East Central Florida - Friday October 20 2023: The National Weather Service in Melbourne has released its forecast for the dry season over east central Florida.
The Florida dry season forecast is issued for the period between November 1, 2023 and April 30, 2024. This seasonal forecast was produced by a team of National Weather Service Melbourne meteorologists, based, in part, on the Nino pattern and historical weather data for the Central Florida region.
El Niño conditions are anticipated to persist through the Northern Hemisphere winter 2023-2024 and spring 2024, with an 80% chance of El Niño conditions continuing during March-May 2024. This will most likely be a strong El Niño event rivaling the El Niño events of 1997-1998 and 2015-2016.
The latest 3-month, July through September, running mean of sea surface temperatures (SST) in the Niño region,( the eastern Pacific), was 1.3°C higher than normal.
The most recent forecasts show sea surface temperatures in the Niño will remain higher than normal, peaking in strength during the winter months and remaining warmer than normal through the spring.
The El Niño Southern Oscillation or ENSO is a complex meteorological phenomenon that relates to changes in sea surface temperature and sea level pressure over the equatorial regions of the Pacific Ocean. ENSO has a warm phase (El Niño) and a cool phase (La Niña). Each has profound influences on the atmospheric circulations over the Pacific Ocean, and consequently, the circulations over North America and other parts of the globe.
Locally, research shows that there is a physical relationship between the state of ENSO and the mean position of the jet stream over North America during the winter and spring seasons. These shifts in the jet stream often influence central Florida in the form of increased/decreased rainfall, storminess, and seasonal temperatures depending on the state of the El Niño Southern Oscillation.
Temperature
The temperature forecast for the 2023-2024 dry season (November-April) across Central Florida are expected to be about normal the 3-month period from November-January. Temperatures in February, March, and April are forecast to be below normal.
Local research and past analogs of strong to very strong El Niño events, favor temperatures below normal overall for the second half of the dry season across Central Florida.
However confidence in this dry season temperature forecast, especially for the first half of the season, is lower than normal.
The latest Climate Prediction Center (CPC) temperature outlooks for both November-January and February-April (fig. 3) currently show equal chances for either above, near, or below normal temperatures occurring across the area, which highlights the uncertainty in the temperature outlook this upcoming dry season.
Freezes across Central Florida are most common in the months of December and January. Freezing conditions can occur during all ENSO states (table 1, page 8), and examination of analog years with stronger El Niño conditions indicate the majority experienced freezes at some point during the winter months, especially across northern portions of east central Florida.
Precipitation
The overall forecast for the 2023-2024 dry season (November-April) favors above normal rainfall across Central Florida, due to ongoing El Niño conditions that will strengthen through the winter and are anticipated to continue through the spring. The latest 3-month outlooks from CPC (fig. 4) show around a 50 to 60 percent chance for above normal rainfall for the November through January period, and near a 70 percent chance for above normal rainfall during February through April.
Local research shows that the El Niño Southern Oscillation (ENSO) has a greater correlation with precipitation patterns across the area, especially the stronger an El Niño or La Niña event becomes. This leads to increasing confidence of wetter than normal conditions throughout the entire dry season, which will decrease the threat of developing drought conditions and wildfire activity across the area this dry season, but will increase the potential for heavy rain and river flooding.
Storminess
The forecast for the 2023-2024 dry season (November-April) is for above to well above normal storminess across the state, due to stronger El Niño conditions that will be in place and persist through this winter and spring.
There is a direct relationship between the presence of a strong El Niño and increased storminess in Florida, due to the extension of the subtropical jet stream across the southern United States. This narrow band of stronger winds several miles above the earth’s surface increases the passage of storm systems across the region, leading to an increased threat for severe weather, especially the potential of strong to violent tornadoes across the region. Past El Niño events, especially strong events, have been highly correlated with well above normal storminess and strong tornadoes (EF2+) across the Florida Peninsula between November and April. Keep in mind, El Niño doesn’t cause violent tornadoes in Florida, but they can set the stage.
2023-24 Dry Season Forecast Overview
▪ An El Niño Advisory is in effect, with ongoing El Niño conditions forecast to strengthen and persist over the equatorial Pacific Ocean through the winter (Dec-Feb), and likely continue through the spring (Mar-May).
▪ This will likely be a strong El Niño event, leading to a higher probability of overall wetter than normal conditions across Central Florida this dry season (Nov-Apr). While this will lower the potential for drought development and wildfire activity this winter and spring, it will increase the threat of heavy rain and river flooding.
▪ ENSO state typically has a weaker influence on temperature patterns across Florida, and therefore the temperature forecast is lower confidence. However, El Niño conditions can lead to overall cooler than normal conditions during the dry season (Nov-Apr), mainly due to increased cloud cover and rainfall.
▪ Seasonal storminess is forecast to be above to well above normal through the dry season, increasing the risk of hazardous weather, including severe thunderstorms, as well as strong to violent tornadoes.
▪ Make sure to have an all-hazards plan in place due to the increased potential for severe weather this dry season, including having multiple ways to receive warnings, especially when severe weather threatens at night!
