National Weather Service United States Department of Commerce
Neutral ENSO Conditions Favored for the Upcoming Winter

The outlook from the Climate Prediction Center for the upcoming winter of 2019-2020 is saying that neutral El Niño Southern Oscillation (ENSO) conditions are in place this year and expected to persist into next spring. Therefore, in the absence of El Niño or La Niña, long-term trends become a key predictor for the outlook, while other climate patterns, such as the Madden-Julian Oscillation and Arctic Oscillation (AO), will likely play a larger role in determining winter weather. For example, the AO influences the number of arctic air masses that intrude into the U.S., but its predictability is limited to a couple weeks.
 
All images on this page can be magnified by clicking, and resized back to original size with a second click.
 
Typical Wintertime Pattern during El Niño
 
      Typical Wintertime Pattern during La Niña
 

Outlook for Winter 2019-2020:

The overall forecast for West Central and Southwest Florida for the upcoming winter is for a better chance of above normal temperatures with equal chances of above, below, or near normal rainfall as can be seen in the Climate Prediction Center Winter Outlook graphics below. However, the long term trend across our area during an ENSO neutral phase indicates near to slightly below normal temperatures during December followed by near to slightly above normal temperatures for January and February. Rainfall during these months is usually near to a little below normal. There will likely be a few freezes across the region, especially the Nature Coast, but prolonged cold weather is not anticipated at this time. Drought conditions are also not anticipated to develop until maybe next Spring when numerous fair and warm days return.
 

CPC Winter 2019-20 Temperature Outlook


CPC Winter 2019-20 Precipitation Outlook


U.S. Seasonal Drought Outlook
 


In the following sections is more detailed information and graphics about how ENSO affects the weather across West Central and Southwest Florida. Click on one of the buttons below to go directly to that section. Also, all images can be magnified by clicking, and resized back to original size with a second click.
 

History:

We had weak El Niño conditions last winter and as is typical during El Niño winters we saw above normal rainfall, but temperatures actually averaged out a couple of degrees above average thanks to a very warm February. Before this, weak La Niña conditions occurred during the winters of 2016-17 and 2017-18 which led to below normal rainfall and temperatures a couple of degrees above normal. This winter into next spring ENSO Neutral conditions are forecast so we are anticipating that rainfall will be near to slightly below normal while temperatures should average out near to slightly above normal overall, but could vary greatly from week to week.

Following are U.S. maps of the Winter (December-February) departure from average precipitation and temperature for each category of El Niño and La Niña since 1950.
 
El Niño PrecipitationWinter (Dec-Feb) Precipitation during strong, moderate, and weak El Niños since 1950   El Niño TemperatureWinter (Dec-Feb) Temperature during strong, moderate, and weak El Niños since 1950
 

 
La Niña PrecipitationWinter (Dec-Feb) Precipitation during strong, moderate, and weak La Niñas since 1950   La Niña TemperatureWinter (Dec-Feb) Temperature during strong, moderate, and weak La Niñas since 1950

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Rainfall:

During El Niño there tends to be more stormy conditions across the Florida peninsula during the winter and early spring. Cold fronts will move across the region and with the jet stream further south and stronger, rainfall is more widespread and therefore usually above average. This can be seen in the graphics below where rainfall totals during the dry season average much higher during El Niño winters then during La Niña winters.
 
Inverness 3 SE Average Monthly Rainfall by ENSO Category   Inverness 3 SE Average Rainfall Total by ENSO Category
 
Brooksville Average Monthly Rainfall by ENSO Category   Brooksville Average Rainfall Total by ENSO Category
 
Tampa Average Monthly Rainfall by ENSO Category   Tampa Average Rainfall Total by ENSO Category
 
Lakeland Average Monthly Rainfall by ENSO Category   Lakeland Average Rainfall Total by ENSO Category
 
Sarasota-Bradenton Average Monthly Rainfall by ENSO Category   Sarasota-Bradenton Average Rainfall Total by ENSO Category
 
Arcadia Average Monthly Rainfall by ENSO Category   Arcadia Average Rainfall Total by ENSO Category
 
Punta Gorda Average Monthly Rainfall by ENSO Category   Punta Gorda Average Rainfall Total by ENSO Category
 
Fort Myers Average Monthly Rainfall by ENSO Category   Fort Myers Average Rainfall Total by ENSO Category

Another way to see this is by viewing the Box and Whisker Distribution Plots* for the three climate zones across the Florida peninsula shown below:
 
DJF Precipitation Distribution for Climate Div. #066 DJF Precipitation Distribution for Climate Div. #067 DJF Precipitation Distribution for Climate Div. #068
Northern Florida Peninsula Central Florida Peninsula Southern Florida Peninsula

*To better understand these plots visit the following CPC web page:
http://www.cpc.ncep.noaa.gov/products/precip/CWlink/ENSO/box_whiskers/info.php

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Temperature:

The link between ENSO and wintertime temperatures is a little bit weaker. With the average storm track farther south during El Niño temperatures tend to average slightly below normal thanks to the increased clouds and rain that keep daytime highs cooler. This is in contrast to La Niña where we usually see drier air over the state with more fair weather days. This drier air leads to warmer daytime and slightly cooler nighttime temperatures that overall result in slightly above average temperatures across the area.

