Prediction of August Atlantic Basin Hurricane Activity

10.1175/814.1 ◽  
2004 ◽  
Vol 19 (6) ◽  
pp. 1044-1060 ◽  
Author(s):  
Eric S. Blake ◽  
William M. Gray
Keyword(s):  
Tropical Cyclone ◽  
Subtropical High ◽  
Northwest Pacific ◽  
Seasonal Forecasts ◽  
Reanalysis Dataset ◽  
Atlantic Basin ◽  
The North ◽  
Hurricane Activity ◽  
Environmental Prediction ◽  
The Bering Sea

Abstract Although skillful seasonal hurricane forecasts for the Atlantic basin are now a reality, large gaps remain in our understanding of observed variations in the distribution of activity within the hurricane season. The month of August roughly spans the first third of the climatologically most active part of the season, but activity during the month is quite variable. This paper reports on an initial investigation into forecasting year-to-year variability of August tropical cyclone (TC) activity using the National Centers for Environmental Prediction–National Center for Atmospheric Research reanalysis dataset. It is shown that 55%–75% of the variance of August TC activity can be hindcast using a combination of 4–5 global predictors chosen from a 12-predictor pool with each of the predictors showing precursor associations with TC activity. The most prominent predictive signal is the equatorial July 200-mb wind off the west coast of South America. When this wind is anomalously strong from the northeast during July, Atlantic TC activity in August is almost always enhanced. Other July conditions associated with active Augusts include a weak subtropical high in the North Atlantic, an enhanced subtropical high in the northwest Pacific, and low pressure in the Bering Sea region. The most important application of the August-only forecast is that predicted net tropical cyclone (NTC) activity in August has a significant relationship with the incidence of U.S. August TC landfall events. Better understanding of August-only TC variability will allow for a more complete perspective of total seasonal variability and, as such, assist in making better seasonal forecasts.

scholarly journals Potential Impacts of the Saharan Air Layer on Numerical Model Forecasts of North Atlantic Tropical Cyclogenesis

2009 ◽  
Vol 24 (2) ◽  
pp. 420-435 ◽  
Author(s):  
Aaron S. Pratt ◽  
Jenni L. Evans
Keyword(s):  
Tropical Cyclones ◽  
North Atlantic ◽  
Forecast Accuracy ◽  
Tropical Cyclogenesis ◽  
Atlantic Basin ◽  
Easterly Waves ◽  
Saharan Air Layer ◽  
The North ◽  
Gfs Model ◽  
Environmental Prediction

Abstract Tropical cyclones have devastating impacts on countries across large parts of the globe, including the Atlantic basin. Thus, forecasting of the genesis of Atlantic tropical cyclones is important, but this problem remains a challenge for researchers and forecasters due to the variety of weather systems that can lead to tropical cyclogenesis (e.g., stalled frontal boundaries, African easterly waves, and extratropical cyclones), as well as the role of the surrounding environment in promoting or inhibiting the development into a tropical depression and beyond. In the North Atlantic, the effects of the Saharan air layer (SAL), a hot, dry dusty layer that moves into the eastern Atlantic basin, must be taken into account when forecasting whether genesis will occur. There are several characteristics of SAL that impact tropical cyclones (decreased midtropospheric moisture, increased midlevel shear, and enhanced stability). The purpose of this study is to examine the forecasting skill of the National Centers for Environmental Prediction (NCEP) Global Forecasting System (GFS) model for the 2002 and 2003 Atlantic hurricane seasons, with particular regard paid to possible SAL effects on model genesis forecast accuracy. Cyclone phase space analyses of GFS 6-hourly forecasts were divided into three possible outcomes: S (successful forecasts that verified in cyclogenesis), F1 (cyclogenesis events that were not forecast to occur), and F2 (forecasted cyclogenesis that did not occur). The spatial variabilities of these outcomes for the early, middle, and late season were analyzed for both years, as well as the background environmental conditions. The large number of F2 forecasts that were seen in both years can be partly explained by the GFS model not capturing the detrimental effects of the SAL on cyclogenesis.

The 1995 and 1996 North Atlantic Hurricane Seasons: A Return of the Tropical-Only Hurricane

1998 ◽  
Vol 11 (8) ◽  
pp. 2062-2069 ◽  
Author(s):  
Todd B. Kimberlain ◽  
James B. Elsner
Keyword(s):  
North Atlantic ◽  
Eastern Pacific ◽  
Tropical Atlantic ◽  
Atlantic Basin ◽  
Local Factors ◽  
North Atlantic Basin ◽  
The North ◽  
Hurricane Activity ◽  
The North Atlantic ◽  
Global And Local

Abstract Hurricane activity over the North Atlantic basin during 1995 and 1996 is compared to the combined hurricane activity over the previous four years (1991–94). The earlier period produced a total of 15 hurricanes compared to a total of 20 hurricanes over the latter period. Despite this similarity in numbers, the hurricanes of 1995 and 1996 were generally of the tropical-only variety, which marks a substantial departure from activity during the early 1990s. The return of tropical-only hurricanes to the Atlantic basin is likely the result of several global and local factors, including cool SST conditions in the equatorial central and eastern Pacific and warm SSTs in the tropical Atlantic. The hurricane activity of 1995 and 1996 is more reminiscent of activity of some seasons during the early and mid-1950s.

scholarly journals Seasonal Forecasts of Tropical Cyclone Activity in a High-Atmospheric-Resolution Coupled Prediction System*

