Dr. Jeff Masters' WunderBlog
Last Updated: 12:37 PM EDT on July 16, 2005
Emily aims at Mexico
Posted By: JeffMasters at 12:37 PM EDT on July 16, 2005
Emily continues to intensify. The satellite presentation of the storm is
spectacular, showing a small hurricane with good symmetry, well-defined
spiral bands, and a healthy-looking circular Central Dense Overcast (CDO)
covering the storm. The eye is large for such an intense hurricane, 13 nm in
diameter, and the storm does not appear close to an eyewall replacement
cycle. These usually occur when the eye diameter reaches 10 nm or less.
Pressure falls of 1-2 mb per hour and continued warming of the eye have been
observed by the Hurricane Hunters, and it appears that Emily is not done yet
with its current deepening phase.
Can Emily become a rare Category 5 storm? It has a ways to go. The central
pressure in a Cat 5 is typically 920 mb or less, and Emily's central
pressure is 941 mb as of 11:15am EDT. Emily's winds at 10,000 feet were 170
mph sustained, which normally would support a surface wind of 150 mph, very
close to Category 5 winds (156 mph or greater). However, the winds measured
near the surface by dropsondes were lower, about 145 mph. If Emily can
maintain its current deepening phase another 12 hours, which I believe is
likely, she will attain Category 5 status tonight.
Where will Emily go? Up until this morning, Emily had been on a steady WNW
track of 285 degrees. This track has now shifted slightly further northward
the past six hours, and is now 290 degrees. Assuming Emily stays on this
track the next 36 hours, Emily will make landfall late Sunday night very
near Cozumel and Cancun. The global models show no major uncertainties in
the steering currents affecting Emily over the next 36 hours. Only minor
wobbles in the track (like we've seen already for both Dennis and Emily) are
likely to affect its course. This will keep the center about 50 - 100 miles
south of Grand Cayman tonight, which will not suffer a repeat of the
terrible blow Hurricane Ivan delivered last year. Ivan brought Category 4
hurricane winds to the island damaging or destroying over 95% of all the
buildings. Emily is likely to pass far enough south tonight to bring only
Category 1 or Category 2 hurricane winds. Still, this will be a harsh blow
for an area still years away from recovering from the $3.5 billion in damage
from Ivan.
Emily is at its closest point to Jamaica, and lies about 100 miles south of
Kingston at noon EDT. Kingston has reported only light rain and maximum
winds of 20 mph thus far. Wunderblogger JamaicanMike is also reporting light
winds and moderate rain. Jamaica appears to be escaping this one unscathed!
Emily is likely to strike Mexico's Yucatan as a Category 4 hurricane,
perhaps even a Category 5. What can we expect the effect on Mexico will be?
Cozumel has the unfortunate distinction of experiencing a strike by the most
powerful hurricane of all time--1988's Hurricane Gilbert. Gilbert struck
Cozumel Island and Cancun as a Category 5 hurricane with sustained winds
estimated at 170 mph. A storm surge of 15 - 20 feet occurred near and north
of Cancun. Damage to Cancun alone was estimated at $80 million. Overall,
Mexico suffered a total of over $2 billion in damage and 202 people killed.
Most of the deaths and damage came not in the Yucatan, but in Monterry.
Gilbert crossed the Gulf of Mexico and struck the Mexican coast south of
Texas, bringing torrential rains of more than ten inches to the mountains
surrounding the Monterry area. The current official NHC forecast puts Emily
in a similar location by Wednesday. The exact location of the landfall in
the Gulf of Mexico will depend critically on the timing and strength of a
small trough of low pressure that is forecast to swing across the northern
U.S. on Tuesday. The global models have been consistent at keeping the
amplitude of this trough small, which means that the threat to the Texas
coast north of Corpus Christi is quite small. However, the timing of the
trough is more uncertain, and will greatly influence the final landfall
location of Emily. If the trough is quick to pass, a high pressure ridge
will build in and force Emily further south. A slower-moving trough could
draw Emily further north and bring a landfall near Brownsville, Texas.
Posted: 2:00pm EDT Saturday July 16
=============================
Emily now has the strongest winds of any hurricane so early in the season,
beating out last week's Hurricane Dennis for the top spot. Emily's central
pressure measured 937 mb in the 1:17pm EDT Hurricane Hunter eye penetration,
and its maximum sustained winds reached 155 mph. Emily still has to get
below Dennis' 930 mb pressure to qualify as the strongest hurricane ever so
early in the year. The eye diameter shrank 2nm, to 11nm, and still has room
to contract before an eyewall replacement cycle stops the current
intensification trend. It is truly phenomenal to see such a powerful
hurricane so early in the season.
Dr. Jeff Masters
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