Major Hurricane Delta continues to pinwheel toward the Louisiana coastline. The storm is still moving north around 12mph. The impacts during the next 24 hours will be spread across parts of Texas, Louisiana, Arkansas, Mississippi and Alabama.
Before I get any further, there is an awesome animation from Dr. Kim Wood at Mississippi State of Delta. This is the entire life of Hurricane Delta so far. Really cool stuff.
Now… Here is the latest from the National Hurricane Center.
From the NHC
SUMMARY OF 1000 AM CDT
LOCATION…28.0N 93.8W
ABOUT 130 MI…205 KM SSW OF CAMERON LOUISIANA
MAXIMUM SUSTAINED WINDS…115 MPH…185 KM/H
PRESENT MOVEMENT…N OR 0 DEGREES AT 13 MPH…20 KM/H
MINIMUM CENTRAL PRESSURE…962 MB…28.41 INCHES
FORECAST POSITIONS AND MAX WINDS
INIT 09/1500Z 28.0N 93.8W 100 KT 115 MPH
12H 10/0000Z 30.0N 93.0W 90 KT 105 MPH…INLAND
24H 10/1200Z 32.2N 91.8W 50 KT 60 MPH…INLAND
36H 11/0000Z 33.7N 90.2W 30 KT 35 MPH…INLAND
48H 11/1200Z 35.0N 88.4W 25 KT 30 MPH…INLAND
60H 12/0000Z 36.7N 86.2W 20 KT 25 MPH…POST-TROP/REMNT LOW
72H 12/1200Z…DISSIPATED
KEY MESSAGES
1. Life-threatening storm surge is expected near and east of where Delta makes landfall this evening, and a Storm Surge Warning is in effect from High Island, Texas, to the Mouth of the Pearl River. The highest inundation of 7 to 11 feet is expected somewhere between Rockefeller Wildlife Refuge and Morgan City, Louisiana. Water levels in this area will rise quickly this afternoon and evening as Delta approaches and efforts to protect life and property should be rushed to completion.
2. Hurricane-force winds are expected this afternoon and evening within portions of the Hurricane Warning area, especially along the coast of southwest Louisiana. Hurricane force winds will also spread inland across portions of southern Louisiana near the path of Deltas center this evening and tonight.
3. Heavy rainfall will lead to significant flash flooding and minor to major river flooding in parts of Louisiana today and Saturday. Additional flooding is expected across portions of the central Gulf Coast into the Lower Mississippi Valley.
OUTLOOK
At 1000 AM CDT (1500 UTC), the center of Hurricane Delta was located near latitude 28.0 North, longitude 93.8 West. Delta is moving toward the north near 13 mph (20 km/h). A turn toward the north-northeast is expected this afternoon, followed by a northeastward motion during the day Saturday. On the forecast track, the center of Delta should make landfall along the coast of southwestern Louisiana later this afternoon or this evening, and then move across central and northeastern Louisiana tonight and Saturday morning.
Maximum sustained winds are near 115 mph (185 km/h) with higher gusts. Delta is a category 3 hurricane on the Saffir-Simpson Hurricane Wind Scale. Slow weakening is expected before landfall, with rapid weakening expected after the center moves inland.
Hurricane-force winds extend outward up to 40 miles (65 km) from the center and tropical-storm-force winds extend outward up to 160 miles (260 km). NOAA buoy 42019 located west of the center of Delta recently reported sustained winds of 49 mph (79 km/h) and a wind gust of 60 mph (97 km/h).
The latest minimum central pressure reported by a NOAA Hurricane Hunter aircraft is 962 mb (28.41 inches).
HAZARDS AFFECTING LAND
STORM SURGE: The combination of a dangerous storm surge and the tide will cause normally dry areas near the coast to be flooded by rising waters moving inland from the shoreline. The water could reach the following heights above ground somewhere in the indicated areas if the peak surge occurs at the time of high tide…
Rockefeller Wildlife Refuge, LA to Morgan City, LA including Vermilion Bay…7-11 ft
Holly Beach, LA to Rockefeller Wildlife Refuge, LA…5-8 ft
Sabine Pass to Holly Beach, LA…3-5 ft
Morgan City, LA to Port Fourchon, LA…4-7 ft
Calcasieu Lake…2-4 ft
High Island, TX to Sabine Pass…2-4 ft
Port Fourchon, LA to the Mouth of the Pearl River…2-4 ft
Lake Borgne…2-4 ft
Lake Pontchartrain and Lake Maurepas…1-3 ft
Mouth of the Pearl River, LA to the AL/FL border including Mobile Bay…1-3 ft
Sabine Lake…1-3 ft
Port O’Connor, TX to High Island, TX including Galveston Bay…1-3 ft
It is important to note that small changes in the track, structure, or intensity of Delta could have large impacts on where the highest storm surge occurs. Users are urged to stay tuned for possible changes and updates.
