Tropical Storm Lorenzo

[Somerset Squall]

We now have TD13 in the southwest Gulf Of Mexico.

TROPICAL DEPRESSION THIRTEEN SPECIAL FORECAST/ADVISORY NUMBER 1

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL132007

2215 UTC TUE SEP 25 2007

A TROPICAL STORM WATCH MAY BE REQUIRED FOR A PORTION OF THE GULF

COAST OF MEXICO THIS EVENING.

TROPICAL DEPRESSION CENTER LOCATED NEAR 21.7N 95.0W AT 25/2215Z

POSITION ACCURATE WITHIN 20 NM

PRESENT MOVEMENT TOWARD THE SOUTHWEST OR 220 DEGREES AT 3 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 1010 MB

MAX SUSTAINED WINDS 25 KT WITH GUSTS TO 35 KT.

WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL

MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 21.7N 95.0W AT 25/2215Z

AT 25/1800Z CENTER WAS LOCATED NEAR 21.8N 94.8W

FORECAST VALID 26/0600Z 21.4N 95.0W

MAX WIND 30 KT...GUSTS 40 KT.

FORECAST VALID 26/1800Z 21.2N 95.0W

MAX WIND 35 KT...GUSTS 45 KT.

34 KT... 50NE 50SE 50SW 50NW.

FORECAST VALID 27/0600Z 21.0N 95.0W

MAX WIND 40 KT...GUSTS 50 KT.

34 KT... 50NE 50SE 50SW 50NW.

FORECAST VALID 27/1800Z 20.8N 95.1W

MAX WIND 45 KT...GUSTS 55 KT.

34 KT... 60NE 60SE 60SW 60NW.

FORECAST VALID 28/1800Z 20.5N 95.5W

MAX WIND 55 KT...GUSTS 65 KT.

50 KT... 20NE 20SE 20SW 20NW.

34 KT... 60NE 60SE 60SW 60NW.

EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 225 NM

ON DAY 4 AND 300 NM ON DAY 5...AND FOR INTENSITY NEAR 20 KT EACH DAY

OUTLOOK VALID 29/1800Z 20.0N 97.0W...INLAND

MAX WIND 50 KT...GUSTS 60 KT.

OUTLOOK VALID 30/1800Z...DISSIPATED

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 21.7N 95.0W

NEXT ADVISORY AT 26/0300Z

$$

FORECASTER FRANKLIN

[Somerset Squall]

TD13 has improved since last night with a healthy blob of convection over the center. The depression may already be a storm but the NHC are waiting for it to be investigated before considering an upgrade. Further strengthening is likely before landfall in around 36-48hrs time. TD13 isn't moving anywhere fast and has been stationary over the last few hours so if it can remain over water for longer it will obviously be stronger than anticipated.

TROPICAL DEPRESSION THIRTEEN DISCUSSION NUMBER 4

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL132007

1100 AM EDT WED SEP 26 2007

THERE HAS BEEN AN INCREASE IN DEEP CONVECTION AND ORGANIZATION OF

THE DEPRESSION'S CLOUD PATTERN OVER THE PAST SEVERAL HOURS. DVORAK

SATELLITE CLASSIFICATIONS FROM TAFB AND SAB ARE AT 30 AND 35 KT

RESPECTIVELY. WE WILL WAIT FOR THE NEXT AIR FORCE HURRICANE HUNTER

FIX SCHEDULED FOR 1800 UTC TO SEE IF THE SYSTEM HAS INDEED

STRENGTHENED INTO A TROPICAL STORM. AN UPPER-LEVEL CYCLONE IN THE

VICINITY OF TUXPAN MEXICO IS MOVING SOUTHWESTWARD...AND AWAY FROM

THE TROPICAL CYCLONE...CREATING AN ENVIRONMENT THAT IS MORE

FAVORABLE FOR STRENGTHENING. CIRRUS MOTIONS SHOW THAT THE

ANTICYCLONIC OUTFLOW IS BECOMING BETTER ESTABLISHED OVER THE

SYSTEM. THE OFFICIAL INTENSITY FORECAST...WHICH IS SIMILAR TO THE

SHIPS AND GFDL GUIDANCE...COULD BE CONSERVATIVE...PARTICULARLY IF

THE TROPICAL CYCLONE REMAINS OVER WATER LONGER THAN EXPECTED.

THE INITIAL MOTION IS AN UNCERTAIN 180/2. A WEAK STEERING CURRENT

HAS PREVAILED OVER THE SOUTHWESTERN GULF OF MEXICO OVER THE PAST

COUPLE OF DAYS...AND THE DEPRESSION WILL PROBABLY MOVE QUITE SLOWLY

AND ERRATICALLY TODAY. GLOBAL MODELS FORECAST A WEAK MID-LEVEL

RIDGE TO BUILD EASTWARD SLOWLY FROM NORTHERN MEXICO OVER THE GULF

OF MEXICO. THIS SHOULD EVENTUALLY RESULT IN A SOUTHWESTWARD TO

WESTWARD MOTION OF THE TROPICAL CYCLONE TOWARD THE COAST OF MEXICO.

