000 AXPZ20 KNHC 291553 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC SUN JUN 29 2008 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1500 UTC. ...SPECIAL FEATURES... TROPICAL STORM BORIS IS CENTERED NEAR 15.0N 116.2W...OR ABOUT 595 NM SW OF CABO SAN LUCAS MEXICO...AT 29/1500 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. THERE HAS BEEN A DRAMATIC INCREASE IN THE COVERAGE AND INTENSITY OF CONVECTION ASSOCIATED WITH BORIS DURING THE PAST 6 TO 12 HOURS...THOUGH MORE RECENTLY SATELLITE IMAGERY REVEALS THAT A NEARLY SOLID BALL OF -80C CLOUD TOPS E OF THE CENTER IS NOW DECREASING. THE RECENT BURST OF CONVECTION IS LIKELY A MANIFESTATION OF A TROPICAL CYCLONE IN A HIGHLY SHEARED ENVIRONMENT...AS CIMSS SHEAR ANALYSES SHOW AT LEAST 20 KT OF NE SHEAR OVER THE STORM. IN ADDITION TO THE SHEAR...BORIS SHOULD MOVE INTO A LESS FAVORABLE THERMODYNAMIC ENVIRONMENT DURING THE NEXT 24 TO 48 HOURS...WHICH SHOULD LEAD TO GRADUAL WEAKENING. NUMEROUS MODERATE/STRONG CONVECTION IS NOTED 150 NM NE QUADRANT AND 210 NM SE QUADRANT...WITH NO SIGNIFICANT CONVECTION TO THE W. TROPICAL STORM CRISTINA IS CENTERED NEAR 14.5N 127.5W...OR ABOUT 1125 NM WSW OF CABO SAN LUCAS MEXICO...AT 29/1500 UTC MOVING W AT 7 KT. MAXIMUM SUSTAINED WIND SPEED HAS DIMINISHED TO 35 KT WITH GUSTS TO 45 KT. ESTIMATED MINIMUM PRESSURE IS 1002 MB. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP3/WTPZ23 KNHC FOR MORE DETAILS. LIKE BORIS...CRISTINA LIES IN A FAIRLY SHEARED ENVIRONMENT...WELL TO THE SW OF A DEEP-LAYERED ANTICYCLONE CENTERED SW OF BAJA CALIFORNIA. IN FACT...LATEST CIMSS ANALYSES SHOW SLIGHTLY LESS THAN 20 KT OF EASTERLY SHEAR OVER THE STORM...WHICH HAS PROVEN ENOUGH TO STRIP MOST OF THE DEEP CLOUDS FROM THE CENTER AND DISPLACE THEM TO THE WEST. IN SPITE OF THE UNFAVORABLE SHEAR...SATELLITE IMAGERY REVEALS PULSATING BURSTS OF DEEP CONVECTION FORMING W OF THE CENTER WHICH IS ALLOWING THE STORM TO MAINTAIN MINIMAL TROPICAL STORM STATUS. HOWEVER...THE THICK DECK OF STRATOCUMULUS CLOUDS TO THE W IS A HARBINGER FOR INCREASINGLY STABLE ENVIRONMENT IN WHICH CRISTINA SHOULD MOVE WITHIN THE NEXT 24 TO 48 HOURS... WHICH SHOULD EVENTUALLY LEAD TO ITS DEMISE. SCATTERED MODERATE/STRONG CONVECTION IS OBSERVED WITHIN 90 NM W OF THE CENTER. