George P. Bancroft
Ocean Forecast Branch, Ocean Prediction Center, College Park, MD
NOAA National Center for Environmental Prediction


The late spring to summer months of 2014 featured mostly a progressive pattern across the North Atlantic with occasional blocking at higher latitudes causing cyclones to move erratically or stall, especially in May and early June over the southwestern waters. The number of intense lows typically declines in May and June, and 2014 was no exception. There were only two cyclones with central pressures in the 970s hPa of non tropical origin during the four month period, with one occurring early in May and the other at the beginning of July, with both occurring north of 55N. With the possible exception of the deeper of two early May Greenland events, there were no hurricane force lows of non tropical origin.

The May to August period includes the first half of the Atlantic hurricane season. The first three named systems, all hurricanes, entered OPC’s marine area north of 31N between Bermuda and the southeast coast of the U.S. and re-curved into the westerlies before becoming extratropical. The first, Arthur in early July, was the strongest and made landfall in eastern North Carolina before moving offshore and becoming post tropical/extratropical over the Canadian Maritime Provinces. The others followed tracks farther offshore, and the last, Cristobal, became an intense extratropical hurricane force low with central pressures as low as 963 hPa at the end of August.

Tropical Activity

Hurricane Arthur: The first named tropical cyclone of 2014 began as Tropical Depression One near the northern Bahamas early on July 1st and intensified, becoming Tropical Storm Arthur later that day with maximum sustained winds 40 kt with gusts to 50 kt. Arthur then followed a coastal track and became a hurricane early on the 3rd while passing north of 31N, with maximum sustained winds 65 kt. Arthur briefly made landfall on the North Carolina Outer Banks on the night of the 3rd with a maximum intensity of 85 kt for sustained winds with gusts to 105 kt. This places it at Category 2 of the Saffir Simpson hurricane wind scale (Reference 4). The cyclone then passed offshore the next day and began to weaken, crossed Georges Bank as a minimal hurricane on the evening of the 4th and then became post tropical as it reached the Bay of Fundy (Figure 1). Figure 2 is a satellite image showing Arthur, still a hurricane with a central dense overcast and hint of an eye, but undergoing extratropical transition, about to merge with a broad frontal band to the north. Table 1 lists some notable observations taken during this event. In Figure 3 a swath of satellite derived significant wave heights cuts across the southeast side of the hurricane center where a maximum of 42.57 ft (13.0 m) appears. Arthur is shown at maximum intensity (980 hPa) as a post tropical low in Figure 1. The cyclone subsequently moved into the Labrador Sea as a gale, where it stalled and weakened late on the 7th.

Hurricane Bertha: Bertha formed in the deep tropics east of the Windward Islands early on August 1st and moved northwest as a tropical storm until the 4th, when it became a hurricane near 29N 74W at 1800 UTC on the 4th with maximum sustained winds of 65 kt with gusts to 80 kt. Bertha then followed a re-curving path farther offshore than Arthur, passing between Bermuda and the southeast coast of the U.S. and maintained its intensity until 0600 UTC on the 5th and then weakened to a tropical storm. Tropical Storm Bertha passed near 39N 64W at 1200 UTC on the 6th with maximum sustained winds of 45 kt and then became a post tropical gale six hours later. Post tropical Bertha then passed over the Grand Banks late on the 7th and moved out over the North Atlantic along 47N before turning northeast toward the British Isles and re intensifying (Figure 4). Bertha became the stronger of two extratropical lows that affected the North Sea from the 9th to the 12th. The ship BATFR27 (49.5N 3.5W) reported west winds of 61 kt at 1000 UTC August 10th . The platform Ekofisk (LF5U) near 56.5N 3.2E reported southwest winds of 46 kt and 6.0 meter seas (20 ft) at 0900 UTC on the 11th. The platform 62119 (57.0N 1.9E) encountered west winds of 51 kt and 6.5 meter seas (21 ft) at 1200 UTC on the 11th and maximum seas of 7.0 m (23 ft) one hour prior. The platform 62113 (56.3N 2.2E) reported southwest winds of 47 kt at 0800 UTC on the 11th and maximum seas of 8.5 m (28 ft) 4 hours later. MQTL6 (58.0N 1.0E), possibly a platform, reported a pressure of 974.3 hPa at 0800 UTC on the 11th. The cyclone subsequently stalled and weakened north of the British Isles late on the 12th.

