WTNT43 KNHC 271818
TCDAT3
TROPICAL STORM LORENZO SPECIAL DISCUSSION NUMBER   9
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL132007
200 PM EDT THU SEP 27 2007
 
DATA FROM AN AIR FORCE RECONNAISSANCE PLANE INDICATE THAT WINDS HAVE
INCREASED TO 50 KNOTS. THIS SPECIAL ADVISORY IS JUST TO UPGRADE THE
INITIAL AND FORECAST INTENSITY OF RECENTLY UPGRADED TROPICAL STORM
LORENZO. NO SIGNIFICANT CHANGE IN TRACK IS INDICATED.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      27/1800Z 20.5N  95.5W    50 KT
 12HR VT     28/0000Z 20.4N  96.0W    55 KT
 24HR VT     28/1200Z 20.3N  96.7W    55 KT
 36HR VT     29/0000Z 20.5N  97.5W    30 KT...INLAND
 48HR VT     29/1200Z 21.0N  99.0W    20 KT...REMNANT LOW
 72HR VT     30/1200Z...DISSIPATED
 
$$
FORECASTER AVILA
 

WTNT43 KNHC 272037
TCDAT3
TROPICAL STORM LORENZO DISCUSSION NUMBER  10
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL132007
500 PM EDT THU SEP 27 2007
 
REPORTS FROM AN AIR FORCE PLANE INVESTIGATING LORENZO
INDICATE THAT THE WINDS HAVE BEEN INCREASING AND THE PRESSURE HAS
COME DOWN TO AT LEAST 999 MB. THE CREW REPORTED A VERY TIGHT CENTER
THAT WAS VERY HARD TO FIX...WITH A LOT OF CONVECTION. INITIAL
INTENSITY IS SET AT 60 KNOTS WHICH IS A COMPROMISE BETWEEN THE
FLIGHT-LEVEL WINDS AND THE SFMR MEASUREMENTS.  THIS INTENSITY
ESTIMATE IS ALSO SUPPORTED BY THE INCREASED ORGANIZATION OF THE THE
CLOUD PATTERN ON SATELLITE IMAGES AND THE CORRESPONDING INCREASE IN
DVORAK T-NUMBERS. 
 
THE CENTER OF LORENZO WILL LIKELY BE MOVING OVER WATER FOR A LITTLE
MORE THAN 12 HOURS BEFORE IT REACHES THE COAST. BECAUSE THE SHEAR
IS LOW AND THE OCEAN IS WARM...LORENZO COULD EASILY CROSS THE COAST
AS A HURRICANE. WE ALL KNOW THAT INTENSITY FORECASTS ARE UNCERTAIN
DESPITE ALL THE RECENT SCIENTIFIC ADVANCES...AND THE WINDS AT
LANDFALL COULD BE A LITTLE BIT STRONGER OR WEAKER THAN INDICATED.
 
LORENZO CONTINUES TO BE TRAPPED SOUTH OF A MID-LEVEL HIGH PRESSURE
RIDGE OVER THE NORTHWESTERN GULF OF MEXICO. THIS PATTERN WILL FORCE
LORENZO ON A GENERAL WESTWARD TO WEST-SOUTHWESTWARD TRACK TOWARD THE
GULF COAST OF MEXICO. THIS IS CONSISTENT WITH ALL OF THE AVAILABLE
TRACK GUIDANCE WHICH UNANIMOUSLY BRING LORENZO TO THE COAST IN
ABOUT 12 TO 18 HOURS.
 
THE SLOW MOTION OF LORENZO WILL LIKELY PRODUCE TORRENTIAL RAINFALL
ALONG ITS PATH.

FORECAST POSITIONS AND MAX WINDS
 
INITIAL      27/2100Z 20.4N  95.9W    60 KT
 12HR VT     28/0600Z 20.4N  96.6W    65 KT
 24HR VT     28/1800Z 20.5N  97.5W    30 KT...INLAND
 36HR VT     29/0600Z 21.0N  98.5W    20 KT...REMNANT LOW
 48HR VT     29/1800Z...DISSIPATED
 
$$
FORECASTER AVILA
 

WTNT43 KNHC 280241
TCDAT3
HURRICANE LORENZO DISCUSSION NUMBER  11
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL132007
1100 PM EDT THU SEP 27 2007
 
