May Verification and June Forecast 2015

First, let's recap the May forecast:

This May will finish with something close to 401 preliminary tornado reports (I will update this when the final May numbers come in).  The 30-year normal (1985-2014) for May is 252 tornado reports, for a final May 2015 tally of 159% of normal.  This falls into the "Above Average" ERTAF category.

Despite a record slow start to the year, April and May have combined to get us back to just shy of 100 tornadoes from the latest ten year average:

Image courtesy of the Storm Prediction Center

I would say this forecast worked out reasonably well, as it called for 90% chance that May would end up average or above average in terms of reported tornado activity. 

Onto the June forecast! 

Based on the current large scale pattern, dynamical models, analog approaches, and ongoing research, here is my forecast for June 2015:

20% Chance Below Average |  50% Chance Average | 30% Chance Above Average

For those interested, sub-monthly forecasts (ERTAF) are being made weekly (issued on Sunday evenings) and can be found here.

Here is a map of reported tornadoes for the month of June:

Caveat emptor: These forecasts are solely my own and do not represent an official forecast from any corporation or government agency. Please use caution when interpreting the results and respect their origin.

5/22/2015 County Rd. J. Colorado Storms

Been quiet over here lately.  The weather pattern has not exactly cooperated with our trip the past few days, but Friday yielded a photogenic storm northeast of Pueblo, CO. We started the morning in Amarillo, TX, to an overcast and murky sky, but quickly broke into sunshine near Campo, CO. We pitted in Eads, CO for lunch (yummy restaurant there!) and traveled northeast toward Limon, CO where persistent convection was starting to look more interesting.  We caught up with the cell near Hugo, CO, before it crossed north of the warm front into cooler air, causing the storm to weaken. Our sites then turned to the Pueblo area, where new development near the mountains was progged to head into a more unstable environment.  We watched this beauty of a storm for almost two hours before packing up and heading to Burlington, CO for the evening.  Below are some pictures of yesterday.

MISC:  Overnighted at the swankey Burlington, CO, Best Western Plus. Also, I have never been so COLD on a storm chase!

Pileus forms over a developing updraft 

5/18/2015 Pecos, TX Supercell and Coyanosa, TX Flash Flooding

Monday featured a well-mixed boundary layer with dewpoint depressions in the 30F range.  While we did not think the environment was favorable for significant tornadoes, we were still very interested in tracking isolated supercell development rolling off of the Davis Mountains in southwest Texas. After getting on the road, we stopped for a quick lunch in Midland, TX, before travelling to Fort Stockton, TX as an initial target.  Our plan was to get to Fort Stockton and launch a weather balloon from the western edge of the better boundary layer moisture.  We met up with the U.S. Naval Academy field group (led by Drs. Brad Barrett and Gina Henderson) in Fort Stockton in anticipation of the launch.  It was nice to mingle with their group and send up our first successful weather balloon launch from the field!

As we launched the balloon (video below) convection was beginning to form near the Davis Mountains as expected. Our sounding confirmed the suspicion that LCLs were too high for a significant tornado threat. After the balloon made it into the stratosphere, we packed up and headed toward Pecos, TX, where the storm was now maturing into a beastly supercell with very large hail.  We sat southeast of Pecos for several hours watching this nearly stationary storm.  It had some nasty inflow (we measured several gusts over 35 mph) but always seemed to have a strong surface cold pool within a few miles or so from the storm.  In fact, it really never had an established updraft area location.  Nevertheless, it was a very pretty storm and made for easy chasing given the slow storm motions.  

After it was clear the storm was not going to get any "better", we fled north behind the core to get back to the interstate (in hindsight, I should have just navigated the team an extra hour out of the way back toward Pecos).  On the way, we encountered the worst flash flooding I have ever seen in my life a few miles south of Coyanosa, TX. We saw (at least) three vehicles swept off of the road into the rapidly rising water! Hail drifts created dense hail fog as waters continued to rise and roads completely covered with at 4-8 inches of water. We found a high/dry spot and waited the worst of the flooding out, but training thunderstorms were creeping from the southwest and I was worried that things we about to get a lot worse.  We got in a train behind some larger vehicles who went first and created a nice wake for us that we were able to comfortably get through.  I am very happy we were able to get out when we did, because we found out later from the NWS that this area now has over 4 ft. of water covering the road!

I never felt we were in a dangerous position until I saw the increase in thunderstorm activity to the southwest of our location.  It was clear that things were about to get ugly fast. A great reminder to always be aware of flash flooding. It is an often overlooked hazard of severe convective storms

MISC: Overnighted at the brand new Courtyard in Lubbock, TX for the second night in a row.

