The 2023 North Atlantic Hurricane Season: University of Pennsylvania Forecast

University of Pennsylvania EES scientists Dr. Michael E. Mann and Shannon Christiansen, and Penn State ESSC alumnus Dr. Michael Kozar have released their seasonal prediction for the 2023 North Atlantic hurricane season, which officially starts on 1 June and runs through 30 November.

The prediction is for 15.9 +/- 4.0 total named tropical cyclones, which corresponds to a range between 12 and 20 storms, with a best estimate of 16 named storms. This prediction was made using the statistical model of Kozar et al. (2012, see PDF here). This statistical model builds upon the past work of Sabbatelli and Mann (2007, see PDF here) by considering a larger number of climate predictors and including corrections for the historical undercount of events (see footnotes).

The assumptions behind this forecast are (a) the persistence of current North Atlantic Main Development Region (MDR) sea surface temperature (SST) anomalies (+1.1°C in late April 2023 from NOAA’s Coral Reef Watch) throughout the 2023 hurricane season, (b) presence of positive El Niño-Southern Oscillation (ENSO) conditions in the equatorial Pacific in late Boreal summer and fall 2022 (ENSO forecasts here; we used mid-April 2023), and (c) climatological mean conditions for the North Atlantic Oscillation in Fall/Winter 2022-2023.

If more mild ENSO conditions take shape later in 2023, then the prediction will be slightly higher: 17.2 +/- 4.1 storms (range of 13 – 21 storms, with a best guess of 17).

Using an alternative model that uses “relative” MDR SST (MDR SST with the average tropical mean SST subtracted) in place of MDR SST yields a lower prediction (12.5 +/- 3.5 total named storms). This alternative model also includes positive ENSO conditions.

 
Previous Forecasts:

Year  Prediction Best Guess Range Actual Count
2022 14.9 +/- 3.8 15 11-19 14
2021 11.9 +/- 3.4 12 9-15 21
2020 19.8 +/- 4.4 20 15-24 30
2019 10.1 +/- 3.2 10 7-13 18
2018 10.2 +/- 3.2 10 7-13 15
2017 15.3 +/- 3.9 15 11-20 17
2016 18.9 +/- 4.4 19 14-24 15
2015 6.9 +/- 2.6 7 4-10 11
2014 9.3 +/- 3.0 9 6-12 8
2013 16.0 +/- 4.0 16 12-20 14
2012 11.2 +/- 3.3 11 8-15 19
2011 16.25 +/- 4.0 16 12-20 19
2010 23.4 +/- 4.8 23 19-28 19
2009 11.5 +/- 3.4 12 8-15 (6-13 if El Niño) 9
2007 n/a 15 n/a 15

 
References:

Kozar, M.E., Mann, M.E., Camargo, S.J., Kossin, J.P., Evans, J.L., 2012: Stratified statistical models of North Atlantic basin-wide and regional tropical cyclone counts, J. Geophys. Res., 117, D18103, doi:10.1029/2011JD017170.

Mann, M.E., Sabbatelli, T.A., Neu, U., 2007: Evidence for a Modest Undercount Bias in Early Historical Atlantic Tropical Cyclone Counts, Geophys. Res. Lett., 34, L22707, doi:10.1029/2007GL031781.

Sabbatelli, T.A., Mann, M.E., 2007: The Influence of Climate State Variables on Atlantic Tropical Cyclone Occurrence Rates, J. Geophys. Res., 112, D17114, doi: 10.1029/2007JD008385.

Vecchi, G.A., Knutson, T.R., 2008: On Estimates of Historical North Atlantic Tropical Cyclone Activity, J.Climate, 21, 3580-3600, doi:10.1175/2008JCLI2178.

Footnotes:
The tropical cyclone series was corrected based on an estimated historical undercount taken from Vecchi and Knutson (2008).

 
Prediction made: 1 May 2023
This webpage last updated: 3 May 2023