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

 965 
 WTNT42 KNHC 242100
 TCDAT2
 TROPICAL STORM KATRINA DISCUSSION NUMBER   5
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
 5 PM EDT WED AUG 24 2005
  
 SATELLITE IMAGERY...DOPPLER RADAR DATA FROM THE BAHAMAS AND MIAMI...
 AND THE LATEST RECONNAISSANCE WIND DATA INDICATE KATRINA HAS
 CONTINUED TO BECOME BETTER ORGANIZED THIS AFTERNOON. BANDING
 FEATURES HAVE INCREASED IN ALL QUADRANTS AND THE UPPER-LEVEL
 OUTFLOW HAS EXPANDED AND REMAINS QUITE SYMMETRICAL. THE INITIAL
 INTENSITY OF 40 KT IS A BLEND OF RECON WIND...38 KT FLIGHT-LEVEL
 WINDS...AND PRESSURE DATA...1002 MB OR ROUGHLY 43 KT...AND
 SATELLITE INTENSITY ESTIMATES OF 45 KT FROM TAFB AND AFWA. THE
 INITIAL POSITION ESTIMATE IS A LITTLE TO SOUTHWEST OF THE 1949Z
 RECON POSITION AND IS CLOSE TO THE CENTER OF THE LARGER-SCALE
 CIRCULATION BASED ON EXTRAPOLATION OF THE ZERO-ISODOP PATTERN NOTED
 IN THE NOAA/NWS MIAMI DOPPLER VELOCITY DATA.
  
 THE INITIAL MOTION ESTIMATE IS 325/08. THERE IS SOME UNCERTAINTY IN
 BOTH THE INITIAL MOTION AND THE CENTER POSITION. I HAVE TRIED TO
 BLEND THE POSITIONS FROM RECON...RADAR AND SATELLITE DATA. THE LAST
 RECON POSITION CAN BE SEEN AS A TIGHT LOW-LEVEL VORTEX MOVING OUT
 FROM UNDERNEATH THE DEEP CONVECTION IN THE EAST SEMICIRCLE. IT IS
 POSSIBLE THAT THAT VORTEX MAY END UP BEING A TRANSIENT FEATURE. IF
 IT TURNS OUT THAT THE CENTER DOES END UP FARTHER NORTH...THEN THE
 FORECAST TRACK WILL HAVE TO BE SHIFTED SLIGHTLY NORTHWARD ON THE
 NEXT ADVISORY. OTHER THAN THE UNCERTAINTY IN THE INITIAL POSITION
 ...THE REST OF THE FORECAST TRACK AND REASONING REMAINS UNCHANGED
 FROM PREVIOUS ADVISORIES. ALL OF THE NHC MODEL GUIDANCE AGREE ON
 THE SUBTROPICAL RIDGE TO THE NORTH OF KATRINA TO KEEP BUILDING
 SLOWLY EASTWARD...WHICH ULTIMATELY FORCES THE CYCLONE WESTWARD
 ACROSS SOUTH FLORIDA IN 36-48 HOURS...AND INTO THE EASTERN GULF OF
 MEXICO BY 72 HOURS. AFTER THAT...HOWEVER...THE MODELS DIFFER
 SIGNIFICANTLY ON WHERE AND WHEN KATRINA IS EXPECTED TO TURN
 NORTHWARD AND MAKE A SECOND LANDFALL ALONG THE NORTHEAST GULF
 COAST. THE GFDN IS THE WESTERNMOST MODEL AND TAKES THE CYCLONE TO
 NEW ORLEANS...WHEREAS THE GFS AND CANADIAN MODELS ARE THE
 EASTERNMOST MODELS AND TAKE KATRINA NORTHEASTWARD ACROSS THE
 NORTHERN FLORIDA PENINSULA. THE OFFICIAL TRACK IS NEAR THE MIDDLE
 OF THE GUIDANCE ENVELOPE AND CLOSE TO THE MODEL CONSENSUS.
  
 WITH THE IMPROVED BANDING FEATURES...SYMMETRICAL UPPER-LEVEL OUTFLOW 
 ...AND RELATIVELY WEAK SHEAR...AT LEAST STEADY INTENSIFICATION OF A
 NORMAL RATE OF 10 KT PER 12 HOURS UNTIL LANDFALL OCCURS SEEMS
 JUSTIFIED. THIS IS SIMILAR TO THE SHIPS INTENSITY MODEL...BUT MUCH
 LESS THAN THE NOW VERY BULLISH GFDL MODEL WHICH BRINGS KATRINA TO
 111 KT JUST BEFORE LANDFALL. IT SHOULD BE POINTED OUT THAT WITH
 SSTS NEAR 31C AND A LOW SHEAR ENVIRONMENT...CONDITIONS ARE
 FAVORABLE FOR POSSIBLE RAPID INTENSIFICATION TO OCCUR BETWEEN NOW
 AND LANDFALL. THIS IS SUGGESTED BY THE SHIPS MODEL EXPERIMENTAL
 RAPID INTENSIFICATION OUTPUT...WHICH INDICATES A 57 PERCENT
 PROBABILITY OF THAT OCCURRING. THE ONLY INHIBITING FACTOR IS THE
 DRY AIR THAT SURROUNDS KATRINA AND HAS BEEN WORKING ITS WAY INTO
 THE INNER-CORE REGION AND ERODING THE DEEP CONVECTION. IF THE DRY
 AIR MIXES OUT WITHIN THE NEXT 12 HOURS...THEN INTENSITIES WOULD
 LIKELY BE HIGHER THAN THE OFFICIAL FORECAST IS INDICATING.
 
 OWING TO THE SLOW FORWARD SPEED...KATRINA HAS THE POTENTIAL TO
 PRODUCE A SIGNIFICANT HEAVY RAINFALL AND FLOODING EVENT ACROSS THE
 CENTRAL AND NORTHWEST BAHAMAS...AND EVENTUALLY ACROSS SOUTH
 FLORIDA.
  
 FORECASTER STEWART
 
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      24/2100Z 25.6N  77.2W    40 KT
  12HR VT     25/0600Z 25.9N  77.8W    50 KT
  24HR VT     25/1800Z 26.1N  78.8W    60 KT
  36HR VT     26/0600Z 26.2N  79.7W    70 KT
  48HR VT     26/1800Z 26.3N  80.7W    50 KT...INLAND
  72HR VT     27/1800Z 26.4N  83.0W    55 KT
  96HR VT     28/1800Z 28.0N  85.0W    70 KT
 120HR VT     29/1800Z 30.5N  85.0W    65 KT...INLAND
  
  
 $$
 
Return to the Tropical Systems Page for KATRINA

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