Fig. 1: NOAA/WPC 7-day rainfall forecast across the U.S.
Discussion: Gathering storm clouds in the northwest Gulf of Mexico leads to a week of heavy rain featuring risk of >10 in. on the southeast Louisiana coast (Fig. 1). Low-pressure is offshore and over the warm Gulf of Mexico therefore monitoring for a possible tropical system later this week is required. Some of the Gulf moisture interacts with a cold front arriving in the Southeast U.S. midweek causing the heavy rain pattern to extend northeastward to the Carolinas. Heavy rains are also likely off the Carolina Coast this week which is another zone monitored for tropical development.
A renegade severe thunderstorm event is moving across western Iowa this morning bringing extreme rainfall. Elsewhere, extreme heat issues dominate California and Texas plus the Southwest U.S. Desert (Fig. 2). Phoenix, AZ is near 112F all week. In central Texas, temperatures approach 110F in San Antonia with heat index in the 115-120F range. The hot weather eases on the Texas Coast due to thunderstorms midweek.
Fig. 2: NOAA/NWS U.S. weather watch, warning and advisory areas.
Fig. 3: Using all operational models, the consensus of population weight CDD forecast through July 28 is indicated and compared with yesterday’s forecast and 30-year/10-year normal.
The U.S. population weight CDD forecast is not quite as hot this week and next week compared to this past Friday’s outlook (Fig. 3). However, the outlook for late July is much hotter.