000 AXPZ20 KNHC 160322 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC TUE SEP 16 2008 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0300 UTC. ...TROPICAL WAVES... TROPICAL WAVE OVER NICARAGUA AND HONDURAS ALONG 85W N OF 04N MOVING W 10-15 KT. A LARGE AREA OF SHOWERS/TSTMS AND WIDESPREAD CLOUDINESS EXTENDS ACROSS MUCH OF THE WESTERN CARIBBEAN SEA...CENTRAL AND SOUTHERN CENTRAL AMERICA...AND THE ADJACENT PACIFIC WATERS S OF PANAMA AND COSTA RICA. IN PARTICULAR... SCATTERED MODERATE/ISOLATED STRONG CONVECTION LIES N OF 04N BETWEEN 78W-88W. TROPICAL WAVE ALONG 107W S OF 15N MOVING W 10 KT. THE WAVE CONTINUES TO BE EMBEDDED WITHIN A BROAD BUT WEAK MONSOON TROUGH WHICH LIES OFF THE MEXICAN COAST BUT IS BEGINNING TO MOVE AWAY FROM THIS REGIME AND SHOULD SOON TAKE ON A STRONGER SIGNATURE AS IT NEARS THE TRADE WIND BELT. MULTI-LAYERED CLOUDINESS EXTENDS ACROSS MUCH OF THE AREA N OF 05N TO MEXICO BETWEEN 96W-112W. SCATTERED MODERATE CONVECTION IS LOCATED NEAR THE ITCZ ON THE SOUTHERN END OF THE WAVE AXIS. ...ITCZ... ITCZ AXIS IS CENTERED FROM 11N84W TO 09N94W TO 12N105W TO 10N115W TO 12N126W TO 08N140W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION N OF 04N BETWEEN 78W-85W. SCATTERED MODERATE FROM 05N-12N BETWEEN 106W-118W. ISOLATED SHOWERS/TSTMS WITHIN 150 NM OF AXIS W OF 124W. ...DISCUSSION... TROPICS... THE UPPER LEVEL ANTICYCLONE OVER THE WESTERN CARIBBEAN SEA HAS SHIFTED SLIGHTLY WESTWARD...NOW LOCATED OVER HONDURAS WITH BROAD ANTICYCLONIC FLOW EXTENDING OVER THE PACIFIC WATERS E OF 96W. THE UPPER LEVEL JET ON THE S SIDE OF THE UPPER HIGH HAS ALSO SHIFTED FARTHER W...WITH 30-35 KT EASTERLY WINDS LOCATED S OF 08N BETWEEN 90W-105W. BROAD UPPER LEVEL DIFFLUENCE ASSOCIATED WITH THE HIGH IS ENHANCING DEEP CONVECTION OVER PARTS OF CENTRAL AMERICA...NEAR THE TROPICAL WAVE ALONG 85W...WITH UPPER LEVEL MOISTURE FLOWING W TO 90W AND NORTHWARD ACROSS THE REST OF CENTRAL AMERICA INTO THE CIRCULATION AROUND A SHARP TROUGH OVER THE GULF OF MEXICO. SCATTERED MODERATE CONVECTION HAS DEVELOPED S OF THE GULF OF TEHUANTEPEC FROM 10N-14N BETWEEN 94W-97W WITHIN THIS AREA OF DEEPER MOISTURE. AN INVERTED UPPER TROUGH EXTENDS FROM NEAR ACAPULCO MEXICO SW TO 00N106W AND MARKS THE LEADING EDGE OF A SURGE OF DRY AIR COMING FROM THE AREA NEAR THE GALAPAGOS ISLANDS. DEEP-LAYERED MOISTURE LIES W OF THE TROUGH...EXTENDING AS FAR N AS THE MOUTH OF THE GULF OF CALIFORNIA...THEN BECOMING ISOLATED INTO A NARROW BELT NEAR THE ITCZ W OF 120W. A WEAK SURFACE TROUGH IS EMBEDDED WITHIN THE ITCZ ALONG 128W AND IS ENHANCING SOME CONVECTION NEAR THE AXIS. HIGH PRES BEHIND A WEAK COLD FRONT OVER THE GULF OF MEXICO IS EXPECTED TO BUILD SOUTHWARD WITH GAP WINDS INCREASING OVER THE GULF OF TEHUANTEPEC BY TUE AFTERNOON. WINDS WILL INCREASE AND HOLD NEAR 20 KT...THEN INCREASE TO 20-25 KT TUE NIGHT AND CONTINUE THROUGH WED. SUBTROPICS... A LARGE UPPER LEVEL HIGH IS LOCATED NEAR 24N136W AND LIES ADJACENT TO AN UPPER TROUGH EXTENDING FROM OFFSHORE SOUTHERN CALIFORNIA TO 20N127W. SUBSIDENCE WITHIN THE HIGH...AND CONFLUENCE INTO THE TROUGH...IS PRODUCING A LARGE AREA OF DRYING MAINLY NW OF A LINE FROM 30N104W TO 13N130W. THE SURFACE RIDGE EXTENDS FROM 30N132W TO 20N120W WITH ONLY A FEW LOW/MID-LEVEL CLOUDS OVER THE AREA. WINDS ARE GENERALLY LIGHT...EXCEPT FOR A SLIGHTLY ENHANCED PRESSURE GRADIENT OFF OF NORTHERN BAJA CALIFORNIA BETWEEN THE RIDGE AND THE HEAT LOW OVER THE NORTHERN GULF OF CALIFORNIA. $$ BERG