Several energetic storms...

Thom and I got to Hays about the time that the tornadic storm north of Russell had a beautiful hook...but it was also moving into colder air. It was part of a discontinuous line of storms extending from north of I70 to about 40 miles south. There was a break in the line on I70, and our intent was to punch through to the other side and then drive north to either the first cell or the second one that now was tornado warned. But, the area filled in, and we had a half hour of driving through torrential rain....with the GRLevel signal dropping out, and also Mobile Threatnet missing every other scan. By the time we cleared the line...almost to 20 miles west of Salina, the first storm had croaked, and the second one was a gigantic HP mess. 


We kept our eyes on the Pratt area...because the bubbling cumulus field down there seemed sure to erupt.   We stayed with it as it was producing strong mesocyclones and tornado warnings near LIncoln. We saw some supercellular structures embedded in the rain, but nothing too dramatic. We also dropped down to the next storm to cross I70....that developed a hook...and parked ourselves and stayed with the inflow notch for a half hour or so....but the inflow base looked ragged and never showed much sign of rotation.  The radar image shown above shows the mesocyclones and the hook (as well as Mobile ThreatNet can depict it).  The yellow range rings really are centered on the GPS location of our car (with the rings at 5 mile intervals).  Note that we were in "the" location to witness any tornado....but it was not to be.

We soon gave up and dropped south to Salina. All in all, kind of a waste of the great potential this pattern had. 

Onto west-central Kansas

 

We arrived...and picked up our vehicle...a Chevy Equinox.   While driving east to the target (still basically the same) we are trying to setup the computer, MIFI, GPS antenna, cell phone signal amplifier and making sure the software is operating correctly.

Southwest KS is clearing out, and moisture is coming northward through Pratt towards Interstate 70, which we are on.  The target is in that general area shown by the box on the surface chart to the right.

Onto the Great Plains

 As we ready for departure to Denver, our target has not shifted.  The wave cyclone currently in southwestern KS will shift northward with the warm front near I70.  We are targeting the area south of Russell, KS, where forecast hodographs have long length.

The hodograph also has large 0-1 km shear values.

More as time permits.

First Day Target --- More or Less Unchanged

Just updating our target on our first day out, tomorrow, Thursday 19 May.  We depart Oakland on a 6:10 AM flight to Denver.  Given the time change, the flight is scheduled to arrive 9:45 AM MDT.  There is a strong jet stream present extending from California to the Plains (see post below), so it's possible we'll get to Denver a bit early.

As you can see from SPC's Day 2 Outlook, the area we are targeting is now within SPC's outlook range.  The red area encompasses the area in which there is a larger than 30% probability that a severe thunderstorm will be within 25 miles of a point.

Also note the hatching.  This indicates that within that area there is an enhanced probability that some of those storms can produce high-end severe weather events (EF2-EF5 tornadoes and/or Hail >2" diameter and/or sustained winds 74 mph or stronger).

Once tomorrow's convective outllook passes into the Day 1 range, they will be honing those risks.  But, we feel that the greatest threat for tornadoes is from the western tip of that red area south through sw Kansas and into the extreme northwestern area of Oklahoma, given the buoyancy and shear fields.  Some of the parameters related to rotation production in storms are at the extreme high end of their ranges (climatologically speaking) for that area, with the largest values in Kansas.

This means that we will have to get the car setup quickly.  A lapstop stand with power inverter, three antennae (onboard radar, GPS, and cell phone amplifier) need to be immediately functional so that we can get data as we are driving...and we need to be driving quickly.  That risk area looks close to Denver on the above map, but there's still at least 200 to 300 miles or more of driving we need to do to get into the target area close to initiation time, which is liable to be around 4PM local time.

Storm Chase Trip 2011 -- In to the Great Plains, May 19th

Well, it's hard to believe that a year has gone by....but here we are about three days before our trip into the Plains. The long range forecasts have been showing a favorable pattern for the first week or so of our trip.

The first graphic here is the composite (average) of 500 mb weather patterns for similar weather maps at this time of year in the past....it shows a fairly dramatic trough in the far West, setting up a favorable jet stream pattern over the Plains.


The dates shown on this figure indicate the best matches from past years, by year and date. We won't try very hard to look at that, because some of those dates include some very significant tornado events.


We'll be posting each day, and probably on the fly during the day, as we can now post images via our cell phones, and we'll have live access to the web in the car. We're looking forward to this, our 26th storm chasing trip....gad...how time has flown. Meanwhile, Thom will be posting updates to his WildGeeseChase.org blog. That's the real story behind the scenes....


The pattern on the day that we arrive in Denver, May 19th, is setting up nicely for some severe thunderstorms in north central and central KS. So our target will be the area from Salina back west to Hill City or so (of course, to be adjusted as approach the time of our departure). The map shows our target as a blue box, and you can see we will be at the intersection of a dry line, cold and warm fronts...often called a "triple point" by storm researchers.

I have plotted a sounding and hodograph for the region between Hill City, KS and Salina for around 6PM CDT for Thursday. The red area shows the surface-based CAPE (the region where an ascending air parcel will be warmer than its surroundings and will freely loft). The hodograph is very interesting, as it shows that the low level wind shear will be quite strong, 20-30 knots underneath a very strong southewesterly jet. If this profile develops, then storms will rotate strongly, and the low level shear tells us that isolated storms are liable to become tornadic.