5-18-2015 Weather Balloon Launch Data

Panorama just southeast of Pecos, TX (looking north)

5/16/2015 Elmer/Tipton EF2 Tornado

Saturday was a rather exciting day for the newbies on Trip 2. Not only did they get to see their first tornado, it just happened to be an EF2 wedge tornado that we watched for 30+ min. and tracked over 30 miles.

Here is the preliminary damage survey report from the local National Weather Service office in Norman, OK:

934 PM CDT SUN MAY 17 2015

...NWS DAMAGE SURVEY FOR 5/16/15 TORNADO EVENT

.ELMER-ODELL-TIPTON-SNYDER TORNADO...

RATING:                 EF-2
ESTIMATED PEAK WIND:    125 MPH
PATH LENGTH /STATUTE/:  35 MILES
PATH WIDTH /MAXIMUM/:   TO BE DETERMINED
FATALITIES:             0
INJURIES:               0 KNOWN

START DATE:             MAY 16 2015
START TIME:             APPROX 535 PM CDT
START LOCATION:         6 SW ELMER / JACKSON COUNTY / OK
START LAT/LON:          34.42 / -99.42

END DATE:               MAY 16 2015
END TIME:               APPROX 645 PM CDT
END LOCATION:           APPROX 3 E SNYDER / KIOWA COUNTY / OK
END LAT/LON:            34.66 / -98.90

SURVEY_SUMMARY: INFORMATION ABOUT THIS TORNADO IS STILL VERY
PRELIMINARY. A LARGE MULTIPLE VORTEX TORNADO DEVELOPED IN
SOUTHERN JACKSON COUNTY OKLAHOMA SOUTHWEST OF ELMER OKLAHOMA AND
NORTH OF ODELL TEXAS... AND MOVED NORTHEAST THROUGH THE FAR
NORTHERN PORTION OF WILBARGER COUNTY TEXAS... THEN BACK INTO
JACKSON COUNTY OKLAHOMA SOUTHEAST OF ELMER. THE TORNADO CONTINUED
NORTHEAST MOVING THROUGH TILLMAN COUNTY FROM WEST OF TIPTON TO
SOUTHWEST OF SNYDER... THEN CONTINUED IN KIOWA COUNTY FROM SOUTHWEST
OF SNYDER TO EAST OF SNYDER. THE DISSIPATION POINT OF THE TORNADO
HAS NOT BEEN DETERMINED YET. THE MOST INTENSE DAMAGE FOUND SO FAR
IS CONSISTENT WITH AN EF2 TORNADO.

.CLEO SPRINGS TORNADO...

RATING:                 EF-1
ESTIMATED PEAK WIND:    105 MPH
PATH LENGTH /STATUTE/:  12 MILES
PATH WIDTH /MAXIMUM/:   50 YARDS
FATALITIES:             0
INJURIES:               0 KNOWN

START DATE:             MAY 16 2015
START TIME:             622 PM CDT
START LOCATION:         5.5 NW FAIRVIEW / MAJOR COUNTY / OK
START LAT/LON:          36.32 / -98.56

END DATE:               MAY 16 2015
END TIME:               642 PM CDT
END LOCATION:           4 NNE CLEO SPRINGS / MAJOR COUNTY / OK
END LAT/LON:            36.46 / -98.42

*SURVEY_SUMMARY: A TORNADO DEVELOPED ABOUT 5.5 MILES NORTHWEST
OF FAIRVIEW IN MAJOR COUNTY AND MOVED NORTHEAST TO 4 MILES NORTH-
NORTHEAST OF CLEO SPRINGS JUST EAST OF HIGHWAY 8 AND SOUTH OF THE
ALFALFA COUNTY LINE. THE TORNADO PASSED ACROSS THE NORTHWEST
CORNER OF CLEO SPRINGS WITH ADDITIONAL DAMAGE IN CLEO SPRINGS
CAUSED BY ADJACENT THUNDERSTORM WINDS. THUNDERSTORM WIND DAMAGE
CONTINUED NORTHEAST FROM WHERE THE TORNADO DISSIPATED TO AREAS
NEAR AND SOUTHWEST OF HELENA IN ALFALFA COUNTY.

EF SCALE: THE ENHANCED FUJITA SCALE CLASSIFIES
TORNADOES INTO THE FOLLOWING CATEGORIES.

