Large Tropical Storm Cristobal Churns Toward Louisiana

Large Tropical Storm Cristobal churned toward the coast of Louisiana on Saturday night.  At 11:00 p.m. EDT on Saturday the center of Tropical Storm Cristobal was located at latitude 26.2°N and longitude 90.2°W which put it about 200 miles (320 km) south of Grand Isle, Louisiana.  Cristobal was moving toward the north at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 50 m.p.h. (80 km/h) and there were wind gusts to 65 m.p.h. (105 km/h).  The minimum surface pressure was 993 mb.

A Tropical Storm Warning was in effect for the portion of the coast from Intracoastal City, Louisiana to the Okaloosa/Walton County Line in Florida including Lake Pontchartrain and Lake Maurepas.

The circulation around Tropical Storm Cristobal continued to be very large.  Winds to tropical storm force extended out 250 miles (400 km) to the east of the center of Cristobal.  A thunderstorm in a rainband on the eastern periphery of the circulation around Tropical Storm Cristobal produced a tornado near Orlando, Florida.  Winds to tropical storm force extended out 160 miles (260 km) in the western half of the circulation.  The winds were blowing at less than tropical storm force near the center of circulation.  The center passed just to the west of NOAA buoy 42001 on Saturday evening.  The buoy measured a surface pressure of 29.34 inches (993.8 mb).  More thunderstorms appeared to be forming north and south of the center of circulation on Saturday night.

Tropical Storm Cristobal will move through an environment favorable for intensification during the next 12 to 18 hours.  Cristobal will move over water where the Sea Surface Temperature is near 27°C.  It will move under the western side of an upper level ridge.  The ridge will produce southerly winds which will blow toward the top of the circulation.  Those winds will cause some vertical wind shear but the the shear will not be great enough to prevent intensification.  Tropical Storm Cristobal will strengthen on Sunday.  If thunderstorms consolidate around the center of circulation, then there is a chance that Cristobal could strengthen into a hurricane.

Tropical Storm Cristobal will move around the western end of a subtropical high pressure system on Sunday.  The high will steer Cristobal toward the north.  A ridge in the middle troposphere will move north of Tropical Storm Cristobal later on Sunday.  The ridge will turn Cristobal toward the north-northwest.  On its anticipated track Tropical Storm Cristobal will approach the coast of Louisiana on Sunday afternoon.  The center of Cristobal could make landfall between Grand Isle and Morgan City.

Tropical Storm Cristobal will bring gusty winds to Northwest Florida, Southwest Alabama, Southern Mississippi and Southeastern Louisiana.  Those winds will push water toward the coast.  A storm surge of 1 to 4 feet (0.3 to 1.3 meters) will be possible.  The water level could rise 3 to 6 feet (1 to 2 meters) in parts of southeastern Louisiana.  Areas outside of levee protection systems could go under water.  Tropical Storm Cristobal will drop heavy rain over parts of southern Mississippi and Southeastern Louisiana.  Flash Flood Watches have been issued for those regions.