The following 4-panel at 2249Z from KTYX shows a nice indication of large hail over Oswego County, NY.  The reflectivity is from 8.0 degrees, with MESH upper right, HSDA lower right, and Dual Pol Correlation Coefficient. (see image below). The hybrid HSDA was still underestimating this storm, but the 8.0 deg Z, MESH, and CC all show the potential for large hail.

About 20 minutes later, our HWT class leader Greg Stumpf took this four panel off of HSDA on FSI.  Note: Not only the TBSS is very evident, but you can actually see a horizontal sidelobe indicative of power loss and beam spreading occurring higher up in the atmosphere.  Pretty cool stuff!

Regarding the warning for:

EXTREME NORTHERN CAYUGA COUNTY IN CENTRAL NEW YORK…
SOUTHWESTERN OSWEGO COUNTY IN CENTRAL NEW YORK…
EXTREME NORTHEASTERN WAYNE COUNTY IN WESTERN NEW YORK…

We (The Buffalo office guys) noticed an increase in both the MESH and an increasing 50 dbz core on the KZYX Z slice at 4.0 degrees elevation and above 25 KFT. The Hybrid HSDA did show a slight increase, but no LH or GH just yet (the sever type). Nonetheless, the CC Dual Pol product indicated low values indicative of larger hail as well. Here’s the 2214Z 4-panel of all these parameters.

Here’s what these parameters looked like from KBUF upstream near Oswego, NY.  Everything mentioned above on the parameters was similar to KTYX.

The theme here is using only MRMS and Dual Pol is helpful, but even using base legacy radar data is more helpful when looking from two different RDAs.

MESH did a great job, and was vital in this warning decision. The 50dbz height was to around 25,000ft AGL and a bit below our Donovan threshold for this area today of 28,000ft AGL. The MESH was indicating the possibility of 1″ hail, while the HSDA was just forecasting hail and not large hail. However there were also a few pixels of over 65dbz at -20C which added to our confidence. Therefore a warning was issued and was verified later on by an LSR.  Wesely

The storm shown below has undergone rapid strengthening lately.  This time, I used the 30 minute MESH, composited with the MRMS -20C reflectivity to generate the warning polygon.  The 30 minute product was useful for quickly determining a reasonable extent to my corresponding 30 minute warning.  It also showed indeed that the storm was undergoing strengthening.  In addition, at 2216 UTC, the >1 inch hail threshold was breached by the MESH data (actually looking back it was breached at 2214 UTC).

At the same time, the -20C Isothermal reflectivity was showing values around 60 dBZ (image 2 below).

Kris and Eric

After I blogged earlier myself, along with others earlier about the more stable airmass near the southern Lake Ontario shoreline, I went ahead and issued a severe for NORTHERN CAYUGA COUNTY IN CENTRAL NEW YORK…SOUTHWESTERN OSWEGO COUNTY IN CENTRAL NEW YORK… NORTHEASTERN WAYNE COUNTY IN WESTERN NEW YORK…despite the fact I knew earlier this activity wasn’t severe (and also per real-time reports).  A no-no on my part, but just to prove my point, this is the MESH product at the time I issued that severe thunderstorm warning. Lesson learned (Eric).

Simulated satellite imagery from 00Z WRF runs showed strong convection near the lake in the early afternoon with clearing in western New York during the late afternoon hours.  Convection only sporadically tries to develops until well after 00Z in western New York.

Hail has been below severe limits in the Monroe and Wayne counties in upstate NY.  As noted on an earlier blog, less stable air has slowly advected south across parts of these counties from Lake Ontario.  Below will is the 2102 UTC reflectivity image and corresponding MESH image from KBUF radar.  This is when storms were at their most intense with only half inch hail being reported out of the southwest Wayne Co storm. Another strong storms was developing across central Monroe Co at the time.

Here’s the 2120 UTC radar reflectivity from KBUF and corresponding MESH. The Wayne Co storm has maintained or slightly weakend as it moves towards the more stable airmass off Lake Ontario.  Meanwhile, the Monroe storm has weakened considerably and was closer to the lakeshore. This is basically 18 minutes later from the first capture.

Okay, here’s another golf ball size hail report, this time from a little bit later in far northern  Cayuga County, NY.  First, before I go further, I have to say I like the name of this county…as it sounds like an old car horn.  Anyway, from 2000-2010 a member of the public reported golf ball size hail near the town of Cato.  Here’s an image from the middle of that period (2004 UTC), using the MRMS and KTYX HSDA data.

Notice again the absence of large or giant hail in the HSDA data from KTYX (the closest radar).  I’m thinking I may have to look at higher slices from the KTYX dual-pol and start analyzing those slices of the HC data.  Of interest, notice also the TBSS appearing in the MRMS reflectivity and the KTYX HSDA data.

Kris and Eric

We had two rotating thunderstorms. One rotating storm across the southeast portion of our CWA (Image 1) and a second storm near our northern CWA border (Image 2).

Storm number 1 as seen in image 1 had a nice long rotating track that had modest rotation at times. This was a good distance from the radar so even at the lowest slice was rather elevated. Felt the rotation was weak enough and elevated enough to just keep it a svr thunderstorm warning. Reflectivity also did not look overly impressive. We did get several severe hail reports.

Storm number 2 as seen below also had a persistent rotating updraft, but rotation was not as strong as in storm number 1 above. This storm did produce golf ball size hail, but the rotation was not significant enough to warrant a tornado warning. Thus we went with severe thunderstorm warnings. WeselyWesely