Wilma: a hurricane today

By: Dr. Jeff Masters , 1:57 PM GMT on October 18, 2005

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Wilma continues to intensify. Satellite imagery shows a dense cirrus overcast (CDO) beginning to form and cover the center of the storm, which is characteristic of a tropical storm intent on becoming a hurricane. Spiral banding and upper-level outflow continue to improve and cover a larger area. Some wind shear and dry air are affecting the northwest side of the storm, but Wilma is gaining a more symmetric appearance characteristic of a hurricane. The hurricane hunters left the storm at 3 am EDT this morning and are not due back until about 3 pm EDT this afternoon, so we will have to wait until then to learn Wilma's true strength.

The upper level environment continues to look favorable for intensification, with low wind shear and an anti-cyclone on top generating good outflow on all sides except the norhtwest. Intensification into a Category 3 hurricane by Thursday still seems like a good bet. There is a small chance Wilma could make it to Category 4 status by Friday, but shear will start to increase by then as the upper-level trough of low pressure generates strong westerly winds over her. This shear will likely reduce Wilma's winds by at least 20 mph, and landfall in Florida as a strong Category 2 hurricane seems like a reasonble intensity forecast.

Steering currents are expected to remain weak today, and some erratic motion is possible. All of the forecast models predict a generally west or west-northwest motion over the next two days. Now that Wilma has stopped moving south, this gives me some confidence that this forecast is the correct one, and the danger to Honduras is considerably lessened. Only the northeast portion of Honduras should see heavy rains over ten inches, and since this part of the country is relatively flat, the threat of life-threatening flash flooding and mud slides like killed thousands in Hurricane Mitch and Hurricane Fifi is low. So far, northeastern Honduras has received only one to two inches of rain from Wilma.

The country that has taken the worst pounding so far from Wilma is Jamaica, where Wilma's rains have already caused millions of dollars of damage to the road infrastructure. Widespread flooding and road blockages due to mudslides are being reported, and will continue as Wilma stays essentially stationary or moves very slowly away from Jamaica today.

Next on Wilma's hit list will be Mexico and Cuba, who have already had their share of major hurricanes this season. Mexico is still cleaning up the damage from Hurricane Emily earlier this year, and Cuba took one of its worst hurricane pouundings ever during Hurricane Dennis in July. Heavy rains in the Cayman Islands, Belize, Nicaragua, and northern Guatemala may also create local flooding problems in those nations. If Wilma grows large enough to tap the Pacific as a source of moisture, Nicaragua and Costa Rica could also experience some moderate flooding problems.


Figures 1. Computer model forecasts for Wilma.

The models have reached a strong consensus that a low pressure system currently bringing rain to the western U.S. will move east and exert a strong pull on Wilma, turning her more northwest by Thursday, through the Yucatan Channel, and then northeastward into the Florida Keys or the west coast of Florida by the weekend. Most of the guidance shows the Keys to be the primary region at risk, but the GFDL model has moved its landfall point further north with its most recent run (2 am EDT), and puts the area between Sarasota and Fort Myers in the bullseye. The NOAA jet is scheduled to makes its first flight tonight, and tomorrow morning we should have a better idea of the reliability of the current model forecasts.

Elsewhere in the tropics, there is a large area of disturbed weather midway between Africa and the Leeward Islands. Upper level winds are not favorable for development of this area, which is also too close to the Equator. I'll be back with a update in this afternoon after the Hurricane Hunters report in.