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 98/99W S OF 20N MOVING W 10 KT OR LESS. A 1007 MB LOW IS LOCATED ALONG THE WAVE NEAR 10N98W. SATELLITE IMAGERY SHOWS A DEFINITE INCREASE IN CONVECTION DURING THE PAST 24 HOURS...ALTHOUGH THE NASCENT SYSTEM IS LOOSELY ORGANIZED AT THE MOMENT. AN 1154 UTC QUIKSCAT PASS INDICATED A BROAD BUT SLOWLY INCREASING WINDFIELD ASSOCIATED WITH THE LOW...WITH E TO SE 20 KT WINDS WITHIN 360 NM OF THE NE QUADRANT AND A S TO SW INFLOW OF UP TO 20 KT N OF 5N BETWEEN 85W AND 100W. NUMEROUS MODERATE/ISOLATED STRONG CONVECTION COVERS AN AREA S OF MEXICO FROM 05N-14N BETWEEN 90W-108W. ISOLATED MODERATE ALSO EXISTS FROM 16N-20N BETWEEN 102W-106W AND OVER PARTS OF S CENTRAL MEXICO...LIKELY IN ASSOCIATION WITH THE WAVE. MODEL GUIDANCE CONTINUES TO INDICATE THAT THIS SYSTEM HAS THE POTENTIAL FOR FURTHER SLOW DEVELOPMENT DURING THE NEXT SEVERAL DAYS. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 08N78W TO 09N90W TO 10N98W TO 15N116W TO 15N127W TO 09N130W TO 06N140W. SCATTERED MODERATE CONVECTION IS WITHIN 150 NM S OF AXIS BETWEEN 84W AND 90W. NUMEROUS MODERATE/ISOLATED STRONG CONVECTION IS FROM 05N TO 14N BETWEEN 90W AND 108W. NUMEROUS MODERATE ISOLATED STRONG CONVECTION IS FROM 16N TO 19N BETWEEN 102W AND 105W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS 90 NM EITHER SIDE OF AXIS BETWEEN 126W AND 140W. ...DISCUSSION... AFTER SEVERAL DAYS OF NEAR CONSTANT NE 20 TO 25 KT WINDS DOWNSTREAM OF THE GULF OF PAPAGAYO...AN 1154 UTC QUIKSCAT PASS INDICATED THAT THE EVENT HAS COME TO AN END. ALTHOUGH MODEL GUIDANCE DOES NOT SHOW GAP WINDS RETURNING TO THE GULF OF PAPAGAYO...THERE IS STILL SOME CHANCE THAT INTERMITTENT NE TO E WINDS OF UP TO 20 KT COULD BE OBSERVED NEAR AND DOWNSTREAM OF THIS REGION TODAY. THESE WINDS MIGHT BE OBSERVED AS RELATIVE HIGH PRESSURE CONTINUES OVER THE CARIBBEAN WHILE LOW PRESSURE BEGINS TO FORM IN THE EAST PACIFIC W OF 100W. ELSEWHERE...MODELS INDICATE THAT HIGH PRESSURE SHOULD BUILD OVER THE SUBTROPICAL EAST PACIFIC DURING THE NEXT 24 TO 48 HOURS ...WHICH SHOULD HELP ACCENTUATE THE TYPICAL PRESSURE GRADIENT OFFSHORE THE BAJA CALIFORNIA PENINSULA. AS THIS OCCURS...EXPECT NW WINDS OF 20 TO PERHAPS 25 KT TO DEVELOP INITIALLY N OF 27N E OF 118W AND THEN EXPAND SOUTHWARD BY MON. IN RESPONSE...SEAS OF UP TO 8 TO 9 FT IN NEWLY-FORMED WIND WAVES AND SW SWELL ARE POSSIBLE WITHIN 180 NM W OF THE W COAST OF THE BAJA PENINSULA N OF 27N. FINALLY...A WEAKENING MID- TO UPPER-LEVEL LOW A FEW HUNDRED MILES W OF THE CENTRAL CALIFORNIA COAST IS LIFTING NE TODAY... ONLY TO BE REPLACED BY A DEEP TROUGH FORMING ALONG 140W BY LATE MON OR TUE. THE TROUGH WILL CAUSE A COLD FRONT TO DIG UNUSUALLY FAR S OVER PARTS OF THE CENTRAL N PACIFIC...WITH MODELS EVEN SHOWING A WEAK FRONTAL PASSAGE ACROSS HAWAII. AHEAD OF THE FRONT...SW WINDS OF 20 KT ARE EXPECTED OVER THE FAR NW WATERS WITH SEAS OF UP TO 8 TO 9 FT IN SW SWELL BY TUE. $$ KIMBERLAIN