july 4 th 2012 severe weather case review and dss andrew loconto nws burlington, vt andrew loconto...
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July 4th 2012 Severe Weather Case Review and DSS
July 4th 2012 Severe Weather Case Review and DSS
Andrew Loconto
NWS Burlington, VT
Andrew Loconto
NWS Burlington, VT
Presentation OutlinePresentation Outline
• Brief Background
• Synoptic-scale & Radar Overview
• NWS Decision Support Activities
• Brief Background
• Synoptic-scale & Radar Overview
• NWS Decision Support Activities
IntroIntro
• High-end severe weather event coinciding with 4th of July holiday (many outdoors)
– Potentially bad things could have happened…
• NWS and Media Partners did an outstanding job given these circumstances
• High-end severe weather event coinciding with 4th of July holiday (many outdoors)
– Potentially bad things could have happened…
• NWS and Media Partners did an outstanding job given these circumstances
Storm Reports from July 4thStorm Reports from July 4th
Notable Reports: 63 mph gust at BTV 75 mph gust at
Diamond Island Tennis Ball Hail in
Peasleeville, NY (Clinton County)
Ping-pong ball Hail in Canton NY
Storms #1: Northeast Kingdom Mini-bow echo
Storm #2: “The Pig” Supercell in St. Lawrence County
Storm #3: Champlain Valley Bow Echo
500mb jet of ~ 85 kts
By 00z, 700mb winds increased to ~35-40kts due to passage of Quebec mid-level shortwave trough
700 mb Analyses
Northwest Unidirectional Deep-layer shear profile
0-6km shear magnitudes support organized multicells/some supercells …
22z LAPS Sfc-based CAPE/CIN & Sfc Obs
Much more stable in eastern VT due to first bow echo passing through ~1 hr earlier
CAPEs exceeded 3000 J/kg in Champlain Valley; similar CAPEs in southern St. Lawrence Cty.
RAP 40km Deep-layer Shear at 21z
North Country deep-layer shear of 40-60kts higher than 00z ALB sounding (closer to strongest mid-level winds)
CAPEs in excess of 2000 J/kg for most of the North Country
Northwest Flow: Bad!
Storm #1: Northeast Kingdom Bow EchoStorm #1: Northeast Kingdom Bow Echo
Evidence of a hook-echo at 0.5° (~10,000 ft elev.)
TBSS signature indicative of hail
68 dbZ to 25 kft upradial of TBSS… probably big hail
5.1° Z (up to ~38 kft) … still had ~60 dbZ up to this height
6.4° Z (up to ~46 kft) … 52 dbz at this level!
Storm #2: “The Pig” – SLV SupercellStorm #2: “The Pig” – SLV Supercell
Storm #2: “The Pig” – SLV SupercellStorm #2: “The Pig” – SLV Supercell
0.5° SRM: Broad Low-/mid-level rotational couplet (~10,000ft AGL)
6.4° SRM: Storm Top Divergence (~46,000 ft AGL)
Storm #3: Champlain Valley Bow Echo @ 2215ZStorm #3: Champlain Valley Bow Echo @ 2215Z
Much of the impacted area very unstable (recall the > 3000 J/kg LAPS CAPE). No reason to believe storms wouldn’t continue to weaken…
Storm #3: Champlain Valley Bow Echo @ 2310ZStorm #3: Champlain Valley Bow Echo @ 2310Z
Office Decision Support Actions
Office Decision Support Actions
DSS Activities: Work Log Entries
DSS Activities: Work Log Entries
Use of Social Media:Storm ExpectationsUse of Social Media:Storm Expectations
Morning Pre-Storm “Heads-Up”
Severe T-Storm Watch issuance – great job of informing the public of the impending destructive wind threat!
NWSChat Logs
Will be updating this form soon Will be placed on the Severe Intranet
page for easy access Good place to document what worked
and what didn’t work out so well: Helps us improve as an office Identify Changes/Best Practices SWOP staffing model changes?
SummarySummary
• High-end severe outbreak that took place during a busy holiday.
• Office decision support activities should serve as a model for future outbreaks.
• MANY THANKS to our media partners for getting the message out!
• High-end severe outbreak that took place during a busy holiday.
• Office decision support activities should serve as a model for future outbreaks.
• MANY THANKS to our media partners for getting the message out!
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