Jeff Masters

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595. snowboy
11:12 PM GMT on October 18, 2005
you nicely spotted a pattern there, chris
Member Since: September 21, 2005 Posts: 10 Comments: 2547
594. weatherwannabe
9:08 PM GMT on October 18, 2005
I'd say she could be a cat 3 easily at landfall
593. primez
9:07 PM GMT on October 18, 2005
Wilma could be a major hurricane by this time tomorrow...and reach category four strength before entering the southeastern Gulf of Mexico. As Wilma accelerates northeastward in the Gulf...wind shear is forecast to increase slightly...but at this time does not appear to be sufficient to weaken Wilma very quickly.
Member Since: September 18, 2005 Posts: 0 Comments: 195
592. ChrisPC24
9:06 PM GMT on October 18, 2005
It almost seems like a 36-year cycle:

1933: 21 named storms (record), 10 hurricanes
1969: 12 hurricanes (record)
2005: 21 (or more) named storms, 12 (or more) hurricanes (ties records)
588. FLCrackerGirl
8:57 PM GMT on October 18, 2005
New Media Download From EOC Director Nathan McCollumIndian River County Tropical Update
Info Specific to Indian River Co and relevant to Martin, St Lucie & Brevard Co.
Member Since: August 12, 2004 Posts: 47 Comments: 597
585. leftyy420
8:48 PM GMT on October 18, 2005
Hurricane Wilma Discussion Number 13


Statement as of 5:00 PM EDT on October 18, 2005



an Air Force reconnaissance aircraft has just made its first pass
through the center of Wilma...finding a minimum central pressure of
970 mb and maximum flight-level winds...so far...of 75 kt. A
dropsonde in the north eyewall reported surface winds of 64 kt.
Satellite intensity estimates from TAFB and SAB are 77 kt. The
advisory intensity of 70 kt is a blend of the satellite and
reconnaissance observations.
There has been no change to the thinking regarding the intensity
forecast. Wilma continues to have very strong upper-level outflow
channels to the northeast and southwest of the center. Oceanic heat
content ahead of Wilma is high...including in the southeastern Gulf
of Mexico. In the short term...the only inhibiting factor is the
dry air mass in the Gulf and extreme northwestern Caribbean. A high
likelihood of rapid strengthening continues to be indicated by the
SHIPS rapid intensification index. Wilma could be a major hurricane
by this time tomorrow...and reach category four strength before
entering the southeastern Gulf of Mexico. As Wilma accelerates
northeastward in the Gulf...wind shear is forecast to increase
slightly...but at this time does not appear to be sufficient to
weaken Wilma very quickly. However...it is Worth remembering that
there is little skill in long-range intensity forecasts.

The initial motion is 290/7. There has also been no change to the
track forecast thinking. The mid- to upper-level low that had been
off the Southern California coast continues northeastward...and as
it progresses high pressure over the Gulf of Mexico is expected to
weaken...allowing Wilma to move through the northwestern Caribbean
and enter the southeastern Gulf of Mexico in about three days. Once
Wilma moves north of the subtropical ridge axis and encounters
mid-level westerly flow...an acceleration northeastward is
expected. Only very modest shifts have occurred with the
tightly-clustered model guidance suite...which...at this time...is
focusing the long-term threat to the southern half of the Florida
Peninsula. The official forecast is very similar to the previous
advisory and remains close to the dynamical model consensus.


Forecaster Franklin


forecast positions and Max winds

initial 18/2100z 16.7n 81.5w 70 kt
12hr VT 19/0600z 17.3n 82.3w 90 kt
24hr VT 19/1800z 18.2n 83.5w 100 kt
36hr VT 20/0600z 19.1n 84.5w 110 kt
48hr VT 20/1800z 20.2n 85.2w 115 kt
72hr VT 21/1800z 22.5n 85.5w 110 kt
96hr VT 22/1800z 25.0n 82.5w 100 kt
120hr VT 23/1800z 30.5n 75.5w 70 kt



