BRIEF SUMMARY OF JANUARY 2008

The weather for the winter continued fairly wet and cold here at the house during January 2008.

There was measurable rainfall on only 4 days but the total, mostly from the storms of the 7th and of the 27th/28th, was 1.00 inch. The storm late in the month produced much flooding and runoff after very heavy rains at higher elevations. The Rillito wash is still running today.

After a very cold December (our gas bill for heating in December was the highest ever during our ten years in the house), January was also fairly cold. There were 18 mornings with low temperatures of 32F or colder. Half of these days had lows of 27F or colder.

The coldest mornings occurred on the 18th - 20th with readings of 20F, 20F, and 21F. This morning, the 31st, was also cold with a low of 22F. There was a period of 14 consecutive days from the 10th through the 23rd with lows of 32F or colder.

So, probably another big gas bill.

Appears that February will also start out unsettled with perhaps more rain during this strange la nina winter.

INTERESTING BUT TOUGH FORECAST FOR LATER IN WEEK

Very interesting situation for the next six days as the complex middle level low off of California coast this morning swings around to south and then minors out across the Great Basin, with stronger wave replacing it. There is also a persistent very tight cyclone far off to the WSW that models may be trying to swing around the south end of the larger-scale trough.

This morning's NAM indicates a precip period Wednesday night through Friday morning. Interestingly, the operational GFS (from 00Z last evening) shows little at Tucson during this period. The GFS tends to keep the subtropical moisture to the south as the first middle level low swings around and minors out, while the second system digs in. The role, if any, of the system out around 140W and 30N is not clear in the model forecasts.

The GFS and the ECMWF (both from 00Z last evening) indicate that the second wave will pull the subtropical moisture much further north and provide the most significant event out toward the weekend. The precip forecast of these long range models is fairly different. The GFS indicates the main precip near Tucson to occur Saturday night and to amount to around a quarter to half an inch. Whereas, the ECMWF indicates that the main precip event would also be Saturday night, but rainfall amounts near Tucson of a half to a bit more than an inch are predicted by this model.

So, the summary is that there may be two distinct precip events over southeastern Arizona with the weekend event likely being the more significant one. Will be interesting to watch how this very complex situation actually evolves. Regardless we're definitely having a more interesting la nina winter than one might have expected!