Tropical Storm Julia, which formed along Venezuela’s northern coast at 11 a.m. EDT Friday with sustained peak winds of 40 miles per hour, is expected to strengthen into a hurricane and bring dangerous heavy rains to much of Central America and southeastern Mexico. Julia is expected to land in Nicaragua on Sunday morning.
Julia’s October 7 inception date is about two weeks later than the typical appearance of the season’s 10th named storm on September 22. This season’s activity now stands at 10 named storms, four hurricanes and two major hurricanes with an Accumulated Cyclone Energy (ACE) Index of 78% of the average for the date. The 1991-2020 averages for October 7 are 11.6 named storms, 5.6 hurricanes, and 2.5 major hurricanes. So, despite Ian’s disastrous rampage, the Atlantic as a whole is still having a slightly less active season than usual.
Julia was formed in an unusual place for a tropical cyclone: just off the coast of Venezuela. When it was tropical depression between Thursday 11:00 p.m. EDT and Friday 8:00 a.m. EDT, Julia crossed two peninsulas of Venezuela, Paraguaná and Guajira, which jut north into the Caribbean Sea. Only one other tropical cyclone on NOAA records made it further south to Venezuela: Tropical Storm Bret (1993), which moved physically through northern Venezuela’s interior and caused devastating flooding that killed more than 200 people.
Figure 1. Tropical Depression 13 (center of circle) as it forms on the eastern side of the Paraguaná Peninsula and all other tropical cyclones that passed within 60 nautical miles of TD 13’s location at 11:00 p.m. EDT on Thursday, October 6 are , 2022. (Photo credit: NOAA Historical Hurricane Tracks)
Figure 1. Tropical Depression 13 (center of circle) as it forms on the eastern side of the Paraguaná Peninsula and all other tropical cyclones that passed within 60 nautical miles of TD 13’s location at 11:00 p.m. EDT on Thursday, October 6 are , 2022. (Photo credit: NOAA Historical Hurricane Tracks)On Friday afternoon, Julia brought severe thunderstorms to northern Venezuela and Colombia, as shown in satellite imagery. Julia had a modest number of severe thunderstorms that gradually increased in area coverage and organization, with significant low-level spiral banding. However, its proximity to the coast of South America disrupted development.
Forecast for Julia
A high-pressure ridge north of Julia will keep it on a westward trajectory at about 15 miles per hour through early next week, with its center just off the coast of South America by Friday afternoon. Aside from the proximity to land, conditions will be favorable for Julia’s development, with warm waters near 29.5 degrees Celsius (85 °F), moderate wind shear of 10-15 knots, and a humid atmosphere (moderate relative humidity). from 75-80%).
Figure 2. Track forecasts up to 10 days for Julia from the Friday 7 October 6Z run of the GFS Ensemble model. Individual forecasts by the 31 ensemble members are the lines, color-coded according to the wind speed in knots they predict for Julia; red colors correspond to a Category 1 hurricane. Time in hours from model initialization time is shown in gray text. (Image credit: weathernerds.org)
Figure 2. Track forecasts up to 10 days for Julia from the Friday 7 October 6Z run of the GFS Ensemble model. Individual forecasts by the 31 ensemble members are the lines, color-coded according to the wind speed in knots they predict for Julia; red colors correspond to a Category 1 hurricane. Time in hours from model initialization time is shown in gray text. (Image credit: weathernerds.org)Models agree well on Julia’s forward speed, with the storm gradually slowing from its current forward speed of 18 mph to about 12 mph by the time it made landfall in Nicaragua Sunday morning. Once Julia is inland, the models show a likely west-northwest curvature that would keep the center overland until it resolves. The models are tightly clustered in their track forecast for Julia and a Nicaragua landfall is highly likely, with the Colombian islands of San Andres and Providencia off the coast of Nicaragua also at risk.
After Julia pulled away from the coast of South America Friday afternoon, a period of steady strengthening is expected, and a burst of faster strengthening is possible Saturday through early Sunday. The western Caribbean will have favorable conditions for Julia to turn into a hurricane this weekend, and this part of the Atlantic is notorious for seeing some fancy fast intensification events. Friday 6Z runs of the top two intensity models, HMON and HWRF, show Julia reaching Category 2 strength on Sunday morning Nicaragua landing in 100-mph winds. As of 12 p.m. Friday, the stats-based SHIPS and DTOPS rapid intensification tools both gave a nearly 30 percent chance that Julia would be near hurricane strength by Saturday morning, and SHIPS gave a 29 percent chance that Julia would face sustained winds 105 mph (category 2) by Sunday morning.
Figure 3. Predicted 5-day precipitation amounts ending Tuesday, October 11, 8 p.m. EDT from the 0Z Friday, October 7 European model run. The model predicted widespread heavy rains over much of Central America and southeastern Mexico, with some areas receiving over 10 inches (dark purple colors). (Image credit: weathermodels.com)
Figure 3. Predicted 5-day precipitation amounts ending Tuesday, October 11, 8 p.m. EDT from the 0Z Friday, October 7 European model run. The model predicted widespread heavy rains over much of Central America and southeastern Mexico, with some areas receiving over 10 inches (dark purple colors). (Image credit: weathermodels.com)Heavy rains the biggest threat
The main threat from Julia will be dangerous heavy rains of 5 to 10 inches, with some higher amounts expected across much of Central America and southeastern Mexico beginning Saturday. Much of Central America, including that part of eastern Nicaragua where Julia’s heaviest rains will fall, has been relatively dry for the past three months, receiving 50% to 80% of average precipitation. However, the arrival of heavy rains in north-western Honduras will be undesirable: the region is struggling with flooding as a result of heavy rains in the last week of September. This flooding on the Ulúa River in the Sula Valley killed 12 people and resulted in the evacuation of 16,000 people. Saturated soils in the region will lead to further flooding when there are rains in Julia. The European model’s Friday run 0Z (Figure 3) projected that Julia would bring five-day rainfall amounts of 5 to 10 inches to northwestern Honduras.
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