[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT42 KNHC 270247
TCDAT2
HURRICANE KATRINA DISCUSSION NUMBER  15
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
11 PM EDT FRI AUG 26 2005

THE SATELLITE PRESENTATION HAS CONTINUED TO IMPROVE AND CONSISTS OF
A PERFECT A COMMA-SHAPED CLOUD PATTERN WHICH BEGINS OVER WESTERN
CUBA AND WRAPS AROUND A LARGE CLUSTER OF VERY DEEP CONVECTION. THIS
BAND IS PROBABLY PRODUCING NEAR TROPICAL STORM FORCE WINDS ALONG
THE NORTH COAST OF WESTERN CUBA. ALTHOUGH THE EYE IS NOT CLEARLY
VISIBLE ON IR IMAGES...RADAR DATA INDICATE THAT THE EYE IS EMBEDDED
WITHIN THIS CIRCULAR AREA OF DEEP CONVECTION. T-NUMBERS FROM SAB
AND TAFB HAVE INCREASED TO 5.0 ON THE DVORAK SCALE. THEREFORE...
THE INITIAL INTENSITY HAS BEEN ADJUSTED TO 90 KNOTS. AN AIR FORCE
RECONNAISSANCE PLANE IS SCHEDULED TO BE IN KATRINA IN THE NEXT FEW
HOURS. THE HURRICANE IS EXPECTED TO BE UNDER A TYPICAL 200 MB
ANTICYLONE...WITH A CYCLONIC CIRCULATION EXTENDING UPWARD TO THAT
LEVEL. THIS IS THE TYPICAL PATTERN OBSERVED IN INTENSE HURRICANES.
IN ADDITION...KATRINA IS FORECAST TO MOVE DIRECTLY OVER THE WARM
LOOP CURRENT OF THE GULF OF MEXICO...WHICH IS LIKE ADDING HIGH
OCTANE FUEL TO THE FIRE. THEREFORE...THE OFFICIAL FORECAST BRINGS
KATRINA TO 115 KNOTS...OR A CATEGORY FOUR ON THE SAFFIR-SIMPSON
HURRICANE SCALE. THE GFDL IS MORE AGGRESSIVE AND CALLS FOR 124
KNOTS AND 922 MB. THE FSU SUPERENSEMBLE IS EVEN MORE AGGRESSIVE
BRINGING KATRINA TO 131 KNOTS.

KATRINA CONTINUES TO MOVE STUBBORNLY TOWARD THE WEST-SOUTHWEST OR
250 DEGREES AT 7 KNOTS ALONG THE EASTERN SIDE OF A VERY STRONG
DEEP-LAYER MEAN HIGH CENTERED OVER TEXAS. IN FACT...DATA FROM THE
NOAA JET JUST RELAYED BY THE METEOROLOGIST ONBOARD INDICATE THAT
THE HIGH CONTINUES TO BE VERY STRONG. HOWEVER...THIS FEATURE IS
EXPECTED TO MOVE WESTWARD AND LEAVE A WEAKNESS OVER THE CENTRAL
GULF OF MEXICO.  KATRINA WILL LIKELY TAKE THAT OPPORTUNITY AND
BEGIN TO TURN GRADUALLY TOWARD THE WEST-NORTHWEST AND THEN
NORTHWARD. THE OFFICIAL FORECAST BRINGS THE CORE OF THE INTENSE
HURRICANE OVER THE NORTH CENTRAL GULF OF MEXICO IN 48 HOURS OR SO.
IT IS WORTH NOTING THAT THE GUIDANCE SPREAD HAS DECREASED AND MOST
OF THE RELIABLE NUMERICAL MODEL TRACKS ARE NOW CLUSTERED BETWEEN
THE EASTERN COAST OF LOUISIANA AND THE COAST OF MISSISSIPPI.  THIS
CLUSTERING INCREASES THE CONFIDENCE IN THE FORECAST.

FORECASTER AVILA

FORECAST POSITIONS AND MAX WINDS

INITIAL      27/0300Z 24.6N  83.6W    90 KT
 12HR VT     27/1200Z 24.6N  84.6W   100 KT
 24HR VT     28/0000Z 25.0N  86.0W   115 KT
 36HR VT     28/1200Z 26.0N  87.5W   115 KT
 48HR VT     29/0000Z 27.0N  89.0W   115 KT
 72HR VT     30/0000Z 30.5N  89.5W   115 KT
 96HR VT     31/0000Z 35.0N  87.5W    35 KT...INLAND
120HR VT     01/0000Z 40.5N  81.0W    25 KT...BECOMING EXTRATROPICAL


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