CoCoRaHS

FLORIDA

A Community Collaborative

Rain, Hail & Snow Network

Spring 2024 Newsletter

Greetings from the Coordinators,

We are pleased to present the spring 2024 quarterly newsletter that includes highlights during the past few months and what to expect this summer. This spring brought severe weather and multiple rounds of heavy rainfall to the state, as well as record heat and drought. Spring 2024 (March - May) was the 6th-warmest spring on record in Florida. May 2024 became the warmest May on record in Florida, while it was the 13th-warmest for the U.S. as a whole. Drought emerged in late April in central and southern Florida and degraded through May due to below-normal rainfall and record-breaking heat.

So far June has been much wetter than normal across south Florida, signaling the start of the rainy season there and a quick end to drought. Elsewhere, drier conditions are setting in with a slow start to the hurricane season. This winter's strong El Niño climatological pattern in the tropical Pacific Ocean began to weaken and give way to ENSO-neutral conditions. La Niña conditions are forecast to emerge later this summer.

We'd like to welcome all of our new observers since the last newsletter went out. As always, your contributions to this network are greatly appreciated. Over the past few months, your observations helped to document these and other events. Thank you for your continued support and dedication to the CoCoRaHS program. As always, feel free to reach out to us at any time.

Sincerely,

Emily Powell

epowell@coaps.fsu.edu

Ivetta Abramyan

ivetta.abramyan@fscj.edu

Florida CoCoRaHS Program Highlights

During this spring season, 56,108 reports were submitted through daily and multi-day reports. There were an additional 23 significant weather reports and 147 condition monitoring reports submitted during the spring months. These observations have helped the National Weather Service and the Water Management Districts in Florida monitor changing conditions and have provided on-the-ground impacts for additional context and ground truthing. Reports of local impacts are extremely useful during times of drought in understanding how local conditions are changing and being impacted.

A Glance Back at Spring 2024

The Florida Panhandle had a much wetter than normal spring season (MAM). The 3-month precipitation departures from normal were over 9 inches in Leon, Jefferson, and Madison Counties. The CoCoRaHS sites with the heaviest observed daily rainfall totals during spring were in Tallahasse and Monticello.

Below normal rainfall was observed from a line stretching roughly from Hernando County south, except for Monroe and southwest Miami-Dade Counties, and along much of the east coast. Observers across the Peninsula began reporting moderate to severely dry conditions in April. Maps showing the seasonal precipitation departures from normal and condition monitoring reports during the last week of spring are shown below.

CoCoRaHS_Condition_Monitoring_reports_May28-June3_2024 image

Recent Heavy Rainfall Events

Tallahassee Heavy Rainfall Event - April 10-11, 2024

Heavy rain and multiple severe weather outbreaks impacted Florida this spring. On April 10-11, strong storms moved through the Panhandle producing heavy rain and flash flooding. Tallahassee received 7.11 inches of rain in the overnight hours of April 10-11, which was 96% of their month's total rainfall in just a few hours. The storm led to flooding of roadways and buildings and closed schools. The maps below show the area-wide rainfall totals from NWS, as well as storm totals from our CoCoRaHS observers in Leon County.

South Florida Heavy Rainfall Event – Week of June 10, 2024

Sarasota (from Austen Flannery, CoCoRaHS Regional Coordinator - Florida West Coast, National Weather Service)

As a tropical disturbance and surge of moisture lifted northward over portions of the Florida peninsula during the week of June 10, several rounds of heavy rainfall occurred across West Central and Southwest Florida. During the evening of June 11, one storm in particular produced an estimated 8 to 10 inches of rainfall across northern Sarasota and southern Manatee County, causing Flash Flooding in Downtown Sarasota and St. Armands Circle.

At Sarasota-Bradenton Airport, a new all-time one-hour record rainfall total was set at 3.93 inches. The airport observed a total of 6.47 inches on June 11th, which is a new daily record that surpassed the previous record set in 1940. Records for Sarasota-Bradenton Airport date back to 1911.

Observations from CoCoRaHS Observers helped meteorologists from NWS Tampa Bay better understand the spatial extent of the event post mortem. Additionally, these observations provide ground truth for radar estimates for rainfall across the region.

Southeast Florida

South Florida was impacted by the same system during the week of June 10. Southeast Florida reported some of the highest 72-hour rainfall totals from June 11 - 14. A total of 20.65" was reported at Hallandale and 17.60" was recorded at the 14E Miccosukee Indian station. The highest storm totals reported by CoCoRaHS observers were also in Hollywood at 19.96" (BW-140) and 17.55" (BW-174).

The outlook for the remainder of the rainy season suggests that rainfall could continue to be above average, according to the Climate Prediction Center. This is generally welcome for the West Coast of Florida where summer rains never quite materialized last year, and drier-than-normal conditions have continued to impact coastal communities. CoCoRaHS observers continue to provide additional supplemental data that allows NWS Meteorologists to better understand these long term trends. Thanks for your continued support of this fantastic citizen science initiative!

Spring Extremes Across Florida CoCoRaHS

Between 1 March 2024 and 31 May 2024:

Highest seasonal rainfall total: 28.70" in Tallahassee, Leon Co. (LN-25)
Lowest seasonal rainfall total: 1.88" in Winter Haven, Polk Co. (PK-96)
Highest daily rainfall total: 10.49" on April 11 in Tallahassee, Leon Co. (LN-47)

*based on stations with at least 90% completeness

Significant Weather Reports

Between 1 March 2024 and 31 May 2024, there were:

23 total Significant Weather reports submitted.
15 reports of Minor flooding.
1 report of Unusual flooding.

