Jan. 11 - Cold is back as the front did its business and brought in a cold air mass from the north. Low at the NMSU Cooperative station was 23F, 24F at the Las Cruces airport, and 23F at the Deming airport. Haze in the afternoon as I sit in my office looking out toward the west. The haze is not a surprise since we have some southeasterly flow this afternoon. So far from my experience an easterly or southerly wind flow pattern seems to bring in hazy air.
To help understand the origin of the haze I ran HYSPLIT to see where the airmass has been over the past 24-hours. Here a backtrajectory was run every hour starting at 21 UTC (2 pm) and going back to 15 UTC (8 am) this morning. Looks like our easterly winds were just in the past few hours and winds were from the north this morning. It makes sense since that's the path of the cold front that ran its course overnight. We should be getting WNW winds aloft based on the upper air pattern of trailing the end of a trough.
Particulates at the core site slowly build up since the morning and are at the highest in the evening.
The NMED Sunland Park City Yard station had a breezy morning but the particulates stayed low with PM10 (red line) not exceeding 45 µg/m3 throughout the day.