundings from DRT/MAF/FWD/OUN/TOP show the presence of steep mid-level lapse rates atop rich low-level moisture (generally 14-15 g/kg mean mixing ratios) along/east of the surface dryline. Southwesterly mid-level flow and modest ascent preceding the upper trough over the Southwest/southern Rockies will gradually overspread the warm sector by mid to late afternoon. Moderate to strong instability (MLCAPE around 2000-3000 J/kg, locally stronger possible) and 35-45 kt of deep-layer shear will support multiple intense supercells. Explosive convective initiation across parts of western OK into south-central/southeast KS is expected by 20-21Z as lingering MLCIN erodes with filtered daytime heating and as convective temperatures are breached. The overall thermodynamic and kinematic environment appears quite favorable for very large to potentially giant hail (up to 3-4 inches in diameter) with any supercells that spread east-northeastward through the afternoon/evening. A gradually strengthening low-level jet across OK/KS by 00Z will also support a threat for a few tornadoes, a couple of which could be strong as low-level hodographs become enlarged. Gradual upscale growth/clustering should occur with time through the evening, with some risk for severe/damaging winds. The Enhanced Risk has been expanded a bit northeastward into south-central/southeast KS for a focused severe wind corridor. Farther south along the length of the dryline in TX, isolated to scattered supercells may develop this afternoon and evening, with a risk for mainly large to very large hail and occasional severe gusts. Northeast Ongoing convection across southern Ontario and the Lower Great Lakes will continue to track eastward this afternoon into NY and parts of New England in tandem with a low-amplitude shortwave trough. Gradual clearing of low/mid-level clouds has already encouraged surface temperatures to warm into the 70s along/south of west-east oriented front. Thunderstorms are expected to gradually increase in coverage and intensity as weak to locally moderate instability and strong deep-layer shear support organized updrafts, including the potential for some supercells initially. The greatest severe risk will probably be scattered damaging winds given a tendency for convection to consolidate into one or more clusters. But, an isolated severe hail threat may exist with any sustained supercell, along with some chance for a tornado or two near the front where low-level shear will be locally enhanced.

Pollen Index: 9.2 Pollen Level: medium-high Predominant Pollen: Maple, Elm and Alder. Concentration of pollen grains in the air for Wednesday will be unchanged in the high range. Constant and seasonally normal weather conditions tend to stabilize pollen concentrations in the outdoor air.