Member Since: August 24, 2005 Posts: 35 Comments: 1987
584. stormygace
8:45 PM GMT on October 18, 2005
kilgores97 - I share your concern about the effect of the low pressure system pulling Wilma up the coast in our direction. Happy to acknowlege both my lack of meteorolgical training & love of watching these storms (with a little vested interest as a property owner thrown in). Appreciate the prognostications (& graphics) folks with more background offer up.
Member Since: September 7, 2005 Posts: 23 Comments: 1107
583. kilgores97
8:45 PM GMT on October 18, 2005
I have heard that there are folks out there trying to say that Katrina was less than a Cat 3 at landfall. However, people that were in the area have observed things that only a 4/5 would bring. Does anyone else believe that on the advisories that come out, the wind speeds are manipulated somehow? It seems that to be more accurate, pressure should be used to determine strength, as almost always the wind speed will catch up to what the pressure says it should be, not what someone thinks would be less dramatic to hear.
Member Since: July 11, 2005 Posts: 7 Comments: 72
582. kilgores97
8:39 PM GMT on October 18, 2005
The only thing I find informative about Joe Bastardi's columns is that he dares to go out on a limb where local/TPC people won't, due to concern of scaring people. The models used do not tend to be precise either more than 3 days out and the forecasters use these to make their predictions. With each model run, nothing is ever the same as the previous one. It will never be an exact science, but that's part of the beauty of tropical weather!
Member Since: July 11, 2005 Posts: 7 Comments: 72
581. FtLauderdalepunk
8:37 PM GMT on October 18, 2005
Hurricane Wilma Advisory Number 13

Statement as of 5:00 PM EDT on October 18, 2005
...Hurricane watches issued for Cuba and Mexico...

At 5 PM EDT...2100z...the government of Cuba has issued a Hurricane Watch for the provinces of Matanzas westward through Pinar del Rio...and for the Isle of Youth. A Hurricane Watch means that hurricane conditions are possible within the watch area...generally within 36 hours.

At 5 PM EDT...2100z...the government of Mexico has issued a Hurricane Watch for the Yucatan Peninsula from Punta Allen to Cabo Catoche.

A Tropical Storm Warning remains in effect for Honduras from the Honduras/Nicaragua border westward to Cabo camaron.

A Tropical Storm Warning and a Hurricane Watch remain in effect for the Cayman Islands.

All interests in the Florida Keys and the Florida Peninsula should closely monitor the progress of Wilma.

For storm information specific to your area...including possible inland watches and warnings...please monitor products issued by your local weather office.

At 5 PM EDT...2100z...the center of Hurricane Wilma was located near latitude 16.7 north... longitude 81.5 west or about 180 miles... 290 km... south of Grand Cayman.

Wilma is moving toward the west-northwest near 8 mph...13 km/hr. A turn to the northwest is expected during the next 24 hours.

Maximum sustained winds are near 80 mph...130 km/hr...with higher gusts. Wilma is a category one hurricane on the Saffir-Simpson scale. Additional strengthening is forecast during the next 24 hours...and Wilma is expected to become a major hurricane during the next day or two.

Hurricane force winds extend outward up to 15 miles... 30 km... from the center...and tropical storm force winds extend outward up to 140 miles...220 km.

The latest minimum central pressure reported by a reconnaissance aircraft was 970 mb...28.64 inches.

Wilma is expected to produce additional rainfall accumulations of 5 to 10 inches...with isolated amounts of 15 inches...over the Cayman Islands...Jamaica...Haiti...and Cuba. Total rainfall accumulations of 4 to 6 inches...with isolated amounts of 12 inches...are possible over portions of Honduras and Nicaragua.

Repeating the 5 PM EDT position...16.7 N... 81.5 W. Movement toward...west-northwest near 8 mph. Maximum sustained winds... 80 mph. Minimum central pressure... 970 mb.

An intermediate advisory will be issued by the National Hurricane Center at 8 PM EDT followed by the next complete advisory at 11 PM EDT.

Forecaster Franklin


$$



577. dcw
8:34 PM GMT on October 18, 2005
Excellent plan!

What eye, weatherman? Seems to be to be weakening a little to temporarily reorganize. 75kt MFL winds only barely support the 80mph 2:00PM.
Member Since: August 2, 2001 Posts: 2 Comments: 3
572. Weatherman65
8:31 PM GMT on October 18, 2005
1. the last two frames or so of the goes floater is showing CDO, or an eye opening. (look closely)

2. my other concern is watch the forecast pts along with the center of circulation... its alread west of the current track. This will result in a shift in track and something to be watched seeing that the models have had a tough time with storms with weak steering currents.

