The sea surface temperature anomaly (SSTA) is the difference between the observed SST and the climatological SST. These anomalies are calculated on a weekly basis.
Positive SSTAs are usually correlated with increased regions of convection (cloudiness and rainfall) while negative SSTAs are usually correlated to reduced convection.
SSTAs can be used as an indicator of the phase of global climate fluctuations, such as the El Nino/Southern Oscillation (ENSO).
The data displayed in this map is the weekly average, centred on the date shown.
16:28 EDT Hail is caused when raindrops are lifted up into the atmosphere during a thunderstorm and then supercooled by temperatures below freezing, turning them into ice balls.