Saturday, May 02, 2015

Summer Preview

We're having a preview of summer with a 500 mb anticyclone moving slowly eastward across the Southwest yesterday and today. There were thunderstorms yesterday in the Rim Country and mountains of eastern Arizona and western new Mexico - plot of CG flashes (above from Vaisala) shows detections through 1 am MST this morning. Current NWS forecast (below, for TUS grid point), certainly looks like summer sneaked in for a brief preview. High at airport reached 97 F yesterday, hottest so far this season.

This morning there are middle-level buildups around, with some mammatus and virga. The 500 mb analysis (above from NCAR RAL) for 12 UTC shows the anticyclone over New Mexico with some moisture around its west side, where winds are fairly strong. Temperatures are very cool, with TWC coming in at -14 C. The morning sounding from TWC (below from SPC) shows the middle-level moisture above a very dry lower troposphere. Sounding has no CAPE, but if the more moist lower levels were to mix out to 600 mb, there would be at least a sliver of CAPE. 

The WRF NAM forecast from the 06 UTC cycle forecasts the well-mixed boundary layer this afternoon (skew-T above for TWC valid at 4 pm MST) to reach to 600 mb, with a bit over 400 J/Kg of CAPE - probably a bit optimistic. The model's forecast of composite radar echoes valid at 4 pm (below) actually forecasts a thunderstorm over the east metro/west Rincons this afternoon. So, a few things to keep an eye on today, since dry microbursts could be a possibility. 

1 comment:

  1. K7ZBob10:25 AM

    Based on this it is a very good thing the Buckhorn Prescribed Fire was terminated yesterday afternoon...