3. The shear is all what us floridians need to look out for... email clyde he will show you very informative models on shear. This will be floridas only help!

and my info on the westerly shear wilma encountered i guess is all just old information... wow hop please just stop lol... no new info huh? wow
570. kilgores97
8:29 PM GMT on October 18, 2005
Living here in SE Virginia, I am concerned that once Wilma crosses into the Atlantic, she may try and phase with the trough coming in from the west about the same time Sun/Mon. The threat is there that she may try and hand off energy into the trough or some sort of secondary, unnamed storm may try and form on her outskirts. Either case would bring nasty weather to the East Coast. I also believe Wilma may feel the westward pull of the trough and may not go as far out as indicated previously.
Member Since: July 11, 2005 Posts: 7 Comments: 72
563. weatherwannabe
8:22 PM GMT on October 18, 2005
pressure dropping about 1 mb per hour. Not bad.
561. weatherwannabe
8:21 PM GMT on October 18, 2005
OLD VORTEX

000
URNT12 KNHC 180614
VORTEX DATA MESSAGE
A. 18/05:56:30Z
B. 15 deg 40 min N
079 deg 56 min W
C. 850 mb 1278 m
D. NA kt
E. deg nm
F. 241 deg 065 kt
G. 152 deg 009 nm
H. 982 mb
I. 15 C/ 1530 m
J. 23 C/ 1521 m
K. 16 C/ NA
L. NA
M. NA
N. 1345 / 8
O. 0.02 / 3 nm
P. AF309 0424A WILMA OB 14
MAX FL WIND 65 KT SE QUAD 05:53:30 Z
RADAR PRESENTATION POOR DUE TO ATTENUATION

New Vortex

000
URNT12 KNHC 182009
VORTEX DATA MESSAGE
A. 18/19:54:00Z
B. 16 deg 36 min N
081 deg 25 min W
C. 850 mb 1169 m
D. 55 kt
E. 335 deg 020 nm
F. 080 deg 075 kt
G. 348 deg 010 nm
H. 970 mb
I. 16 C/ 1526 m
J. 20 C/ 1526 m
K. 20 C/ NA
L. RAGGED
M. C10
N. 12345/ 8
O. 0.02 / 2 nm
P. AF302 0524A WILMA OB 06
MAX FL WIND 75 KT N QUAD 19:50:40 Z
VERY SMALL WIND CENTER

557. weatherwannabe
8:18 PM GMT on October 18, 2005
New Vortex

000
URNT12 KNHC 182009
VORTEX DATA MESSAGE
A. 18/19:54:00Z
B. 16 deg 36 min N
081 deg 25 min W
C. 850 mb 1169 m
D. 55 kt
E. 335 deg 020 nm
F. 080 deg 075 kt
G. 348 deg 010 nm
H. 970 mb
I. 16 C/ 1526 m
J. 20 C/ 1526 m
K. 20 C/ NA
L. RAGGED
M. C10
N. 12345/ 8
O. 0.02 / 2 nm
P. AF302 0524A WILMA OB 06
MAX FL WIND 75 KT N QUAD 19:50:40 Z
VERY SMALL WIND CENTER


553. leftyy420
8:14 PM GMT on October 18, 2005
if u want to disscuss the storm u should coem to my blog. here is the new recon

VORTEX DATA MESSAGE
A. 18/19:54:00Z
B. 16 deg 36 min N
081 deg 25 min W
C. 850 mb 1169 m
D. 55 kt
E. 335 deg 020 nm
F. 080 deg 075 kt
G. 348 deg 010 nm
H. 970 mb
I. 16 C/ 1526 m
J. 20 C/ 1526 m
K. 20 C/ NA
L. RAGGED
M. C10
N. 12345/ 8
O. 0.02 / 2 nm
P. AF302 0524A WILMA OB 06
MAX FL WIND 75 KT N QUAD 19:50:40 Z
VERY SMALL WIND CENTER
Member Since: August 24, 2005 Posts: 35 Comments: 1987

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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.