000 AXPZ20 KNHC 040944 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC FRI JUL 04 2014 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 0830 UTC. ...SPECIAL FEATURES... DESPITE LIMITED CONVECTION PERSISTING NEAR DOUGLAS...0500 UTC ASCAT PASSES REVEALED TROPICAL STORM FORCE WINDS ACROSS THE NORTH SEMICIRCLE OF THE CENTER...AND DOUGLAS HAS BEEN UPGRADED TO A TROPICAL STORM...CENTERED AT 21.3N 117.5W 1006 MB AT 0900 UTC MOVING NW OR 315 DEG AT 5 KT. MAXIMUM SUSTAINED WINDS 35 KT GUSTS 45 KT WITH SEAS TO 13 FT WITHIN 45 NM N SEMICIRCLE. DOUGLAS IS EXPECTED TO INCREASE ITS FORWARD SPEED TODAY AND MOVE ACROSS COOLER WATERS AND A MORE STABLE ATMOSPHERE...LEADING TO WEAKENING AND TRANSITION TO A POST TROPICAL REMNANT LOW WITHIN THE NEXT 24 HOURS. BEYOND THAT TIME...THE REMNANTS OF DOUGLAS WILL CONTINUE TO MOVE NW AND GRADUALLY WEAKEN FURTHER. SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP4/WTPZ24 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... A TROPICAL WAVE WAS ALONG ABOUT 92W EARLY THIS MORNING N OF 10N EXTENDING N INTO THE EASTERN BAY OF CAMPECHE. THIS WAVE IS MOVING W 15-20 KT. SCATTERED MODERATE TO STRONG CONVECTION WAS SEEN FROM 12N TO THE COAST BETWEEN 90W AND 93W. THIS WAVE IS EXPECTED TO CONTINUE TO MOVE WWD ACROSS THE EPAC DURING THE NEXT FEW DAYS...WITH ACTIVE CONVECTION GRADUALLY SHIFTING S OF 15N. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... MONSOON TROUGH EXTENDS FROM 09N74W TO 09N84W TO 07N90W TO 09N98W TO 08N112W...WHERE IT REMAINS FRACTURED...THEN RESUMES FROM NEAR 15N115W TO 09.5N125W TO 10N131W...WHERE IT TRANSITIONS TO ITCZ CONTINUING ON TO BEYOND 10N140W. SCATTERED MODERATE TO STRONG CONVECTION NOTED E OF 79W TO COLOMBIAN COAST. SCATTERED MODERATE TO STRONG CONVECTION NOTED WITHIN 210 NM EITHER SIDE OF TROUGH BETWEEN 97W AND 111W. SCATTERED MODERATE ISOLATED STRONG CONVECTION NOTED WITHIN 90 NM EITHER SIDE OF TROUGH BETWEEN 118W AND 131W. ...DISCUSSION... A 1025 MB SUBTROPICAL HIGH WAS CENTERED NEAR 37N136W AND EXTENDS A WEAK RIDGE SE TO NORTH OF DOUGLAS NEAR 28N117W. AN UPPER TROUGH OVER NW WATERS HAS DISRUPTED THE DEEP-LAYER RIDGING OVER THE AREA...WEAKENING THE RIDGING AT THE SURFACE. THIS TROUGH IS EXPECTED TO PINCH OFF A LOW THAT WILL LINGER OVER THE AREA FOR THE NEXT FEW DAYS. THE PRESSURE GRADIENT BETWEEN THE HIGH AND THE MONSOON TROUGH/ITCZ IS ONLY SUFFICIENT ENOUGH TO SUPPORT GENTLE TO MODERATE TRADE WINDS S OF 25N. SOUTHERLY FLOW ON THE EAST SIDE OF DOUGLAS HAS TRANSPORTED LOW LEVEL MOISTURE THROUGH THE GULF OF CALIFORNIA...AND HAS HELPED TO FUEL EVENING THUNDERSTORMS OVER THE SIERRA MADRE OCCIDENTAL AND BAJA CALIFORNIA SUR THAT HAVE LINGERED INTO THE EARLY MORNING HOURS. LOOK FOR THIS MOISTURE TO REMAIN IN PLACE TODAY AND CONTRIBUTE TO ANOTHER ROUND OF ACTIVE AFTERNOON CONVECTION. THE LEADING EDGE OF THE NEXT CROSS-EQUATORIAL SOUTHERLY SWELL EVENT IS PRESENTLY MOVING INTO THE CENTRAL AMERICA COASTS FROM PANAMA TO SOUTHERN MEXICO...WITH WAVE PERIODS IN THE 20-22 SECOND RANGE. S TO SW SWELL WILL INCREASE DURING THE NEXT 24 HOURS ACROSS THESE WATERS AND COASTAL ZONES TO CREATE LARGE BREAKING WAVES ALONG THE BEACHES AND REEF LINES. THIS WILL GENERATE DANGEROUS SURF CONDITIONS AND STRONG RIP CURRENTS. GAP WINDS... GULF OF PAPAGAYO...THE ATLANTIC SUBTROPICAL RIDGE IS BUILDING WESTWARD TO THE S OF ATLANTIC HURRICANE ARTHUR...INCREASING THE TRADE WINDS IN THE WESTERN CARIBBEAN. WINDS WILL FUNNEL THROUGH THE GULF OF PAPAGAYO INTO THE PACIFIC AND PULSE TO 25 KT WITH THE ASSISTANCE OF NOCTURNAL DRAINAGE FLOW BOTH EARLY THIS MORNING AND AGAIN EARLY SAT. GULF OF TEHUANTEPEC... PRESSURES WILL RISE OVER THE GULF OF MEXICO BEHIND A COLD FRONT CURRENTLY DRAPED OVER THE N CENTRAL GULF OF MEXICO. THIS COUPLED WITH THE WESTWARD EXPANDING SUBTROPICAL RIDGE WILL INCREASE THE PRESSURE GRADIENT BETWEEN THE HIGH TO THE NORTH AND THE MONSOON TROUGH TO THE SOUTH...FORCING N-NE WINDS TO FUNNEL THROUGH THE GULF OF TEHUANTEPEC. WINDS WILL PULSE TO A FRESH TO STRONG BREEZE AS NOCTURNAL DRAINAGE FLOW OFF THE LAND ENHANCES THE WINDS EACH OF THE NEXT FEW NIGHTS. $$ STRIPLING