Tuesday, November 21, 2017

Verification For Seven-Day Model Forecasts

In earlier post I mentioned how very different the ECMWF and GFS forecasts were for 00 UTC on 21 November. Here is a look at the final outcome. The forecast from ECMWF for 500 mb is above and the same for the GFS is at bottom. In the middle is the NAM 500 mb analysis for 00 UTC on the 21st - last evening.

Very hard to make a call as to which model was better. The ECMWF was clearly closer to reality over eastern North America. Western North America and eastern Pacific were handled badly by both models. The ECMWF was seriously too intense and too far north with the Gulf of Alaska system, while the GFS was about the right intensity, but was too far south and west. The GFS was much in error over Alaska; whereas the split in the flow over Northwest and bowling-ball short-wave for Southwest were purely fiction in the ECMWF.

So, just a good illustration of the inherent dangers of making routine seven-day forecasts!

Monday, November 20, 2017

Chances For Rain Before December Dimming

The operational GFS forecast above is for total precipitation through 5:00 pm MST on November 30th - not good. However, 500 mb heights build toward summertime values for the long Thanksgiving weekend.

Sunday, November 19, 2017

Very Cool This Morning

Low here at house was 40 F this morning - lowest minimum temperature so far this Fall. Lows during past 5 days have ranged 45 to 40 F. Previous coolest this Fall was 43 F on the 15th. Maybe into 30s tomorrow, but variable winds may lead to strong differences in am temperatures across the metro area.

Thursday, November 16, 2017

Any Rain Here Last Half November?

For a change - sunset on 15 November - above.

Operational GFS (from 06 UTC last night) forecasts almost no precipitation during next 10 days from west Texas westward to southern California. The GEFS plumes from same time remain flat-lined for TUS. Looks like we'll have to pin our hopes for a bit more rain on final days of the month.

Finally, two ski area webcams for this morning. Squaw Valley, California, (above) looks very sloppy, while Taos Ski Valley (below) looks very skiffy.

Wednesday, November 15, 2017

Webcams Galore

Tony Haffer sent the following link - http://www.wrh.noaa.gov/slc/webcam_map_CSV/
which goes to an NWS webcam site that has a tremendous number of cameras available. Below is a zoom to the SLC area, but user can shift around across entire country. It is quite an amazing site - warning: can be addictive. It appears the Bloomsky cameras provide all sky views, but I can only find summertime views, so that net may not be active currently. Below are three images I grabbed in the Northwest a bit ago. 

A ski area in Idaho above; two views along the west coast - one just north of San Francisco and the other at LaPush, Washington.

Tuesday, November 14, 2017

ECMWF Versus GFS At 168 Hours

The operational versions of the ECMWF and GFS are HUGE at 168-hours (VT 00 UTC 21 November), over both eastern North America and the east Pacific. Top graphics are the 500 mb forecasts and the bottom two are the surface forecasts. Note the surface pressure difference south of Anchorage - ~964 mb in ECMWF and ~ 991 mb in the GFS - quite something. The little bowling ball short wave that ECMWF forecasts rolling toward Arizona could also be interesting.

Sunday, November 12, 2017

Some Photos From Nearby Grasslands

We were at Santa Rita Abbey Friday afternoon and Saturday - no rain out there either. Two photos here of yesterday's sunrise.

Mt. Wrightson through the cottonwoods (above) - which have not completed changed over to golden yellow yet. But after the heavy July rains brought amazing greens, the grasses on the hills are now fully brown (below).

It is the time of the walking sticks out there - they migrate to window screens that face the sun from late October to early December, and then vanish for rest of winter. I assume that they are green during the summer, and then gradually change to gray/brown along with the grasses.