Saturday, November 30, 2019

ALERT Data For End Of November Event

November ends up with an extended damp and rainy (also snowy) period. Here at house I measured a total of 0.88", including a bit of a surprise shower around 5:00 am MST this morning. The 0.88" cames as per: 0.06" early night of 27th; 0.78" yesterday on the 29th; and 0.04" early this morning.

Cold morning across the state - reported temperatures at 7:00 am ranged from -7 F at the Grand Canyon to 44 F at Yuma (low here was 38 F).

Morning view from campus shows snow level on Catalinas got down fairly low during the per-dawn hours today. Image down at bottom shows street plowing in Flagstaff this morning, where there was over a foot of snow yesterday. 

ALERT maps for the event are shown here. Above is 6 hour rainfall ending at 7:00 am this morning.

Below is three day rainfall ending at same time for north part of network. Second and third maps below show the period for the middle and southern parts of network. Almost all of sites had amounts more than half an inch (yellow numbers) and a significant number of stations had an inch (white and red plots) or more during the three days. Heaviest amounts in mountains and east half of network.

Friday, November 29, 2019

Stormy Morning

Composite radar above shows line of strong thunderstorms approaching metro area at about 7:00 am MST this morning. Raining heavily here with a power surge a few minutes ago. Some recent CG flashes detected in eastern Pima County (below) as indicated by white to purple points (plot from Atmo and Vaisala).

Hazard alerts in effect currently over southeast Arizona - bit of everything happening this morning! Webcam at Kitt Peak below indicates snow there.

Thursday, November 28, 2019

First Day Of Storm

Heavy cloud cover over Catalinas at about 7:00 am MST on Thanksgiving morning.

Rainfall ending at 7:00 am for the storm so far (above from MesoWest). Amounts over metro area were generally light - less than 0.20" (here at house there was 0.06"). However, over Cochise and parts of Santa Cruz Counties amounts have been very heavy - many sites recording over two inches and several over three inches. San Pedro flow at Palominas, AZ (southeast of Sierra Vista on Highway 92), shown below, is over 7,000 CFS. Art Douglas sent this graphic, and also reports just less than three inches of rain at his place this morning.

Analysis for 500 mb this morning (above from NCAR RAP) shows that closed low is centered along the northern California coast. System forecast to move eastward slowly - GFS forecast below is valid at 5:00 pm MST tomorrow afternoon.

At bottom is precipitation forecast through 5:00 pm tomorrow, from the 06 UTC run of the WRF-GFS at Atmo. The GEFS system forecasts that most of this fall on the 29th, with just light showers around the metro today.

Hope all who visit have a great Thanksgiving Holiday.

Wednesday, November 27, 2019

A Weather Smorgasbord For Thanksgiving

Skies mostly covered by high cirrus this morning, but with a few low clouds hanging on top of the Catalinas. Photo down at bottom shows a snowy morning at Houghton, Michigan.

The forecast map of hazards from the NWS forecast offices this morning (below) indicates a bit of everything for much of western two-thirds of the country.

GFS Forecast above (from 06 UTC last night) is for the 500 mb level at noon tomorrow, with a deep and cold trough across the West. The GEFS plumes for the airport below (also from 06 UTC) forecast a damp Thanksgiving Day for here, followed by a more significant event on Friday.

Here are two precipitation forecasts for rest of week: above is from 06 UTC GFS and is valid through midnight Friday, and below is from 06 UTC WRF-GFS and is valid through 5:00 pm MST on Friday. 

As per all the national news stories - definitely not a good Holiday travel situation. 

Monday, November 25, 2019

November To End With Rain And Snow

Another dreary morning, as middle and high cloudiness streams in from west of Baja (IR image below is from 7:00 am MST). Way down at bottom is photo of Saturday's sunrise east of Sonoita.

Models continue to forecast (GEFS plumes for QPF at airport above) another significant storm - this one centered on the 29, but beginning on Thanksgiving. The 500 mb forecast below (from 06 UTC GFS valid at noon on Thanksgiving) shows a high amplitude trough and closed lows over the West.

These forecasts for accumulated precipitation (above) and accumulated snow (below) are for the period ending at midnight on Friday the 29th (from 00 UTC WRF-GFS run at Atmo). Heavy amounts of snow forecast across the Rim country and also on the Sky Islands of southeast Arizona.

Special statement from Flagstaff NWS this morning is shown below.

Sunday, November 24, 2019

Unsettled For End Of November

Heavy middle clouds drifting around early this morning - view from Atmo above.

Tucson radar above (from CoD - base scan from 7:40 am MST) shows the mountains returning strong ground echoes this morning. First couple of tilts evidently trapped below several inversions from surface to 700 mb this morning - TWC sounding from 12 UTC below.

Models are forecasting another large, cold trough at 500 mb for the second half of Thanksgiving week (average forecast from GEFS ensembles above is valid at 5:00 pm on Thanksgiving Day).

GEFS plumes from 06 UTC indicate heavy rains and strong winds for second half of the coming week. So the possibility is setting up for another big rain event here in metro Tucson before end of November.

Friday, November 22, 2019

Crisp, Cool Morning After The Storm

It's a cool and mostly clear morning, after our first significant storm since September. Down at bottom are views of Snow Bowl in the San Francisco Peaks yesterday, and just for color - sunset over the Front Range on Monday, from Broomfield, Colorado.

Rain amounts above over metro for 24-hours ending at 7:30 am MST this morning (from MesoWest) - we added 0.08" here during the morning yesterday (total event at house was 1.67").

Models suggest a possible repeat for the Thanksgiving weekend. The 500 mb forecast below is valid at 5:00 pm Friday the 29th (from 00 UTC WRF-GFS). The closed low forecast near Las Vegas is somewhat colder than the event just ended. November could end up as very wet month - but we'll have to wait for the Holiday to see.

Thursday, November 21, 2019

Addendum To Below

Figure above is event rainfall through a bit after 8:00 am MST, zoomed in to make numbers a bit more readable. Note event amounts of 3 to 5+ inches over the Catalinas.

Love A Rainy (And Snowy) Night

Several inches of snow this morning at the Mt. Lemmon General Store. But, right now there are a few patches of blue sky around after a very rainy night.

Radar above, for 6:35 am MST, shows moderate to heavy showers over and east of metro area. Plot of CG flashes for 24-hours ending at 7:00 am (below from Atmo and Vaisala) shows that the most recent thunderstorm activity was over our part of state.

Precipitation amounts have been very impressive over night - ALERT amounts for past 24-hours ending at 7:30 am above and below. Numerous sites with over an inch of rain (numbers hard to read but red numbers are over an inch), while mountains had amounts up to right at 3.00 inches, and then there was snow before dawn which didn't get into the measurements. Here at house there was 1.29" in gauge this morning - added to yesterday's 0.30" makes this a 1.59" storm. This is largest two day total here since early August. Airport reported total of 1.32"; DM AFB had 1.09"; and Atmo 1.02". All-in-all, quite some event.

This morning's 500 mb analysis (above, from SPC) shows the cyclone between Las Vegas and Reno - low is expected to move slowly east-northeastward today. The morning TWC sounding (below, also from SPC) is very moist up to 400 mb; has small CAPE; and southwest winds over a 100 mph around 300 mb.

Still some chance for a bit more rain later today. Forecast below is of snow accumulation from the 06 UTC run of the WRF-GFS - and we know that that has already verified.