000 AXPZ20 KNHC 080947 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC FRI NOV 08 2013 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0945 UTC. ...SPECIAL FEATURES... STRONG POST-FRONTAL HIGH PRESSURE IS BUILDING SOUTHWARD ALONG THE SW GULF OF MEXICO AND SURGING THROUGH THE CHIVELA PASS INTO AND DOWNSTREAM OF THE GULF OF TEHUANTEPEC AT GALE FORCE OF 30-40 KT...WITH SEAS BUILDING TO A MAX OF 17 FT. ALTHOUGH THE GRADIENT WILL RELAX SOME LATE TODAY...EXPECT THE MINIMAL GALE FORCE SURGES TO PERSIST THROUGH SUNRISE ON SAT...THEN THE GRADIENT WILL FURTHER RELAX SUPPORTING A MAX OF 30 KT THROUGH SUN EVENING. LATEST GUIDANCE SHIFTS THE RESPONSIBLE SURFACE HIGH SOUTHWARD ON SUN EVENING TO OVER MEXICO AT 22N101W...AND STRENGTHENS IT SLIGHTLY...RESULTING IN ANOTHER BLAST OF MINIMAL GALE FORCE WINDS LATE SUN NIGHT THROUGH SUNRISE ON MON. THEN THE NORTHERLY FLOW PULSES TO 30 KT THROUGH SUNRISE TUE WITH THE GRADIENT RELAXING ON TUE AFTERNOON AS WINDS DIMINISH BRIEFLY TO A 25 KT MAX. GUIDANCE THEN SUGGESTS AN INCREASE TO 30 KT TUE NIGHT THROUGH WED MORNING...THEN ANOTHER BLAST AT GALE FORCE LATE WED THROUGH SUNRISE ON SAT. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS E TO W ACROSS THE CARIBBEAN BETWEEN 09N-10N FROM THE COLOMBIA/PANAMA BORDER AT 09N77W TO THE COAST OF COSTA RICA AT 10N83W...THEN CONTINUES W ACROSS NORTHERN COSTA RICA TO OVER THE PACIFIC AT 09N94W...THEN TURNS NW THROUGH A 1010 MB EMBEDDED WEAK SURFACE LOW PRESSURE AT 13N111W...WITH THE MONSOON TROUGH THEN CONTINUING W TO 11N128W WHERE SCATTEROMETER WINDS INDICATE A TRANSITION TO AN ITCZ WHICH CONTINUES WSW TO BEYOND 09N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS OBSERVED PARALLEL TO THE COAST OF CENTRAL AMERICA WITHIN 60 NM EITHER SIDE OF A LINE FROM 05N79W TO 13N90W...WITH FREQUENT LIGHTNING CURRENTLY DETECTED WITHIN 90 NM OF 12N89W. SIMILAR CONVECTION IS NOTED WITHIN 60 NM OF 11N126W AND WITHIN 30 NM OF 09N136W. ISOLATED MODERATE TO OCCASIONALLY STRONG CONVECTION IS OBSERVED ALONG THE MONSOON TROUGH FROM 07-11N BETWEEN 100-122W. ...DISCUSSION... A LONGWAVE UPPER TROUGH HAS SHIFTED E OVER EASTERN N AMERICA AND IS BEING REINFORCED BY A SHORTWAVE TROUGH OVER WESTERN N AMERICA WITH ITS MEAN AXIS CONTINUING SW INTO THE DISCUSSION AREA ALONG 32N107W...AND CONTINUING S ACROSS THE GULF OF CALIFORNIA ALONG 27N113W...AND THROUGH AN EMBEDDED UPPER CYCLONE AT 20N115W TO A BASE OVER THE DEEP TROPICS AT 11N118W. DRY UPPER AIR IS INDICATED WITHIN 300 NM W OF THE TROUGH AXIS TO THE N OF 29N... THEN WIDENS TO ABOUT 720 NM W OF THE TROUGH AXIS ACROSS THE AREA S OF 29N. AN UPPER ANTICYCLONE IS OVER THE DEEP TROPICS AT 11N143W WITH A SHORTWAVE RIDGE EXTENDING NE ACROSS THE AREA FROM 20N133W TO 30N118W. AN UPPER MOISTURE PLUME...ORIGINATING IN THE CENTRAL PACIFIC...IS STREAMING E ACROSS THE AREA WITHIN 240 NM OF LINE FROM 22N140W TO 22N130W...THEN