000 AXPZ20 KNHC 040245 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0100 UTC. ...SPECIAL FEATURES... TROPICAL DEPRESSION DOUGLAS IS CENTERED NEAR 20.9N 117.1W...OR ABOUT 415 NM W-SW OF THE SOUTHERN TIP OF BAJA CALIFORNIA AT 04/0300 UTC MOVING NW OR 315 DEGREES AT 4 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1006 MB. MAXIMUM SUSTAINED WIND SPEED IS 30 KT WITH GUSTS TO 40 KT. SCATTERED MODERATE CONVECTION WAS WITHIN 150 NM E AND SE QUADRANTS OF CENTER. AN INCREASE IN FORWARD SPEED IS EXPECTED TO BEGIN TONIGHT AND SHOULD CONTINUE THROUGH SATURDAY. WEAKENING IS FORECAST...AND DOUGLAS IS EXPECTED TO DEGENERATE INTO A REMNANT LOW BY FRIDAY. PLEASE SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP4/WTPZ24 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... A TROPICAL WAVE WAS ANALYZED FROM NEAR 10N96W THROUGH PUERTO ANGEL MEXICO AND INLAND INTO OAXACA AND VERACRUZ. THIS WAVE IS MOVING W AROUND 15-20 KT. SCATTERED MODERATE CONVECTION WAS NOTED NEAR THE WAVE FROM 09N TO 12N BETWEEN 96W AND 100W. A SECOND TROPICAL WAVE WAS ANALYZED FROM 10N90W THROUGH THE COAST AT THE BORDER OF EL SALVADOR AND GUATEMALA INTO THE EASTERN YUCATAN PENINSULA. THIS WAVE IS MOVING W AROUND 15-20 KT. SCATTERED MODERATE CONVECTION WAS E OF THE WAVE TO THE COAST N OF 11N AND SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION WAS FOUND INLAND WITHIN 210 NM E OF THE WAVE S OF 18N AND WITHIN 210 NM W OF THE WAVE N OF 16N. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH AXIS WAS ANALYZED FROM 09N83W TO 07N91W TO 11N107W TO 10N111W THEN CONTINUES FROM 15N117W TO 11N123W TO 10N134W. THE ITCZ WAS ANALYZED FROM 10N134W TO 09N140W. SCATTERED MODERATE CONVECTION WAS S OF THE AXIS TO 07N BETWEEN 81W AND 84W. SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION WAS WITHIN 330 NM S OF THE AXIS BETWEEN 101W AND 110W AS WELL AS WITHIN 120 NM N OF THE AXIS BETWEEN 102W AND 105W. ...DISCUSSION... A 1025 MB SUBTROPICAL HIGH WAS ANALYZED NEAR 37N137W AND EXTENDS A RIDGE THROUGH 32N130W INTO THE CENTRAL GULF OF CALIFORNIA NEAR 26N109W. 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 TIGHT ENOUGH TO SUPPORT GENTLE TO MODERATE TRADE WINDS AS A RESULT. THE RIDGE EXTENDS N OF TROPICAL DEPRESSION DOUGLAS. CONDITIONS DIRECTLY ASSOCIATED WITH DOUGLAS ARE DESCRIED IN THE SPECIAL FEATURES SECTION ABOVE. SOUTHERLY FLOW ON THE EAST SIDE OF DOUGLAS HAS TRANSPORTED LOW LEVEL MOISTURE THROUGH THE GULF OF CALIFORNIA WITH PRECIPITABLE WATER VALUES GENERALLY AROUND 2 INCHES. THIS MOISTURE IS HELPING TO FUEL EVENING THUNDERSTORMS OVER THE SIERRA MADRE OCCIDENTAL AND BAJA CALIFORNIA SUR. THE LEADING EDGE OF THE NEXT CROSS-EQUATORIAL SOUTHERLY SWELL TRAIN IS IS MOVING INTO CENTRAL AMERICA WITH PERIODS IN THE 20- 22 SECOND RANGE. THIS SWELL HAS REACHED THE COAST OF COSTA RICA AND WESTERN PANAMA THIS EVENING AND WILL SPREAD NORTHWARD THROUGH FRI NIGHT...BRINGING ROUGH SURF CONDITIONS. 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 FRI AND 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. $$ SCHAUER