000 AXPZ20 KNHC 290921 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC SUN JUN 29 2008 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0900 UTC. ...SPECIAL FEATURES... TROPICAL STORM BORIS IS CENTERED NEAR 15.0N 115.4W...OR ABOUT 570 NM SW OF CABO SAN LUCAS MEXICO...AT 29/0900 UTC MOVING W AT 8 KT. MAXIMUM SUSTAINED WIND SPEED IS 45 KT WITH GUSTS TO 55 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1000 MB. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP2/WTPZ22 KNHC FOR MORE DETAILS. THE SATELLITE PRESENTATION OF BORIS HAS CHANGED LITTLE FOR ABOUT 24 HRS NOW...WITH THE LOW-LEVEL CENTER STILL LOCATED NEAR THE NORTHERN EDGE OF THE DEEP CONVECTION. THE SYSTEM IS WITHSTANDING ABOUT 20 KT OF ENE SHEAR ON THE S SIDE OF A STRONG UPPER LEVEL HIGH...BUT IS STILL EMBEDDED WITHIN AN UNSTABLE MOISTURE-LADEN ENVIRONMENT. SOME SLOW WEAKENING IS EXPECTED OVER THE NEXT FEW DAYS AS BORIS APPROACHES SLIGHTLY COOLER WATERS AND A MORE STABLE ENVIRONMENT. NUMEROUS MODERATE/ STRONG CONVECTION WITHIN 150 NM S SEMICIRCLE...AND 90 NM NE AND 60 NM NW QUADRANTS. SCATTERED MODERATE ELSEWHERE FROM 08N-12N BETWEEN 113W-117W. TROPICAL STORM CHRISTINA IS CENTERED NEAR 14.6N 126.8W...OR ABOUT 1080 WSW OF CABO SAN LUCAS MEXICO...AT 29/0900 UTC MOVING W AT 8 KT. MAXIMUM SUSTAINED WIND SPEED HAS DIMINISHED TO 40 KT WITH GUSTS TO 55 KT. ESTIMATED MINIMUM PRESSURE IS 1002 MB. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP3/WTPZ23 KNHC FOR MORE DETAILS. SHORTLY AFTER 0000 UTC TONIGHT...THE CONVECTION NEAR CRISTINA COMPLETELY COLLAPSED AND NOW ONLY ONE SMALL CLUSTER LIES NEAR THE CENTER. CRISTINA IS UNDER A LITTLE BIT LESS SHEAR THAN BORIS...ABOUT 16 KT...BUT HAS ALREADY BEGUN TO RUN INTO A MORE STABLE AIR MASS AND HAS LESS ABILITY TO RECOVER FROM THE SHEAR. TSTM ACTIVITY WILL LIKELY CONTINUE TO BURST FOR ANOTHER 1-2 DAYS BUT CRISTINA WILL WEAKEN AND PROBABLY DEGENERATE INTO A REMNANT LOW BY MON. SCATTERED MODERATE/STRONG CONVECTION IS WITHIN 45 NM OF THE CENTER. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 97W N OF 04N MOVING W 10 KT. A 1010 MB LOW IS LOCATED ALONG THE WAVE NEAR 09N97W. DEEP CONVECTION HAS SIGNIFICANTLY INCREASED IN COVERAGE AND INTENSITY OVER THE PAST 24 HRS ALTHOUGH THE PATTERN IS STILL RATHER DISORGANIZED. NUMEROUS MODERATE/ISOLATED STRONG CONVECTION COVERS A LARGE AREA S OF MEXICO FROM 04N-13N BETWEEN 90W-107W. ISOLATED MODERATE ALSO LIES FROM 13N-16N BETWEEN 93W-97W FARTHER N ALONG THE WAVE. MODEL GUIDANCE CONTINUES TO INDICATE THAT THIS SYSTEM WILL BECOME INCREASINGLY MORE ORGANIZED OVER THE NEXT FEW DAYS WITH SOME SLOW DEVELOPMENT POSSIBLE. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 08N77W TO 10N90W TO 09N97W TO 15N115W TO 9N130W TO 07N140W. SCATTERED MODERATE CONVECTION FROM 05N-09N BETWEEN 79W-83W. NUMEROUS MODERATE/ISOLATED STRONG FROM 04N-13N BETWEEN 90W-107W. SCATTERED MODERATE WITHIN 60 NM OF AXIS BETWEEN 123W-135W. ...DISCUSSION... SUBTROPICS... BROAD UPPER LEVEL TROUGHING HAS MOVED ACROSS THE NW CORNER OF THE DISCUSSION AREA WITH TWO UPPER LOW CENTERS NEAR 36N130W AND 32N137W WHICH APPEAR TO BE ROTATING AROUND EACH OTHER. A SHORTWAVE TROUGH TRAILS THE SECOND LOW THROUGH THE AREA FROM 30N137W TO 23N140W WITH A 75 KT SUBTROPICAL JET STREAK EXTENDING FROM 23N140W TO 30N123W. THE UPPER TROUGH HAS WEAKENED THE SUBTROPICAL RIDGE AND A WEAK 1012 MB LOW LIES OFF THE CALIFORNIA COAST NEAR 36N128W. A FEW PATCHES OF STRATOCUMULUS STILL COVER THE WATERS W OF 116W BUT THE COVERAGE HAS BEEN DECREASING FROM NIGHT TO NIGHT. HIGH PRES WILL BUILD ACROSS THE REGION OVER THE NEXT 48 HRS AHEAD OF A COLD FRONT WHICH IS EXPECTED TO CROSS E OF 30N140W BY TUE AFTERNOON. AS THE HIGH PUSHES E...THIS WILL ALSO INCREASE NORTHERLY WINDS ALONG THE W COAST OF BAJA CALIFORNIA BEGINNING TONIGHT THROUGH MUCH OF THE UPCOMING WEEK. FARTHER E...AN UPPER HIGH IS LOCATED NEAR 21N122W WITH A RIDGE AXIS EXTENDING TO THE MOUTH OF THE GULF OF CALIFORNIA AND N/CENTRAL MEXICO. SCATTERED SHOWERS/TSTMS DEVELOPED OVER MUCH OF WESTERN MEXICO ON SAT AND A FEW OF THE STORMS ARE PERSISTING NEAR THE SIERRA MADRE OCCIDENTALS. TROPICS... THE TROPICAL BELT LIES S OF BROAD UPPER RIDGING AND IS DOMINATED MAINLY BY UPPER LEVEL EASTERLIES. A FEW EMBEDDED INVERTED TROUGHS ARE LOCATED ALONG 97W AND FROM 17N125W TO 02N130W WITH LITTLE EFFECT ON THE OVERALL WEATHER. ONE UPPER HIGH IS CENTERED NEAR 13N139W WITH DRIER AIR FILTERING WELL S TO 10N W OF 130W. OTHERWISE...DEEP TROPICAL MOISTURE COVERS THE REMAINDER OF THE AREA S OF 18N. $$ BERG