Wednesday, June 13, 2018 5:34 PM

Gulf Tropical Threat And Southwest Moisture

Christopher Nunley

Gulf Coast Tropical Moisture

Tropical moisture is expected to move into Texas and Louisiana this weekend and next week. A large area of thunderstorms is located across the western Caribbean. This area of thunderstorms will move over the Yucatan Peninsula into the southern Gulf over the next 24 hours. At this hour, the National Hurricane Center (NHC) is keeping a close eye on this tropical wave and currently is giving it a 20% of tropical cyclone development over the next 5 days (see Fig. 1). The main hinderance are the strong upper-level winds.

Fig. 1: NHC Area Being Monitored For Tropical Development

Even if the area of thunderstorms does not develop further, heavy rainfall is likely for parts of Texas and Louisiana from Saturday through Monday. This includes some major cities, which include: Houston, San Antonio, Austin, and New Orleans. Widespread 2-4″ is possible across the northwestern Gulf States with isolated amounts greatly exceeding this (see Fig. 2).

Fig. 2: WPC Precipitation Forecast Through 7 Days

Southwest Tropical Moisture

The Southwest can expect tropical moisture, too, but from a different system. Tropical Storm Bud is moving northward off of the coast of Mexico at this hour. Bud is weakening as it moves northward but is expected to bring heavy rainfall to parts of western Mexico, eastern parts of the Baja of California, and Southwest parts of the United States as it moves into the Gulf of California and eventually into northern Mexico (see Fig. 3). This rainfall moving into the Southwest (Arizona, New Mexico, and southern Colorado) will likely create flash flooding in localized areas. Rain chances increase by Thursday with the best chances Friday night into Saturday. Widespread 0.75-1.50″ are likely with isolated 2-4″ amounts (see Fig. 4). Dangerous flash flooding looks likely in areas that have terrain in southern Colorado, eastern Arizona, and central and western New Mexico.

Along with flash flooding, cloud-to-ground lighting is possible, along with the potential for microbursts during the afternoon hours where strong heating occurs. High temperatures will be well below normal over the weekend (see Fig. 5). A trough will dig into the West, which should move the remnants of Bud eastward by early next week but isolated rain chances look to continue in this region due to the trough.

Fig. 3: NHC Bud Forecast Track

Fig. 4: WPC Precipitation Forecast Through 7 Days


Fig. 5: Saturday and Sunday High Temperature Anomalies