HOT, Followed by SEVERE

UPDATED 5/18/13 1:00 PM CDT

Ironically, our last blog post was about how cool spring has been so far. Well, the relatively cool temperatures we have seen for the past couple of months and even the past couple of days will give way to warm, or should we say HOT, temperatures for the next few days as a ridge of high pressure dominates across the region. Then, a trough and associated cold front will push eastward across the state, bringing not only more seasonable temperatures for the start of the week but also a significant threat for severe weather from late Saturday afternoon through Tuesday. The eastward-moving trough will interact with warm air and abundant moisture surging northward from the Gulf of Mexico, providing instability in the atmosphere. We expect the severe weather to occur primarily during the late-afternoon and evening hours due to a capping inversion, the increase of temperature with height, in place during the morning hours. Once the capping inversion vanishes as the days progress, storms will begin to fire and will be quite dangerous. We will now step through the next few days one at a time to give you all the details, but first, here is a quick overview.

 

Today/Tonight
Ahead of the cold front and severe weather, high temperatures will soar across the state this afternoon due to a ridge of high pressure. We are expecting highs in the mid-to-upper-90s across western Oklahoma and the panhandle, with parts of southwest Oklahoma potentially seeing their first triple-digits of the year! In central Oklahoma, highs will be primarily in the low-90s, but for many of you farther to the east, these will be the first 90s you have seen all year. Finally, eastern Oklahoma will only see highs topping out in the mid-to-upper-80s, but even these highs are still on the warm side. Due to the warm weather, we encourage you to remember your heat safety tips. If you must be outside, wear light clothes and drink plenty of water. Most importantly, never leave children or pets unattended in a vehicle that is sitting outside in the sun!

Skies will be partly cloudy across the state this afternoon, but cloud cover will increase beginning in the late afternoon and evening hours as the severe weather threat begins to ramp up. The Storm Prediction Center currently has a slight risk issued for all of western Oklahoma central Oklahoma and a moderate risk issued for parts of western Oklahoma, mainly in the northwest. A dry line will be positioned along the Oklahoma-Texas border in western Oklahoma and slowly push eastward across the state, allowing storms to fire up in the western part of the state. Any storms that do develop will move towards the east or northeast. A TORNADO threat is now in place for today’s storms, so please be aware; the greatest risk area for tornadoes is shaded in red on the graphic above. Overall, today’s severe weather will be confined primarily to western and central Oklahoma. Storms are still possible in eastern Oklahoma but will not be severe. We are expecting low temperatures tonight to be in the mid-to-upper-60s across the core of the state, with the mid-to-upper-50s invading the panhandle as the front starts to move through.

THREATS:
Large hail
Damaging winds
Tornadoes

Sunday/Sunday Night

On Sunday, high temperatures will still be on the warm side and above average for this time of year. Extreme southwestern Oklahoma may very well see another day of triple-digit heat, with highs topping out in the low-100s. The rest of southwest Oklahoma will see highs in the mid-to-upper-90s. Other areas of western Oklahoma and central Oklahoma will see highs in the low-90s. The rest of the state will have highs in the mid-to-upper-80s. Skies will be mostly sunny to partly cloudy throughout the day, but do not let this deceive you. Cloud formation will begin Sunday afternoon, and storms will fire up.

Sunday will bring a greater severe threat than Saturday. All of Oklahoma may see some scattered, pop-up storms Sunday night, but the most likely location for severe storms will be in central and northeastern Oklahoma. The Storm Prediction Center has issued a moderate risk for the aforementioned areas, with a slight risk encompassing all of central and eastern Oklahoma. The dry line will continue its slow track eastward across the state. Again, the timing of these storms will be in the late-afternoon and evening hours and will have the potential to last through the late-night hours. With Sunday’s storms comes an increased TORNADO threat, so we urge you to be extra aware. The graphic above shows the elevated tornado risk shaded in red. With the approaching cold front from the northwest, low temperatures Sunday night will dip down to the 50s in the northwest part of the state, while remaining in the 60s elsewhere.

THREATS:
Very Large hail
Damaging winds
Tornadoes

Monday/Monday Night

Monday presents the same story in terms of the severe weather threat. First of all, high temperatures will start to cool across the state, as we see the invasion of the 70s in the panhandle and far eastern Oklahoma. The rest of the state will see highs in the 80s, but southwest Oklahoma will still see highs soar as high as the mid-to-upper-90s: quite a temperature contrast. Skies across the state will be partly cloudy. Then, again, during the afternoon, the cloud cover will increase in central and eastern Oklahoma as the storms fire up.

Again, Monday may be a déjà vu scenario in terms of severe weather. The most likely location for severe thunderstorms is in central and northeastern Oklahoma, however, because this is still a few days out, the Storm Prediction Center is only able to issue a potential area of threat. Their current highlighted area for “Day 4” is more than likely to change, so please check back often. Tomorrow, the appropriate risk levels will be issued as needed on the Day 3 Convective Outlook. However, because the Storm Prediction Center has highlighted an area of interest this many days in advance, a severe threat is likely for Monday. All threats are still possible, and the timing of the storms will be in the late afternoon through evening hours, lasting overnight.

THREATS:
Very large hail
Damaging winds
Tornadoes


Isolated thunderstorms will continue across the state for the rest of the week. Areas of southeast Oklahoma may see some severe weather Tuesday afternoon and evening. Otherwise, the severe threat looks to be diminishing for the rest of the week. We will continue to keep you updated.


In light of the tornado outbreak in North Texas recently, we urge you to take this severe weather threat very seriously and be prepared for any changing weather conditions as they happen. We will update this blog as necessary to inform you of the latest details. Please know that, although we are unable to put out screencasts in our media department this summer, the National Weather Service office in Norman, OK are providing video briefings, which can be found on their YouTube page HERE. We also want to take this time to clear up any confusion you may have about the terms “slight risk,” “moderate risk,” and “high risk” that are used by the Storm Prediction Center. For more information on what a slight risk is, please click HERE. For more information on what moderate and high risks are, please click HERE. These graphics and information have been provided by the National Weather Service Office in Norman, OK and are available on their Facebook page.

RESOURCES:
Storm Prediction Center
National Weather Service Amarillo, TX
National Weather Service Norman, OK
National Weather Service Tulsa, OK

Sources: NWS, SPC, HOOT