Wednesday, September 14, 2011

Peace out Monsoon Season

All good things must come to end at some point I suppose, and looks like the North American Monsoon season is all wrapped up.  However, it went out with a BANG!   Cold upper trough camped out across southern California the past 5 days now-which has allowed rich monsoon moisture to interact with some dynamic forcing from the low.   The result being pretty vigorous thunderstorm activity.   On Sept 12, Flagstaff had one of the biggest hailstorms in recent memory blowing in at 6am of all times, the past several days also witnessed numerous tornado warned supercells with impressive wind velocity structures evident on radar, not the typical weak monsoon storms we are used to seeing.   And finally, today, as the low kicked out across the state, cold temperatures aloft, a little wind shear, and some dynamics resulted in a few rotating supercells producing large hail.


Given the end is so near, I took to my afternoon to get one more storm chase in before the dry fall air set in.  Storms took off to the southwest of Flagstaff and moved quickly northeast.  The initial storm had a strongly rotating though broad cloud lowering, which eventually blew outward into an impressive low hanging gust front.  Check out the pic below.


Some small hail followed but the storm weakened rapidly as the gust front blew overhead.  Meanwhile, another strong storm blew up to the southwest taking a similar trajectory.  This storm intensified very quickly while it approached.  I pulled off on Fox Ranch Road and took some pictures.  An interesting cloud feature of some kind developed over the freeway as the storm moved just to my north.    Very low, rising clouds, not visibly rotating but moving upwards and eastwards very quickly formed in a mater of 60 seconds.  Not exactly sure what it signals, cloud be a gust front, low level mesocyclone, both, but in any case...a pretty dramatic storm.  There was also some incredible lightning!



I drove back up the freeway where the storm core had just blown through.  I found a 3 or 4 mile from north to south swath of hail extending up to the south edge of Munds Park (Again).  Most of the hail was dime to nickel size, with a smattering of Quarter and larger stones.  Lots of hard, clear ice stones....so I'm glad I didn't get caught in it with the new Kia, might have ended up with some good dings.





As you can see above, the hail shreded a lot of leaves off the trees and there was a lot of little debris in Munds Park.    There may still be a stray storm or two left before winter sets in across the high country, but with dry weather returning next week and the sun angle getting lower by the day...it's becoming less and less likely unless some big storm system comes through to help us out.   So I thoroughly enjoyed what the past 5 days brought, and got some great footage as well.  If you haven't, check out my lightning video, pretty cool!

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Friday, September 9, 2011

Munds Park Hailstorm!

Pretty cool weather pattern Northern Arizona finds itself in this week with a cool upper trough nearby and some residual monsoon moisture around.   The result-STORMS!  Yesterday we had some very impressive storms in Bellemont and Flag with pretty good organizational structure unlike what we normally see.  And today as well!

Around 12pm storms began to erupt across the I-40 corridor, and I was interested to see if a stronger more organized cell could develop. One cell deviated in motion a little to the right of the mean flow, and moved towards Munds Park.  I jetted down I-17 to try and catch it, it was still kinda weak at that point and not the most promising storm I've ever seen, but I figured why not, its my day off.   Little did I know it would really take off as I approached it.  Below is the radar image of the storm as its moved towards me, I'm basically where the pink is, indicating probable hail. It even has a bit of a supercell structure to it, but that's just speculation without a high res velocity image, which I lack when I am not working.


When I got to Munds Park, a nice shelf cloud was moving in from the west, rather quickly, with nearly constant cloud to ground lightning strokes.  I pulled into a gas station parking lot and took some pics, managed to catch a lightning strike even!









I drove further south of Munds Park a few minutes later to catch a better view of the shelf cloud, but if your travel too far south you fall of the edge of the Mogollon Rim into the desert, and I wanted to stay on the higher terrain.   The clouds were very agitated in appearance, with a slight tinge in color which was rather ominous.

So then I moved back towards Munds Park, when it really let loose.  I pulled into the Chevron Parking lot and saw a lightning strike no more than 300 feet away right behind the building, I don't know if I've even been so close while looking the right direction. It was AWESOME! It really started to hail so I decided to travel south to try and avoid hail damage on my brand new car, but the hail ended up getting bigger (Sometimes I wish I had mobile internet to know these things), so I pulled off about 2 miles south where the hail had begun to rapidly accumulate.  







As the hail let up, I took some pictures of the hail and motorists hiding under overpasses from the hail.  The hail was 3-4 inches deep at some places on I-17 southbound.   Pretty cool stuff!   Most of the hail was between nickel and quarters, so nearly 1 inch hail.  Wouldn't be surprised at all if a few stones out there approached 1.5" or so.   I did hear a couple very loud bangs on my Kia, but no damage fortunately.








Headed back to Flag around 230pm and took some pics of nice hail fog on the way back.  With the weather pattern not changing a whole lot in the next few days, I'm hoping to catch some more cool storms on my 3 day weekend!  Finally, I'll attach a video of the hail storm at its peak when I pulled off on Schnebly hill Road and waited for the hail to subside, pretty intense!


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