City of Central

Southeast Louisiana and Southern Mississippi partners - 

Here is an update concerning Tropical Storm Rafael currently in the western Caribbean Sea.

Changes from previous update: 

• No significant changes to the forecast track, just a subtle westward shift in the Gulf of Mexico since the previous advisory.
• The forecast intensity is unchanged from the previous advisory, near Category 2 intensity near Cuba then gradual weakening in the Gulf of Mexico.

Overview:

• Tropical Storm Rafael continues to gradually strengthen and is forecast to become a hurricane tonight as it approaches western Cuba.
• Strong wind shear and dry air will likely cause the storm to weaken when it reaches the central Gulf of Mexico.
• Rafael is expected to enter the Gulf of Mexico as a hurricane on Wednesday evening, and begin to turn more westward. Exactly how sharp of a west turn occurs in the Gulf remains the primary source of uncertainty with the track forecast beyond Wednesday.
• Uncertainty remains regarding the extent of local impacts, if any, we can expect by late Friday and through Saturday time frame.

Confidence: 

·  There is medium confidence in the intensity forecast for Rafael through Cuba. Once the storm reaches the Gulf of Mexico, there is higher uncertainty with the rate of weakening of the storm due to its dependency on the track forecast and where the storm is in relation to the hostile environment along the Gulf coast. If the system stays farther south, it would weaken slower as it moves west. If the system stays farther north toward the Gulf coast, it would weaken faster due to the stronger wind shear and cooler shelf waters.

·  There is low confidence in the track forecast once Rafael reaches the Gulf of Mexico. There remain two different scenarios on the table which will hopefully be resolved within the next 24-36 hours as we get better data and sampling of the atmosphere to know whether the storm will favor the northeast side of the cone or more southwest side of the cone, or meet somewhere in the middle (where the current track forecast is).

Impacts:

• Given the high uncertainty in the forecast beyond midweek, it is too soon to say exactly what impacts this system could bring to the local area besides increased rain chances.
• *IF* this storm continues to move toward the local area, any impacts would most likely occur during the Friday night through Saturday time frame.
• Probability of tropical storm-force winds has continued to slowly increase since yesterday for immediate coastal areas, but these probabilities are likely to go up or down as the forecast is refined over the coming days.

The attached briefing/graphic(s) below highlights the threats associated with Rafael.

Coastal Flooding Overview:

·  Persistent east and southeasterly winds over the Gulf waters, unrelated to TS Rafael, have resulted in tides rising above normal.

·  Minor to moderate flooding is occurring and is expected to continue Tuesday night. A coastal flood advisory is in effect for all coastal areas with the exception of coastal Hancock, southeast St Tammany, and eastern Orleans which are under a coastal flood warning. Waters will recede during the low tide cycle today.

·  High tide is generally forecast to occur between 6pm and 6am along the open coast, with delayed arrival farther inland along bays, rivers, bayous, etc.

Coastal Flooding Impacts:

·  Minor flooding of low lying roads, lots, and parks is likely around the time of high tide tonight in the advisory area.

·  Moderate flooding with inundation of low lying parks, lots, and ground-level storage, and some road closures are possible around the time of Monday night in the warning area.