Synoptic climatology and sea surface temperatures teleconnections for warm season heat waves in Saudi Arabia

Using a time-sensitive approach, a HW was defined as a period of at least two consecutive days with a daily maximum temperature equal or higher than the 90th percentile of the monthly maximum and with a daily minimum temperature equal or higher than the 85th percentile of the monthly minimum for the decade in question. Using reanalysis data for 1985-2014, three weather/circulation types were identified using Ward's method for cluster determination. Together, weather types 1 and 3 induced 57.5% of HW days and connected with negative anomalies in sea level pressure with lower heights and warmer temperatures at the 850 hPa level. Weather type 2 induced 42.5% of HW days and was related to positive anomalies at all heights. Intensification of Indian Summer Monsoon Trough and Arabian heat lows were key atmospheric features related to weather types 1 and 3. Anomalies of SSTs of the Red Sea, Arabian Gulf, Caspian Sea, Black Sea, and Mediterranean Sea displayed positive values for both weather types 1 and 3. SSTs anomalies seem to be a more important factor for intensity of a HW day. HWs in Saudi Arabia tend to occur during regional warming due to atmospheric circulation conditions and SST teleconnections.