Previous Day
A very active day over much of the eastern two thirds of the state. Storms didn't make it to Phoenix, but a moderate outflow and big dust storm did.
Model performance was quite good as the locations, timings, and amounts were fairly accurate. The only issue was no significant activity made it to the Phoenix area as was forecast by some of the runs.
I have been running WRF using the operational RR and the development version and they, to put it mildly, have been bad. The development version is somewhat better, but both do not have nearly enough deep convection. Note the lack of precipitation in SE Arizona and much of NM. I have also noticed significant initialization errors in the operational RR such as yesterday where it had strong winds blowing out of the GofC up into western Arizona. The runs have been so poor that I almost never use them. When I have time, I also look at the HRRR which gets its initial conditions from the RR and it too produces poor forecasts using the 12Z or 15Z data. It improves as the day goes on, but a 2-4 hour ahead forecast isn't as useful as a 12-18 hour forecast.
Initializations
Some clouds are present across central Arizona and in far SE Arizona. The 12Z initializations were mainly clear, but the observed clouds seem to be dissipating and this error shouldn't impact the forecast too much.
A weak IT was noted in the upper air data across southwestern Arizona and the upper IT that impacted eastern Arizona has opened up and is lifting northward across eastern Arizona. Both features were initialized well. Another bit of good news is that there was a 12Z sounding from Guaymas Mexico this morning. Let's hope that continues throughout the summer as that is such a critical location for us in Arizona. In fact, that data helped better define the weak IT over far SW Arizona.
The NAM had a 3-4mm wet bias over much of northern Mexico and into Arizona/NM. Not enough to cause issues with the correction routine. Overall, initializations are good.
Day 1, July 20
Moisture continues to be sufficient for showers and storms across most of the state.
The SW AZ IT remains mostly stationary. Steering winds are mainly southerly over eastern Arizona while around Phoenix, it's mainly light and not favorable.
Yesterday's runs were forecasting less CAPE for today, but that is not the case today as both the WRGFS and NAM have moderate CAPE over many areas of the state.
The vertical wind profile over Tucson isn't that great as it's mainly unidirectional and fairly weak with steering from the south, usually not very good. However, moderate CAPE is forecast thus it's likely for deep convection to form over nearby mountains with a few storms in the valley.
Storms form quickly today with quite a bit of activity underway by early afternoon over the higher elevations.
Scattered activity continues into the late afternoon/early evening with isolated activity forming in the lower deserts.
The WRGFS is a bit more active this evening with a fair amount of activity around Tucson and up towards Phoenix.
It looks like activity won't quite make it to Phoenix as CAPE isn't quite high enough. However, outflows and dust storms are again possible.
Too bad there isn't more CAPE as outflows may come in from the north and south intersect in Maricopa and Pinal counties.
Day 2, July 21
I'm not sure I should even bother with a Day 2 forecast as they have been usually wrong recently. Not surprising during the monsoon season though. Same story as moderate amounts of moisture continue. One interesting possibility is low level convergence setting up on the edge of the easterly flow across Cochise county.
CAPE is forecast to again be moderate across the eastern 1/2 of the state so another active day at higher elevations.
Mid level flow is still marginal as it's mainly light and southerly plus temperatures are a bit higher around -6C. Still, a few storms could move into/form in the lower elevations around Tucson and Phoenix.
A very active day over much of the eastern two thirds of the state. Storms didn't make it to Phoenix, but a moderate outflow and big dust storm did.
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| WRFNAM |
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| WRFGFS |
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| 12Z WRFRR (ops) |
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| 15Z WRFRR (dev) |
Some clouds are present across central Arizona and in far SE Arizona. The 12Z initializations were mainly clear, but the observed clouds seem to be dissipating and this error shouldn't impact the forecast too much.
A weak IT was noted in the upper air data across southwestern Arizona and the upper IT that impacted eastern Arizona has opened up and is lifting northward across eastern Arizona. Both features were initialized well. Another bit of good news is that there was a 12Z sounding from Guaymas Mexico this morning. Let's hope that continues throughout the summer as that is such a critical location for us in Arizona. In fact, that data helped better define the weak IT over far SW Arizona.
The NAM had a 3-4mm wet bias over much of northern Mexico and into Arizona/NM. Not enough to cause issues with the correction routine. Overall, initializations are good.
Day 1, July 20
Moisture continues to be sufficient for showers and storms across most of the state.
The SW AZ IT remains mostly stationary. Steering winds are mainly southerly over eastern Arizona while around Phoenix, it's mainly light and not favorable.
Yesterday's runs were forecasting less CAPE for today, but that is not the case today as both the WRGFS and NAM have moderate CAPE over many areas of the state.
The vertical wind profile over Tucson isn't that great as it's mainly unidirectional and fairly weak with steering from the south, usually not very good. However, moderate CAPE is forecast thus it's likely for deep convection to form over nearby mountains with a few storms in the valley.
Storms form quickly today with quite a bit of activity underway by early afternoon over the higher elevations.
Scattered activity continues into the late afternoon/early evening with isolated activity forming in the lower deserts.
The WRGFS is a bit more active this evening with a fair amount of activity around Tucson and up towards Phoenix.
It looks like activity won't quite make it to Phoenix as CAPE isn't quite high enough. However, outflows and dust storms are again possible.
Too bad there isn't more CAPE as outflows may come in from the north and south intersect in Maricopa and Pinal counties.
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| WRFGFS |
Day 2, July 21
I'm not sure I should even bother with a Day 2 forecast as they have been usually wrong recently. Not surprising during the monsoon season though. Same story as moderate amounts of moisture continue. One interesting possibility is low level convergence setting up on the edge of the easterly flow across Cochise county.
CAPE is forecast to again be moderate across the eastern 1/2 of the state so another active day at higher elevations.
Mid level flow is still marginal as it's mainly light and southerly plus temperatures are a bit higher around -6C. Still, a few storms could move into/form in the lower elevations around Tucson and Phoenix.
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