000 AXPZ20 KNHC 120934 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC SAT FEB 12 2011 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 0915 UTC. ...ITCZ... THE INTERTROPICAL CONVERGENCE ZONE AXIS IS ANALYZED FROM 03N77W TO 04N104W TO 08N130W THEN FROM 07N133W TO 05N140W. SCATTERED MODERATE CONVECTION IS WITHIN 120 NM EITHER SIDE OF THE AXIS BETWEEN 116W AND 123W. ...DISCUSSION... ALOFT...A STRONG POSITIVELY TILTED MID TO UPPER LEVEL TROUGH AXIS EXTENDS FROM THE PANHANDLE OF TEXAS TO ACROSS THE NORTHERN BAJA CALIFORNIA PENINSULA TO AN ELONGATED CYCLONIC CIRCULATION NEAR 24N136W. A SUBTROPICAL JET STREAM BRANCH WITH CORE SPEEDS IN THE RANGE OF 60 TO 80 KT E OF THE TROUGH AXIS CONTINUES TO ADVECT MID TO UPPER LEVEL MOISTURE FROM THE DEEP TROPICS NORTHEASTWARD TO ACROSS EXTREME SOUTHERN BAJA CALIFORNIA AND EASTWARD OVER THE MAJORITY OF NORTHERN MEXICO. A LARGE ANTICYCLONE IS N OF THE TROUGH N OF THE AREA NEAR 34N124W W OF POINT CONCEPTION CALIFORNIA WHICH IS ALLOWING FOR A BROAD AREA OF ANTICYCLONIC FLOW OVER THE AREA N OF THE TROUGH. MODERATE SUBSIDENCE IS MAINTAINING STABLE AND DRY CONDITIONS OVER MUCH OF THE AREA N OF THE TROUGH AS NOTED BY A BROKEN STRATOCUMULUS CLOUD FIELD LOCATED N OF 20N AND W OF 120W...WITH CLEAR SKIES N OF 20N AND E OF 120W. OVER THE CENTRAL PORTION OF THE AREA...A MID TO UPPER LEVEL TROUGH EXTENDS FROM THE BROAD CYCLONIC CIRCULATION TO NEAR 08N123W. UPPER LEVEL DIFFLUENCE EXISTS ROUGHLY FROM 03N TO 14N BETWEEN 110W AND 121W HELPING TO ENHANCE CONVECTION ALONG THE ITCZ SE OF THE TROUGH AXIS. A RATHER ROBUST DEEP LAYER TROUGH WELL NW OF THE AREA IS QUICKLY MOVING E AND SE. THIS TROUGH IS FORECAST TO CLIP THE FAR NW CORNER OF THE AREA THIS EVENING TROUGH SUN NIGHT AS THE AFOREMENTIONED ANTICYCLONE AHEAD OF IT MOVES INLAND AND OVER THE WESTERN AND CENTRAL U.S. THIS TROUGH WILL PUSH A COLD FRONT TOWARDS THE FAR NW CORNER OF THE AREA TONIGHT AND ACROSS THE FAR NW WATERS THROUGH SUN NIGHT WHEN IT WILL REACH FROM 30N132W TO 24N140W. SOUTHERLY WINDS OF 20 TO 25 KT WILL PRECEDE THE FRONT WITH NORTHERLY WINDS TO 20 KT BEHIND THE FRONT. NW SWELL WILL BUILD TO UP TO 13 FT BEHIND THE FRONT BY SUN NIGHT. AT THE SURFACE...A RIDGE AXIS EXTENDS FROM 1023 MB HIGH LOCATED N OF THE AREA NEAR 34N127W INTO THE NW PORTION OF THE AREA TO NEAR 23N140W. THE HIGH AND RIDGE AXIS WILL MIGRATE SLOWLY E THROUGH THE NEXT 24 HOURS AS THE UPPER LEVEL ANTICYCLONE SHIFTS E. A SURFACE TROUGH ANALYZED FROM 13N130W TO 04N133W IS MOVING W AROUND 10 KT. THE INTERACTION BETWEEN