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Pulse Thunderstorm Operating Strategies. Mike Cammarata NOAA/NWS Columbia, SC. Overview. Introduction What we look at What we look for An example. Climatology. Thunderstorm days at CAE (per LCD) May 6.1 June 9.3 July 12.3 August 9.4

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Pulse Thunderstorm Operating Strategies


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pulse thunderstorm operating strategies

Pulse Thunderstorm Operating Strategies

Mike Cammarata

NOAA/NWS Columbia, SC

overview
Overview
  • Introduction
  • What we look at
  • What we look for
  • An example
climatology
Climatology
  • Thunderstorm days at CAE (per LCD)
    • May 6.1
    • June 9.3
    • July 12.3
    • August 9.4
  • That’s at a point…we have radar ops for predominately pulse storms on the order of twice those numbers
  • Prime time … noon through 8 pm
pulse storm severe weather threat
Pulse Storm Severe Weather Threat
  • Microbursts
    • Less than 4 km in outflow diameter
    • Peak winds last 2-5 min at most
    • Potential for F0 – F1 wind damage
    • Wind shear may reduce aircraft performance
  • Large Hail
    • Usually 0.75 to 1.00 in
convective potential analysis
Convective Potential Analysis
  • Analysis of stability and shear paramteters
  • During the convective season we do this every day at least twice per day
  • Important to anticipate convective mode and type of threat
  • Factors into warning decision e.g., if downburst threat is high, more likely to issue warning for marginal criteria
mesoscale desk
Mesoscale Desk
  • Ongoing meso analysis helps us to anticipate convective initiation and monitor Near Storm Environment for ongoing event
  • Satellite and lightning data very important
  • Look for trends
  • Satellite sounder data
  • ACARS data
mesoscale desk http www orbit nesdis noaa gov smcd opdb aviation mb html
Mesoscale Deskhttp://www.orbit.nesdis.noaa.gov/smcd/opdb/aviation/mb.html
mesoscale desk13
Mesoscale Desk
  • http://www.orbit.nesdis.noaa.gov/smcd/opdb/aviation/mb.html
    • LI
    • TPW
    • CAPE
    • CIN
    • WINDEX
    • Theta-e deficit SFC – 300 mb
    • Wet Microburst Severity Index (WMSI)
    • GOES Soundings
mesoscale desk http www orbit nesdis noaa gov smcd opdb aviation mb html14
Mesoscale Deskhttp://www.orbit.nesdis.noaa.gov/smcd/opdb/aviation/mb.html
mesoscale desk15
Mesoscale Desk
  • The Local Analysis and Prediction System (LAPS) integrates data from virtually every meteorological observation system into a very high-resolution gridded framework centered on a forecast office's domain of responsibility. Thus, the data from local mesonetworks of surface observing systems, Doppler radars, satellites, wind and temperature (RASS) profilers (404 and boundary-layer 915 MHz), radiometric profilers, as well as aircraft are incorporated every hour into a three-dimensional grid covering a 1040km by 1240km area.
mesoscale desk16
Mesoscale Desk
  • LAPS Sounding for CAE
mesoscale desk17
Mesoscale Desk
  • LAPS CAPE
  • LAPS SFC Wind
  • Radar mosaic
  • LAPS analyses are available for a variety of surface and upper air fields
slide18
Mesoscale DeskSPC Web site – Composite Maps and Hourly Mesoscale Analyseshttp://www.spc.noaa.gov/exper/mesoanalysis/s1/index2.html
staffing
Staffing
  • Minimum requirements
    • Radar operator/Warning Met
    • Meso (TAF’s, NOW, SPS, ongoing convective and meso analysis)
    • Synoptic (grids, updates to public products)
    • HMT (2) (NWR, NOW, SPS, LSR, Hydro)
    • Coordinator
    • Ham Radio Net Controller(s)
    • Additional staff if widespread convection
    • Sectorize if you can
    • Polygon beta test site
  • Verification … real time and subsequentday
what we look at
What we look at
