A tropical wave emerged into the Bay of Campeche on June 12th. The associated tropical disturbance moved into northeast Mexico on the 14th. A pre-existing baroclinic trough lie near the Gulf Coast at that time. An area of thunderstorms on the northeast side of the disturbance's broad low over Mexico near the periphery of the Sierra Madre Oriental, which spawned a convective low. This low moved into southern Texas on the 16th. Westerly vertical wind shear displaced thunderstorm activity to its east. The low moved east-northeast slightly offshore Texas, with the National Hurricane Center declaring it a tropical storm on the 17th. Very soon afterward, Arthur moved back inland just inside the Middle and Upper Texas coast, with Arthur designated as a post-tropical cyclone near Galveston on the night of the 17th. A strong area of low pressure across the Plains, near record strength for June, along with its lee trough across the Southern Plains briefly disrupted Arthur's surface circulation as it moved across the Golden Triangle of Southeast Texas. After it moved into western Louisiana, the center became apparent once more on the morning of the 18th. This low moved east-northeast with occasional hesitation when two short, training thunderstorm bands formed near the southern MS/LA border and across east-central Louisiana on the 18th, with the cyclone picking up the pace once convection waned. Arthur eventually moved offshore North Carolina late on the morning of the 19th when it linked up with a frontal boundary, becoming extratropical.
The graphics below show the storm total rainfall for Arthur, which used rain gage information from National Weather Service Forecast Offices/xMACIS2 and CoCoRAHS. The heavy rainfall southeast of Cottonport on the 18th led to the preliminary establishment of a new 24 hour rainfall record for the state of Louisiana -- 29.06" The site's storm total for Arthur reached 37.58", which preliminarily establishes a new tropical cylone/tropical cyclone remnant rainfall record for the state of Louisiana, barely surpassing the 37.5" which fell in the Rice Country during a slow-moving hurricane in early August 1940.
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The heavy rainfall southeast of Cottonport on the 18th led to the preliminary establishment of a new 24 hour rainfall record for the state of Louisiana -- 29.06" The site's storm total for Arthur reached 37.58", which preliminarily establishes a new tropical cylone/tropical cyclone remnant rainfall record for the state of Louisiana, barely surpassing the 37.5" which fell in the Rice Country during a slow-moving hurricane in early August 1940. Below are zoomed in images that cover the areas of heaviest rainfall from Arthur.
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