000 AXPZ20 KNHC 011555 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC TUE JUL 01 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... HURRICANE BORIS IS CENTERED NEAR 14.6N 125.0W...OR ABOUT 990 NM...1835 KM...WEST-SOUTHWEST OF THE SOUTHERN TIP OF BAJA CALIFORNIA AT 01/1500 UTC MOVING W AT 10 KT. MAXIMUM SUSTAINED WINDS ARE 65 KT WITH GUSTS TO 80 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 989 MB. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP2/WTPZ22 KNHC FOR MORE DETAILS. SATELLITE IMAGERY INDICATES THAT THE RAGGED EYE FEATURE OBSERVED OVERNIGHT HAS BECOME OBSCURED AND INCREASINGLY LESS DEFINED DURING THE PAST 6 HOURS. A 0904 UTC TRMM PASS SEEMS TO CONFIRM THIS DECREASE IN ORGANIZATION...REVEALING A DEGRADATION OF THE NEARLY CIRCULAR EYEWALL IN THE NE SEMICIRCLE. THE TRMM PASS DID...HOWEVER...SHOW A PARTIAL EYEWALL TO THE SW...LIKELY AN INDICATION THAT NE SHEAR CONTINUES TO PLAGUE BORIS. LATEST CIMSS SHEAR ANALYSES SUGGEST 10 TO 15 KT OF NORTHEASTERLY SHEAR...WHICH COULD BE ENOUGH TO PREVENT BORIS FROM CONSOLIDATING FURTHER. THE OVERALL CONVECTIVE STRUCTURE HAS BECOME MORE ASYMMETRIC TOO...WITH NUMEROUS STRONG CONVECTION WITHIN 120 NM S OF THE CENTER AND SCATTERED MODERATE/ISOLATED STRONG WITHIN 30 NM N OF THE CENTER. LIKE YESTERDAY...A PROMINENT BAND WRAPS AROUND THE N AND E SIDE WITH SCATTERED MODERATE CONVECTION. THE BAND BECOMES STRONGER TO THE E WITH SCATTERED MODERATE ISOLATED STRONG CONVECTION AND CONNECTS INTO THE ITCZ ON THE S SIDE. BORIS IS EXPECTED TO MAINTAIN HURRICANE STRENGTH FOR 12 HOURS FOLLOWED BY A GRADUAL WEAKENING AS IT FLIRTS WITH THE 80 F SST ISOTHERM. A 1007 MB LOW IS LOCATED NEAR 14N105.5W MOVING WNW TO NW ABOUT 10 KT. A 1244 UTC QUIKSCAT PASS AND SATELLITE IMAGERY SHOW A SYSTEM WHICH HAS CONSOLIDATED SUBSTANTIALLY SINCE THIS TIME YESTERDAY. IN SPITE OF ITS RECENT CONSOLIDATION...THE SYSTEM STILL REMAINS ONLY LOOSELY ORGANIZED WITH A FAIRLY BROAD WIND FIELD. IN FACT...A QUIKSCAT AMBIGUITY ANALYSIS REVEALS THE POSSIBILITY OF TWO CIRCULATIONS FEATURES ROTATING AROUND EACH OTHER. ALTHOUGH THERE ARE NO DISTINCT CENTRAL FEATURES EMERGING AS OF YET...TWO PARTIALLY-DEVELOPED BANDS WITH VERY COLD CLOUD TOP TEMPERATURES HAVE MAINTAINED THEMSELVES DURING THE LAST 6 TO 12 HOURS....ONE TO THE NE AND THE OTHER TO THE SW OF THE CIRCULATION CENTER. IN ADDITION...A WELL-DEFINED MID-LEVEL CYCLONIC CIRCULATION IS NOTED IN THE NORTHERN BAND CLOSE TO 17.5N106W...LEAVING OPEN THE POSSIBILITY THAT THE CENTER COULD TRY TO REFORM TO THE N DURING THE NEXT 24 HOURS. NUMEROUS STRONG CONVECTION IS OBSERVED WITHIN 90 NM EITHER SIDE OF A LINE FROM 15N100W TO 18N108W. NUMEROUS MODERATE SCATTERED STRONG CONVECTION IS ALSO NOTED FROM 10N TO 16N BETWEEN 105W AND 110W. THIS SYSTEM CONTINUES TO HAVE THE POTENTIAL TO BECOME A TROPICAL CYCLONE DURING THE NEXT 24 TO 48 HOURS AS IT TRACKS NW SLOWLY OFFSHORE THE MEXICAN COAST. THE REMNANTS OF TROPICAL STORM CRISTINA ARE NOW CENTERED NEAR 14N134.5W...MOVING W AT 10 KT. SATELLITE IMAGERY REVEALS A SWIRL OF LOW CLOUDS BEING STEERED BY THE LOW-LEVEL TRADES. A NIGHT- TIME QUIKSCAT PASS STILL INDICATED