Mike Evans NWS WFO BGM CSTAR V Severe convection in scenarios with lowpredictive skill SUNY Albany researchers are examining SPC forecasts and associated severe weather occurrence to identify events with lowpredictive skill ID: 132023
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Slide1
An assessment of local forecaster’s ability to anticipate convective event severity using the Hazardous Weather Outlook at WFO Binghamton
Mike Evans
NWS / WFO BGMSlide2
CSTAR V – Severe convection in scenarios with low-predictive skill
SUNY Albany researchers are examining SPC forecasts and associated severe weather occurrence to identify events with low-predictive skill.
Their
project covers the CONUS, with an emphasis on the northeast.
Goal will be to identify environments with low predictive skill, and to improve forecasts in
those
environments.Slide3
Local study outline
Examine day 1 NWS BGM forecasts issued on the midnight shift from 2011-August
2014.
Define
a “warning” as any time
Hazardous Weather Outlook
product indicates “severe”, “large hail” or “damaging wind” during the next 24 hours.
Define an “event” as a day when at least 5 severe weather reports were received.
How good are our warnings? What factors influence the quality of our warnings?
Note… Joe
Villani
in Albany has been working on a similar study for the ALY county warning area. Slide4
Hazardous Weather Outlooks
Example of a “warning”
Example of a “non-warning”Slide5
How many severe reports are needed for an “event” to be identified?
So… bigger events are more likely to be caught than marginal events.
Using a high threshold results in lots of false alarms.
For the rest of this study, an event is defined as 5 or more reports. Slide6
POD and FARSlide7
POD and FAR by month
Events: 5 10 13 17
7
6
1
59
Warnings: 7 14 15 24 7
8
1
76Slide8
POD and FAR by season
Events: 22 37
Warnings: 30 46Slide9
Do “dry-spells” bias our forecasts?
Events:
7
of 15 30 of 44 Slide10
What about the large-scale environment?
Define – “good forecast” events as events with a warning.
Define – “over-achieving” events as events with no warning.
Define – “under-achieving” events as a warning issued with no event.Slide11
POD and FAR
MLCAPE (J/kg)
0-3 km shear (kt)Slide12
High CAPE / High shear eventsSlide13
Low CAPE / High shear eventsSlide14
High CAPE / Low shear eventsSlide15
SummarySlide16
Example – June 24, 2013Slide17
SPC damaging wind outlookSlide18
SPC hail outlookSlide19
500 mb heights and vorticitySlide20
Sea-level pressure and satelliteSlide21
2 hour RAP Sounding at BGM valid 20zSlide22
Radar reflectivity animationSlide23
BGM Hazardous Weather Outlook – issued at 422 AM June 24, 2013
“SCATTERED THUNDERSTORMS ARE EXPECTED TODAY WITH THE BEST CHANCES
THIS AFTERNOON… SOME MAY CONTAIN HEAVY RAINFALL”. Slide24
Severe reports – June 24, 201322 large hail reports
16 damaging wind reports
7 days since the previous severe weather occurrenceSlide25
Future WorkResults from this study and work at ALY will be compared to results from the larger study at SUNY ALY.
These results will
be available next year.