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AXPZ20 KNHC 062152
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC WED MAY 06 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2145 UTC.


...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...

SCATTEROMETER WINDS INDICATE THAT THE ITCZ FORMS NEAR 07N102W AND EXTENDS WNW TO EMBEDDED TROUGH AT 10N125W...THEN THE ITCZ CONTINUES SW TO BEYOND 03N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS OBSERVED E OF THE ITCZ WITHIN 120 NM EITHER SIDE OF A LINE FROM 03N92W TO 06.5N98W. SIMILAR CONVECTION IS NOTED OVER AND TO THE N OF THE ITCZ WITHIN 150 NM EITHER SIDE OF A LINE FROM 09.5N110W TO 11.5N124W AND ALONG THE ITCZ WITHIN 75 NM EITHER SIDE OF A LINES FROM 11.5N124W TO 08N130W AND FROM 04N133W TO 03N140W. CLUSTERS OF SCATTERED MODERATE ISOLATED STRONG CONVECTION ARE OBSERVED WELL S OF THE ITCZ WITHIN 90 NM EITHER SIDE OF A LINE FROM 02N107W TO 05N113W.

A 1008 MB LOW PRESSURE CENTER IS ANALYZED OVER CARIBBEAN COAST OF COLOMBIA AT 10N75W WITH A LOW LEVEL TROUGH EXTENDING SW ALONG THE PACIFIC COAST OF COLOMBIA TO A BASE OVER THE TROPICAL PACIFIC AT AT 03N81W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS FLARING WITHIN 120 NM OF THE TROUGH AXIS. ISOLATED CLUSTERS OF MODERATE CONVECTION IS NOTED ELSEWHERE FROM 03-09N BETWEEN 80-92W.


...DISCUSSION...

AN UPPER TROUGH EXTENDS SW FROM SOUTHERN CALIFORNIA AT 34N120W TO 17N139W. AN UPPER ANTICYCLONE IS CENTERED OVER THE TROPICS NEAR 13N110W WITH AN UPPER RIDGE EXTENDING W TO A SHARP CREST AT 10N133W WITH SEVERAL MORE EMBEDDED SMALL ANTICYCLONIC CENTERS INDICATED ALONG THE RIDGE BY THE CLOUD MOTION VECTORS. AN UPPER RIDGE ALSO EXTENDS E FROM THE ANTICYCLONE TO ANOTHER FAIRLY SHARP CREST NEAR 10N87W. A SHORTWAVE RIDGE EXTENDS N ACROSS CENTRAL MEXICO TO A CREST OVER SOUTHERN TEXAS. AN UPPER TROUGH EXTENDS S ACROSS THE WESTERN CARIBBEAN FROM CENTRAL CUBA TO ACROSS PANAMA TO A BASE OVER THE DEEP TROPICAL PACIFIC AT 04N85W.

A BAND OF UPPER MOISTURE IS MOVING ACROSS THE SHORTWAVE RIDGE FROM 19-26N BETWEEN FROM PACIFIC AT 111W ACROSS MEXICO AND THE GULF OF MEXICO ALONG 94W. THERE ARE EMBEDDED CLUSTERS OF CONVECTION WITHIN THIS AREA AND THESE WILL LIKELY CONTINUE INTO EARLY TONIGHT. VERY DRY UPPER AIR IS INDICATED ELSEWHERE OVER THE NORTHERN PORTION OF THE DISCUSSION AREA INCLUDING NORTHERN MEXICO IN NEARLY ZONAL UPPER FLOW...ALL ROUGHLY N OF A LINE FROM 27N97W TO 10N140W.

