Alert archive / Arizona / Special Weather Statements in 2021
Special Weather Statement, NWS Tucson, AZ
NWS Tucson, AZ issued this special weather statement at Jul 29, 2021, 2:08 PM MST. It was in force for 37 min. No storm report in the archive falls inside the area while it was in force.
The area
The outline as issued.
The facts
- Issued
- Jul 29, 2021, 2:08 PM MST (21:08 UTC)
- Expired
- Jul 29, 2021, 2:45 PM MST
- In force
- 37 min
- Issued by
- NWS Tucson, AZ
The radar
The Yuma radar (KYUX), 158 km from the middle of the area, began a volume at 21:07 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
The nearest sounding before it
Phoenix, AZ (KPSR), launched 12:00Z, 9.1 hours before the alert went out and 179 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 371 J/kg
- Mixed-layer CIN
- -231 J/kg
- Mixed-layer LCL
- 2650 m above ground
- 0-6 km bulk shear
- 4 kt
- 0-1 km storm-relative helicity
- 11 m²/s²
- 0-3 km storm-relative helicity
- 5 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
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</html>What forecasters said that day
The local office's own words before this special weather statement went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Tucson, AZ wrote its last area forecast discussion before this special weather statement went out at Jul 29, 9:38 AM MST, 4 hours 30 minutes earlier.
Area forecast discussion, Jul 29, 9:38 AM MST, 4 hours 30 minutes before
Area Forecast Discussion National Weather Service Tucson AZ 938 AM MST Thu Jul 29 2021 .SYNOPSIS...Scattered to perhaps numerous storms are expected today into the weekend. High temperatures will run near to a few degrees below seasonal normals. && .DISCUSSION...No updates necessary this morning as the current forecast appeared to handle the trends well for today. Please refer to the previous discussion for more details on the current and projected weather. && .AVIATION...Valid through 30/18Z. Light shower activity this morning accompanied by CIGS between 10k- 15k feet. Widespread SHRA/TSRA is expected to develop this afternoon with multiple rounds of activity possible through late tonight. Storm impacts include strong erratic wind gusts in excess of 30 knots, heavy downpours, lowered vsbys, and CIGS dropping to 5k-9k feet. Storms will decrease in coverage overnight. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...More widespread storm activity is expected today with development beginning early this afternoon and lasting into tonight. Another active day is anticipated for Friday before a downward trend in storm activity begins going into early next week. Storms will likely produce erratic, gusty winds and locally heavy downpours. RH values remain well above critical thresholds through early next week. Temps will remain near to slightly below normal. 20- foot winds will generally be less than 15 mph when not influenced by thunderstorms. && .PREV DISCUSSION.../Issued 329 AM MST Thu Jul 29 2021/ Currently across southeastern Arizona a decaying MCV can be seen in radar imagery over the western portion of Cochise County moving west. This will continue to produce some light/moderate rain showers or sprinkles through the morning as it moves into Santa Cruz and southern Pima Counties. Another area of showers and a few embedded thunderstorms are moving across extreme northern Graham and Greenlee counties associated with a weak vort max, which is seen nicely in water vapor. It also appears to be shearing and weakening, but could certainly influence the weather for the northern half of the area later this afternoon as it moves west. Some of the high res models are hinting at this along with the HREF showing a focused area for convection across the northern portions of the CWA. If some organization can occur, strong gusty winds, heavy rain, and some blowing dust may be possible as storms move off the higher terrain and into portions of eastern Pinal County. A localized flash flood threat will also be possible given how saturated the ground is. Another area to watch will be outflows originating from northern Sonora convection. Some of the high res models hint at this moving southeast to northwest, likely generating thunderstorms along the bndrys. Some of this activity may persist into the overnight hours thanks to the easterly wave moving into the region. Heavy rain and gusty winds would be the main threats with this activity. A localized flash flood threat is also possible, especially with saturated grounds in place. Any training or cell mergers will enhance the threat. By Friday, the easterly wave will continue to move across northern Sonora. This will influence our weather with another round of showers and thunderstorms. There is lesser confidence on storm evolution depending on what happens later today. However, the western half of the CWA from Tucson to Ajo should be favored. The weakening easterly wave will begin to push north through Arizona later Friday into Saturday with lessening activity by as early as Sunday. There is decent agreement among the ensembles the high pressure briefly shifts to SW AZ and SoCal, before gradually moving back into the vicinity of the 4-Corners by late week. This return to the 4-Corners would signal another possible uptick if activity. Still plenty of time to watch how this evolves. && .TWC WATCHES/WARNINGS/ADVISORIES...None. && Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
In the hours before
Special weather statement, Jul 29, 2:08 PM MST, 0 minutes before
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</html>The office that day
Everything else NWS Tucson, AZ issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 28, 8:12 PM MST | Areal Flood Advisory | TWC | Cochise | 63 min |
| Jul 29, 1:20 PM MST | Severe Thunderstorm Warning | TWC | Pima | 40 min |
| Jul 29, 1:55 PM MST | Areal Flood Advisory | TWC | Pima | 2 hr |
| Jul 29, 2:06 PM MST | Flash Flood Watch | TWC | Pima, Pinal | 39 hr |
| Jul 29, 2:42 PM MST | Flash Flood Warning | TWC | Pima | 2 hr |
| Jul 29, 2:44 PM MST | Special Weather Statement | TWC | Cochise | 61 min |
| Jul 29, 3:03 PM MST | Areal Flood Advisory | TWC | Cochise | 117 min |
| Jul 29, 3:10 PM MST | Special Weather Statement | TWC | Graham | 35 min |
| Jul 29, 4:54 PM MST | Areal Flood Advisory | TWC | Graham | 2 hr |
| Jul 29, 4:54 PM MST | Special Weather Statement | TWC | 36 min |
Nearby
Special Weather Statements in Arizona, 2021Every special weather statement in 2021
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.