Strong to Severe Thunderstorms Possible Today

The National Weather Service
Building a Weather-Ready Nation


Summary | Forecast | Monitoring & Reporting | Safety

Strong to severe thunderstorms will be possible this afternoon and evening, primarily across Johnson and Natrona counties. The primary threats with these storms will be large hail (greater than 1 inch in diameter) and severe wind gusts over 60 MPH. Frequent lightning and heavy rain is also expected with thises storms. Multiple storms passing over the same area could increase the threat of local flooding.

Elsewhere across western and central Wyoming, isolated to scattered showers and thunderstorms will develop today. Brief heavy rain, smaller hail, gusty winds, and dangerous lightning will be the primary threats. 

Monsoonal moisture surging northward from the southwest will combine with low-level moisture moving in from the east and a disturbance moving across the area (see animation below) to bring the potential for strong to severe thunderstorms across Johnson and Natrona counties. Storms are expected to move northeast at 20-30 MPH. In addition the Storm Prediction Center (SPC) has updated its Day 1 Outlook to included much of Johnson and Natrona Counties. See the two graphics below for additional information.

PRIMARY THREATS

  • Large Hail (> 1" diameter)
  • Damaging Wind Gusts (> 60 MPH)
  • Frequent Dangerous Lightning
  • Heavy Rain (multiple storms could cause local flooding)

Please see the Monitoring & Reporting section below for storm monitoring and reporting information.

Monsoonal Moisure and Disturbaces

CLICK IMAGE TO ENLARGE
In the left panel you will see the upper-level pressure pattern (highs and lows) in contours and mid-level moisture in colors (wamer colors = more moisture). In the right panel you will see the same upper-level pressure pattern and the disturbances highlighted in the grays, whites, and blues.

Loop runs from 6PM Wednesday through 6PM Saturday.

CLICK IMAGE TO ENLARGE
Strong/Severe thunderstorm potential is maximized when instability, moisture, lift, and shear are high. Comparing the four panels here, you can see that the area of greatest overlap of these ingredients is within Johnson and Natrona counties.

This graphic shows the forecast for 6PM this evening of the 4 primary ingredients for the creation of strong to severe thunderstorms.

-In the upper left panel is a measure of instability (warmer colors mean greater instability).
-In the upper right panel is the dewpoint termperature (darker blues & purples mean greater moisture).
-In the lower left panel is the 12-hr change in 500mb height, which is a measure of the potential lifting (lighter greys indicated greater lifting). Mean storm motion is indicated by the blue arrows.
-In the lower right panel is the 0-6km wind shear (lighter blues and greens indicate greater shear).

 

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