NHC Predicts Near Normal Hurricane Season
Hurricane season starts this week. Offsetting factors, some of which would call for an above-normal hurricane season and others of which would call for a below-normal season, led forecasters at the NOAA Climate Prediction Center to split the difference in their seasonal outlook.
They are giving almost equal probabilities to average, above-average, and below-average seasons. But average gets a slight edge. See below.
NOAA predicts 12 to 17 named storms (winds of 39 mph or higher). Of those, 5 to 9 could become hurricanes (winds of 74 mph or higher), including 1 to 4 major hurricanes (category 3, 4 or 5; with winds of 111 mph or higher). NOAA has a 70% confidence in these ranges.
2023 Hurricane Season Names
Below is a list of storm names for this hurricane season.
Competing Factors Make Forecast Difficult
Competing factors both suppress and encourage storm formation.
After three hurricane seasons with La Nina present, NOAA scientists predict a high potential for El Niño to develop this summer. It can suppress Atlantic hurricane activity.
El Niño’s strong winds from the west produce sheer that can discourage tropical storms approaching from the east.
However, favorable conditions include:
- Above-normal west African monsoon formation that produces some of the stronger and longer-lived Atlantic storms
- Warmer-than-normal sea surface temperatures in the tropical Atlantic Ocean and Caribbean Sea which creates more energy to fuel storm development.
The last two factors have produced more active Atlantic hurricane seasons since 1995, according to NOAA.
New Policies, Models, Technologies Will Improve Future Forecasts
To improve forecasts, NOAA is adopting new policies, forecasting models and technologies this year. Improvements include:
- In late June, the Hurricane Analysis and Forecast System (HAFS) will become operational. HAFS will become NOAA’s primary hurricane model. Compared to previous models, it improves track forecasts 10-15%.
- A Probabilistic Storm Surge model upgrade gives forecasters the ability to run the model for two storms simultaneously.
- The National Hurricane Center’s Tropical Weather Outlook graphics will expand the forecast range from five to seven days.
- Over the last 10 years, flooding from tropical rainfall was the single deadliest hazard. To give communities more time to prepare, the Weather Prediction Center is also extending the Excessive Rainfall Outlook two days. It will now provide forecasts up to five days in advance. The outlook shows general areas at risk for flash flooding due to excessive rainfall.
- The National Weather Service will unveil a new generation of forecast flood inundation mapping for portions of Texas in September 2023. These maps will show the extent of flooding at the street level.
- New small aircraft drone systems, the deployment of additional saildrones, underwater gliders, and WindBorne global sounding balloons will fill critical data gaps and improve hurricane forecast accuracy.
- Upgrades to the Tropical Atmosphere Ocean buoy array will provide new capabilities, updated instruments, more strategic placement of buoys, and more detailed observations.
NOAA emphasizes that its hurricane forecast is not a landfall forecast. Many storms die at sea and never reach land.
Peak of Season Still Three Months Away, But…
The Climate Prediction Center will update the 2023 Atlantic seasonal outlook in early August, just prior to the historical peak of the season.
Historically, the peak of hurricane season hits on September 10. However, storms can develop any time of year. Interestingly, NHC determined that a subtropical storm formed in the Atlantic Basin in Mid-January 2023.
And minutes after I first posted this story, the National Hurricane Center issued this 7-day outlook. It shows a disorganized area of showers and thunderstorms over the central Gulf of Mexico trying to get organized. But the chances of tropical formation are slim: 10% in the next two days and 20% in the next seven.
So remain alert and prepared.
Posted by Bob Rehak on 5/30/2023
2100 Days since Hurricane Harvey