February Second 2023

Groundhog Day in Tucson dawns with perfectly clear skies. According to legend we can look forward to 6 more weeks of winter. But here in Tucson we have to ask: "What winter?" Down at bottom is a frame of Bill Murray in the original movie.

Plumes from the 06 UTC GEFS (above QPF and below temperature) indicate mild weather through the weekend but with an unsettled start to next week.

January Summary

The GEFS and GFS model forecasts for chances of showers yesterday were a bit over-done and we ended up with no rainfall (note that a number of WRF runs yesterday kept all the precipitation west of here). 

During the month we had measurable precipitation here at the house on the 1st and 2nd and also the 15th through 17th. Final total for the month was 1.86", which was the 5th wettest January since I began my records back in 1999. View above is from the morning of January 17th.

I lost track of the morning lows and can only report that there were a number of mornings with temperatures between 25 and 32 F during the last several weeks.

End Of January

View of vivid blues skies over the Catalinas at 8:25 am MST this morning. Forecast models continue to indicate chances for light showers at end of the month.

The GFS forecast for 500 mb (above from 06 UTC runs) forecasts a very sharp trough over Arizona at 11:00 pm MST on the 31st. However, forecast of PW from same runs (below) indicates that the trough will have little moisture to work with.

Forecast for precipitation through that time (above) indicates little over most of Arizona. The 00 UTC run of the WRF-GFS at Atmo (below) is a bit more optimistic for area with precipitation (mostly very light) for all of Pima County. So, there'll be some chance for a bit more January at the airport and across the Metro area.

Dry Rest Of Month?

Pristine blue skies over the Catalinas this morning at about 7:30 am MST. Lows over night (below) were mostly in the 20s F, but note the colder temperatures on the mountains. Low here at house was 24 F.

At 500 mb (above) there is a long stream of northerly flow from Canada south across Arizona, with cold low now shifted over the Big Bend of Texas.

GEFS plumes from 06 UTC (above for QPF and below for temperature) indicate slight chances for light rain at airport on last day of January, with moderating temperatures following this morning's cold. 

At bottom is GFS forecast for precipitation through 11:00 pm on January 31st. Little in the way of weather to look forward to through the last week of the month.

Quick Overview Sunday to Today

View of rain shower over eastern Catalinas yesterday morning at 10:30 am MST.

We had a widespread and heavy rain event across the entire region during past three days. ALERT maps shown here are for the three day period ending at 10:30 am yesterday. Total event amount here at house was 1.55 inches. This was heaviest rain event at the house since August 2021!

Flow in the Rillito peaked at just over 6000 CFS yesterday.

Forecast from NWS this morning indicates fair weather next couple of days, but with cold morning lows, resulting in frost and freeze warnings. Morning view today (below) is from 9:15 am.

Brief Update

Partly cloudy over the Catalinas and metro area at 10:49 am MST this morning.

Two strong shortwaves will impact Arizona over the next several days. The GFS forecast for 500 mb (above - valid at 18 UTC on Tuesday the 17th shows the leading wave over the Great Lakes, while the second wave extends north-to-south over western Arizona.

Winds will become gusty tomorrow ahead of the first wave - 12 UTC WRF-HRRR forecast above shows steady wind speeds forecast by the model valid at 10:30 am tomorrow morning. Forecast below from same model run is forecast for total precipitation through midnight tomorrow.

Current statement from the NWS webpage is below.

Friday The Thirteenth - A Look To Next Week

View toward the Rincons at 7:15 am MST this morning, with a bit of a short contrail captured also.

Forecasts are trending wet from late Saturday through Wednesday night next week. Above shows morning forecast from Tucson NWS Forecast Office, while below shows 06 UTC plumes from GEFS for QPF at the airport - very large range of amounts in the GEFS continues. Second below shows the temperatures plumes forecast for the airport, with strong cooling beginning on Sunday.

The 500 mb forecast above is from the 06 GFS and is valid at 18 UTC on Tuesday the 17th - a broad trough has settled over the West with a number of embedded shortwaves.

Forecast below is from the 00 UTC WRF-GFS run at Atmo, showing a major precipitation event for Arizona - forecast goes through midnight next Wednesday. Amount at airport (one inch) is similar to the GEFS plumes.