Storm Clouds Over Northwestern Mexico

[Ptarmigan]

I notice through satellite images, almost every night in the summer, there are massive storm clouds over Mexico, east of the Baja California. I wonder if there any stations down there that record rain amount?

[Aslkahuna]

There may be some automated stations that were installed during the NAME project but the answer otherwise is only Hemosillo is in that area-there are no other reporting stations. We've often watched those storms from here and wondered about how many people are killed and injured each year by them

Steve

[Ptarmigan]

There may be some automated stations that were installed during the NAME project but the answer otherwise is only Hemosillo is in that area-there are no other reporting stations. We've often watched those storms from here and wondered about how many people are killed and injured each year by them

Steve

You see those storms all the time? Sometimes I see photos of lightning over Tucson. I wonder if they are from those storms over Mexico? Hermosillo is the only city I can think of that is under the storm clouds. These storm clouds are usually near the Pacific Ocean and south of Arizona. You know I wonder if people are injured or killed or if there is any property damage.

[Aslkahuna]

Those storms in Mexico you are talking about are a result of the North American Monsoon which is a seasonal windshift that extends into Arizona and other parts of the SW US resulting in a very definite Summer rainy season with lots of thunderstorms. To give some idea as to the intensity of these storms, their weaker brethren in AZ can have short term rainfall rates in excess of 10 inches per hour with total rainfalls in an hour or less as much as 3-6 inches.

Steve

[Ptarmigan]

Those storms in Mexico you are talking about are a result of the North American Monsoon which is a seasonal windshift that extends into Arizona and other parts of the SW US resulting in a very definite Summer rainy season with lots of thunderstorms. To give some idea as to the intensity of these storms, their weaker brethren in AZ can have short term rainfall rates in excess of 10 inches per hour with total rainfalls in an hour or less as much as 3-6 inches.

Steve

Is it 10 inches per hour? If so, that is really intense!

[Aslkahuna]

Our optical rainrate sensors on a couple of occasions recorded short period rates of 12 inches per hour. I computed a peak rate of 7.2 inches per hour off a recording gauge record in a severe thunderstorm that hit us back in 1986. During the July 25, 2003 severe storm that hit Sierra Vista, 2-4 inches of rain were recorded on guages on Post and in town during a 20 minute interval and I had nearly 2 inches in that same time period. These are the kinds of storms that occur down in Mexico as well. Vaisala in Tucson is anxious to extend the NLDN network down into Northern Mexico because they feel that if they do that that area will replace FL as the Lightning Capital of North America.

[Ptarmigan]

Our optical rainrate sensors on a couple of occasions recorded short period rates of 12 inches per hour. I computed a peak rate of 7.2 inches per hour off a recording gauge record in a severe thunderstorm that hit us back in 1986. During the July 25, 2003 severe storm that hit Sierra Vista, 2-4 inches of rain were recorded on guages on Post and in town during a 20 minute interval and I had nearly 2 inches in that same time period. These are the kinds of storms that occur down in Mexico as well. Vaisala in Tucson is anxious to extend the NLDN network down into Northern Mexico because they feel that if they do that that area will replace FL as the Lightning Capital of North America.

Oh my goodness! That's even more intense than hurricanes! If 12 inches of rain fell per hour in 24 hours, it would 288 inches of rain and that would cause a flood of Biblical proportions. I wonder if these storm clouds sometimes move over the Pacific Ocean and become hurricanes?

[Aslkahuna]

Not usually, because the Pacific Ocean west of Baja is too cold to sustain hurricane development. The MCV's (Mesoscale Convective Vortex) from the Mexican MCS's have been shown to be players in Summertime severe weather events in US when they move up here. The NAME forecasters tracked one in 2004 that caused severe weather from the western US all of the way to the East Coast. Those extreme rainfall rates, it should be pointed out only exist for relatively short periods of time. The storm of July 25,2003 did indeed resemble a hurricane at it's peak (except for the winds which were only in the 60+ mph range) with extreme rainfall and very poor visibility (less than 1/16 mile) and one I videotaped in 1995 I call my 10 minute hurricane because for that period of time it was like an eyewall passage.

Steve

[Ptarmigan]

Not usually, because the Pacific Ocean west of Baja is too cold to sustain hurricane development. The MCV's (Mesoscale Convective Vortex) from the Mexican MCS's have been shown to be players in Summertime severe weather events in US when they move up here. The NAME forecasters tracked one in 2004 that caused severe weather from the western US all of the way to the East Coast. Those extreme rainfall rates, it should be pointed out only exist for relatively short periods of time. The storm of July 25,2003 did indeed resemble a hurricane at it's peak (except for the winds which were only in the 60+ mph range) with extreme rainfall and very poor visibility (less than 1/16 mile) and one I videotaped in 1995 I call my 10 minute hurricane because for that period of time it was like an eyewall passage.

Steve

Interesting. I am surprised we don't here reports from Mexico about those storms. Being under those storms would be no fun. Low visibility and threats of flooding.

[Aslkahuna]

That's remote backcountry with few towns of any size and much of that area has nothing in the way of modern communications (or even electricity for that matter). The NAME Project set up some automated sites but that was for research purposes and the information is not accessible to the Public for a period of time after collection or until the Investigators release it in their Papers.

Steve

[Ptarmigan]

That's remote backcountry with few towns of any size and much of that area has nothing in the way of modern communications (or even electricity for that matter). The NAME Project set up some automated sites but that was for research purposes and the information is not accessible to the Public for a period of time after collection or until the Investigators release it in their Papers.

Steve

I see. I hope to see the research soon. Sounds very interesting. I've seen TRMM measurements of that area, sometimes they get up to 20 inches of rain a week.

[Aslkahuna]

My son was on the NAME forecasting team so maybe he knows what kind of rain measurements they got in 2004.

Steve

[Ptarmigan]

My son was on the NAME forecasting team so maybe he knows what kind of rain measurements they got in 2004.

Steve

Cool. Maybe he will come forward about this.

[Ptarmigan]

I notice Hurricane John is near the area where those storm clouds form over in Mexico.

[peteywheatstraw]

There's a website with many agriclimatic stations to compare data from in Sonora.
Also check the automated stations (EMAS) page on the Servicio Meteorologico Nacional website.