Hurricane Cristobal: Tropical Depression Four formed near the southeastern Bahamas late on August 23rd and moved north while intensifying, becoming Tropical Storm Cristobal twelve hours later and then a hurricane at 0600 UTC on the 26th while passing near 25N 72W. Cristobal followed a track parallel to and a bit east of Bertha’s track and maintained Category 1 hurricane strength all the up to 45N 49W 1200 UTC on the 29th before becoming post tropical. Buoy 41048 (32.0N 69.5W) reported southwest winds of 39 kt with gusts to 51 kt and 7.5 meter seas (25 ft) at 2300 UTC on the 27th and maximum seas of 8.0 m (26 ft) one hour prior. Hibernia Platform (VEP717, 46.7N 48.7W) reported northeast winds of 59 kt at 1500 UTC on the 29th, and seas as high as 5.8 m (19 ft) nine hours later. The anemometer height is 139 m. The cyclone briefly developed a maximum intensity of 75 kt for sustained winds and gusts to 90 kt at 0600 UTC on the 29th. Figure 5 shows Cristobal becoming an intense post tropical hurricane force low over a twelve hour period as it merges with a frontal zone. The ASCAT image in Figure 6 shows retrieved winds around the hurricane with the highest winds, up to 70 kt but mostly 50 to 60 kt, on the south side. Figure 7 depicts further intensification of Post tropical Cristobal as it re forms northeast toward Iceland while absorbing the low near Greenland. The lowest central pressure was 963 hPa at 0600 UTC on the 31st. The ASCAT image in Figure 8 shows a swath of west to southwest winds up to 60 kt on the south side of the cyclone which is centered north of 60N close to the time of the second part of Figure 7. The ship UDYG (65N 33W) reported northeast winds of 45 kt at 1200 UTC on the 31st. Late on the 31st the cyclone passed north of Iceland and weakened.

Other Significant Events of the Period

North Atlantic Storms/ Greenland area, May 1-4: The first two significant events of the period developed in close succession. The storm near Greenland in the first part of Figure 9 originated near 43N 45W at 1800 UTC April 29. The development of the stronger of the two lows is shown in Figure 9, originating from the 1003 hPa low at 40N 39W. The ASCAT image of the stronger system (Figure 10) taken about 4 ˝ hours later shows retrieved winds of up to 60 kt. This indicates possible hurricane force as the low moved closer to Greenland and with low bias of winds at high speeds. The stronger low subsequently looped back to the southwest and then southeast and weakened, similar to the first low.

North Atlantic Storm/ Greenland area, May 11-14: A developing low moved off the Labrador coast early on May 10th and passed south of Greenland with a lowest central pressure of 982 hPa on the afternoon of the 12th as shown in Figure 11. An ASCAT (METOP-A) pass from 2234 UTC on the 12th is similar to Figure 10 except not quite as high, up to 50 kt. The cyclone subsequently drifted northeast and weakened, and dissipated near 60N 30W on the 15th.

North Atlantic Storms, May 14-17: The development of the first storm is shown in Figure 11. The frontal wave of low pressure over New England moved southeast and slowed down while getting trapped under a building high to the north over a 2 ˝ day period. At 1800 UTC on the 15th a new low formed on the front south of the old low near 30N 42W and moved north while strengthening, becoming the stronger 998 hPa low shown in the first part of Figure 12. A vessel with a SHIP call sign reported east winds of 45 kt near 46N 35W at 2100 UTC May 16th. The Canmar Honour (ZCBP5) encountered north winds of 37 kt and 4.5 meter seas (15 ft) near 42N 47W at 1600 UTC on the 16th. In Figure 12 the low has stalled and lost frontal features while blocked by the ridge to the north. The infrared satellite image in Figure 13 shows a cyclone unlike an ordinary mid latitude system with an eye like feature surrounded by convective clouds. An ASCAT (METOP-B) pass from 0101 UTC May 18th showed a circular area of gales surrounding a core of lighter winds. The cyclone subsequently continued its weakening trend while drifting north.