Observer Comment Corner

Observer comments are encouraged! Thanks to the many who regularly post comments with their reports. Comments provide valuable context to observations, which can be very helpful to those who later use the observations. If nothing else, comments are interesting for us and other observers to read. Here are a select few of the comments shared during the past few months. We’ll continue to share your comments in these newsletters.

1. 11 April, Tallahassee 5.2 E, Leon County (LN-47) – 10.49 inches

"Epic rainfall overnight, flash flood emergency in Leon county, roads closed, water emergency rescues, sprinkling at obs time, lowest pressure 1002.0 mb at 620 am edt."

2. 11 April, Monticello 4.3 ENE, Jefferson County (JF-9) - 9.69 inches:

"WOW! Rain started about 840p Wed evening and not sure it ever stopped. Tornado watch, severe TS warning, flood warning, lots of thunder and lightning, minimal wind gusts. Reading as of 630a during a rain lull. Gauge was so full and heavy I was afraid I’d drop it. Rain started again."

3. 9 May, St. Petersburg 2.5 S, Pinellas County (PN-81) - 0.00 inches:

"Clear, very warm morning and unseasonably hot afternoon. The heat index was 106 today. This heat index of over 100 will continue for the next 7 months. No rain here since April 11th."

4. 10 May, Tallahassee 6.2 E, Leon County (LN-60) - 1.52 inches:

"TORNADOS! and heavy rains Friday morning, over by noon. Severe damage around Tallahassee, FSU and Woodville."

5. 11 May, Fort Pierce 5.8 SSE, St. Lucie County (SL-59) - 0.00 inches:

"Our area is under a red flag warning for brush fires, with dry and windy conditions. This morning when I took my readings, I could smell smoke. The South Florida dry season has two weeks to go."

6. 29 May, Graceville 7.0 S, Jackson County (JK-7) - 0.00 inches:

"Dry. Fields need rain in this part of the Wiregrass area."

NOAA Issues Final El Niño Advisory; La Niña Around the Corner

El Niño conditions, the warm phase of the El Niño Southern Oscillation climate pattern in the tropical equatorial Pacific Ocean, continued to weaken over the past few months. Currently, ENSO-neutral conditions are present. Near-to-below average sea surface temperature (SST) anomalies expanded across the eastern equatorial Pacific Ocean. La Niña is favored to develop during July-September (65% chance) and persist into the Northern Hemisphere winter 2024-25 (85% chance during November-January).

Summer Season Outlook

Although it was rather dry in late May and early June across much of the Peninsula, June has been extremely wet in South Florida. The onset of the rainy season may have been reached on June 10 in the South Florida Water Management District (SFWMD) and the Southwest Florida Water Management District (SWFWMD), according to the FSU Center for Ocean Atmospheric-Prediction Studies (COAPS). This is late according to the rainy season's onset date climatology, which is May 23 and 30 for the SFWMD and SWFWMD, respectively. Throughout the rest of the state, the onset of the rainy season is still uncertain and will be confirmed in the coming weeks.

The NOAA Climate Prediction Center's outlook for the next three months is leaning toward warmer and wetter than normal on average, July through September, for Florida. While drought conditions currently exist in North Florida, drought is not expected to impact the state as the season progresses.

Important Reminders

It is Officially Hurricane Season - Tips to Prepare

MODIS NASA Aqua satellite of Tropical Storm Alberto nearing northeast Mexico, June 19, 2024.

While this hurricane season has gotten off to a slow start, the Atlantic hurricane season is expected to be very active - and things can turn quickly. On June 19, the first storm of the season was named - Tropical Storm Alberto, which impacted large areas of Central America and the Texas Coast. Alberto was the latest first named storm in the Atlantic Basin since 2014, and occurred right at the long-term average date of June 20 based on climatology.

The National Hurricane Center (https://www.nhc.noaa.gov/) is the leading authority and best source of information on active storms and storms that have the potential to develop. This hurricane season, the NHC will be adding inland watches and warnings to its standard forecast cone graphic to better communicate inland risks as well as risks to coastal areas.

There is also a NWS Experimental Beach Forecast page where you can find your local rip current risk and other hazards at your local beach.

As you make your storm preparations, it's a good idea to know the risks for your home or community. Find out if your home is in a flood risk zone. The Florida Division of Emergency Management provides information on evacuation zones by county. Also consider how to secure and protect your home, secure your boat, and make a plan for your pets. Do not take rainfall measurements in any inclement weather. Wait until it is safe to go outdoors to do so!

CoCoRaHS WeatherTalk Webinar Series Continues this Fall

These webinars take place bi-monthly as one-hour interactive webinar sessions featuring engaging experts in the fields of atmospheric science, climatology and other pertinent disciplines. These easy-to-follow presentations are live and the audience is given the chance to submit questions which the presenter answers live during the webinar.

The next talk is in September 2024 on the topic of "Measuring beyond precipitation. How is your forest responding to drought?" Register and view recordings of past webinars at: https://www.cocorahs.org/Content.aspx?page=wxtalk.

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