Friday, December 30, 2011

Dec. 30 -

Forecasting another low wind event tonight. Below are this morning's observations at a couple Cooperative weather stations.
                 Yesterday           Today
Station       High(F)  Normal     Low(F)  Normal  Record Low
NMSU            59        56        29      28      4 (1895)
Hachita         64        56        23      26      6 (1969)

Temperatures have finally climbed above average in Las Cruces. The NWS forecast is calling for low winds tonight but from the north. Below is a wind forecast from the 15Z RUC model at 8 pm tonight.
 The AQI forecast for today again shows our patch of moderate air quality over the Paso del Norte and El Paso county.
Looking past the weekend and into next week the 12Z GFS forecast conditions look good for low wind events from the 3rd to 5th but after that I'm not that confident since the winds start to increase due to an upper level trough moving in to the area.
6 pm Minivols are set to run from 6pm to midnight tonight to capture a low wind high PM event. Filters used today include DUPT001 (Teflon) on sampler SN5360 and DUPQ001 (quartz) on sampler with SN5361.  I also downloaded the data from the profiler and a time series plot of particle counts for small (0.3 micron) and coarse (10 micro) is shown below. During the low wind spike yesterday, highlighted in yellow, the small particle counts increased greatly compared to the mid-day values. Coarse particle counts also spiked as well showing the plume is also mixed with larger particles. Particles with diameters of 0.3 micron are likely combustion related as opposed to coarse particles that are probably derived from soil dust.
10 pm Forecast was on the mark. A moderate to strong, low wind, high PM event was recorded at the SPCY station tonight. Peak hourly PM2.5 was 85 µg/m3 at 10 pm. 

The NMED AQB website showed orange stage AQI late tonight for PM2.5. Orange AQI is "unhealthy for sensitive groups."
From satellite the OMI NO2 product shows a pattern of a stagnating air mass with accumulating NO2 over urban and polluted industrial areas. Below shows the El Paso area shaded in yellow. While not as intense as the NO2 in the Four Corners and Albuquerque it still indicates a build-up of pollutants in this air basin.

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