Premium
Synoptic situations of severe local convective storms during the pre‐monsoon season in Bangladesh
Author(s) -
Yamane Yusuke,
Hayashi Taiichi,
Kiguchi Masashi,
Akter Fatima,
Dewan Ashraf Mahmmood
Publication year - 2012
Publication title -
international journal of climatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.58
H-Index - 166
eISSN - 1097-0088
pISSN - 0899-8418
DOI - 10.1002/joc.3460
Subject(s) - climatology , precipitable water , convective available potential energy , environmental science , monsoon , mesoscale convective system , convective instability , convective inhibition , convective storm detection , storm , trough (economics) , mesoscale meteorology , convection , tropical cyclone , severe weather , advection , atmospheric sciences , meteorology , geography , precipitation , geology , thermodynamics , natural convection , physics , economics , macroeconomics , combined forced and natural convection
This study examines synoptic situations of severe local convective storms (mesoscale severe weather associated with deep convections such as tornado and hail) during the pre‐monsoon season (from March to May) in Bangladesh. We compared composite meteorological fields on severe local convective storm days (SLCSD) with those on non‐severe local convective storm days (NSLCSD). Moisture inflow from the Bay of Bengal is enhanced with intensification of southwesterly wind at 950 hPa on SLCSD compared with NSLCSD. The temperature is higher at 800 hPa over the inland area of the Indian subcontinent including Bangladesh on SLCSD than NSLCSD. At 550 hPa, a trough over Bangladesh develops on SLCSD compared with NSLCSD. This leads to the development of a thermal trough over the inland area of the Indian subcontinent and enhancement of cold advection from the northwest into Bangladesh on SLCSD at this level. This synoptic situation produces great potential instability of the atmosphere in Bangladesh on SLCSD during the pre‐monsoon season. Composite distributions of lifted index, precipitable water and convective available potential energy on SLCSD and NSLCSD over south Asia show distinct differences of these parameters between these two categories with statistical significance especially in and around Bangladesh. These differences indicate that the atmospheric environment has great potential instability especially in and around Bangladesh on SCLSD under the synoptic situations shown in this study. Copyright © 2012 Royal Meteorological Society