Recent helpful research published in the AMS Journal of Climate identifies deep layer soil moisture deficits as a potential catalyst to future drought (and flash drought during the warm season). Northern hemisphere summer has ended BUT there area significant deep layer soil moisture shortages likely to cause Southwest U.S. drought to expand to the central and southern Great Plains. Similarly, emerging deep layer soil moisture anomalies in Southwest/West-central Russia foreshadow intensifying drought ahead.

La Nina is intact and plenty of subsurface eastern equatorial Pacific Ocean cool water is present to sustain La Nina. Forecast models indicate La Nina peaks later this year. Interestingly, a reversal toward a weak El Nino next summer is also indicated.

Meanwhile another area of concern has evolved in the southwest Gulf of Mexico. NOAA/NHC indicates tropical cyclone risk is 40% within the next 48 hours and >60% after 48 hours. The midday GFS develops this system into a tropical cyclone Friday by midday just north of the central Bay of Campeche. Unclear is whether this system sits in the west-central Gulf of Mexico into early weekend or drifts north toward Louisiana.

Sally is slowly organizing in that the associated convection is becoming more concentric. The interaction between the convection east of Sally and the Florida coastline has eased and dry air entrainment off the Yucatan Peninsula has also dissipated. Northwest shear across Salley is still present but weaker. The environment improves as Sally shifts west and west-northwest and intensification to a hurricane is likely today.