Strong convergences initiated northeast of Lubbock, TX near Floydada in Floyd County.  CTC product caught -16-17K/15 min around 18:15 UTC on this storm. Tornado warning was issued 19:21 UTC which resulted in 1 hr/6 min lead time if you had warned initially off the CTC projection.

CTC product W/Visible Satellite

The OUN_WRF progged Surface Merged Reflectivity Composite also nailed the point of storm initiation around 1900 UTC(See image below).

Below is the 1900 UTC 2.5KM Theta-E image clearly indicate moisture converging near the point where this supercell developed up through Floyd and Brisco counties northeast of Lubbock. Also, the wind fields verify that there was like good moisture convergence in this same area.

Some of the MRMS (MESH/30 min MESH swath) and HSDA (0.5 degrees showing potential for large hail as well) real-time data gave quick indications that this atmosphere was volatile and showed the storms potential with little latency at 1900 UTC.

This storm has already produced quarter-size hail at 1923Z and a few land spouts (weak tornadoes).

Well, there’s a severe thunderstorm down in the Lubbock CWA and all is quiet here on the northern front…way down south in the TX panhandle that is.  Anyway, an outflow boundary has moved across the area and appears to be settling in west-central portions of the TX panhandle so far.  The image below shows the latest GOES-15 Vis image combined with the 2.5km LAPS theta-e (1845 UTC).  METAR observations are laid atop the image (1900 UTC).  Hopefully, you can notice the reddish colors in the southwest part of our CWA just south of the Amarillo area.   A strong theta-e ridge extends from the Lubbock area into the southern portions of our area per the LAPS data.  So, we’ll be watching that area and the leading edge of the cu field in assoc/w the outflow for development.

Kris

Texas panhandle is the area of main focus for the first part of this afternoon. Analyzing CI, as seen below, indicated development was expected to quickly form by 19z.

Image 1 – CIMSS CTC prior to CI around 18z.

Image 2 – Cloud Top Cooling at the time of CI over the central parts of Texas panhandle around 1815z. Values right around -17oC.

Image 3 – Vis sat around 1815z, with CI. Vis at 1845z shows the explosion of the storm in the panhandle, with the CTC product thus providing around a 30 mins lead time.

Image 4 – With the radar products unavailable at this time, using MESH and probability of severe hail to show the development of the storm to severe levels.  The CI on CTC developed around an hour prior to the MRMS products reaching severe levels.

A very impressive-looking storm produced severe hail in Oswego and Oneida Counties earlier today.  A report of golf ball size hail was received at 2310 UTC near the town of Central Square, which was the largest hail report received while the storm was in the BUF CWA.  Below is an image of MRMS and KYTX radar data at that time.  The MRMS reflectivity at -20C had reached values as high as 71 dBZ at this time!  Additionally, MRMS MESH values had reached a maximum of 3.31 inches.  Interestingly, the HSDA did not indicate the presence of large or giant hail, although there were areas of UK, or uknown classification.

While severe thunderstorm warnings had been ongoing with this storm since 2144 UTC, the steady increase in MESH and reflectivity values at -20C prompted me (the warning forecaster) to issue a new thunderstorm warning with a mention of 2-inch hail.  Granted, we never got reports that large, although that doesn’t necessarily mean it didn’t happen.  Anyway, this was the theme on this day…where the MESH appeared to overestimate the size of hail to an extent, and probably more so as the hail became larger, while the HSDA underestimated the size, or else due to some issues with the algorithm was assigning a UK classification.

Kris and Eric

This was a possible wind event. The MESH and HSDA were nice in helping to quickly determine that the hail threat was very low and thus we just called for wind in our severe thunderstorm warning.  Wesely

The WRF simulated satellite image forecast for 23 UTC (top) compared well with the observed IR satellite (bottom) with respect to the mid-level boundary location across Indiana.  However, it did not handle to convection well which formed over PA.  Instead it showed more convection east of the higher terrain across MD and northern VA.

Isolated severe thunderstorm progressing across north central NY early this evening. MRMS and HSDA along with the local storm reports were utilized in issuing a warning for this storm as it moved from BUF CWA to BGM. MRMS 60 min accum indicated strengthening of the storm as it progressed through the BUF CWA, with reports of between 1 and 2 inches. Both the MRMS and HSDA were both indicative of this.

Issued a severe warning with the increasing trend, mentioning up to 2 inch hail and possible wind damage, with hail being the bigger threat.

Image 1 – Reflectivity with initial warning. Guidance enabled the warning to be issued with plenty of time before even reaching the CWA.

Image 2 – MESH values with 60 min accum indicates hail sizes between 2 and 3 inches. Reports since the warning has been issued have confirmed up to 2.5 inches.

Image 3 – Severe hail probability bringing in 80-90% over areas reporting severe hail.

Image 4 – HSDA indicating large to giant hail.