The deepest water will occur along the immediate coast near and to the east of the landfall location, where the surge will be accompanied by large and dangerous waves. Surge-related flooding depends on the relative timing of the surge and the tidal cycle, and can vary greatly over short distances. For information specific to your area, please see products issued by your local National Weather Service forecast office.
WIND: Hurricane conditions are expected within the hurricane warning area by this afternoon, with tropical storm conditions beginning within this area in the next few hours. Tropical storm conditions are expected within the tropical storm warning areas during the next several hours.
RAINFALL: Today through Saturday, Delta is expected to produce 5 to 10 inches of rain, with isolated maximum totals of 15 inches, from southwest into central Louisiana. These rainfall amounts will lead to significant flash, urban, small stream flooding, along with minor to major river flooding.
For extreme east Texas into northern Louisiana, southern Arkansas, and western Mississippi, Delta is expected to produce 3 to 6 inches of rain, with isolated maximum totals of 10 inches. These rainfall amounts will lead to flash, urban, small stream, and isolated minor river flooding.
As the remnants of Delta move further inland, 1 to 3 inches of rain, with locally higher amounts, are expected in the Tennessee Valley and Mid Atlantic this weekend. There is a potential for 3 to 6 inches in the Southern Appalachians, which could lead to isolated flash, urban, and small stream flooding.
TORNADOES: A few tornadoes are possible today and tonight over southern portions of Louisiana and Mississippi.
SURF: Swells from Delta are affecting portions of the northern and western Gulf coast. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office.
TECHNICAL DISCUSSION
Reports from NOAA and Air Force Reserve Hurricane Hunter aircraft indicate that Delta has weakened a little since the last advisory. The central pressure has risen to 962 mb, and the strongest 700-mb flight-level winds reported by the NOAA plane were 107 kt. In addition, SFMR wind estimates have been in the 85-95 kt range. Based on these data, the initial intensity is lowered to 100 kt.
Delta is moving northward or 360/11 kt between a deep-layer ridge over the eastern Gulf of Mexico and a mid- to upper-level trough over the U.S. Southern Plains. A turn toward the north-northeast is expected during the next few hours, and the center is forecast to cross the southwestern coast of Louisiana late this afternoon or this evening. After landfall, a continued north-northeastward motion should bring the center across central and northeastern Louisiana by the 24 h point. Thereafter, Delta is expected to move generally northeastward through the lower Mississippi and Tennessee Valleys until it dissipates. The track forecast guidance remains tightly clustered, and the new forecast track is little changed from the previous forecast.
Increasing vertical shear and decreasing oceanic heat content along the forecast track should cause Delta to continue to weaken before landfall. However, there will still be significant impacts from winds and storm surge (see Key Messages below). After landfall, rapid weakening is anticipated, with Delta expected to weaken to a tropical storm tonight and to a tropical depression by Saturday afternoon or evening. The cyclone is forecast to dissipate between 60-72 h based on the consensus of the global models.
For South Mississippi
I posted the Karrie Meter Map over on twitter a bit earlier. This is a higher-resolution Karrie Meter Map.
12z NAM NEST Karrie Meter for overnight tonight and into tomorrow morning…. pic.twitter.com/xLYt6HOHPR
— Nick Lilja (@NickLilja) October 9, 2020
While the numbers aren’t as high for south Mississippi, keep in mind that during a tropical system, the numbers are going to naturally be lower. So the threshold for the potential for “severe” weather will be lower. In this case the concern for wind gusts up to 60mph and tropical tornadoes is warranted, even with numbers in the 1-to-3 range.
Timeline
Friday 4pm – 10pm: Passing showers, Wind gusts up to 30mph) as the first rainbands start to move through the area
Friday 10pm – Saturday 4am: Heavy rain at times, wind gusts up to 60mph, and the potential for brief tropical tornadoes west of I-59
Saturday 4am – Saturday 10am: Heavy rain at times, wind gusts up to 60mph and the potential for tropical tornadoes in all areas of south Mississippi
Saturday 10am – 4pm: Heavy rain at times, wind gusts up to 40mph and the potential for tropical tornadoes east of I-59
Saturday 4pm – 10pm: Mostly cloudy, wind gusts up to 30mph, drying out
Expectations
– There will be some localized flooding, with water coming up in people’s yards and the creeks may rise a bit for a short period of time during some of the heavy rain within the rainbands.
– Power outages will be likely. Prepare to be without power for up to 6 to 12 hours. The combination of a constant breeze and higher gusts as well as some of the rain means trees are likely to come down. On top of that, tropical tornadoes will be possible within some of the rainbands.
– Based on the latest available data, this will not be a widespread catastrophic event for our area. But a some places will still see damage from gusty wind, downed trees and possible tornadoes.
Tornado Threat
The SPC has pegged southern Mississippi with a Marginal Risk for severe weather on Friday and Saturday. This lines up with the Karrie Meter numbers. Remember that tornadoes from tropical systems are usually brief and weak (EF-0 and EF-1). They tend to be smaller and move much faster, too. So when a warning is issued for your area, don’t try to look outside to see it. Simply take cover and wait it out.