Northeastern Atlantic Storm, May 15-17: This short lived event began as a new frontal wave of low pressure near 58N 20W at 1800 UTC May 18th which moved northeast and passed east of Iceland twenty four hours later as a storm force low with a central pressure of 989 hPa. With the central pressure falling 29 hPa during this period, this development could be considered a meteorological bomb (Reference 1). An ASCAT (METOP-A) pass from 2112 UTC May 16th shows a swath of west winds to 45 kt south of the center and resembles Figure 15 for the early July event. The cyclone then moved northeast away from the area by the 17th.

Southwestern North Atlantic Storm, May 31-June 1: A new low formed off the mid Atlantic coast of the U.S, near 37N 68W with a 1012 hPa central pressure at 0000 UTC May 31st and drifted east over the next twenty four hours while the pressure fell 11 hPa. This was enough for the cyclone to develop storm force winds with a relatively modest central pressure at 0000 UTC June 1st, with the center near 38N 62W. An ASCAT pass from 0157 UTC June 1st reveals wind retrievals of 40 and 45 kt around the west semicircle and is similar to Figure 17 for the mid August event. The ship 9HJC9 (35N 68W) reported northwest winds of 45 kt and 5.5 m seas (18 ft) at 1300 UTC May 31st The cyclone subsequently stalled and weakened with winds dropping to below gale force late on June 2nd.

Northeastern Atlantic Storm, July 1-2: An unseasonably deep low developed near Iceland on July 2nd. It originated from a wave of low pressure near the Labrador coast at 0600 UTC June 30th. It intensified gradually while tracking across the northern waters (Figure 14). The lowest central pressure was 975 hPa at 1200 UTC July 2nd as the center moved over Iceland. The ASCAT image in Figure 15 reveals a swath of west winds to 45 kt south of Iceland. The low bias of ASCAT at higher wind speeds supports analysis of this system as a storm. This was the deepest cyclone of non tropical origin in the Atlantic during the four month period. The cyclone remained nearly stationary and weakened slowly over the next two days before drifting southeast and dissipating near 61N 11W late on the 7th.

North Atlantic Storm, Greenland area, July 26-27: A developing low originating just south of Nova Scotia at 1200 UTC July 25th moved northeast across Newfoundland and the Labrador Sea to the east Greenland waters on the 27th, where it briefly developed storm force winds and a 990 hPa central pressure. An ASCAT (METOP-B) pass from 1404 UTC on the 27th returns a swath of north to northwest winds to 45 kt to the west of the low and is similar to Figure 17 for the mid August event. The cyclone subsequently moved east and passed near Iceland the following night with winds weakening to gale force.

Northeastern Atlantic Storm, August 15-16: Low pressure originating near Greenland at 0000 UTC August 14th remained nearly stationary over the next twenty four hours before spawning a new low to the east near 64N 30W by 0600 UTC on the 15th. The new low moved east southeast, briefly developing storm force winds and a lowest central pressure of 988 hPa near 61N 1W late on the 16th (Figure 16). The ASCAT image in Figure 17 reveals north winds to 45 kt west of the Faroe Islands. Buoy 64045 reported highest seas of 8.0 m (26 ft) at 0700 UTC on the 17th.


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2.Ocean Surface Winds,

3. VonAhn, Joan. and Sienkiewicz, Joe, Hurricane Force Extratropical Cyclones Observed Using QuikSCAT Near Real Time Winds, Mariners Weather Log, Vol. 49, No. 1, April 2005.

4. Saffir-Simpson Scale of Hurricane Intensity:

5. Tropical Cyclone Reports, 2014, National Hurricane Center,

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