  • CR/VIL Combo
    • Lower values filtered (<30 dBz, <30 g/kg)
    • Highlights stronger cells, cuts down on clutter
    • Looping reveals trends
    • Filtering can highlight outflows
  • Overlay
    • Lightning (look for trends)
    • MSAS wind barbs (convergence)
    • LAPS/MSAS LI or Cape (instability)
what we look at21
What we look at
  • CR
  • Laps wind barbs
  • Lightning
what we look at22
What we look at
  • Good example of color scheme highlighting outflow boundaries
what we look at23
What we look at
  • LRM2 (24-34kft), LRM3 (>34kft), ULR, VIL, ET
    • Lower values filtered
    • Look for values surpassing thresholds
    • ULR can be set based on expected height of storm or temp level e.g., -20C
what we look at24
What we look at
  • 4 Panel
    • VIL
    • CR
    • LRM2
    • LRM3
  • 63 dBZ > 24k ft
  • 56 dBZ > 33k ft
what we look at25
What we look at
  • All tilts Z/V 8 bit – monitor data as it arrives
    • Elevated high reflectivity cores
    • MARC signatures
    • Storm top divergence
    • Strong low level winds
  • 4-panel Displays can be used as well
what we look at26
What we look at
  • 4 Panel display shows high reflectivity cores and TBSS
what we look at27
What we look at
  • RCS (used heavily)
    • High reflectivity cores
    • Tilt
  • VCS (used by some)
    • Storm Top Divergence
    • Mid-level convergence
    • Near ground divergence – outflow
what we look at29
What we look at
  • CR/VIL, LRM’s, ET’s from adjacent offices
    • Different perspective
    • Corroboration
    • Cone of silence
what we look at30
What we look at
  • Base Velocity 0.5 8 bit
    • Look for strong low level radial velocities
    • use a “compressed” 8 bit color curve to better highlight velocities near threshold values.
    • Only good within 30 nm of radar
    • By the time a downburst signature shows up in the data it may be too late for lead time
what we look at31
What we look at
  • Base Velocity image showing thunderstorm downburst signature
what we look at32
What we look at
  • Scan
    • Trend Set – VIL, dBZ, dBZ ht, top, posh
    • Good for prioritizing and assessing trends with individual cells
    • Filter based on VIL or dbz
what we look at34
What we look at
  • Satellite and observed data
    • IR and VIS
    • Surface obs including mesonet data
    • MSAS and LAPS
      • LI CAPE
      • Pressure change
      • Wind barbs
what we look at35
What we look at
  • ASOS sites (yellow)
  • Mesonet sites (blue)
what we look for
What we look for
  • VIL decreases by at least 10 kg/m2 and
  • Height of max reflectivity decreases by at least 8 kft. (Storm collapse)
  • POD .88 and FAR .25
    • Reference … An Overview of Operational Forecasting for Wet Microbursts. William P. Roeder 45th Weather Squadron, USAF
    • http://www.wdtb.noaa.gov/workshop/psdp/
    • WDTB Pulse Storm Downburst Prediction Workshop
  • Use VIL … SCAN
  • May be too late for lead time by the time the storm collapses
what we look for see 02 aug 2002 wes sim guide
What we look forSee 02 Aug 2002 WES Sim guide
  • Relatively higher height of first echo appearance (20-30 kft) for severe storms vs. non-severe (10-20 kft)
  • Usually maintain 50-55 dBZ closed reflectivity contour as core descends
  • Centroid of high reflectivity core above 25 kft and top of core above 30 kft
  • Old rule 55 dBZ above 30 kft
  • Use RCS and/or All tilts Z/V 8 bit
what we look for see 02 aug 2003 wes sim guide
What we look for See 02 Aug 2003 WES Sim guide
  • MARC signature
    • 50 kt convergence in 5-11 kft AGL layer
    • Convergence in or near high reflectivity core
    • Works up to 90 miles from radar (Falk et al. 1998)
  • Use All tilts Z/V 8 bit, VCS
what we look for marc signature http www srh noaa gov shv downburst climo htm
