Presentation is loading. Please wait.

Presentation is loading. Please wait.

Matthew Vaughan, Brian Tang, and Lance Bosart Department of Atmospheric and Environmental Sciences University at Albany/SUNY Albany, NY 12222 NROW XV Nano-scale.

Similar presentations


Presentation on theme: "Matthew Vaughan, Brian Tang, and Lance Bosart Department of Atmospheric and Environmental Sciences University at Albany/SUNY Albany, NY 12222 NROW XV Nano-scale."— Presentation transcript:

1 Matthew Vaughan, Brian Tang, and Lance Bosart Department of Atmospheric and Environmental Sciences University at Albany/SUNY Albany, NY NROW XV Nano-scale College South Auditorium Albany, New York Thursday 13 November 2014 Supported by the NOAA Collaborative Science, Technology and Applied Research Program

2  CSTAR initiative to investigate severe convection with low predictive skill  Cooperation between SUNY-Albany and NWS offices at ALB, BGM, and PIT  Improve forecasting skill of severe convection by focusing study on environments with poor predictive skill

3

4  Identify and evaluate poor forecast performance  Use forecasting performance as a proxy for predictability  Underlying assumption: If forecasters had trouble, the event had low predictability.

5  Create Northeast domain to evaluate forecast skill  Plot SPC convective outlook contours over the domains.  Verify SLIGHT contours with storm reports  Sound familiar? Hitchens and Brooks (2012) evaluated SLIGHT contours over CONUS domain  MOD and HIGH contours were treated the same as SLIGHT

6  Algorithm details  40-km grid spacing  Use 0600 UTC SLIGHT risk valid UTC  Plot all valid storm reports for forecast period  Every grid point <40km from report is designated: “hit” Legend: = False Alarm (grid) = Correct Hit (grid) = Missed report

7  Analysis grid over the Northeast Legend: = False Alarm (grid) = Correct Hit (grid) = Missed report = Correct Hit (report) = Incorrect Hit (grid)

8  For inclusion in the dataset, an event must meet 1 of 2 criteria:  Have a SLIGHT risk contour within the NE domain  Contain at least 20 reports within the domain Given a SLIGHT in NE, 20 reports = 55th percentile

9  Event days = 1508  SLIGHT days = 1331  Events >20 reports without SLIGHT = 177

10

11

12

13

14

15

16 Low POD High FAR  Type 1  20+ reports;  Lowest 25 th percentile POD  Type 2  Highest 75 th percentile FA area  Lowest 25 th percentile severe report area Type 1Type 2 Type 3  No events meet Type 3 requirements as defined here

17 Type 1Type 2  N = 189 events  25 th POD percentile = 2.15%  All but 3 events have POD = 0  Median: 37 reports per event  Average: 50 reports per event  N = 66 events  All but 4 events have FAR > 95%  Median: 2.5 reports per event  Average: 3 reports per event

18

19

20

21

22  0.5° Climate Forecast System Reanalysis (CFSR)  Chose morning (1200 UTC) for following analysis.  Type 1 centered on maximum report density  Type 2 centered at centroid of SLIGHT risk region  Chose largest of SLIGHT risk contours for composite center

23

24 Geopotential height (meters; contoured every 100 m), wind speed (knots; fill), and wind vector (knots; barbed) on the 250 hPa pressure surface. The red dot indicates event-composite center and the median location of the maximum report density. 250 hPaN=60

25 Geopotential height (meters; contoured every 40 m) and total wind(knots; barbed) on the 500 hPa pressure surface. The red dot indicates event-composite center and the median location of the maximum report density. 500 hPaN=60

26 Geopotential height (meters; contoured every 25 m), relative humidity (%; fill contoured every 5%) on the 700 hPa pressure surface. The red dot indicates event- composite center and the median location of the maximum report density. 700 hPaN=60

27 Geopotential height (meters; solid contour every 20 m), temperature (Celsius; dashed), and wind vector (knots; barbed) on the 850 hPa pressure surface. The red dot indicates event- composite center and the median location of the maximum report density. 850 hPaN=60

28 MSLP (hPa; contoured every 2 hPa), precipitable water (mm; fill), and total surface wind (knots; barbed). The red dot indicates event-composite center and the median location of the maximum report density. SurfaceN=60

29 hPa lapse rates (°C/km; contoured every.5 °C/km), MUCAPE (J/kg; fill), and hPa shear vector (knots; barbed). The red dot indicates event-composite center and the median location of the maximum report density. CAPE & ShearN=60

30

31 Geopotential height (meters; contoured every 100 m), wind speed (knots; fill), and wind vector (knots; barbed) on the 250 hPa pressure surface. The red dot indicates event-composite center and the median location of the centroid of the NE SLIGHT risk areas. 250 hPaN=32

32 Geopotential height (meters; contoured every 40 m) and total wind(knots; barbed) on the 500 hPa pressure surface. The red dot indicates event-composite center and the median location of the centroid of the NE SLIGHT risk areas. 500 hPaN=32

33 Geopotential height (meters; contoured every 25 m), relative humidity (%; fill contoured every 5%) on the 700 hPa pressure surface. The red dot indicates event- composite center and the median location of the centroid of the NE SLIGHT risk areas. 700 hPaN=32

34 Geopotential height (meters; solid contour every 20 m), temperature (Celsius; dashed), and wind vector (knots; barbed) on the 850 hPa pressure surface. The red dot indicates event- composite center and the median location of the centroid of the NE SLIGHT risk areas. 850 hPaN=32

35 MSLP (hPa; contoured every 2 hPa), precipitable water (mm; fill), and total surface wind (knots; barbed). The red dot indicates event-composite center and the median location of the centroid of the NE SLIGHT risk areas. SurfaceN=32

36 hPa lapse rates (°C/km; contoured every.5 °C/km), MUCAPE (J/kg; fill), and hPa shear vector (knots; barbed). The red dot indicates event-composite center and the median location of the centroid of the NE SLIGHT risk areas. CAPE & ShearN=32

37  Assess variability in composites  Analyze deviation among cases and reassess compositing method  Compare Type 1 & Type 2 flow regimes to cases with good predictive skill scores  May extend comparison to events of similar scale  Expand composites  Investigate variables identified in Hurlbut and Cohen (2014)

38  NE predictive skill  Flat POD, decreasing FAR, increasing CSI  Number of reports per event increasing  NE low predictive skill event climatology  Type 1: 5 median events per year (Trending up)  Type 2: 2 median events per year (Trending down)  Peak in warm season  Most cases with low predictive skill follow climatology except rare N-ly, S-ly flow

39  Type 1 (Low POD)  Westerly Anticyclonic side of jet, relatively low humidity at 700 hPa, higher mid-level lapse rates  Type 2 (High FAR)  Westerly Anticyclonic side of jet, higher 700 hPa humidity, higher precipitable water values, more confluent 850 hPa flow

40


Download ppt "Matthew Vaughan, Brian Tang, and Lance Bosart Department of Atmospheric and Environmental Sciences University at Albany/SUNY Albany, NY 12222 NROW XV Nano-scale."

Similar presentations


Ads by Google