Now in our fourth day of an active weather pattern, we are seeing a little bit of a change. Sunday through Tuesday brought strong scattered thunderstorm activity. With these storms, that stretched across the entire region, we had a plethora of threats that accompanied them. Between Sunday and Wednesday morning, we had thousands of lightning strikes recorded (most of which were dry), wind gusts up to 50 mph, locally heavy rainfall that was short-lived, and hail that got up to about 1/2″ in diameter. In fact, a strong thunderstorm tracked through the Rogue Valley Tuesday afternoon that dropped hailstones at our station. While hail in the valley an interesting and rare occurrence, it can also bring damage to the crops around the region.
Today is a change in the pattern from the last few days. Instead of scattered thunderstorms with very little rain; we will now see weaker, isolated thunderstorms that come with measurable rainfall. In fact, as of 8:30 a.m. Medford’s 24 hour rainfall total was just over a 1/4.” More rain is expected to fall throughout today. The reason for this change stems from two reason. First, the reason why we are seeing more rain today is because the upper-level winds have shifted out of the southwest. Enough tropical moisture is in the atmosphere to condense out and fall. Plus, the air above the surface didn’t take long to re-saturate, due to the rain we received yesterday. Therefore virga only lasted a few hours this morning.
The second change is the weaker, more isolated thunderstorms we will receive today. This comes from a cold front that passed through our region early Wednesday morning. Thunderstorms need a list of ingredients to develop into strong storms. Some of these include, instability and daytime heating. We still have some instability in out area. The difference now is, we have cooler air as well. The arctic air that moved down into our region will keep the surface temperatures 5-15 degrees cooler for inland locations. Therefore the air above the surface will still heat up, but not as warm as usual. Therefore, storms will not get the updrafts they need to become severe.
Mind you, this is all for our local region. To the northeast of us, there will still be another round of strong thunderstorms that can produce threats like what we got yesterday. That is why there is still a RED FLAG WARNING for the northern fringes of Klamath and Lake Counties and areas to the north until 11 p.m. tonight. Areas like La Pine, Crescent, Bend, and Brothers all still have the potential for strong to severe thunderstorms this afternoon.
High pressure returns Thursday and we will clear up and warm up all the way into next week.
Thanks for logging on and have a great day!
Meteorologist Seth Phillips