What plays a larger role in controlling temperatures across Florida during the winter and early spring is the Arctic Oscillation (AO) as we saw back in early 2010. This oscillation shifts on a monthly and sometimes weekly basis and typically is not included in long term forecasts. For more details visit Arctic Oscillation: Impacts on West Central and Southwest Florida.

 
Inverness 3 SE Monthly Departure from Normal Temperature by ENSO Category   Inverness 3 SE Season Average Temperature by ENSO Category
 
Brooksville Monthly Departure from Normal Temperature by ENSO Category   Brooksville Season Average Temperature by ENSO Category
 
Tampa Monthly Departure from Normal Temperature by ENSO Category   Tampa Season Average Temperature by ENSO Category
 
Lakeland Monthly Departure from Normal Temperature by ENSO Category   Lakeland Season Average Temperature by ENSO Category
 
Sarasota-Bradenton Monthly Departure from Normal Temperature by ENSO Category   Sarasota-Bradenton Season Average Temperature by ENSO Category
 
Arcadia Monthly Departure from Normal Temperature by ENSO Category   Arcadia Season Average Temperature by ENSO Category
 
Punta Gorda Monthly Departure from Normal Temperature by ENSO Category   Punta Gorda Season Average Temperature by ENSO Category
 
Fort Myers Monthly Departure from Normal Temperature by ENSO Category   Fort Myers Season Average Temperature by ENSO Category


This can also be seen in the Box and Whisker Distribution Plots* for the three climate zones across the Florida peninsula shown below:
 
DJF Temperature Distribution for Climate Div. #066 DJF Temperature Distribution for Climate Div. #067 DJF Temperature Distribution for Climate Div. #068
Northern Florida Peninsula Central Florida Peninsula Southern Florida Peninsula

*To better understand these plots visit the following CPC web page:
http://www.cpc.ncep.noaa.gov/products/precip/CWlink/ENSO/box_whiskers/info.php

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Freezes:

Freezing temperatures are possible into Central and South Florida during any winter no matter what the ENSO phase is that year. During El Niño conditions the likely cause of freezing temperatures is advection of cold air dragged southward behind low pressure systems that pass across the state. This is unlike La Niña conditions where the main cause is radiational cooling under clear skies and calm winds.

Long term averages indicate three to six days of freezing temperatures each winter across inland portions of Central Florida with only about one freeze over Southwest Florida. Farther north across the Nature Coast many more days of freezing temperatures occur with some locations such as Inverness and Bushnell having on average around 12 days, while farther north near Chiefland there are as many as 20 days with temperatures falling to or below 32° each winter. Overall the difference in the number of days with freezing temperatures each winter is not that much between the ENSO phases as seen in the graphics below, but more dependent on the phase of the Arctic Oscillation (AO). For more details visit Arctic Oscillation: Impacts on West Central and Southwest Florida.

 
Inverness 3 SE Average Number of Freezes per Cool Season by ENSO Category   Brooksville Average Number of Freezes per Cool Season by ENSO Category
 
Tampa Average Number of Freezes per Cool Season by ENSO Category   Lakeland Average Number of Freezes per Cool Season by ENSO Category
 
Sarasota-Bradenton Average Number of Freezes per Cool Season by ENSO Category   Arcadia Average Number of Freezes per Cool Season by ENSO Category
 
Punta Gorda Average Number of Freezes per Cool Season by ENSO Category   Fort Myers Average Number of Freezes per Cool Season by ENSO Category

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Other Web Sites:

NOAA Winter Outlook Press Release
https://www.noaa.gov/media-release/winter-outlook-warmer-than-average-for-many-wetter-in-north

Climate Prediction Center
http://www.cpc.ncep.noaa.gov/

NOAA Climate.gov ENSO Page
https://www.climate.gov/enso

NOAA Climate.gov Arctic Oscillation Page
https://www.climate.gov/news-features/understanding-climate/climate-variability-arctic-oscillation

NWS Tampa Bay Local Arctic Oscillation Page
https://www.weather.gov/tbw/tampabayaopage

January 2010 Cold Snap
NWS Tampa Bay 2009-2010 Winter Newsletter

Current Drought Conditions in Florida
https://droughtmonitor.unl.edu/CurrentMap/StateDroughtMonitor.aspx?FL

Drought Outlook
http://www.cpc.ncep.noaa.gov/products/expert_assessment/sdo_summary.php

NWS Tampa Bay Local Drought Page
https://www.weather.gov/tbw/droughtinfo
 

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