An area of showers and thunderstorms near the Yucatan Peninsula has shown signs of a cyclonic circulation, although the rotation may be in the middle troposphere and not at the surface.\u00a0 The formal designation of this system is Invest 91L.\u00a0 At 2:00 p.m EDT on Saturday the center of Invest 91L was located at latitude 20.0\u00b0N and longitude 88.4\u00b0W which put it about 100 miles (165 km) southeast of Merida, Mexico and about 760 miles (1220 km) south-southeast of Galveston, Texas.\u00a0 Invest 91L was moving toward the northwest at 5 m.p.h. (8 km\/h).\u00a0 The maximum sustained wind speed was 35 m.p.h. (55 km\/h) and there were wind gusts to 45 m.p.h. (70 km\/h).\u00a0 The minimum surface pressure was 1009 mb.\u00a0 The National Hurricane Center is now giving Invest 91L a 50% chance of developing into a tropical depression or tropical storm in the next five days.\u00a0 An additional reconnaissance plane has been scheduled to investigate it on Sunday afternoon.<\/p>\n
The circulation of Invest 91L is not very well organized.\u00a0 Almost all of the showers and thunderstorms are occurring in the eastern half of the circulation.\u00a0 Visible satellite images indicate a possible center of cyclonic rotation over the Yucatan peninsula, but it is not clear if the rotation extends all of the way down to the surface.\u00a0 Counterclockwise winds around an upper level low over the Gulf of Mexico are generating significant vertical wind shear over Invest 91L.\u00a0 However, the upper level winds east of the upper low are diverging, which is enhancing rising motion and is supporting the development of the showers and thunderstorms in that area.\u00a0 The upper level divergence is also causing the surface pressure to decrease slowly, which could lead to the formation of a surface center of low pressure.<\/p>\n
When Invest 91L moves into the southern Gulf of Mexico, it will move over water where the Sea Surface Temperature is near 27\u00b0C to 28\u00b0C.\u00a0 So, there is sufficient energy in the upper ocean to support the development of a tropical cyclone.\u00a0 The key factor will be the interaction between the upper low and any surface center that forms.\u00a0 If the surface center forms too close to the upper low, then vertical wind shear will likely inhibit development and the system will remain fairly weak.\u00a0 If the surface low develops a little farther southeast of the upper low, then there will be less shear and more upper level divergence.\u00a0 That could allow for more intensification.<\/p>\n
Invest 91L is expected to move with the upper low as the upper low moves northward.\u00a0 Most guidance from numerical models moves the system toward the north-northwest toward the Upper Texas Coast.\u00a0 However, there will be above normal uncertainty in the track until a well defined center of circulation forms at the surface.<\/p>\n
Interests in the western Gulf of Mexico should monitor the progress of Invest 91L.<\/p>\n","protected":false},"excerpt":{"rendered":"
An area of showers and thunderstorms near the Yucatan Peninsula has shown signs of a cyclonic circulation, although the rotation may be in the middle troposphere and not at the surface.\u00a0 The formal designation of this system is Invest 91L.\u00a0 At 2:00 p.m EDT on Saturday the center of Invest 91L was located at latitude […]<\/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":[38,113,24,112,53],"_links":{"self":[{"href":"https:\/\/jayhobgood.com\/index.php?rest_route=\/wp\/v2\/posts\/982"}],"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=982"}],"version-history":[{"count":2,"href":"https:\/\/jayhobgood.com\/index.php?rest_route=\/wp\/v2\/posts\/982\/revisions"}],"predecessor-version":[{"id":985,"href":"https:\/\/jayhobgood.com\/index.php?rest_route=\/wp\/v2\/posts\/982\/revisions\/985"}],"wp:attachment":[{"href":"https:\/\/jayhobgood.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=982"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/jayhobgood.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=982"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/jayhobgood.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=982"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}