Image Department Meteorology
Meteorology_Home Weather_Server News/Seminars
People
Research
Academics Application Contact_Us

Hawaiian_Weather
US_Mainland_Weather
Tropical_Weather
Satellite_Imagery
Radar_Imagery
Marine
Numerical_Models
LAPS
Forecasts
Observations
Archive
Links Disclaimer
Space
SOEST_Home
University_of_Hawaii_Home

 325 
 WTPA41 PHFO 310255
 TCDCP1
 TROPICAL STORM LANA DISCUSSION NUMBER   3
 NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   EP062009
 ISSUED BY NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
 500 PM HST THU JUL 30 2009
  
 LANA HAS CONTINUED TO INTENSIFY THIS AFTERNOON WITH A WELL-DEFINED
 SPIRAL BAND PATTERN PRESENT ON SATELLITE IMAGERY.  IN ADDITION...
 AN AQUA MICROWAVE PASS AT 2240 UTC SHOWS SIGNIFICANT INNER-CORE
 STRUCTURE WITH A BROKEN RING OF CONVECTION AROUND THE STORM CENTER. 
 DVORAK ESTIMATES AT 0000 UTC WERE 45 KT FROM TAFB/CIMSS...AND SINCE
 THAT TIME...THE CYCLONE IS BECOMING BETTER-ORGANIZED WITH
 INCREASING CONVECTION ON THE WESTERN SIDE.  THE INITIAL INTENSITY
 IS RAISED TO 50 KT...AND THIS COULD BE CONSERVATIVE BASED ON THE
 MICROWAVE AND RECENT INFRARED SATELLITE DATA.
  
 VERTICAL WIND SHEAR IS EXPECTED TO BE LOW FOR THE NEXT DAY OR SO AS
 LANA REMAINS UNDER THE INFLUENCE OF THE SOUTHWESTERN PORTION OF AN
 UPPER HIGH.  THIS LIGHT SHEAR ALONG WITH WARM SSTS SHOULD ALLOW
 STRENGTHENING UNTIL THE CYCLONE INTERACTS WITH A LARGE MIDDLE- TO
 UPPER-LEVEL LOW CURRENTLY SEEN OVER HAWAII.  THIS UPPER-LOW SHOULD
 START TO INCREASE THE SHEAR OVER THE SYSTEM IN A COUPLE OF DAYS AND
 SIGNIFICANTLY WEAKEN LANA BY THE END OF THE FORECAST PERIOD.
 THE OFFICIAL NHC FORECAST IS CLOSE TO...BUT A LITTLE HIGHER
 THAN...THE MODEL CONSENSUS INITIALLY...AND IS CLOSE TO THE SHIPS
 MODEL IN 3-5 DAYS.     
  
 THE BEST ESTIMATE OF INITIAL MOTION IS 285/17.  A MID-LEVEL HIGH
 LOCATED TO THE NORTHEAST OF HAWAII SHOULD PROVIDE THE STEERING
 FOR LANA DURING THE NEXT SEVERAL DAYS...KEEPING THE STORM
 ON A WEST OR WEST-NORTHWEST HEADING.  ALL OF THE GLOBAL MODELS
 WEAKEN THE STRONG MIDDLE-TO UPPER-LEVEL LOW NEAR HAWAII AND SHOW
 ENOUGH RIDGING TO ALLOW THE STORM TO REMAIN SOUTH OF THE HAWAIIAN
 ISLANDS.  THERE HAS BEEN A NOTICEABLE NORTHWARD SHIFT OF THE STORM
 TRACK IN THE RECENT GUIDANCE FROM THE GFS/GFDL/HWRF MODELS.  THIS
 CHANGE COULD BE ATTRIBUTED TO THE GFS MODEL HAVING A MORE
 REALISTIC REPRESENTATION OF THE STORM THAN EARLIER...ALTHOUGH IT IS
 DIFFICULT TO TELL THE EXACT REASON AT THIS TIME.  THE OFFICIAL NHC
 FORECAST IS SHIFTED TO THE NORTH FROM THE PREVIOUS ONE...BUT STILL
 LIES SOUTH OF THE MODEL CONSENSUS...SIGNIFICANTLY SO AT THE
 LONG-RANGE.
  
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      31/0300Z 12.8N 143.1W    50 KT
  12HR VT     31/1200Z 13.2N 145.5W    60 KT
  24HR VT     01/0000Z 13.7N 148.4W    65 KT
  36HR VT     01/1200Z 14.2N 151.2W    65 KT
  48HR VT     02/0000Z 14.6N 153.9W    60 KT
  72HR VT     03/0000Z 15.2N 159.5W    50 KT
  96HR VT     04/0000Z 16.0N 165.5W    35 KT
 120HR VT     05/0000Z 16.5N 171.0W    25 KT...REMNANT LOW
  
 $$
 FORECASTER BLAKE
  
 
Return to the Tropical Systems Page for LANA

Back to main Tropical Weather page




This page is maintained voluntarily by the MKWC and the UHMET faculty, staff, and students.
It was last modified on: Thu, Jul 23 2020 - 2003 UTC
Send comments to: Ryan Lyman