
Severe Threats to Hit Tornado Alley, Upper Midwest
Severe storms are set to rumble from the Texas Panhandle to Lake Superior today.
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 PARTS OF THE CENTRAL/SOUTHERN PLAINS...AND EASTERN MINNESOTA INTO NORTHWEST WISCONSIN SUMMARY Scattered severe thunderstorms are likely across parts of the central/southern Plains this afternoon and evening, and also possible across portions of the upper Mississippi Valley. Severe wind gusts and large hail are the primary hazards. Central/Southern Plains Between upper ridging centered over the Southwest and a shortwave trough over south-central Canada, the large-scale pattern across the central/southern Plains will undergo modest amplification, with a resultant increase in northwesterly flow aloft by late today into tonight. A surface cold front will also move southeastward across the central High Plains. Ongoing convection notwithstanding, this front will intercept a moist and unstable airmass into parts of western/central NE, which will likely aid additional thunderstorm development by mid to late afternoon. An orographically influenced increase in thunderstorms is also expected along the Raton Mesa/Front Range regions. With gradually strengthening northwesterlies aloft through the afternoon, effective bulk shear across NE and western KS will generally reach 30-40 kt. This region will exist on the eastern periphery of a stout EML, which should support some initial supercells capable of large hail, most probable across western/southern NE into northern/western KS. Influenced by the front and aggregating outflow, one or more southeastward-moving clusters capable of producing severe gusts (some 75+ mph) and wind damage should evolve this evening across southern NE into KS. Farther south, a similar upscale-growing trend will probably also occur with high-based thunderstorms developing off the Raton Mesa vicinity into the OK/TX Panhandles, and perhaps eventually western OK. Even though mid-level winds and deep-layer shear will remain more modest with southward extent into these areas, a favorable thermodynamic environment with rather steep low/mid-level lapse rates should support isolated to scattered severe/damaging winds spreading east-southeastward through the evening with this convection. Eastern Minnesota/Western Wisconsin/Western Upper Michigan A mid-level shortwave trough (and related mid/high-level westerly jet) will dig southeastward from southern Manitoba toward northern MN and Lake Superior through the period. Ongoing morning convection and cloud cover may curb destabilization to some extent, and keep the surface warm sector relatively narrow this afternoon. Even so, strong to severe thunderstorm development should still occur near an eastward-advancing cold front by mid/late afternoon. Diurnal heating of a moist low-level airmass (generally 60s surface dewpoints) will contribute to a narrow zone of around 1000-2000 J/kg MLCAPE across the eastern half of MN/far northwest WI ahead of the front by late afternoon. Some supercells will be possible initially, aside from more prevalent multicells/clusters. Large hail and damaging winds are expected to be the primary hazards as convection tracks eastward through the evening, before weakening commences with the onset of nocturnal cooling. Southeast While mid-level flow and related deep-layer shear are expected to remain weak, a moist and moderately unstable airmass will exist along/south of a stalled front across the Southeast today. As low-level lapse rates gradually steepen through the afternoon, isolated pulse-type thunderstorms capable of producing water-loaded downdrafts and occasional wind damage may occur. This currently appears most probable across parts of coastal SC into southern GA and northern FL, although some gusty thunderstorm winds may also occur across parts of the central Gulf Coast, such as southern LA.
Pollen Index: 10.1 Pollen Level: high Predominant Pollen: Ragweed, Nettle and Hemp. Based on past pollen counts and expected weather conditions, pollen levels for Wednesday will be on the increase and extend further into the very high range. This is likely to be caused in part by higher temperatures and the lower dewpoint.