What we look forMARC signaturehttp://www.srh.noaa.gov/shv/Downburst_Climo.htm
what we look for reference mackey 1998 http www wdtb noaa gov workshop psdp index htm
What we look forReference Mackey 1998http://www.wdtb.noaa.gov/workshop/psdp/index.htm
what we look for reference mackey 1998 http www wdtb noaa gov workshop psdp index htm41
What we look forReference Mackey 1998http://www.wdtb.noaa.gov/workshop/psdp/index.htm
what we look for44
What we look for
  • 4 Panel display showing monster TBSS and high reflectivity core
  • This storm produced baseball size hail
what we look for cae vil of the day
What we look forCAE VIL of the Day
  • Computed as part of Convective potential analysis
  • Logistic Regression equation …predictand is the probability of large hail
  • Predictors include VIL, VIL density, 500mb T, and Totals Totals index
what we look for47
What we look for
  • VIL Density = VIL (g/kg) / ET (kft)
  • Values > 3.5 had a .9 POD at TUL
    • Amburn, S. A. and P. L. Wolf, 1997:  VIL density as a hail indicator.  Wea. and Forecasting, 12, 473-478.
    • Greg Tipton, John DiStefano WFO Wilmington, Ohio
  • Use 4 panel VIL ET LRM2 LRM3
what we look for from otb now wdtb
What we look forFrom OTB now WDTB
  • Storm Top Divergence |Vout| + |Vin|
    • > .75 in 80 – 110 kt
    • 1.75 in 110 – 135 kt
    • 2.50 in 135 – 175 kt
    • 2.75 in 175 – 225 kt
    • 4.00+ in > 225 kt
  • Use All tilts Z/V 8 bit, VCS
what we look for49
What we look for
  • Height of 65 dBZ
  • 96% severe if above freezing level
    • Gerard, A., 1998: Operational observations of Extreme Reflectivity values in Convective Cells.  Natl. Wea. Digest, 22, 3-8.
    • Greg Tipton, John DiStefano WFO Wilmington, Ohio
  • Very soon after getting 88D in 1994 we noticed this to be highly reliable indicator
  • Good for severe hail and/or wind
  • Use RCS and/or All tilts Z/V 8 bit
verification
Verification
  • Sources
    • County EM Directors
    • County EM Dispatch
    • Local Sheriff, Police, Fire depts.
    • Spotters
    • HAM net
    • Post Offices
    • Local and regional Utilities
    • State and local parks and marinas
    • Media
    • Churches
    • Phone book and Street Atlas
an example 17 may 2005
An Example – 17 May 2005
  • Weakly sheared environment
  • Weak to moderate instability
  • Cold pool aloft with upper low over area
  • WBZ 9400 ft
  • Freezing level around 12000 ft
  • VIL of Day 43 g/kg
an example 17 may 200552
An Example – 17 May 2005
  • Reflectivity
  • 1905 GMT
  • Core - 17200 ft
  • 43 dBZ
an example 17 may 200553
An Example – 17 May 2005
  • Reflectivity
  • 1911 GMT
  • Core 18500 ft
  • 67 dBZ
  • TBSS
  • WBZ 9400 ft
an example 17 may 200554
An Example – 17 May 2005
  • Reflectivity
  • 1915 GMT
  • Core 19600 ft
  • 68 dBZ
  • TBSS
an example 17 may 200555
An Example – 17 May 2005
  • LRM 2 24-33k ft
  • 1905 GMT
  • Nothing
an example 17 may 200556
An Example – 17 May 2005
  • LRM 2 24-33k ft
  • 1915 GMT
  • 50-57 dBZ
  • Significant increase in 10 min
an example 17 may 200557
An Example – 17 May 2005
  • RCS
  • 1915 GMT
  • 65-70 dBZ elevated core to around 15k ft
an example 17 may 200558
An Example – 17 May 2005
  • KCLX VIL
  • 1905 GMT
  • 10-15 g/kg
  • KCAE VIL never got above 35 g/kg … close to radar
an example 17 may 200559
An Example – 17 May 2005
  • KCLX VIL
  • 1910 GMT
  • 5-10 g/kg
an example 17 may 200560
An Example – 17 May 2005
  • KCLX VIL
  • 1915 GMT
  • 25-30 g/kg
an example 17 may 200561
An Example – 17 May 2005
  • KCLX VIL
  • 1920 GMT
  • 45-50 g/kg
  • VIL of day was 43 g/kg
  • Note that VIL reached highest value about 10 mins after other products
an example 17 may 200562
An Example – 17 May 2005
  • Warning was issued based on TBSS from 1911 GMT scan
  • At 1930 received several reports of .88 in hail