2016 ◽  
Vol 29 (3) ◽  
pp. 1179-1200 ◽  
Author(s):  
Julia V. Manganello ◽  
Kevin I. Hodges ◽  
Benjamin A. Cash ◽  
James L. Kinter ◽  
Eric L. Altshuler ◽  
...  
Keyword(s):  
Tropical Cyclone ◽  
North Pacific ◽  
Large Scale ◽  
Coupled Model ◽  
Prediction System ◽  
Seasonal Forecasts ◽  
The North ◽  
Skill Scores ◽  
Activity Measures ◽  
The Tropical Pacific

Abstract Seasonal forecast skill of the basinwide and regional tropical cyclone (TC) activity in an experimental coupled prediction system based on the ECMWF System 4 is assessed. As part of a collaboration between the Center for Ocean–Land–Atmosphere Studies (COLA) and the ECMWF called Project Minerva, the system is integrated at the atmospheric horizontal spectral resolutions of T319, T639, and T1279. Seven-month hindcasts starting from 1 May for the years 1980–2011 are produced at all three resolutions with at least 15 ensemble members. The Minerva system demonstrates statistically significant skill for retrospective forecasts of TC frequency and accumulated cyclone energy (ACE) in the North Atlantic (NA), eastern North Pacific (EP), and western North Pacific. While the highest scores overall are achieved in the North Pacific, the skill in the NA appears to be limited by an overly strong influence of the tropical Pacific variability. Higher model resolution improves skill scores for the ACE and, to a lesser extent, the TC frequency, even though the influence of large-scale climate variations on these TC activity measures is largely independent of resolution changes. The biggest gain occurs in transition from T319 to T639. Significant skill in regional TC forecasts is achieved over broad areas of the Northern Hemisphere. The highest-resolution hindcasts exhibit additional locations with skill in the NA and EP, including land-adjacent areas. The feasibility of regional intensity forecasts is assessed. In the presence of the coupled model biases, the benefits of high resolution for seasonal TC forecasting may be underestimated.

scholarly journals Multidecadal Variability in North Atlantic Tropical Cyclone Activity

2008 ◽  
Vol 21 (15) ◽  
pp. 3929-3935 ◽  
Author(s):  
Philip J. Klotzbach ◽  
William M. Gray
Keyword(s):  
Tropical Cyclone ◽  
North Atlantic ◽  
Tropical Cyclone Activity ◽  
Cyclone Activity ◽  
Sea Level Pressure ◽  
Atlantic Basin ◽  
Multidecadal Variability ◽  
The North ◽  
Sea Surface Temperature Anomalies ◽  
Using Data

Abstract Recent increases in Atlantic basin tropical cyclone activity since 1995 and the associated destructive U.S. landfall events in 2004 and 2005 have generated considerable interest into why there has been such a sharp upturn. Natural variability, human-induced global warming, or a combination of both factors, have been suggested. Several previous studies have discussed observed multidecadal variability in the North Atlantic over 25–40-yr time scales. This study, using data from 1878 to the present, creates a metric based on far North Atlantic sea surface temperature anomalies and basinwide North Atlantic sea level pressure anomalies that shows remarkable agreement with observed multidecadal variability in both Atlantic basin tropical cyclone activity and in U.S. landfall frequency.

scholarly journals Evaluating Outer Tropical Cyclone Size in Reanalysis Datasets Using QuikSCAT Data

2017 ◽  
Vol 30 (21) ◽  
pp. 8745-8762 ◽  
Author(s):  
Benjamin A. Schenkel ◽  
Ning Lin ◽  
Daniel Chavas ◽  
Michael Oppenheimer ◽  
Alan Brammer
Keyword(s):  
Tropical Cyclone ◽  
North Atlantic ◽  
Japan Meteorological Agency ◽  
Strong Correlations ◽  
Climate Forecast System ◽  
Climate Forecast System Reanalysis ◽  
The North ◽  
Environmental Prediction ◽  
Size And Structure

The present study examines the fidelity of outer tropical cyclone (TC) size and wind field structure in four atmospheric reanalysis datasets to evaluate whether reanalyses can be used to derive a long-term TC size dataset. Specifically, the precision and accuracy of reanalysis TC size for the North Atlantic (NA) and western North Pacific (WNP) basins are analyzed through comparison with a recently developed QuikSCAT TC size dataset (2000–09). Both outer TC size and structure in reanalyses closely match QuikSCAT data as revealed by strong correlations, similar standard deviations, and generally small biases. Of the TC size metrics examined, the radii of 6–8 m s−1 winds in the NA and radii of 6–10 m s−1 winds in the WNP are generally most comparable to QuikSCAT data. Compared to WNP TCs, NA TC size and structure are represented with greater fidelity. Among the four reanalyses examined, the National Centers for Environmental Prediction Climate Forecast System Reanalysis and the Japan Meteorological Agency Japanese 55-year Reanalysis represent TC size and structure with the greatest fidelity for both basins. Differences between reanalysis and QuikSCAT TC size increase with increasing QuikSCAT TC size in both basins and with decreasing TC latitude in the WNP. Finally, comparison of the distribution of reanalysis TC size during the satellite era with the distribution of QuikSCAT TC size suggests that reanalysis TC size is represented with reasonable fidelity throughout the satellite era and, thus, may be useful for constructing a multidecadal TC size dataset.

Sign in / Sign up

Export Citation Format

Share Document