1 / 4

WV images to diagnose the context favourable for deep convection

WV images to diagnose the context favourable for deep convection. Patrick Santurette Forecast Laboratory METEO-FRANCE. Christo Georgiev National Institute of Meteorology and Hydrology, Bulgarian. 11 UTC. 13 UTC. IR, 925 hPa wind , θ ’ w 850 hPa , 12 UTC.

stacey-curtis
Download Presentation

WV images to diagnose the context favourable for deep convection

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. WV images to diagnose the context favourable for deep convection Patrick Santurette Forecast Laboratory METEO-FRANCE Christo Georgiev National Institute of Meteorology and Hydrology, Bulgarian

  2. 11 UTC 13 UTC IR, 925 hPa wind, θ’w 850 hPa, 12 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 > 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. 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 • …

  3. Z,T 500 hPa 24 Sep 2006 12 UTC Hail near Toulouse, highway temporarily closed EX 1 : Strong thunderstorms with hail, southwest of France, due to destabilisation by upper-level PV advection (1) Upper-level dry and cold air overhanging warm moist air at low level Convection development Infrared Image (colour), WV_6.2 µm (BT>= -39°C, grey shade), lightening

  4. Radar 15 UTC 1100 UTC 1200 UTC EX 1 : Strong thunderstorms with hail, southwest of France, due to destabilisation by upper-level PV advection (2) WV 6.2 m = observation of upper-level moisture flow and upper-level dynamics (PV anomalies) WV 7.3 µm = observation of low- to mid-level moisture flow 6.2 – 7.3µm, 10 m MOCON analysis >necessity to add information: WV 6.2 µm Image WV 7.3 µm, BT < - 19°C Low-level convergence (LLConv) for example is a crucial parameter Strong convection is NOT ONLY potential INSTABILITY, motion field is crucial • Necessity to add information • as regards to the low-level forcing on ascending motion - Superimp. of LLConv on WVBTDiff can help as precursor of convective development • as regards to upper-level divergence, • as regard to ground parameters evolution? • …

More Related