THE SURFACE TROUGH AND THE RIDGE TO THE N IS MAINTAINING A TIGHT PRES GRADIENT MAINLY W OF THE TROUGH WHERE NE 20 KT WINDS ARE OCCURRING. THE TROUGH WILL WEAKEN AS IT CONTINUES WESTWARD SHIFTING W OF 140W BY SUN NIGHT. NW SWELL OF 8 TO 10 FT WILL GRADUALLY DECAY DURING THE NEXT 48 HOURS WHILE SW SWELL TO 8 FT CROSSES THE EQUATOR ARRIVING IN THE FAR SOUTH CENTRAL PORTION OF THE AREA BY SUN AFTERNOON. GAP WINDS... GULF OF TEHUANTEPEC...COLD AIR CONTINUES TO SURGE THROUGH THE CHIVELA PASS ACROSS THE ISTHMUS OF TEHUANTEPEC. RECENT OBSERVATIONS AT LAND-BASED STATION IXTEPEC MEXICO WERE REPORTING 30 KT GUSTS 40 KT AND A 0404 UTC ASCAT PASS CAPTURED 35 KT N-NE WINDS. HIGH PRES OVER SE TEXAS IS FORECAST TO INTENSIFY THIS AFTERNOON AND EVENING SENDING A REINFORCING SURGE OF COLD AIR THROUGH THE PASS WHICH WILL INCREASE WINDS TO STORM FORCE BEGINNING AROUND 03 UTC SUN AS THE PRES GRADIENT OVER SE MEXICO TIGHTENS. A SLIGHT LESSENING OF THE GRADIENT ON SUN AFTERNOON SHOULD ALLOW FOR THE WINDS TO DIMINISH TO GALE FORCE IN THE 35 TO 45 KT RANGE. SEAS ARE FORECAST TO BUILD TO UP TO 18 FT COINCIDENT WITH THE STORM FORCE CONDITIONS. NE SWELL GENERATED BY THESE WINDS WILL SPREAD SW TO 04N BY SUN NIGHT. GULF OF PAPAGAYO...AN EARLIER WINDSAT PASS CAPTURED ONLY 10 TO 15 KT FLOW IN THE GULF OF PAPAGAYO ALTHOUGH WINDS ARE EXPECTED TO INCREASE TO 20 KT IN THE NEXT FEW HOURS WITH ENHANCED DRAINAGE FLOW RESUMING OFF OF CENTRAL AMERICA DURING THE EARLY MORNING HOURS. WINDS WILL FURTHER INCREASE TO 20 TO 25 KT BY SAT NIGHT PERSISTING THROUGH AT LEAST SUN NIGHT AS TRADES IN THE WESTERN CARIBBEAN SEA ALSO INCREASE. GULF OF PANAMA...NE TRADE WINDS IN THE CARIBBEAN SEA ARE FILTERING ACROSS THE ISTHMUS OF PANAMA AND INTO THE FAR E PACIFIC WITH 20 KT NORTHERLY FLOW IN THE GULF OF PANAMA N OF 06N BETWEEN 78W AND 80W AS INDICATED BY A 0222 UTC ASCAT PASS. THESE WINDS WILL EXPAND SLIGHTLY TO N OF 05N WHILE INCREASING TO 20 TO 25 KT BY 24 HOURS THEN WILL DIMINISH TO LESS THAN 20 KT BY 36 HOURS AS THE TRADES N OF THE ISTHMUS WEAKEN SLIGHTLY. GULF OF CALIFORNIA...A TIGHT PRES GRADIENT BETWEEN HIGH PRES OVER THE U.S. INTER-MOUNTAIN WEST AND BROAD SURFACE TROUGHING OVER NW MEXICO IS GENERATING 20 KT NW TO N WINDS WHICH ARE FUNNELING THROUGH THE GULF OF CALIFORNIA N OF 26N. THESE WINDS WERE CAPTURED BY A 0408 UTC ASCAT PASS. WINDS WILL REMAIN 20 KT THROUGH 24 HOURS WHILE SHRINKING...EXTENDING FROM 25N TO 29N BY 24 HOURS AND THEN DIMINISHING TO LESS THAN 20 KT BY 30 HOURS AS THE GRADIENT RELAXES. $$ LEWITSKY