[Tropical] Tropical Cyclone Discussion

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WTNT42 KNHC 282100
TCDAT2
TROPICAL STORM GUSTAV DISCUSSION NUMBER  16
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL072008
500 PM EDT THU AUG 28 2008

THE CENTER OF GUSTAV MADE LANDFALL ALONG THE EASTERN TIP OF JAMAICA
AT ABOUT 1800 UTC TODAY...BASED ON FLIGHT-LEVEL WIND DATA FROM AN
AIR FORCE RECONNAISSANCE AIRCRAFT THAT WAS ABLE TO FLY THROUGH THE
CENTER NEAR THAT TIME.  FLIGHT-LEVEL WIND SPEEDS INDICATED THAT
GUSTAV WAS RIGHT NEAR THE THRESHOLD BETWEEN TROPICAL STORM AND
HURRICANE INTENSITY...BUT THE DATA WERE NOT QUITE CONVINCING ENOUGH
TO INCREASE THE INTENSITY WHICH REMAINS 60 KT.  THE AIRCRAFT
SUBSEQUENTLY DETECTED THE CENTER LOCATED INLAND OVER THE EASTERN
PORTION OF THE ISLAND.  A LITTLE WEAKENING IS FORECAST IN THE SHORT
TERM AS GUSTAV INTERACTS WITH LAND...BUT ONCE IT EMERGES OVER THE
OPEN WATERS OF THE NORTHWESTERN CARIBBEAN BY TOMORROW...CONDITIONS
APPEAR RATHER FAVORABLE FOR STRENGTHENING.  DUE TO THE VERY WARM
WATERS SOUTH OF CUBA...COMBINED WITH ANTICYCLONIC FLOW ALOFT...IT
IS POSSIBLE THAT GUSTAV COULD RAPIDLY INTENSIFY AT SOME POINT
WITHIN THE NEXT COUPLE OF DAYS...ALTHOUGH THAT IS NOT EXPLICITLY
SHOWN IN THE OFFICIAL FORECAST.  CONDITIONS OVER THE GULF ARE NOT
FORECAST TO BE PROHIBITIVE FOR STRENGTHENING EITHER...SO GUSTAV
COULD REACH MAJOR HURRICANE STATUS WITHIN A FEW DAYS...AS FORECAST
BY ESSENTIALLY ALL AVAILABLE INTENSITY GUIDANCE.

GUSTAV IS RESPONDING TO THE MID-LEVEL RIDGE TO ITS NORTH BY
CONTINUING WESTWARD AT ABOUT 275/5.  A WEAKNESS DEVELOPING IN THAT
RIDGE OVER THE EASTERN GULF OF MEXICO DURING THE NEXT DAY OR TWO
SHOULD IMPART A GRADUAL RIGHT TURN ACROSS THE NORTHWESTERN
CARIBBEAN AND GENERALLY INTO THE CENTRAL GULF.  TRACK MODEL
GUIDANCE IS MOSTLY IN GOOD AGREEMENT ON A TRACK NEAR OR OVER THE
WESTERNMOST PROVINCES OF CUBA IN A COUPLE OF DAYS.  THE MODEL
SPREAD INCREASES OVER THE GULF...HOWEVER...BOTH IN TERMS OF PATH
AND FORWARD SPEED...BOUNDED BY THE FAST GFDL ON THE RIGHT AND A
MUCH SLOWER GFS ON THE LEFT.  DESPITE SOME CHANGES IN THE
INDIVIDUAL MODEL TRACKS...THE CONSENSUS HAS BARELY BUDGED AND THE
NEW OFFICIAL TRACK FORECAST IS VERY SIMILAR TO THE PREVIOUS ONE.
SINCE TRACK FORECASTS ARE ALWAYS SUBJECT TO LARGE ERRORS AT 3-5
DAYS...AND ESPECIALLY GIVEN THE NOTABLE MODEL SPREAD OVER THE GULF
OF MEXICO...IT IS SIMPLY IMPOSSIBLE TO DETERMINE EXACTLY WHERE AND
WHEN GUSTAV WILL MAKE FINAL LANDFALL.  IN FACT...TAKING INTO
ACCOUNT THE UNCERTAINTIES IN TRACK...INTENSITY...AND SIZE
FORECASTS...THE CHANCES OF HURRICANE-FORCE WINDS WITHIN THE NEXT
FIVE DAYS ARE ESSENTIALLY THE SAME AT EACH INDIVIDUAL LOCATION FROM
THE FLORIDA PANHANDLE COAST WESTWARD THROUGH THE ENTIRE COASTLINE
OF LOUISIANA.


FORECAST POSITIONS AND MAX WINDS

INITIAL      28/2100Z 18.1N  76.6W    60 KT
 12HR VT     29/0600Z 18.4N  77.8W    55 KT...INLAND OVER JAMAICA
 24HR VT     29/1800Z 19.1N  79.7W    70 KT
 36HR VT     30/0600Z 20.1N  81.7W    80 KT
 48HR VT     30/1800Z 21.5N  83.6W    95 KT
 72HR VT     31/1800Z 25.0N  87.0W   100 KT
 96HR VT     01/1800Z 28.0N  89.5W   100 KT
120HR VT     02/1800Z 30.0N  91.5W    85 KT...INLAND

$$
FORECASTER KNABB
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