Jacksonville, FL — Still some late season “activity” to track in the tropics: “Talking the Tropics With Mike” updated every day during the hurricane season (through Nov. 30th).
'Tis the season for king tides - an annual astronomical/marine phenomenon that occurs every mid to late autumn in Oct. & Nov. often resulting in some of the highest tides of the year. Throw in some meteorological input such as onshore (out of the east) winds &/or heavy rain & the tides can be especially high. King tides are the result of the new moon phase in conjunction with the sun & earth causing an increased gravitational pull. The result is at least some minor/nuisance flooding along the coast, intracoastal, St. Johns River & its tributaries along with beach erosion. The new moon in Nov. is on the 15th & will be the next round of king tides.
(2) A weak La Nina for Jacksonville & nearby areas has been - in the past - subject to big temp. swings favoring short but intense cold snaps. The current La Nina is forecast to be at least weak but possibly reaching moderate strength.
NOAA has issued their winter outlook. The forecast is largely predicated on the developing & maturing La Nina - cooling of the equatorial Pacific. In general... the pattern is expected to favor cooler than avg. temps. across the Northern Plains/Pacific NW to warmer than avg. across much of the south & eastern third of the U.S. Precip. tends to be above avg. in the Ohio Valley & Northern U.S. .... below avg. across the South. For Jacksonville/NE Fl./SE Ga.: the “call” is for above avg. temps. & below avg. precip. so dry & mild. Several points to ponder:
(1) The ENSO (El Nino Southern Oscillation) has been less “predictable” (reliable/consistent) - in my opinion - since the earth has warmed.
(3) A dry winter could lead to an enhanced wildfire season in the spring.
Jacksonville N.W.S. ENSO phase & freeze climatology. A weak La Nina has coincided with some of the most intense freezes on record (19 degrees F or lower) for Jacksonville. A strong La Nina - not so much.
From Brian Brettschneider - map indicates the trend toward milder temps. across much of the south for moderate-strong La Ninas with an average of 9-11 months above avg. during an at least 12 month La Nina episode:
NOAA sea surface temp. anomalies nicely shows the La Nina - cooler water - near the equator in the Pacific Basin:
The winter ahead comes after a hot summer for much of the Lower 48 *but not so much* for Jacksonville & nearby areas (only slightly above avg. temps with a lower than avg. July). Having said that, our warming earth has led to a later date of the avg. last 90 temp. of the year for Jacksonville - between Sept. 26th & Oct. 5th vs. about a week earlier in the 1970s, ’80s & ’90s. So far - as of Oct. 15th - there have been no 90 degree days in Oct. with the total this year at 90 which is 8 days above avg. but far from the record of 110+ days (which has occurred twice [2011 & 1990] since 1871). Were it not for a hot start to spring with five 90-degree days in March, 2020 would be very near the annual avg. of 82 ninety- degree days. The latest 90 degree day on record, by the way - Oct. 31st, last year in 2019.