000 AXPZ20 KNHC 151527 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC FRI MAY 15 2015 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1515 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM 10N85W 5N96W 6N106W TO 4N117W WHERE ITCZ BEGINS AND CONTINUES ALONG 3N126W TO 5N130W THEN RESUMES NEAR 9N130W TO 1009 MB LOW NEAR 7N136W TO 7N140W. SCATTERED MODERATE TO STRONG CONVECTION IS FROM 8N-9.5N E OF 86W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS WITHIN 60 NM OF MONSOON TROUGH BETWEEN 85W-90W...FROM THE EQUATOR TO MONSOON TROUGH BETWEEN 87W-101W AND BETWEEN 104W AND 117W...FROM 10N-13N BETWEEN 130W-135W...AND WITHIN 150 NM S AND 180W NM N OF ITCZ BETWEEN 135W-139W. ...DISCUSSION... A COLD FRONT THAT ENTERS THE REGION FROM A 1008 MB LOW NEAR 32N120W EXTENDS ALONG 28N128W TO 31N138W. THERE ARE STRONG BREEZES BOTH SE AND NW OF THE FRONT WITH SEAS REACHING TO 10 FT. THIS FRONT WILL SHIFT SE THEN DISSIPATING EARLY SAT FROM ACROSS BAJA CALIFORNIA NORTE NEAR 29N115W TO 27N120W. A WEAKENING 1024 MB SUBTROPICAL HIGH CENTERED JUST W OF THE AREA NEAR 31N146W EXTENDS A RIDGE AXIS SE OF THE ABOVE FRONT THROUGH 25N135W THEN E TO NEAR 23N117W. THE PRESSURE GRADIENT BETWEEN THIS RIDGE AND LOWER PRESSURE IN THE VICINITY OF THE MONSOON TROUGH IS GENERATING FRESH TO STRONG NE TRADE WINDS S OF THE RIDGE AS OBSERVED BY A RECENT ASCAT PASS. SE OF THE MONSOON TROUGH IS A SURFACE TROUGH THAT EXTENDS FROM A 1008 MB LOW IN THE SW CARIBBEAN NEAR 9N77W ACROSS FAR E PANAMA INTO THE REGION NEAR 8N78W TO A SECOND 1008 MB LOW NEAR 5N80W TO 3N80W. SCATTERED MODERATE TO STRONG ISOLATED CONVECTION IS WITHIN 120 NM OF LINE FROM 7N83W TO 3N77W. A SERIES OF SHORTWAVE UPPER TROUGHS ARE MIGRATING THROUGH THE BROAD UPPER TROUGH LOCATED N OF 25N E OF 130W. THE ABOVE FRONT IS SUPPORTED BY ONE OF THESE SHORTWAVES. THIS PATTERN OF SHORTWAVES WITH ASSOCIATED A SURFACE FRONTS WILL CONTINUE TO KEEP THE PRESSURE GRADIENT STRONG ENOUGH TO SUPPORT FRESH TO STRONG TRADE WINDS DESPITE THE EXPECTED TRANSIENT NATURE OF THE LOW SYSTEMS ALONG THE MONSOON TROUGH. THE SUBTROPICAL HIGH WILL DISSIPATE BY EARLY SAT THEN BE REPLACED BY YET ANOTHER HIGH W OF ANOTHER FRONT THAT WILL MOVE INTO THE AREA SUN AFTERNOON. TRADE WINDS ARE EXPECTED TO DIMINISH TO A FRESH BREEZE BY SAT AFTERNOON AS A RESULT. A BROAD AND PERSISTENT ANTICYCLONE ALOFT IS CENTERED NEAR 12N116W AND EXTENDS RIDGE AXIS NW TO BEYOND 30N140W AND NE ACROSS S/CENTRAL MEXICO. VERY ACTIVE CONVECTION CONTINUES UNDERNEATH THIS UPPER RIDGE IN THE VICINITY OF THE MONSOON TROUGH. GAP WINDS... GULF OF CALIFORNIA...THE PRESSURE GRADIENT BETWEEN THE SUBTROPICAL RIDGE AND TROUGHING OVER THE DESERT SW/NW MEXICO AND THE APPROACHING FRONT ARE SUPPORTING FRESH TO STRONG SW WINDS IN THE GULF OF CALIFORNIA N OF 29N...WITH WINDS FUNNELING THROUGH THE MOUNTAIN PASSES LIKELY REACHING TO NEAR GALE FORCE IN THOSE THE MOUNTAIN PASSES. SEAS COULD BE TO 8 FT. WINDS AND SEAS EXPECTED TO DIMINISH AROUND SUNRISE SAT. GULF OF PAPAGAYO...THE PRESSURE GRADIENT BETWEEN RIDGING OVER THE NW CARIBBEAN AND LOWER PRESSURE NEAR THE MONSOON TROUGH IS SUPPORTING A FRESH TO STRONG BREEZES IN THE GULF OF PAPAGAYO... ENHANCED BY NOCTURNAL DRAINAGE FLOW. THESE WINDS WILL DIMINISH TO FRESH BREEZES THIS AFTERNOON. THESE SEAS WILL PULSE AGAIN FRI NIGHT/SAT MORNING BEFORE THE RIDGING WEAKENS IN THE NW CARIBBEAN. $$ PAW