WV images to diagnose WV images to diagnose the context the context favourable for deep favourable for deep convection convection Patrick Santurette Forecast Laboratory METEO-FRANCE Christo Georgiev National Institute of Meteorology and Hydrology, Bulgarian
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WV images to diagnose the context favourable for deep convection Patrick Santurette Forecast Laboratory METEO-FRANCE Christo Georgiev National Institute.
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WV images to diagnose WV images to diagnose the context favourable for the context favourable for
deep convectiondeep convectionPatrick Santurette
Forecast Laboratory METEO-FRANCE
Christo GeorgievNational Institute of Meteorology
and Hydrology, Bulgarian
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13 UTC11 UTC
About pre-convective environment and WV information
WV Imagery information 6.2 m imagery is (almost the only) information about upper-level 7.3 m gives information about low- to mid-level
Potential instability pronounced when upper-levels cold and dry whilst low-levels moist and warm, so potential instability when: warm brightness temperature on 6.2 m and cold brightness temperature on 7.3 m So making the difference 6.2 BT – 7.3 BT
can provide an instability index >
But pre-convective environment is NOT ONLY potential INSTABILITY Necessity to add information about the motion field
as regards to the low-level forcing on ascending motion …
IR, 925 hPa wind, θ’w 850 hPa, 12 UTC
WV BT difference (WVBTDiff = 6.2 m BT – 7.3 m BT); dark blue for BT difference -18 to -10 dg C, light blue -10 to -5, green -5 to 0, yellow for > 0 dg. If WVBTDiff < -18 dg, grey when 6.2 BT >= -39 dg, light grey when 6.2 >, = -39 dg AND 7.3 <, = -19dg.
Convection develops after 12 UTC from Greece to Bulgaria inside the light grey area.
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EX 1 : Strong thunderstorms with hail, southwest of France, EX 1 : Strong thunderstorms with hail, southwest of France, due to destabilisation by upper-level PV advection due to destabilisation by upper-level PV advection (1)(1)
EX 1 : Strong thunderstorms with hail, southwest of France, EX 1 : Strong thunderstorms with hail, southwest of France, due to destabilisation by upper-level PV advection due to destabilisation by upper-level PV advection (2)(2)