Dr. Philip Klotzbach of Colorado State University writes on Twitter:
Seasonal #hurricane forecast from @ColoradoStateU predicts slightly below-average season: 13 named storms, 5 hurricanes & 2 major (Cat 3+, >=111 mph) hurricanes. Primary reason for slightly below-avg forecast is anticipated continuation of weak #ElNino.
We anticipate that the 2019 Atlantic basin hurricane season will have slightly belownormal activity. The current weak El Niño event appears likely to persist and perhaps even strengthen this summer/fall. Sea surface temperatures averaged across the tropical Atlantic are slightly below normal, and the far North Atlantic is anomalously cool.
Our Atlantic Multi-decadal Oscillation index is below its long-term average. We anticipate a slightly below-average probability for major hurricanes making landfall along the continental United States coastline and in the Caribbean. As is the case with all hurricane seasons, coastal residents are reminded that it only takes one hurricane making landfall to make it an active season for them. They should prepare the same for every season, regardless of how much activity is predicted.
PROBABILITIES FOR AT LEAST ONE MAJOR (CATEGORY 3-4-5) HURRICANE LANDFALL ON EACH OF THE FOLLOWING COASTAL AREAS:
1) Entire continental U.S. coastline – 48% (average for last century is 52%)
2) U.S. East Coast Including Peninsula Florida – 28% (average for last century is 31%)
3) Gulf Coast from the Florida Panhandle westward to Brownsville – 28% (average for last century is 30%)
PROBABILITY FOR AT LEAST ONE MAJOR (CATEGORY 3-4-5) HURRICANE TRACKING INTO THE CARIBBEAN
(10-20°N, 88-60°W) 1) 39% (average for last century is 42%)
Information obtained through March 2019 indicates that the 2019 Atlantic hurricane season will have activity slightly below the 1981-2010 average. We estimate that 2019 will have about 5 hurricanes (average is 6.4), 13 named storms (average is 12.1), 50 named storm days (average is 59.4), 16 hurricane days (average is 24.2), 2 major (Category 3-4-5) hurricanes (average is 2.7) and 4 major hurricane days (average is 6.2).
The probability of U.S. major hurricane landfall is estimated to be about 90 percent of the long-period average. We expect Atlantic basin Accumulated Cyclone Energy (ACE) and Net Tropical Cyclone (NTC) activity in 2019 to be approximately 75 percent of their long-term averages. This forecast is based on an extended-range early April statistical prediction scheme that was developed using 29 years of past data.
Analog predictors are also utilized. For the first time, we are also using a statistical/dynamical model based off of data from the ECMWF System 5 as an additional forecast guidance tool. The current weak El Niño event appears likely to maintain intensity or perhaps even strengthen during the summer/fall. The tropical Atlantic is slightly cooler than normal, while the subtropical Atlantic is quite warm, and the far North Atlantic is anomalously cool.
The anomalously cold sea surface temperatures in the far North Atlantic lead us to believe that the Atlantic Multi-decadal Oscillation is in its negative phase. There is considerable uncertainty as to what the configuration of Atlantic sea surface temperatures will look like for the peak of the Atlantic hurricane season.
Coastal residents are reminded that it only takes one hurricane making landfall to make it an active season for them, and they need to prepare the same for every season, regardless of how much activity is predicted. The early April forecast is the earliest seasonal forecast issued by Colorado State University and has modest long-term skill when evaluated in hindcast mode. The skill of CSU’s forecast updates increases as the peak of the Atlantic hurricane season approaches.