Monday, July 10, 2017

Increased Chances For Low Elevation Storms

Thunderstorms stayed mostly on the higher elevations yesterday. Above view of Catalinas at 2:54 pm yesterday shows rain staying to east side of mountains.

Composite radar at 2:46 pm MST (above) indicates heavy storms on Rincons, but these dissipated as they tried to move west off the mountains. We had just a spit of rain drops here from debris cloud.

The only measurable rain over the ALERT network (above for 24-hours ending at 7:30 am this morning) was over the mountains - there were three sites with more than half an inch. The CG flash density plot (below for 24-hours ending 07:30 am) depicts a large kidney bean shape from here to Phoenix with no storms. There was just no outflow kick from the Rincon storms.

The morning sounding from TWC (above) continues to improve with PW up to 1.56 inches and low-level moist air extending up to 700 mb. Much improved thermodynamics for the low elevations. However, winds in troposphere have vanished and there is no distinct steering level - so storms will likely propagate along their outflows.

The 6 UTC WRF-GFS forecast sounding for TWC (below valid at 4:00 pm) has PW of almost an inch and a half, CAPE of about 600 J/kg, and cloud base still around 600 mb - an excellent sounding for hybrid downbursts (which means heavy rains possible but with deep BL below cloud base).

The WRF-GFS forecasts significant storms for the metro area (above is radar forecast valid at 6:00 pm and below is total precipitation forecast through 5:00 am tomorrow morning. If it verifies it will mean first meaningful rain here at house in more than three months.

1 comment:

  1. Anonymous9:50 AM

    I can't believe how poorly the GFS/NAM/WRF model initialized the anticyclone associated with the hurricane. Yesterday anvils killed us but models hinting at a little better situation at 300 MB today and tomorrow. But which day?