NARROWS AND THINS SOMEWHAT AS IT CONTINUES NE THROUGH 32N118W...EVENTUALLY FANNING OUT OVER SOUTHERN CALIFORNIA. A DEEP LAYERED CYCLONE IS NW OF THE AREA NEAR 33N141W WITH AN UPPER TROUGH EXTENDING S TO 25N140W. THE CYCLONE WILL SHIFT SE TODAY JUST BRUSHING THE FAR NORTHERN PORTION...THEN ACCELERATE NE ON SAT. THE ASSOCIATED SURFACE LOW WILL DIP S TO NEAR 30N140W TONIGHT DEEPENING TO ABOUT 1012 MB AS IT OCCLUDES. ALTHOUGH WINDS WILL ONLY BE 15-20 KT WITHIN 150 NM E SEMICIRCLE OF THE LOW CENTER TODAY...IT WILL DRIVE NW SWELLS INTO THE AREA MIXING WITH LONG PERIOD CROSS-EQUATORIAL SE SWELL...WITH COMBINED SEAS REACHING 9 FT OVER THE FAR NW PORTION BRIEFLY TODAY. THE LOW WILL THEN MEANDER OVER THE FAR NW CORNER TONIGHT WITH A SIGNIFICANT COLD FRONT THEN FORMING W OF THE LOW. THE FRONT WILL MOVE INTO THE NW PORTION ON SAT NIGHT AS THE SURFACE LOW LIFTS RAPIDLY NE OF THE AREA. NORTHERLY WIND SHIFT AT 15-20 KT WILL ACCOMPANY THE FRONT THROUGH MON NIGHT...THEN DIMINISH TO 10-15 KT. HOWEVER NW SWELL WILL PROPAGATE SE INTO THE NW WATERS WITH SEAS BUILDING 8-13 FT NW OF A LINE FROM 32N132W TO 23N140W LATE SAT NIGHT. THE FRONT WILL REACH FROM 32N130W TO 22N140W ON MON AS SEAS SUBSIDE TO 7-10 FT W OF THE FRONT. THE FRONT WILL LOSE IDENTITY LATE TUE AS HIGH PRESSURE BUILDS S ACROSS THE SUBTROPICAL PORTION OF THE DISCUSSION AREA. NW WINDS WILL INCREASE TO 15-20 KT ALONG THE NORTHERN PACIFIC COAST OF THE BAJA CALIFORNIA PENINSULA EARLY TUE INCREASING TO 20-25 KT ACROSS THESE COASTAL WATERS N OF 28N LATE TUE. BY THEN NE TRADES ACROSS THE TROPICS FROM 10-20N BETWEEN 120-140W...WILL INCREASE TO 20-25 KT WITH SEAS 7-10 FT. AN UPPER LEVEL CYCLONE IS LOSING IDENTITY OVER MEXICO AT 19N98W. AN UPPER LEVEL ANTICYCLONE IS CENTERED OVER THE NW CARIBBEAN AT 19N86W WITH AN UPPER RIDGE EXTENDING SW TO A SHARP CREST OVER THE DEEP TROPICS AT 10N117W...AND BECOMING THE DOMINATE UPPER FEATURE ACROSS THE E PORTION OF THE DISCUSSION AREA. THIS UPPER PATTERN SETS UP AN AREA OF UPPER DIFFLUENCE OVER THE MONSOON TROUGH ENHANCING THE CONVECTION AS PREVIOUSLY DESCRIBED. THE RESULTANT DEBRIS MOISTURE IS ADVECTED N ALONG THE W PERIPHERY OF THE UPPER RIDGE...CONCENTRATING INTO A 420 NM WIDE PLUME MOVING N BETWEEN 103-110W TO OVER NW OLD MEXICO. THE MOISTURE THEN MERGES WITH ADDITIONAL MOISTURE FROM SCATTERED MODERATE ISOLATED STRONG CONVECTION NOTED OVER THE PACIFIC WITHIN 30 NM EITHER SIDE OF A LINE FROM 15N109W TO 20N106W AND FROM PREVIOUS CONVECTION ON THE MEXICAN COAST AT 23N106W. THIS TROPICAL PLUME THEN BECOMES VERY DENSE AS IT CONTINUES NE AND E ACROSS TEXAS. GULF OF CALIFORNIA...LIGHT...MOSTLY NW...WINDS AT 5-10 KT WILL CONTINUE ACROSS THE GULF WATERS THROUGH LATE SAT NIGHT THEN INCREASE TO 10-15 KT ON SUN...FURTHER INCREASING TO 15-20 KT ON SUN NIGHT ACROSS THE GULF WATERS S OF 28N. LITTLE CHANGE THEN EXPECTED THROUGH TUE NIGHT. $$ NELSON