WINDS OF 20 TO 25 KT IN THE N SEMICIRCLE BUT ALSO INDICATED THAT THE LOW-LEVEL CIRCULATION WAS BECOMING DISTORTING AND INCREASINGLY LESS DEFINED. THE REMNANTS SHOULD CONTINUE TRACKING W INTO THE CENTRAL N PACIFIC BEFORE DISSIPATING ALTOGETHER. TROPICAL WAVES... NEXT TROPICAL WAVE ALONG 86W S OF 17N MOVING W 10-15 KT. SATELLITE PICTURES INDICATE AN INCREASE IN CONVECTION ASSOCIATED WITH THIS FEATURE DURING THE PAST 6-12 HOURS...WITH THE BULK OF THE CONVECTION WITHIN 90 NM EITHER SIDE OF A LINE EXTENDING FROM 07N92W TO 15N95W. VISIBLE SATELLITE IMAGERY SHOWS LOW-LEVEL WESTERLY FLOW INTERSECTING THE CONVECTION NEAR 11N93W...WHILE CLOUD-TRACKED WINDS AND SATELLITE IMAGERY INDICATE THE PRESENCE OF EASTERLY TRADES TO THE E...JUST S OF THE CENTRAL AMERICAN COAST. THESE WINDS ARE EVIDENCE OF A BROAD LOW-LEVEL CYCLONIC TURNING ACROSS THIS AREA...AND GLOBAL MODELS ARE HINTING AT THE POTENTIAL FOR TROPICAL CYCLONE FORMATION IN THIS AREA DURING THE NEXT SEVERAL DAYS. ...ITCZ... ITCZ AXIS IS CENTERED ALONG AXIS 08N78W TO 12N100W TO 10N112W TO 11N120W TO 10N130W TO 06N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS WITHIN 300 NM OF AXIS BETWEEN 78W AND 84W. NUMEROUS MODERATE SCATTERED STRONG CONVECTION IS WITHIN 120 NM S AND 240 NM N OF AXIS BETWEEN 86W AND 95W. NUMEROUS MODERATE SCATTERED STRONG CONVECTION IS WITHIN 120 NM S OF AXIS BETWEEN 100W AND 103W AND WITHIN 120 NM EITHER SIDE OF AXIS BETWEEN 108W AND 113W. SCATTERED MODERATE CONVECTION IS WITHIN 60 NM OF AXIS BETWEEN 124W AND 136W. ...DISCUSSION... AN ENHANCED SUBTROPICAL RIDGE OVER THE EAST PACIFIC SHOULD REMAIN IN PLACE DURING THE NEXT 24 TO 48 HOURS ...WHICH SHOULD HELP ACCENTUATE THE TYPICAL PRESSURE GRADIENT OFFSHORE THE BAJA CALIFORNIA PENINSULA. UNDER THIS PATTERN...NW TO N WINDS OF 20 TO PERHAPS 25 KT ALREADY OVER THE AREA N OF 28N E OF 120W SHOULD EXPAND SOUTH AND WEST BY TUE. IN RESPONSE...SEAS OF UP TO 8 TO 9 FT IN NEWLY-FORMED NW WIND WAVES AND SW SWELL ARE OCCURRING WITHIN 180 NM W OF THE W COAST OF THE BAJA PENINSULA BUT BEGIN TO INFLUENCE THE AREA WITHIN 300 NM OF THE BAJA PENINSULA BY THU. AN UNUSUALLY AMPLIFIED MID- TO UPPER-LEVEL TROUGH DIGGING ALONG 140W SHOULD DRIVE A COLD FRONT THROUGH HAWAII THIS AFTERNOON... WITH THE NE PORTION OF THE FRONT ENTERING THE FAR NW WATERS OF THE EAST PACIFIC EARLY TOMORROW. AHEAD OF THE FRONT MODEL MICROWAVE DATA AND SHIP REPORTS ARE INDICATING S TO SW WINDS UP TO 20 KT NW OF A LINE FROM 29N140W TO 30N138W. EXPECT THESE WINDS TO DISSIPATE WITHIN 18 HOURS...THOUGH SEAS OF UP TO 9 FT IN LONG PERIOD NW SWELL PROPAGATING OUT OF THE CENTRAL NORTH PACIFIC ARE POSSIBLE TILL AT LEAST LATE TODAY. FINALLY...A FRESH CROSS-EQUATORIAL FLOW FLOWING NORTHWARD INTO THE BROAD SURFACE LOW NEAR 14N106W IS AGITATING SEAS FROM 3N TO 10N BETWEEN 95W AND 108W. IN FACT...A 1242 UTC QUIKSCAT PASS SHOWED S TO SW WINDS OF UP TO 20 KT OVER THIS AREA...AND THE NOAA WAVEWATCH III MODEL INDICATES THE POTENTIAL FOR UP TO 9 FT IN SW SWELL. EXPECT THESE WINDS AND SEAS TO PERSIST AT LEAST THROUGH WED OR THU...WITH A SLOW MIGRATION NORTHWARD FOLLOWING THE TRACK OF THE LOW. $$ KIMBERLAIN