Foggy conditions prevailing over east Uttar Pradesh, Bihar and sub-Himalayan West Bengal have intensified again. The fog cover may last for the next two to three days. Conditions are also becoming more suitable for expansion of the fog cover towards the west areas of Uttar Pradesh where it is already being witnessed.
This expansion and prevalence is due to low minimum temperatures, slow; cool and dry winds, moisture fed easterly winds from the Bay of Bengal. The minimum temperatures are near dew point (temperature at which condensation take place) helping the heavy cool winds condense to form clouds on the ground, which is called fog in general terms.
Cooler and dry northwesterly to northerly winds are not only keeping the minimum low but at the same time they are slow and unable to push out other winds reaching the region. The winds are blowing at a speed of 3 to 5kmph, which is near perfect to form fog as they are also consuming moisture from the easterly winds.
Such weather condition if expends then the foggy conditions would follow suit. Fog could also cover Delhi region during the next three days if the temperature and wind-speed drops further. Rain is expected at one or two places over northeastern states of Assam and Arunachal Pradesh as the remnant cyclonic circulation from just-passed Western Disturbance is present over Assam and Meghalaya.
In the south, Tamil Nadu and Kerala will receive rain in its southern parts during the next 24 to 48 hours. These areas are being affected by a cyclonic circulation over Lakshadweep. The trough of low pressure area in the south Andaman Sea will give rain at a few places over the Andaman & Nicobar Islands during the next 24 hours.
Photograph by Nigel Cox
