Forecast for Wednesday, April 17, 2013

The threat for heavy rain, large hail and tornadoes (some strong) will be possible across North Texas, Oklahoma and southern Kansas during the afternoon into evening hours along the dryline.  Later Wednesday night and into Thursday morning strong to severe storms will be possible as the strong cold front makes progress southeastward.  We will continue to monitor this potentially significant weather situation.  Keep checking back to our blog for more info!

Ensure you’re prepared with iMap Weather Radio and RadarScope – available on the App Store and GooglePlay.

iMap Weather Radio on the App Store

iMap Weather Radio on Google Play

RadarScope on the App Store

RadarScope available on Google Play 

Behind the passage of the front showers are expected across most of the Southern Plains into Wednesday morning and as temperatures continue to plummet into the lower 30s and upper 20s the chance of light freezing rain, sleet, and some wet snow is possible. Winter Weather Advisories have already been issued for parts of Western and Central Oklahoma and should expand into portions of the Texas Panhandle. While accumulations appear to be light as this time any freezing precipitation could allow for slick roads, down power lines, and difficult travel conditions for Wednesday morning.

Further north heavy snow and blizzard-like conditions are expected across South Dakota, Nebraska, and Southern Minnesota into Wednesday with snow amounts up to 18 inches possible. Strong winds between 25 to 40 mph will make travel difficult to imposable at times across this region for the next 24-36 hours. Additionally, a light period of freezing rain and sleet is possible during the afternoon and early evening hours as temperatures hover around the freezing mark. Any ice that does fall, combined with the strong winds will allow for a wide area of possible power outages across this region.

This massive storm system will move eastward allowing for a good chance of severe weather expected for the Lower Mississippi Valley and the Southern US on Wednesday and Thursday and could go as far north as the Central Ohio Valley.

Stay tuned to WeatherOps this week for all the latest updates as this system continues to steadily move across the country.

One factor that will come in to play is the strength of the cap, or warm air above the surface that acts to inhibit thunderstorm development.  In order for thunderstorms to form and maintain themselves, rising of the air has to occur.  A parcel of air needs to be warmer than its surroundings in order for it to rise.  When the parcel of air encounters air that is at the same temperature or warmer it will stop rising.  The cap is usually in place around 850Mb (~5000 feet) in the atmosphere and can be “broken” by surface heating or some sort of convergence along a boundary such as a dryline.

WeatherOps Severe Weather Outlook for Sunday, April 7, 2013.

Right now it looks like the cap will break in south-central and perhaps central Kansas, which is why we have highlighted the area in red where we expect the highest chance for severe weather later today.  Further south into Oklahoma severe weather becomes more of a gamble, as strong capping looks to stay in place much of the day.  Should the cap break, a storm would be expected to become severe very quickly.  We will keep this blog updated throughout the day today, so keep checking back!

The severe weather threat will continue over the Southern Plains through the beginning of the week.  As of now, Tuesday looks to be the day with the most widespread and impactful severe weather for locations such as Kansas City, Oklahoma City and Dallas.  Keep checking back to our blog for more details!

Showers and thunderstorms are expected to continue to develop overnight and through the day on Sunday in Central and Southern Oklahoma, into North Texas and expand eastward into Arkansas.  Severe weather is not currently anticipated, though some storms could produce small hail less than 3/4 of an inch and strong wind gusts of up to 50 mph.

Scattered showers and thunderstorms along with a winter mix of rain and snow will be possible through the day in the Northern High Plains in response to the low pressure system moving north of the Great Lakes.  Heavy snow accumulations are not expected, though some areas could see up to 4 inches of snow.

To the west, scattered showers are expected to develop in California and Southern Oregon in response to the onshore flow from a low pressure system offshore.  This area of low pressure is expected to continue progressing slowly eastward through the week.  For Sunday, most showers generated should be isolated to the coastal areas.  In the Southwest, mostly sunny to partly cloudy skies are expected through the area with light winds.

WeatherOps forecast for March 31, 2013. Valid at 6:00 AM CDT

Much of the snow cover on the map valid today is thanks to a recent, fairly significant snowstorm that tracked through the central Plains and into the Midwest last weekend into early this week.  Since we are now past the vernal equinox, the sun is at a much higher angle and the days are getting much longer, most of this snow will begin to rapidly melt over the coming days.  What do WeatherOps Meteorologists think is in store for the remainder of spring?  Check out our recent Webinar for the answer!  http://ow.ly/jrE5I

Snow depth across the U.S. on March 27, 2012.

Snow depth across the U.S. on March 27, 2013.

Here’s what we’ll be covering:

• A look at severe weather episodes that occurred late this winter
• Examination of why the current ENSO (El Nino Southern Oscillation) is neutral, and determine if this will continue into spring. We’ll also take a look at the current AO (Arctic Oscillation) index and determine if this will change as we go into spring
• Update on the ongoing U.S. drought
• Temperature and Precipitation outlooks for spring
• Identification of the regions of the U.S. likely to see the greatest severe weather impacts this spring Q & A

Here’s a quick update on an ongoing winter storm progressing across the country, which is expected to impact portions of the Central U.S. and Midwest regions with significant snow through Sunday night into Monday.