Saturday, 23 April 2016

StormChase 2016

With just 10 days to go until we head across the pond for our annual trip to Tornado Alley thought I would update this blog and look ahead at what might be in store.

The upcoming week looks pretty big for the Southern and Central Plains with a series of ejecting shortwaves crossing the Plains States eminating from a large Upper Low over the Rockies, this begins a series of troughs over the next 7-10 days and a very active pattern looks to set up bumping up the numbers of Tornadoes from what has been a very quiet April and quiet start to the year for traditional Tornado Alley. After a long El Nino dominated winter which has favoured East Coast troughing and west coast ridging the pattern looks to be starting to shift towards one of an East Coast Block allowing troughs to impact the Western States.

Looking ahead to Sunday 24th April this brings the first shot at some severe weather from this period and SPC Have gone with a Slight Risk from mainly Kansas, Missouri and parts of the Midwest, moisture has not really had time to advect northwards for this risk and although Supercells are likely a mainly hail and wind damage threat seems to be likely. Monday looks more benign with H5 Winds more into the west and no such trigger mechanism in place.

Onto Tuesday, this looks to be the big day with another 24 hours of moisture being firmly in place and most models showing high 60's to low 70's dewpoints in place with a sharpening dryline out to the west of I35. A surface low will be situated over Eastern Colorado with a warm front draped from West to East near the Triple Point. 850mb winds look very nice out of the south with H5 Winds initially from the WSW At 30-40kts swinging to the SW Around 00z and increasing to 50-60knts. Would expect a 45% Hatched risk when the SPC updates on Sunday on the SWODY3 And a Day 3 Enhanced or Moderate Risk put out there. There are currently 2 very obvious risk areas for this day with the Warm Front in Central Kansas and the trailing dryline from SW Kansas through Western Oklahoma down to west of Dallas Fort Worth. All the ingredients are there for a Severe Weather Outbreak with Very Large Hail and Strong Long Track Tornadoes. Cape looks to be coming in around 5000jkg promoting very large hail values.

At this present time we would 100% target the Warm Front triple point in Kansas if we were chasing, the Dryline does look amazingly good but I would like to see the models slow down and back a bit west if we were considering this option due to Oklahoma City Metro and also when Supercells mature maybe putting the risk in the Jungles to the East.

Wednesdays Risk also looks like a Solid Enhanced Risk as it stands with the LP Moving towards NE Kansas and Southern Iowa, once again all severe hazards are possible with this Set-Up but have not looked much into the mesoscale features just yet on this one.

Thursday sees the LP Spin away through the Ohio River Valley so expect another risk much further east and with another large Upper Trough already ashore on the West Coast and Surface South Easterly winds advecting moisture Northwards I am expecting almost a repeat performance on Friday 29th April for the Southern and Central Plains.

Things looks to get a lot quieter over the later part of the Weekend as May swings by and with the Jetstream starting to head towards Canada this heralds a return to lower severe weather for the w/b Monday 2nd May.

The Models go out to around the 7th May at this present time so we really cant look much further than the middle of next week, lets hope the 12z GFS Shows the active pattern continuing through the 2nd week of May as the GFS 06z was a little depressing with Northerly winds screaming down the Plains scouring moisture away into the Gulf Of Mexico.

Will update again early part of the next week.

Paul