Opening day

One of the first things I noticed was the displacement of the GLM from the storm cores. The lightning as indicated was not in locations I would expect - did not match up with the location of the storm cores indicated in ProbSevere/NEXRAD... nor was there much agreement with CG locations from NLDN.

Watching line of convective storms moving through Albany CWA. Tested the SNPP NUCAPS sounding. The legacy product showed very low SBCAPE 349 (2) ahead of approaching squall line, as surface temp was cooler than surrounding obs. Manually corrected the legacy sounding to nearest ob, and increased the SBCAPE to approximately 2000 j/kg. Waited another few minutes and when the experimental NUCAPS sounding came out (2), the same location (nearest point Charleston 4 Corners) already included the warmer surface temperature, and resulted in a SBCAPE of 2804.


    (1)                                                                (2)

Watched a line of thunderstorms move into this area. ProbSevere wind increased from 40%  to 54%. Noted velocity on KALY radar. I issued a warning for wind threat, leaning heavily on ProbSevere trend upward.



Squall line moved into the box, and ProbSevere wind increased in time, 57% to 72% to 75%. 



During this time, at least three LSR's were produced:

(08:48:33 PM) nwsbot: Local Storm Report by NWS ALY: Charlton [Saratoga Co, NY] 911 call center reports TSTM WND DMG at 04:19 PM EDT -- wires down. time estimated by radar.
(08:51:07 PM) nwsbot: Local Storm Report by NWS ALY: Ballston Center [Saratoga Co, NY] 911 call center reports TSTM WND DMG at 04:31 PM EDT -- downed tree.
(09:00:08 PM) nwsbot: Local Storm Report by NWS ALY: Amsterdam [Montgomery Co, NY] facebook reports TSTM WND DMG at 04:01 PM EDT -- reports of two downed trees in amsterdam. one on truax road and second near intersection of church street and cornell street.

As squall line moved out of my box, I had to decide what to do with it. Based upon ProbSevere trend, and as my partner pointed out, lightning trend diminished, I downgraded to SPS.



I issued SPS for 30 minutes, and there was one LSR generated during the valid time...

 (10:28:49 PM) nwsbot: Local Storm Report by NWS ALY: Clifton Park [Saratoga Co, NY] 911 call center reports TSTM WND DMG at 04:51 PM EDT -- trees down.

... but actually the line diminished in intensity very quickly a few minutes later.

It appears that if a forecaster had used ProbSevere only, they would have done just fine in handling this event.

Two issues that affected satellite usage:
-Data unavailable due to cloud cover from neighboring convection
-Concerns about using satellite data in specific locations due to satellite displacement of features


-tvguy