The upper ridge over Brazil breaks down during the medium range. An energetic mid-latitude flow enables cold fronts to push farther north. Frontal systems deliver much needed rain to key crop areas in Brazil most notably in the medium range. Meanwhile, a marine heatwave is forming off the Brazil Coast.

The U.S. Weekly Crop Moisture Index analysis for late September reveals widespread regions of significant soil moisture deficit particularly in the Great Plains to Texas while Helene eased the previous dryness in the eastern and southern Ohio Valley. Outside of tropical cyclone risk, apparently focused on Florida in the AIFS 15-day outlook, the entire U.S. AG Belt is very dry featuring no rain throughout the Great Plains.

Beginning tomorrow, high temperatures reach the 90’s at the coast with up to 105F inland lasting into the midweek for Central California. Consequently, NOAA/NWS has issued a Heat Advisory. Excessive heat warrants an Excessive Heat Warning across the Desert Southwest States. The ECM ENS identifies the hot weather risk in the 1-5-day forecast likely to extend to the 6-10-day period.

Helene made landfall at 11:10PM EDT last evening as a category-4 major hurricane near the mouth of the Aucilla River in the northwest Florida Big Bend area. Helene is downgraded to a tropical storm located about 40 miles east of Macon, GA. Widespread destructive effects associated with this storm continue.