000 WTPZ45 KNHC 070259 TCDEP5 TROPICAL STORM JOVA DISCUSSION NUMBER 5 NWS NATIONAL HURRICANE CENTER MIAMI FL EP102011 800 PM PDT THU OCT 06 2011 JOVA IS CURRENTLY BEING AFFECTED BY 10-15 KT OF NORTHEASTERLY VERTICAL WIND SHEAR. THIS HAS DISPLACED THE STRONG AND PERSISTENT CONVECTION TO THE SOUTHWEST OF THE LOW-LEVEL CENTER. SATELLITE INTENSITY ESTIMATES ARE 45 KT FROM TAFB AND 35 KT FROM SAB...SO THE INITIAL INTENSITY IS INCREASED TO 40 KT. THE INITIAL MOTION IS NOW 300/9. JOVA IS LOCATED SOUTH OF A MID-LEVEL RIDGE THAT SHOULD WEAKEN AS A DEEP-LAYER TROUGH OVER THE WESTERN UNIDTED STATES DIGS SOUTHWARD. THIS...COMBINED WITH THE PRESENCE OF TROPICAL STORM IRWIN TO THE WEST...SHOULD STEER JOVA GENERALLY NORTHWESTWARD FOR THE FIRST 36 HOURS...FOLLOWED BY RECURVATURE TOWARD THE NORTHEAST. 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 07/0300Z 13.0N 108.3W 40 KT 45 MPH 12H 07/1200Z 13.9N 109.3W 45 KT 50 MPH 24H 08/0000Z 14.8N 110.0W 50 KT 60 MPH 36H 08/1200Z 15.7N 110.2W 60 KT 70 MPH 48H 09/0000Z 16.6N 109.9W 70 KT 80 MPH 72H 10/0000Z 18.0N 108.0W 80 KT 90 MPH 96H 11/0000Z 20.0N 106.0W 85 KT 100 MPH 120H 12/0000Z 21.5N 104.0W 25 KT 30 MPH...INLAND $$ FORECASTER BEVEN