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Tropical Storm JOVA (Text)

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TROPICAL STORM JOVA DISCUSSION NUMBER   4
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP102011
200 PM PDT THU OCT 06 2011
 
DEEP CONVECTION HAS PERSISTED NEAR THE CENTER OF THE CYCLONE AND THE
SHEAR PATTERN APPEARS TO BE STEADILY EVOLVING INTO MORE OF A
BANDING PATTERN. THE INITIAL INTENSITY OF 35 KT IS BASED ON A BLEND
OF SATELLITE INTENSITY ESTIMATES OF T2.5/35 KT FROM TAFB AND SAB...
AND AN ADT ESTIMATE OF T2.6/37 KT FROM UW-CIMSS. THESE ESTIMATES
ARE FURTHER SUPPORTED BY A 06/1654Z ASCAT OVERPASS THAT INDICATED
30-KT WINDS EXISTED IN THE SOUTHEAST QUADRANT OUTSIDE OF DEEP
CONVECTION. AS A RESULT...TD-10E HAS BEEN UPGRADED TO TROPICAL
STORM JOVA.
 
THE INITIAL MOTION ESTIMATE IS 310/09 KT...BASED MOSTLY ON MICROWAVE
SATELLITE FIXES. JOVA IS CURRENTLY LOCATED ABOUT 650 NMI EAST OF
STRENGTHENING TROPICAL STORM IRWIN. ALTHOUGH IRWIN PRESENTLY HAS
BETTER BANDING FEATURES...THE TWO CYCLONES ARE COMPARABLE IN SIZE.
GIVEN THE PROXIMITY TO EACH OTHER...SOME BINARY/FUJIWHARA
INTERACTION IS LIKELY FOR THE NEXT 2 DAYS OR SO...WHICH SHOULD
BRING THE TWO CYCLONES CLOSER TO EACH OTHER AND ALSO SLOW DOWN THE
FORWARD SPEED OF BOTH SYSTEMS. BY 72 HOURS...A BROAD MID-LATITUDE
TROUGH IS FORECAST TO DROP SLOWLY SOUTHWARD INTO THE SOUTHWESTERN
U.S. AND NORTHWESTERN MEXICO...WHICH IS EXPECTED TO ERODE THE
WESTERN PORTION OF A NARROW SUBTROPICAL RIDGE LOCATED TO THE NORTH
OF JOVA. THE RESULT SHOULD BE FOR JOVA TO GRADUALLY RECURVE TO THE
NORTHEAST ACCOMPANIED BY A STEADY INCREASE IN FORWARD SPEED. THE
OFFICIAL FORECAST TRACK IS SIMILAR TO THE PREVIOUS ADVISORY
TRACK...AND LIES SOUTH OF THE MODEL CONSENSUS...BUT NOT NEARLY AS
FAR SOUTH AND AS SLOW AS THE ECMWF MODEL SOLUTION. GIVEN THAT AT
LEAST HALF OF THE AFOREMENTIONED MID-LATITUDE TROUGH LIES TO THE
WEST OF AND...THEREFORE...OUTSIDE OF THE NORTH AMERICAN UPPER-AIR
OBSERVING NETWORK...IT WOULD PRUDENT NOT TO MAKE ANY SIGNIFICANT
TRACK CHANGES AT THIS TIME.

JOVA IS FORECAST TO REMAIN OVER SSTS GREATER THAN 28C... IN A
LOW VERTICAL WIND SHEAR REGIME...AND IN A VERY MOIST MID-LEVEL
ENVIRONMENT WITH HUMIDITY VALUES OF 70-80 PERCENT. THIS WOULD
USUALLY EQUATES TO A PATTERN CONDUCIVE FOR STEADY OR EVEN RAPID
STRENGTHENING TO OCCUR. HOWEVER...THE SHIPS AND LGEM MODELS ARE NOT
REFLECTING ANY SIGNIFICANT INTENSIFICATION AND BARELY MAKE JOVA A
HURRICANE BY 72 HOURS...WITH STEADY WEAKENING FORECAST AFTER THAT.
IN CONTRAST...THE HWRF AND GFDL MODELS STEADILY STRENGTHEN JOVA TO
85 KT AND 100 KT...RESPECTIVELY...BY 96 HOURS. GIVEN THE FAVORABLE
PARAMETERS MENTIONED PREVIOUSLY...THE OFFICIAL INTENSITY FORECAST
HAS BEEN INCREASED ABOVE THE SHIPS/LGEM MODELS AND IS SIMILAR TO
THE HWRF MODEL SOLUTION. ALTHOUGH JOVA IS FORECAST TO BE INLAND
OVER SOUTHWESTERN MEXICO BY 120 HOURS...TROPICAL STORM INTENSITY IS
BEING INDICATED AT THAT TIME DUE TO THE OUTER WIND FIELD...WHICH
COULD STILL CONTAIN TROPICAL-STORM-FORCE WINDS...EXPECTED TO REMAIN
OFFSHORE AT THAT TIME.

IT IS IMPORTANT NOT TO FOCUS ON THE EXACT TRACK FORECAST AT DAYS 4
AND 5 SINCE THE AVERAGE TRACK ERRORS IN THE EASTERN PACIFIC BASIN AT
THAT THOSE TIME PERIODS ARE 175 TO 225 MILES.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  06/2100Z 12.5N 107.5W   35 KT  40 MPH
 12H  07/0600Z 13.4N 108.5W   40 KT  45 MPH
 24H  07/1800Z 14.3N 109.2W   45 KT  50 MPH
 36H  08/0600Z 15.0N 109.6W   55 KT  65 MPH
 48H  08/1800Z 16.2N 109.7W   65 KT  75 MPH
 72H  09/1800Z 18.0N 108.7W   75 KT  85 MPH
 96H  10/1800Z 19.2N 106.7W   85 KT 100 MPH
120H  11/1800Z 20.5N 104.0W   35 KT  40 MPH...INLAND
 
$$
FORECASTER STEWART
 
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