Norbert will make landfall as a strong Category 2 hurricane
Hurricane Norbert has weakened since yesterday’s impressive Category 4 showing, but still remains a dangerous major hurricane over the Eastern Pacific Ocean. Infrared satellite loops show a well-formed eye with a large area of heavy thunderstorms, but the cloud tops have warmed today, indicating that they are not as vigorous and do not extend as high into the atmosphere. There is excellent upper-level outflow in all quadrants, and wind shear remains low, near 5 knots. The satellite appearance has not changed significantly in the past eight hours. Norbert may go through an eyewall replacement cycle today, where the main inner eyewall collapses, and a new outer eyewall forms. This process could cause a temporary weakening of the storm. The first Hurricane Hunter mission into Norbert is scheduled for this afternoon.
With the exception of the GFS, the computer models continue to be tightly clustered around a landfall in southwestern Baja near San Carlos, 150 miles north of the southern tip of Baja, on Saturday afternoon. The GFS solution of Norbert stalling off the coast and dissipating is unrealistic. Wind shear is about 5 knots over Norbert, and the waters are a warm 28.5°C. The waters along Norbert’s path are unusually warm for this time of year, about 1-3° C above average. However, these warm waters do not extend very deep, and the total oceanic heat content is low.
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Once Norbert crosses Baja and enters the Gulf of California, total heat content increases, but Norbert will not be over these warm waters long enough to take advantage of the extra heat. As Norbert approaches Baja on Friday, wind shear is expected to increase to 15 knots and sea surface temperatures will cool to 27°C. These conditions will still support a major hurricane, and it is possible that Norbert will make landfall as a major hurricane. The latest 2 am EDT run of the GFDL model predicts landfall Saturday afternoon as a strong Category 2 hurricane with 110 mph winds. The latest HWRF model predicts a Category 3 hurricane with 120 mph winds. The SHIPS models is weaker, putting Norbert at Category 1 strength with 95 mph winds. The official NHC forecast of a Category 2 hurricane at landfall looks like a reasonable compromise. Tropical storm force winds should extend outwards about 130 miles at landfall, so the southern tip of Baja (San Lucas) will probably see sustained winds of 30-35 mph, should Norbert hit near San Carlos.
One can look at the forecast radius of tropical storm force winds by clicking on the wundermap for Norbert, then selecting “wind radius” in the check boxes at the bottom of the page.
Crossing rugged Baja will probably knock Norbert down a full Category, by about 20-25 mph. The storm will still pack a solid punch when it makes it second landfall on mainland Mexico north of Los Mochis. Rainfall amounts in mainland Mexico will be 4-8 inches, and 6-10 inches over Baja. Norbert’s remains should bring 1-2 inches of rain to portions of western Texas and southeastern New Mexico.
The content of this post originates of Dr. Jeff Masters’ Blog, He flew with the NOAA Hurricane Hunters from 1986-1990 and is the co-founder of the Weather Underground website, full credits too him
