Update from Tucson

Just a quick initial note to show a few things we have been looking at with NASA SPoRT LIS and some of the satellite imagery so far.

1) We have had a limited sample size so far this year, but we have been looking at integrating LIS volumetric soil moisture and relative soil moisture into the Dust Storm decision making process (both short fused warnings and our longer term new “Watch”-like product).  Here is the 0-10cm Volumetric soil moisture image from Wednesday,  coincident with a moderate outflow (up to 20 kts) that pushed northward from Pima county into Pinal County. Not a strong outflow, but  one that can generate enough dust for reduced visibilities (likely not to warning levels).   soilmoisture2

In this case, with percentages in the 18 to 21 percent range in the origin area and 12 to 14 percent in the path of the outflow, there were no indications whatsoever of reduced visibilities.  We will be watching to see if the (relatively) elevated soil moisture in the origin area is any indication of limited potential and strength of blowing dust issues as the season progresses.

We are also trying to incorporate the more shallow volumetric and relative soil moisture levels into heightened awareness for flash flood threat areas daily.  More on this later.

2) We have been impressed with the superior accuracy and versatility of the CIRA LPW products.  Here is a recent comparison with the AMSU and SSM/I Blended Total Precipitable Water product: tpw compare

About 1.3″ from CIRA versus 22mm (0.86″) for the Tucson area.  12Z sounding showed 1.76″.  Add afternoon mixing in there and 1.3″ worked much better.  With our typically deep boundary layer and elevated subcloud layer, the individual lower layers of the LPW have also been useful to help determine the threat of dry vs. wet microburst activity with initial convective development.

We continue to evaluate the NESDIS QPE and  Passive Microwave Rain Rate imagery.  More on this later as well.

8 thoughts on “Update from Tucson

  1. Thanks for your post, Jim! We are excited to work with you on evaluating the LIS and satellite-derived precipitation datasets with you over the next few weeks.

    I think the “Dust Watch” application is a very intriguing one. In your post you note that you are looking for elevated soil moisture values as a precursor for blowing dust events. I’m not too familiar with the origins of dust storms, so I would have expected that it would be lower soil moisture that would correlate to higher dust potential. This is interesting. Can you help me better understand the mechanism(s) that trigger a dust event? I am extremely curious to see whether you are able to find correlations between a particular antecedent soil moisture value and dust storms.

    • I was not very clear in my post. What I should have said was “limits the potential.” I will make that edit to try to clarify things. Thanks Brad!

      • No worries, Jim. I just wanted to make sure that I was understanding the forecast challenge properly. I am very interested in hearing about ways in which you are able to use the soil moisture products for dust forecasting. This is an application we have not done a lot of analysis on but could potentially pay big dividends in your neck of the woods.

  2. Jim, I agree with Brad that the dust application is interesting. SPoRT has worked quite a bit with the ABQ WFO on the use of the Dust RGB imagery from MODIS and VIIRS to detect blowing dust, both during the day and at night. A paper on the topic has recently be submitted to NWA/JOM on the changes to operations at ABQ due to the incorporation of the Dust RGB. I would encourage you to also look at this imagery and consult your WFO neighbor, as time allows, to benefit from their prior experiences with the product. And, hopefully, you can provide insight to them on the use of the LIS soil moisture fields to them.

  3. Hi Jim, I’m a little late here, but thanks for your post! This is a great contribution to the blog and exactly the type of feedback and experimental application of the data for which we’re looking during this trial period. It will be really interesting to see how the dust application works for the data. Here in the TN Valley, we of course have no experience with this! I suspect that you may find some significant thresholds for the 0-10 cm relative or volumetric soil moisture based on a combination of wind speeds and soil moisture values. I did some digging and found this paper that appeared in Geophysical Research Letters very recently in April 2015. http://onlinelibrary.wiley.com/doi/10.1002/2015GL063325/full

    We should collaborate some more on this unique application of the SPoRT LIS data!

  4. This is an intriguing potential application of real-time soil moisture data from the SPoRT-LIS. We definitely need to read up on this to better understand the connection between soil moisture dryness and duststorm events. If you have some good cases in your archive, we could consider modeling them, as one of our colleagues Aaron Naeger has experience in running WRF-Chem and modeling AOD related to dust and particulates.

  5. Here is a portion of my operational AFD issued this afternoon. We have some interesting weather the next 2 days where this might come into play:

    “BY THURSDAY AFTERNOON A RETURN OF MOISTURE THROUGH LOWER DESERTS FROM GULF SURGE ACTIVITY AS WELL AS DIRECT OUTFLOW FROM THE EXPECTED COMPLEX SOUTH OF THE BORDER SHOULD SET US UP NICELY FOR A RETURN OF THUNDERSTORMS. WE CONTINUE TO SEE STRONG H7 THETA-E TRENDS FOR AREAS MAINLY SOUTH AND WEST OF TUCSON TOMORROW. THIS FAVORS SANTA CRUZ COUNTY AND MUCH OF THE TOHONO O’ODHAM NATION FOR STRONG THUNDERSTORM ACTIVITY TOMORROW AFTERNOON. ECMWF HAS BEEN ADVERTISING THIS FEATURE FOR SEVERAL DAYS AND RECENT UOFA WRF-NAM TRENDS HAVE REFINED THIS IDEA PRETTY WELL. WE WILL NEED TO WATCH FOR POTENTIAL DUST ISSUES FROM ORGANIZED CONVECTION. TAKING A LOOK AT NASA SPORT REAL-TIME
    LAND INFORMATION SYSTEM DATA…SOIL MOISTURES HAVE REMAINED ELEVATED ACROSS SANTA CRUZ COUNTY AND AREAS IMMEDIATELY WEST. HOWEVER ONCE YOU GET TO CENTRAL PORTIONS OF THE TOHONO O’ODHAM NATION THINGS HAVE DRIED OUT SINCE THIS WEEKEND. 0-10CM VOLUMETRIC SOIL MOISTURE HAS FALLEN ABOUT 6 OR 7 PERCENT (TO BELOW 15 PERCENT) WITH RELATIVE SOIL
    MOISTURES NOW DOWN TO ABOUT 30 PERCENT. WE WILL NEED TO KEEP AN EYE ON CONVECTIVE OUTFLOWS THAT ORIGINATE IN THAT AREA FOR POTENTIAL DUST ISSUES.”

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