Severe Storm Risk - Atlantic, IA

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 FROM PARTS OF THE CENTRAL PLAINS INTO THE MID MISSOURI AND UPPER MISSISSIPPI VALLEYS SUMMARY Thunderstorms with severe wind gusts and hail will be possible this evening from parts of the central Plains into the mid Missouri and upper Mississippi Valleys. Isolated severe gusts may also occur in parts of the northern High Plains, in eastern North Carolina, and in southeast Arizona. Central Plains/Mid Missouri and Upper Mississippi Valleys At mid-levels, a subtle shortwave trough is evident on water vapor imagery over the central High Plains. Ahead of this feature, a moist airmass is located from the central Plains into upper Mississippi Valley, where surface dewpoints range from the 60s F west to the lower to mid 70s F east. A front is located from southern Nebraska east-northeastward into central and northeast Iowa, where low-level convergence is maximized and scattered strong to severe thunderstorms are ongoing. Ahead of the front, the RAP has an axis of moderate instability with MLCAPE from 2000 to 3500 J/kg. The instability, combined with moderate deep-layer shear and steep low to mid-level lapse rates, will support a threat for severe wind gusts and hail. The threat will be concentrated along and just ahead of the more intense short line segments. Further west into the central High Plains, a surface trough is located from western Kansas extending northwestward into southwest Nebraska. Low-level convergence is maximized further west into eastern Colorado and southeast Wyoming, where an outflow boundary is located and a broken line segment is ongoing. Ahead of the storms, winds are backed to the east and surface dewpoints are in the mid to upper 50s F. This is contributing to moderate instability. In addition, the WSR-88D VWP at Denver has 40 knots of 0-6 km shear, suggesting that supercells and organized line segments will be possible. The RAP also shows 0-3 km lapse rates exceeding 7.5 C/km. This environment will support a potential for severe wind gusts this evening. A swath of wind damage will be possible across eastern Colorado, northwest Kansas and southern Nebraska, once a more sustained cold pool becomes established. Northern High Plains/Intermountain West A mid-level shortwave ridge will move through the northern High Plains this evening. Beneath the ridge, a pocket of moderate instability is located across central and northeast Montana where the RAP has MLCAPE in the 2000 to 3500 J/kg range. To the southwest of the instability max, thunderstorms are developing in the higher terrain of central Montana. These storms will move eastward into the stronger instability. Moderate deep-layer shear and steep mid-level lapse rates will support an isolated threat for severe wind gusts. Eastern North Carolina A very moist airmass is located over eastern North Carolina, where surface dewpoints are in the lower to mid 70s F, and the RAP has a pocket of moderate instability (MLCAPE of 2000 to 3000 J/kg). Scattered thunderstorms have developed near this pocket of instability. Low-level lapse rates will remain steep for a couple more hours suggesting potential for isolated severe gusts. Southeast Arizona The latest RAP has an south-to-north axis of instability analyzed across southeast Arizona. Near this axis, low-level convergence is maximized and 0-3 km lapse rates are very steep. Thunderstorms that develop near this axis of instability may produce a few severe wind gusts early this evening.