UPPER DIFFLUENCE AROUND THE TROPICAL UPPER ANTICYCLONE AND ITS WESTERN RIDGE IS ENHANCING CONVECTION ALONG THE ITCZ AND ITS EMBEDDED LOW LEVEL TROUGH AS PREVIOUSLY DESCRIBED. THE RESULTANT DEBRIS MOISTURE SEEMS TO EVAPORATE WITHIN A FEW HUNDRED MILES OF THE CLUSTERS. A THIN TROPICAL MOISTURE PLUME ORIGINATING IN THE CENTRAL PACIFIC IS STILL STREAMING ENE ACROSS THE DISCUSSION AREA WITHIN 120 NM EITHER SIDE OF A LINE FROM 16N140W TO JUST S OF THE SOUTHERN BAJA PENINSULA WHERE IT MERGES WITH THE DENSE PLUME ALREADY DESCRIBED. WEAK UPPER DIFFLUENCE BETWEEN THE PREVIOUSLY MENTIONED EASTERN TROPICAL RIDGE AND THE CARIBBEAN UPPER TROUGH IS ENHANCING THE CONVECTION OVER THE AREA S OF 10N BETWEEN 83-100W...WITH THE UPPER DEBRIS MOISTURE EVAPORATING AS IT SPREADS SW ACROSS THE EQUATOR BETWEEN 90-120W.

ELSEWHERE AT THE LOW LEVELS A SURFACE RIDGE EXTENDS FROM 33N140W TO 12N91W. A SURFACE TROUGH IS EMBEDDED IN THE ITCZ FROM 08N126W TO 15N124W...AND IS FORECAST TO SHIFT W FROM 05N135W TO 12N130W ON THU AND NEARLY FILL FROM 04N139W TO 11N138W LATE FRI. THE GRADIENT SW OF THE RIDGE IS SUPPORTING 20-25 KT NE TRADES ACROSS THE WATERS FROM 10-18N BETWEEN 120-140W. THE NE WIND WAVES ARE MIXING WITH LONG PERIOD SW AND NW SWELL RESULTING IN COMBINED SEAS OF 7-10 FT. THE GRADIENT WILL GRADUALLY RELAX THROUGH SAT WITH THE WINDS DIMINISHED TO 15-20 KT ON SUN...AND THE AFFECTED AREA OF ENHANCED SEAS OF 7-9 FT WILL SHRINK FROM 06-13N BETWEEN 130-140W ON TUE. FRESH NW-N WINDS ARE EXPECTED ACROSS THE SUBTROPICAL WATERS NE OF THE RIDGE INTO THE UPCOMING WEEKEND. LONG PERIOD NW SWELL WILL PROPAGATE S INTO THE DISCUSSION AREA AND MIX WITH LONG PERIOD SOUTHERLY SWELL DRIVING THE COMBINED SEAS TO 7-10 FT ACROSS THE WATERS N OF 28N BETWEEN 117-130W THROUGH FRI EVENING...THEN GRADUALLY SUBSIDING THEREAFTER.

ANOTHER BATCH OF LONG PERIOD SW SWELL WILL CROSS THE EQUATOR E OF 120W ON SUN NIGHT REACHING ALONG 06N ON TUE.

GULF OF CALIFORNIA...WEAK LOW PRESSURE IS EXPECTED TO SOON DEVELOP ALONG A SURFACE TOUGH OVER THE NORTHERN GULF OF CALIFORNIA WHERE IT WILL MEANDER THROUGH FRI...AND MOVE E OVER EXTREME NW MEXICO ON FRI NIGHT. THE GRADIENT WILL SUPPORT S-SW 20-25 KT PULSES WITHIN ABOUT 90 NM S OF THE CENTER. THE LIMITED FETCH SHOULD ONLY ALLOW SEAS TO BUILD TO A MAXIMUM OF 7 FT. GUIDANCE IS SUGGESTING THE GRADIENT NE OF THE PACIFIC RIDGE WILL SUPPORT NW WINDS OF 20-25 KT ALONG THE PACIFIC COAST OF THE BAJA PENINSULA ON FRI NIGHT THROUGH SAT NIGHT.

GULF OF PAPAGAYO...EXTENDED GUIDANCE INDICATES NE-E 20-25 KT WINDS OVER AND SW OF THE GULF OF PAPAGAYO ON MON NIGHT.

$$ NELSON

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