Issued today: Latest week 2-4 outlooks/Australia seasonal climate forecast.    Fig. 1-4: Potential Tropical Cyclone 16 becomes a tropical storm over the warm Gulf Stream tonight but note how much cooler than normal the ocean surface east of New England which is a large change during the past 2-4 weeks and related to a recent cooler temperature pattern in the eastern U.S. Discussion: Potential Tropical Cyclone 16 – as NOAA/NHC calls it – will become a tropical storm moving over the very warm (86F/30C) Gulf Stream tonight (Fig. 1). Enough ocean heat exists in this region to create a vigorous tropical storm which goes inland in eastern North Carolina Saturday morning. This system is unable to maintain intensity once turning back into the North Atlantic due to the MUCH COOLER ocean surface off the Northeast Coast (Fig. 2). In fact, SSTA are wildly cooler than normal to finish calendar summer east and southeast of New England southward to near Bermuda and east of the Bahamas! During the past 2-4 weeks, tropical cyclones moving through this region have caused the cooler SSTA change and following troughs turning systems northeastward have cooled waters east of New England (Fig. 3). This large area of cooler than normal SSTA was present during MAY/JUN 2023 causing the East U.S. to turn cooler than normal after a record warm JAN-APR 2023. Note that during the past week, air temperatures have cooled off in the East (Fig. 4). The SSTA pattern is unlikely to change much through October and may continue to provide a cooler bias to East U.S. climate compared to the warming indicated by forecast models. Fig. 5-7: ECMWF 24-hour rainfall profiles for the weekend Northeast/Mid-Atlantic storm. The ocean SSTA regime affects the rainfall profile of the Mid-Atlantic tropical storm. Typical of landfall, heavy rains move into eastern North Carolina overnight (Fig. 5). However, on Saturday the heavy rain shifts to the west side of the tropical system unloading several inches (or more) of rain on Central Virginia, a forecast change (Fig. 6). The system is much weaker by Sunday as the rainfall profile shifts north and loses intensity (Fig. 7). Fig. 8: NOAA/WPC 5-day rainfall forecast. The 5-day rainfall forecast by NOAA/WPC continues to indicate three areas of heavy rain (Fig. 8). The heavy rain in the East is previously described. Showers and thundershowers are present each day into early next week to soak the Central U.S. The forecast trend is wetter into East Texas. The Northwest Coast rainfall is heavier. As a reminder, NOAA/CPC issued a seasonal drought outlook yesterday that erodes or dissipates the Central U.S. drought (Fig. 9). The last week of CDD projections…HDD start next week! The U.S. population weight CDD forecast projects a slightly warmer change from 24 hours ago (Fig. 10). By Oct. 6-12, U.S. gas population weight HDD begin to outgain CDD projections. Fig. 9: The NOAA/CPC seasonal drought outlook valid for Q4/2023. Fig. 10: U.S. population weight CDD projection utilizing all models, their consensus and comparison with 24 hours ago plus the 10-year/30-year normal.