ALTHOUGH THE CONSENSUS OF THE TRACK GUIDANCE MODELS INDICATES THE

ABOVEMENTIONED MOTION...THERE ARE SIGNIFICANT DIFFERENCES AMONGST

THE INDIVIDUAL MODELS. IT SHOULD BE NOTED... HOWEVER...THAT ALL OF

THE DYNAMICAL MODELS KEEP THE SYSTEM OFFSHORE THROUGH 36 HOURS.

THE OFFICIAL FORECAST FOLLOWS THE CONSENSUS AND IS SIMILAR TO THE

TRACK FORECAST FROM THE PREVIOUS NHC PACKAGE.

A TROPICAL STORM WATCH WILL LIKELY BE REQUIRED FOR A PORTION OF THE

GULF COAST OF MEXICO LATER TODAY.

FORECAST POSITIONS AND MAX WINDS

INITIAL 26/1500Z 20.9N 95.0W 30 KT

12HR VT 27/0000Z 20.7N 95.1W 35 KT

24HR VT 27/1200Z 20.5N 95.4W 40 KT

36HR VT 28/0000Z 20.3N 95.9W 45 KT

48HR VT 28/1200Z 20.1N 96.6W 50 KT

72HR VT 29/1200Z 20.0N 97.7W 20 KT...INLAND

96HR VT 30/1200Z...DISSIPATED

$$

FORECASTER PASCH

[kold weather]

Quick update, TD13 has become tropcial storm Lorenzo and winds have jumped upto 60mph, massive increase in the estimated wind speeds over the last 6hrs from a massive convective burst on the southern side of the LLC, indeed the iwnds have raised every bit as fast as Humberto, if not even faster!!

System is stil lbeing sheared on its northern side but the LLC appears to be just on the right side of this higher shear and the southern side of the convection which is really explosive is in a weak shear set-up and the whole system is heading towards that. I certainly wouldn't rule out hurricane status from this system given the way Humberto strengthened.

Could get close to cat-2 status actually if shear does ease off a touch, given how fast Humberto also developed.

Edited September 27, 2007 by kold weather

[Somerset Squall]

This certainly has blown up, I was only expecting a 40kt tropical storm at best when I checked this evening and was surprised just like with Humberto at how the system has rapidly intensified. I was never expecting Lorenzo to become a hurricane but indeed it has a good shot at becoming one.

[Iceberg]

A Hurricane indeed it is. !. And a possible CAT 2 according to NHC.

[Somerset Squall]

A Hurricane indeed it is. !. And a possible CAT 2 according to NHC.

Yes, I suspect Lorenzo will come under some post-season analysis especially as recon didn't manage to get to him until 2 hours after landfall. At the rate he was strengthening he might have been a cat 2 just before landfall.

Latest Discussion:

TROPICAL STORM LORENZO DISCUSSION NUMBER 12

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL132007

500 AM EDT FRI SEP 28 2007

LORENZO MADE LANDFALL BEFORE THE LAST AIR FORCE RECONNAISSANCE PLANE

ARRIVED....BUT RADAR IMAGERY FROM ALVARADO MEXICO SUGGESTS THAT THE

CENTER MADE LANDFALL AT APPROXIMATELY 0500 UTC...ABOUT 40 N MI

SOUTH-SOUTHEAST OF TUXPAN. THE RADAR PRESENTATION OF THE EYEWALL

WAS DEGRADING AS THE CENTER WAS CROSSING THE COAST...SO THE

LANDFALL INTENSITY IS RATHER UNCERTAIN BUT ESTIMATED TO BE 65 KT.

GOES IMAGERY AFTER THE SATELLITE ECLIPSE PERIOD SHOWS MUCH WARMER

CLOUD TOPS NEAR THE CENTER THAN PRIOR TO LANDFALL...BUT A RATHER

POTENT BAND OF DEEP CONVECTION NOW EXTENDS SOUTHWARD FROM NEAR THE

CENTER OF LORENZO TO SOUTH OF VERACRUZ. THE SLOW MOTION OF THIS

SYSTEM WILL LIKELY PRODUCE TORRENTIAL RAINS...POSSIBLY UP TO 15

INCHES IN SOME LOCATIONS...THAT ARE EXPECTED TO CAUSE LIFE-

THREATENING FLASH FLOODS AND MUD SLIDES.

SINCE LANDFALL...THE CYCLONE APPEARS TO HAVE STARTED A SLIGHT TURN

TO THE RIGHT AROUND THE MID-LEVEL RIDGE TO ITS NORTH...AND THE

INITIAL MOTION ESTIMATE IS 280/6. A GENERAL WEST-NORTHWESTWARD

MOTION IS FORECAST...SLOWLY TAKING LORENZO FARTHER INLAND OVER

EAST-CENTRAL MEXICO. THE PACE OF DECLINE IN THE OFFICIAL INTENSITY

FORECAST IS A LITTLE FASTER THAN THE DECAY SHIPS DUE TO THE SMALL

SIZE OF THE CYCLONE.

FORECAST POSITIONS AND MAX WINDS

INITIAL 28/0900Z 20.6N 97.5W 55 KT

12HR VT 28/1800Z 20.9N 98.2W 30 KT...INLAND

24HR VT 29/0600Z...DISSIPATED

$$

FORECASTER KNABB

15 inches. Not good.

Edited September 28, 2007 by Somerset Squall