Tropical Depression 01 intensified into Tropical Storm Arlene on Thursday afternoon.\u00a0 Tropical storms rarely form over the Atlantic Ocean in April and Arlene is only the second storm known to do so during the satellite era.\u00a0 Of course, it would have been much harder to detect tropical storms like Arlene prior to the use of geostationary satellites for meteorological monitoring.\u00a0 At 5:00 p.m. EDT on Thursday the center of Tropical Storm Arlene was located at latitude 37.7\u00b0N and longitude 42.0\u00b0W which put it about 815 miles (1315 km) west of the Azores.\u00a0 Tropical Storm Arlene was moving toward the west-northwest at 25 m.p.h. (41 km\/h).\u00a0 The maximum sustained wind speed was 45 m.p.h. (75 km\/h) and there were wind gusts to 60 m.p.h. (95 km\/h).\u00a0 The minimum surface pressure was 936 mb.<\/p>\n
A circular ring of showers and thunderstorms developed around the center of circulation of Subtropical Depression 01.\u00a0 Additional narrow rainbands organized around the core of the circulation and the convection assumed a more circularly symmetrical shape.\u00a0 In addition data from satellites indicated that a weak warm core had formed at the top of the circulation.\u00a0 A more circular shape and a warm core are characteristics of a tropical cyclone and the National Hurricane Center changed the classification of Subtropical Depression 01 to Tropical Depression 01 in the 11:00 a.m. EDT advisory on Thursday.\u00a0 Showers and thunderstorms continued to develop around the center of circulation and Tropical Depression 01 was upgraded to Tropical Storm Arlene in the 5:00 p.m. EDT advisory on Thursday.<\/p>\n
Tropical Storm Arlene is in an environment that would not normally be considered favorable for a purely tropical weather system.\u00a0 It is moving over water where the Sea Surface Temperature (SST) is near 19\u00b0C.\u00a0 However, an upper low just to the west of Arlene contains colder air.\u00a0 Colder air in the upper levels is providing sufficient instability to generate showers and thunderstorms even though the SST is relatively cool.\u00a0 The cooler SST does mean that the showers and thunderstorms are not as tall as they would be if the water was warmer.\u00a0 The upper low west of the system is producing southerly winds which are blowing over the top of Tropical Storm Arlene.\u00a0 However, since the thunderstorms are not as tall, some of the stronger upper level winds are blowing over the top of Arlene’s circulation and the vertical wind shear is not having as much of an effect as might be expected.<\/p>\n
The environment is marginal for further intensification, but the circulation looks fairly intact at the current time.\u00a0 The cool SST is limiting the amount of energy that the tropical depression can extract from the ocean.\u00a0 However, since the vertical wind shear is not having as much of a negative impact on the depression, some intensification may be possible during the next 24 hours.\u00a0 Eventually, the wind shear is forecast to increase and Tropical Storm Arlene is forecast to weaken.<\/p>\n
Tropical Storm Arlene is caught in the circulation of a large low pressure system to its west.\u00a0 Arlene is forecast to make a counterclockwise loop as it moves around the circulation of the larger low pressure system.\u00a0 It is possible that the larger low could absorb the circulation of Tropical Storm Arlene.<\/p>\n","protected":false},"excerpt":{"rendered":"
Tropical Depression 01 intensified into Tropical Storm Arlene on Thursday afternoon.\u00a0 Tropical storms rarely form over the Atlantic Ocean in April and Arlene is only the second storm known to do so during the satellite era.\u00a0 Of course, it would have been much harder to detect tropical storms like Arlene prior to the use of […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3,2],"tags":[316,317,665,31,662,322,663,664],"_links":{"self":[{"href":"https:\/\/jayhobgood.com\/index.php?rest_route=\/wp\/v2\/posts\/3869"}],"collection":[{"href":"https:\/\/jayhobgood.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/jayhobgood.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/jayhobgood.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/jayhobgood.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=3869"}],"version-history":[{"count":3,"href":"https:\/\/jayhobgood.com\/index.php?rest_route=\/wp\/v2\/posts\/3869\/revisions"}],"predecessor-version":[{"id":3872,"href":"https:\/\/jayhobgood.com\/index.php?rest_route=\/wp\/v2\/posts\/3869\/revisions\/3872"}],"wp:attachment":[{"href":"https:\/\/jayhobgood.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=3869"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/jayhobgood.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=3869"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/jayhobgood.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=3869"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}