EF0...WEAK......65 TO 85 MPH
EF1...WEAK......86 TO 110 MPH
EF2...STRONG....111 TO 135 MPH
EF3...STRONG....136 TO 165 MPH
EF4...VIOLENT...166 TO 200 MPH
EF5...VIOLENT...>200 MPH

Photos of the event (some photos have been contrast enhanced):

Courtesy of Trip 2 assistant Matt Piechota

5/15/2015 Norton, KS to Araphahoe, NE Thunderstorms

Day 1 of CoD Thunderstorm Lab trip 2 set sights on central/western NE for severe storm activity.  The prospects for tornadoes trended down throughout the day, but we were able to latch onto a pretty storm near Norton, KS.  Below is a tonemapped shot of that storm.  Tonemapping can occasionally make a photo *pop*, and I thought that this was an appropriate photo to apply the technique to (not all photos look good with tonemapping).

MISC: Overnighted in Lexington, NE.

5/9/2015 Grinnell, KS Tornadoes

Dad and I left for the plains the previous evening in anticipation of Saturday's severe convective risk. It was clear that there would be severe weather somewhere, but a cold pool from overnight thunderstorms ended up greatly reducing the severe weather potential.  Despite the worked over surface air, severe weather still occurred corresponding to the rather impressive upper tropospheric dynamics in place.  Initially targeting southwest KS, the region was slow to clear and we quickly set our sites on strengthening convection in Colorado (storm motions we not in our favor!).  We stopped near Lakin/Tribune, KS, and met up w/ Walker Ashley (NIU meteorology professor), Stephen Strader (NIU Ph.D. student), and Alex Haberlie (NIU Ph.D. student).  It was Alex's first time to the Great Plains, so of course we gave him a hard time about what he had done to the day's setup.  Keeping the warm front in play, we continued northeast out of Tribune to a very turbulent sky. Whirling eddies, interesting cloud formations, and a warm frontal boundary made for interesting conversation in the car while traveling east toward our overnight destination of Salina, KS.  As luck would have it, a cell formed right on the warm front near Wakeeney, KS and immediately produced a tornado.  It wasn't too long before another (what appeared to be stronger) cell formed in southern Gove county Kansas lifting north toward Grinnell.  It was this cell that we targeted, and it really paid off despite some really frustrating initial views of this storm.  We were caught north in the forward flank of the storm and knew it was producing a tornado, we just could not see it.  Every second that passed caused frustration, as we knew we would be in a great place if the precipitation core would just pass north of I-70.  Eventually it did, and a nice elephant trunk tornado came into view. 

We saw at least 4 different tornadoes, with a few of them occurring after dark north of Grinnell (see one of these tornadoes in my poor quality video below).  It was great to get pops his first tornado, despite the dark and rainy conditions which made photographs extremely difficult.

Overall, it was a great quick trip to the Great Plains and Pop's first tornado experience.  I got to test out some new gear in anticipation of our upcoming Thunderstorm Lab field Trip (CoD Trip 2).

Track our trip on twitter (@gensiniwx ; @cod_stormchase)! 

April Verification and May Forecast 2015

First, let's recap the April tornado activity forecast:

The forecast called for 20% chance of being below average, 40% chance of being average, and 40% chance of being above average. 

April averages 131 tornado reports (1950-2014).  This average is slightly higher (163) if considering only the period 1985-2014. This year, the U.S. tallied 181 preliminary tornado reports during April (calculated using the filtered preliminary tornado reports from the Storm Prediction Center), thus putting us at 138% or 111% of normal tornado reports this month, depending on the averaging period.  For ERTAF, I have been using <75%, 75<=x<=125%, and >125% of normal climatology (based on the 85-14 reports) to classify BA, A, and AA activity respectively.  This is obviously subjective and unimportant, as the atmosphere could really care less how we try to split these categories.  I am going to run with the lower, 111% of normal for April 2015, thus putting the month at average tornado reporting activity.  This aligns nicely with the April forecast for a 40/40 split between A and AA conditions. 

Environmentally, one can see that the atmosphere was much more favorable for severe convective storms this April relative to the previous March post! 

Red pixels indicate negative LI anomalies, which are indicative of an anomalously unstable atmosphere supportive of thunderstorms.  The greatest LI anomalies were found in the southern Great Plains and Gulf Coast areas, coincident with the greatest density of tornado and other severe weather reports. 

So, what's up for May?

Based on the current large scale pattern, dynamical models, analog approaches, and ongoing research, here is my forecast for May 2015:

10% Chance Below Average |  50% Chance Average | 40% Chance Above Average

For those interested, sub-monthly forecasts (ERTAF) are being made weekly (issued on Sunday evenings) and can be found here.

Here is a map of reported tornadoes in the month of May: