Recent rains and changes in soil moisture in the Southern Plains…

Significant rains have fallen across portions of the Southern Plains recently.  Widespread rainfall amounts from eastern New Mexico across northern Texas and southern Oklahoma total around 2-4 inches.  Isolated locations have received around 6-8 inches, and most of this has just fallen in the past few days (image 1).

7-Day Observed Precipitation over the Continental U.S., courtesy of the National Weather Service.  Data ending 12 UTC 23 Oct 2015.  Notice the heavy rainfall across the Southern Plains.

Image 1.  7-Day Observed Precipitation over the Continental U.S., courtesy of the National Weather Service. Data ending 12 UTC 23 Oct 2015. Notice the heavy rainfall across the Southern Plains.

More rain is on the way, especially for eastern portions of Texas and the southern Mississippi Valley over the next couple of days as a plume of deep tropical moisture and the remnants of Hurricane Patricia become swept into the region ahead of an advancing trough of low pressure.  Numerous flash flood watches and warnings have been posted for much of this area.  Interestingly, parts of this same region, are still considered in D4 drought, due primarily to very dry conditions that have persisted since the summer months (image 2).

Image 2.  US Drought Monitor over the South Region, 20 October 2015

Image 2. US Drought Monitor over the South Region, 20 October 2015

Drought reductions will very likely be in order with upcoming weekly issuances of the Drought Monitor.

Soil moisture across the region, per the 3-km SPoRT LIS has increased dramatically, especially the shallow layer soil moisture.  I thought I’d take a moment to share a loop of 0-10 cm Relative Soil Moisture values during the past few days.  These values go from as low as ~5% in the beginning of the image across a large swath of Texas to ~70-80%, especially in northern parts of Texas and around the DFW metro area.  Further rains in the area of recently, nearly saturated soils will only increase the risk for runoff and the potential for further flooding.  These data are being ported into some NWS offices to aid forecasters in situational awareness for the risk for flooding and for drought analysis.  Little did some forecasters know that they would have the opportunity to utilize the data for both purposes in the same week!  Having the data in AWIPS is just one advantage of the SPoRT LIS data.  Other advantages are the spatial resolution (3 km) and the temporal latency (~2-8 hours).  This relatively short latency over other legacy soil moisture data sets is possible due to the incorporation of MRMS precipitation data for forcing the model in the shorter term (~<4 days).

Image 3.  SPoRT LIS 0-10 cm Relative Soil Moisture, 21 UTC 21 Oct to 15 UTC 23 Oct 2015.

Image 3. SPoRT LIS 0-10 cm Relative Soil Moisture, 21 UTC 21 Oct to 15 UTC 23 Oct 2015.  (you may need to click on the image to see the loop)

Of course, soil moisture will be slower to increase in deeper layers, as this recent depiction of 0-200 cm Relative Soil Moisture shows.  Nevertheless, look for future increases in this deeper layer over the next couple of days.

Image 4.  0-200 cm Relative Soil Moisture 15 UTC 23 Oct 2015.

Image 4. 0-200 cm Relative Soil Moisture 15 UTC 23 Oct 2015.

 

 

One thought on “Recent rains and changes in soil moisture in the Southern Plains…

  1. Great post, Kris! I could see visually how dry it was in western Mississippi, driving back from the NWA meeting last Friday (23rd). Animations of the full column (0-2 m) relative soil moisture should help determine how much relief will come in the drought areas of eastern TX to MS. Amazingly, we’re seeing another 10-20″+ rainfall this month on top of very dry soils in an existing severe drought region. Imagine how bad flooding would be if antecedent soils weren’t so dry?

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