Can You Find the Circulation?
Remember that pesky area of low pressure over the past week? Take a look at this image of accumulated rainfall. You can clearly see the streaks of precipitation rotating in a counter-clockwise direction around the upper low over the Southeast U.S. Also, note the welcome significant precipitation over much of Virginia.
So far this week, rainfall over Texas has been quite scattered and not all that focused in coverage. Here is a summary of rainfall for the past 3 days. As has been the spring trend, more concentrated coverage was noted in Oklahoma.
Take a look at the following image. It indicates the transport of moisture from the Gulf of Mexico into Texas. The red lines indicate moisture flow vectors. The green-shaded areas indicate high levels of Precipitable Water (PW). The medium-green-shaded areas indicate PW of 1.5 inch or more, with indicates significant levels of atmospheric moisture.
The small area of storms over central portions of Texas will move into this area of ample moisture today with pockets of heavy rain, primarily over East Texas.
Here is a short-term model predicting where the heaviest rain might occur through this evening. From this models perspective, heavier rain remains somewhat scattered in Texas, and quite isolated in Oklahoma.
U.S. Drought Monitor Update
Following is the latest update to the U.S. Drought Monitor. There remains a clear dividing line between areas in drought and area with ample, if not too much, recent precipitation. Coverage of (D0-D4) drought over the contiguous U.S. has only been modestly reduced–from 68% three months ago to 63% as of early May.
The more significant improvements have been over the Upper Midwest due to above-normal amounts of rain and snow this past spring. Another area of significant improvement was over Oklahoma. Areas shaded in medium-green experienced a 2-class drought classification improvement over the past 4 weeks.
Persistent cooler-than-normal temperatures have reduced evaporation, leading towards saturated upper soils over portions of the Midwest and Eastern U.S. The latest weather model runs indicate that cool temperatures will persist for the next several days before moderating next week. Blue lines indicate cooler-than-normal anomalies while red lines indicate warmer-than-normal anomalies. The thicker line indicates the diving lines between positive and negative anomalies.
The core of cooler temperatures remains over the Northeast U.S. It is also interesting to see the warming trend that pushes into the Upper Midwest next week. This region could use a week of warm temperatures to help dry out upper soils.