WHEN THE LAST RECONNAISSANCE AIRCRAFT LEFT LORENZO AROUND 1930Z...
THE CENTRAL PRESSURE WAS FALLING AT A RATE OF ABOUT 2 TO 3 MB/HR.
AT THAT TIME...LORENZO WAS VERY CLOSE TO HURRICANE STRENGTH. SINCE
THEN...LORENZO HAS BEEN MAINTAINING VERY VIGOROUS CONVECTION THAT
HAS BECOME INCREASINGLY SYMMETRIC OVER THE CENTER. THE PRESENTATION
OF THE CENTER HAS ALSO IMPROVED DRAMATICALLY ON THE ALVARADO
RADAR...WHICH NOW SHOWS A CLOSED EYEWALL. GIVEN THIS...I HAVE NO
REASON TO BELIEVE THAT THE EARLIER DEEPENING TREND HAS ABATED...AND
THE ADVISORY INTENSITY IS INCREASED TO 70 KT. LORENZO STILL HAS
SEVERAL HOURS LEFT OVER WATER TO DEEPEN FURTHER...AND A CATEGORY
TWO HURRICANE AT LANDFALL WOULD NOT BE OUT OF THE QUESTION. THE
NEXT AIRCRAFT WILL ARRIVE IN THE HURRICANE IN 2 TO 3 HOURS. 

THE INITIAL MOTION IS 270/5.  A MID-LEVEL RIDGE TO THE NORTH SHOULD
KEEP THE CYCLONE ON THIS BASIC TRACK FOR THE NEXT 12 HOURS OR
SO...WITH A GRADUAL BEND TO THE RIGHT AROUND THE RIDGE AFTER
LANDFALL.     
 
ALTHOUGH LORENZO IS A VERY SMALL HURRICANE...ITS SLOW MOTION WILL
LIKELY PRODUCE TORRENTIAL RAINS...UP TO 15 INCHES IN SPOTS...THAT
ARE EXPECTED TO CAUSE LIFE-THREATENING FLASH FLOODS AND MUD SLIDES.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      28/0300Z 20.5N  96.5W    70 KT
 12HR VT     28/1200Z 20.6N  97.4W    75 KT...INLAND
 24HR VT     29/0000Z 21.0N  98.5W    30 KT...INLAND
 36HR VT     29/1200Z...DISSIPATED
 
$$
FORECASTER FRANKLIN
 

WTNT43 KNHC 280853
TCDAT3
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
 

WTNT43 KNHC 281442
TCDAT3
TROPICAL DEPRESSION LORENZO DISCUSSION NUMBER  13
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL132007
1100 AM EDT FRI SEP 28 2007
 
SATELLITE IMAGES AND SURFACE OBSERVATIONS INDICATE THAT LORENZO HAS
WEAKENED TO A TROPICAL DEPRESSION AS IT CONTINUES TO MOVE FARTHER
INLAND OVER EASTERN MEXICO.  THERE ARE BANDS OF DEEP CONVECTION
WITH SOME HEAVY SQUALLS ALONG THE COAST. ALTHOUGH THE CENTER IS
DIFFICULT TO LOCATE
THE DEPRESSION APPEARS TO BE MOVING TOWARD THE WEST OR 275 DEGREES
AT 8 KNOTS. THIS GENERAL MOTION IS EXPECTED TO CONTINUE UNTIL
DISSIPATION IN A DAY OR SO OVER THE HIGH TERRAIN. 

SINCE LORENZO IS MOVING SLOWLY...IT CAN STILL PRODUCE TORRENTIAL
RAINS ALONG ITS PATH.   

 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      28/1500Z 20.6N  98.4W    30 KT
 12HR VT     29/0000Z 21.0N  99.5W    20 KT...REMNANT LOW
 24HR VT     29/1200Z 21.5N 101.0W    20 KT...REMNANT LOW
 36HR VT     30/0000Z...DISSIPATED
 
$$
FORECASTER AVILA
 

WTNT43 KNHC 282022
TCDAT3
TROPICAL DEPRESSION LORENZO DISCUSSION NUMBER  14
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL132007
500 PM EDT FRI SEP 28 2007
 
SATELLITE IMAGES AND SURFACE OBSERVATIONS INDICATE THAT LORENZO NO
LONGER HAS A WELL-DEFINED SURFACE CENTER AND IS RAPIDLY BECOMING A
BROAD AREA OF LOW PRESSURE.  THE REMNANTS ARE EXPECTED TO CONTINUE
OF A GENERAL WEST-NORTHWEST TRACK UNTIL DISSIPATION LATER TONIGHT.
THIS WILL BE THE LAST ADVISORY ISSUED BY THE NATIONAL HURRICANE
CENTER ON LORENZO.

 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      28/2100Z 20.8N  99.0W    20 KT
 12HR VT     29/0600Z...DISSIPATED
 
$$
FORECASTER AVILA
 

