Weather Alerts For Grand Teton Natl Park, WY

There is a Marginal 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 A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE SOUTHERN HIGH PLAINS SUMMARY Scattered thunderstorms producing hail and strong wind gusts are possible across portions of the southern High Plains this afternoon and evening. More isolated strong to severe thunderstorms are expected across parts of the central Rockies, central Plains, upper Mississippi Valley, and portions of the California coast. Southern High Plains Thunderstorm development is likely by mid/late-afternoon across southwest Texas and eastern New Mexico as increase forcing for ascent overspreads modest but increasing low-level moisture. Initially discrete cells are likely and will pose a threat for large hail given adequate deep-layer wind shear /generally 30-40 kt/. However, weak capping and strong ascent should promote upscale growth by early evening into several linear clusters. As this transition occurs, strong to severe wind gust potential will increase and become the predominant hazard, though an embedded circulation or two may occur with a tornado possible. Central Plains to the Upper Mississippi Valley Low-level warm air advection will likely become increasingly focused through the day and into the overnight hours from the central Plains into the upper Mississippi Valley. 850 mb winds are forecast to steadily strengthen to 40-60 kt by this evening and will support moistening in the lowest 1-2 km under a plume of 7-7.5 C/km mid-level lapse rates. Forecast soundings suggest that this environment will be weakly capped and should support isolated to widely scattered thunderstorms during the afternoon hours across the central Plains before spreading/re-developing northeastward into the upper Mississippi Valley late tonight. While deep-layer wind shear will not be overly strong (around 30 kt), it should be sufficient for a few organized cells capable of severe hail. A more conditional supercell potential may materialize by mid/late afternoon through early evening across portions of the middle/lower Missouri Valley near/just south of the northward-shifting surface warm front, which may augmented by residual cloud cover/weakening storms across northeast Kansas/far southeast Nebraska in the pre-dawn hours. Forecast soundings from this region suggest a weakly capped, but moderately buoyant airmass, with notably strong low-level/deep-layer wind profiles that would conditionally support supercells including some tornado risk. Central/northern Rockies A northeast-ejecting shortwave trough, along with steep mid-level lapse rates and modest mid-level moisture, will likely support additional thunderstorms across the central to northern Rockies this afternoon as diurnal heating occurs. A combination of modest deep-layer wind shear and well-mixed boundary layers will support potential for strong to severe downburst winds. Northern/central California Coast A progressive upper wave will continue eastward and reach the northern California coast tonight. As this occurs, ascent within the left-exit region of an attendant upper jet, coupled with cool mid-level temperatures near the center of the upper low, will support isolated thunderstorms across northern/central California. Winds within the lowest 1-2 km AGL should increase to around 40 kt as the wave moves onshore, which will contribute to the potential for convective downdrafts to produce a few locally damaging wind gusts.

Pollen Index: 9.7 Pollen Level: high Predominant Pollen: Cedar/Juniper, Poplar/Aspen/Cottonwood and Ash. Concentration of pollen grains in the air for Sunday will be unchanged in the high range. Constant and seasonally normal weather conditions tend to stabilize pollen concentrations in the outdoor air.