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AXPZ20 KNHC 060226
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0215 UTC.


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

SCATTEROMETER WINDS INDICATE THAT THE MONSOON TROUGH FORMS NEAR 06N90W AND EXTENDS SW TO AN EMBEDDED 1009 MB LOW PRESSURE AT 04.5N100W...AND THEN CONTINUES WNW TO 07N107W WHERE SCATTEROMETER WINDS INDICATE A TRANSITION TO AN ITCZ. THE ITCZ EXTENDS NW TO AN EMBEDDED TROUGH AT 10N122W...THEN TURNS SW TO BEYOND 05N140W. THE ITCZ EMBEDDED TROUGH IS ANALYZED FROM 07N122W TO 13N121W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED OVER AND TO THE S OF THE EASTERN PORTION OF THE MONSOON TROUGH...WITHIN 210 NM OF LINE FROM 02N86W TO 07N94W. SIMILAR CONVECTION IS OBSERVED S OF THE EMBEDDED LOW PRESSURE...WITHIN 90 NM EITHER SIDE OF A LINE FROM 01N95W TO 06N105W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS FLARING N OF THE ITCZ AND EXTENDS SW ALONG THE EMBEDDED TROUGH WITHIN 90 NM EITHER SIDE OF A LINE FROM 10N105W TO 11N112W TO 13N126W. ISOLATED CELLS OF MODERATE CONVECTION ARE NOTED ELSEWHERE FROM 02S-10N BETWEEN 84-130W.

A 1007 MB LOW PRESSURE CENTER IS ANALYZED OVER COLOMBIA NEAR 06.5N77W WITH A TROUGH EXTENDING SW ALONG THE PACIFIC COAST OF COLOMBIA. SCATTERED MODERATE CONVECTION IS FLARING ALONG THIS TROUGH.


...DISCUSSION...

AN UPPER CYCLONE IS OBSERVED AT 36N122W WITH AN UPPER TROUGH EXTENDING SSW TO BASE AT 22N127W. AN UPPER ANTICYCLONE IS CENTERED NEAR 09N114W WITH AN UPPER RIDGE EXTENDING W ACROSS THE TROPICAL PACIFIC TO 08N138W. AN UPPER RIDGE ALSO EXTENDS E FROM THE ANTICYCLONE TO A FAIRLY SHARP CREST NEAR 09N89W. AN UPPER TROUGH EXTENDS S ACROSS THE WESTERN CARIBBEAN CROSSING PANAMA TO A BASE OVER THE DEEP TROPICAL PACIFIC AT 04N83W.

UPPER MOISTURE IS ROTATING CYCLONICALLY NE AROUND THE UPPER CYCLONE AND ACROSS SOUTHERN CALIFORNIA AND THE NORTHERN BAJA CALIFORNIA PENINSULA. VERY DRY UPPER AIR IS INDICATED ELSEWHERE OVER THE NORTHERN PORTION OF THE DISCUSSION AREA INCLUDING NORTHERN MEXICO...ROUGHLY N OF A LINE FROM 28N97W TO 22N140W. UPPER DIFFLUENCE UNDER THE PREVIOUSLY DESCRIBED WESTERN TROPICAL RIDGE IS ENHANCING CONVECTION ALONG THE ITCZ AND ITS EMBEDDED TROUGH ALSO PREVIOUSLY DESCRIBED. THE RESULTANT DEBRIS MOISTURE IS ADVECTED NE FROM THE ITCZ BETWEEN 113W AND 120W. THIS MOISTURE MERGES ALONG 20N WITH A TROPICAL PLUME ORIGINATING IN THE CENTRAL PACIFIC THAT STREAMS ENE ACROSS THE DISCUSSION AREA WITHIN 150 NM EITHER SIDE OF A LINE FROM 18N140W TO ACROSS SOUTHERN BAJA AND CENTRAL MEXICO. WEAK UPPER DIFFLUENCE BETWEEN THE PREVIOUSLY MENTIONED EASTERN TROPICAL RIDGE AND AN UPPER TROUGH IS ENHANCING CONVECTION OVER AND TO THE S OF THE MONSOON TROUGH AS PREVIOUSLY DESCRIBED...WITH THE UPPER DEBRIS MOISTURE ADVECTED S ACROSS THE EQUATOR BETWEEN 86-113W.

ELSEWHERE AT THE LOW LEVELS A SURFACE RIDGE EXTENDS FROM 32N140W TO 16N102W. A SURFACE TROUGH EMBEDDED IN THE ITCZ FROM 07N121W TO 13N120W IS FORECAST TO SHIFT W FROM 05N131W TO 14N126W ON WED AND FROM 04N136W TO 13N130W LATE THU. THE GRADIENT IS EXPECTED TO TIGHTEN SW OF THE RIDGE AXIS OVER THE NEXT FEW DAYS INCREASING THE NE TRADES TO 20-25 KT BETWEEN THE TROUGH AND THE RIDGE WITH SEAS BUILDING 7-10 FT IN THE NE WINDS WAVES THAT WILL MIX WITH LONG PERIOD SW AND NW SWELL. ALTHOUGH THE TROUGH WILL MOVE W OF 140W ON FRI...EXPECT THE FRESH NE TRADES TO CONTINUE THROUGH THE UPCOMING WEEKEND ACROSS THE TROPICAL WATERS BETWEEN 08-19W WITH EMBEDDED PATCHES OF STRONG TRADES. 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 116-128W THROUGH THU NIGHT...THEN GRADUALLY SUBSIDING THEREAFTER.

ANOTHER BATCH OF LONG PERIOD SW SWELL WILL CROSS THE EQUATOR BETWEEN 92-120W ON SUN NIGHT REACHING ALONG 03N ON MON.

GULF OF CALIFORNIA...A SURFACE LOW WILL MOVE E OVER THE FAR NORTHERN GULF OF CALIFORNIA TONIGHT WHERE IT WILL MEANDER THROUGH FRI. THE GRADIENT WILL SUPPORT S-SW 20-25 KT PULSES WITHIN ABOUT 90 NM S OF THE CENTER. AS THE LOW MOVES E ON THU NIGHT THE GRADIENT WILL BRIEFLY SUPPORT NW-N 20-25 KT WINDS OVER THE NW QUADRANT AS WELL. THE BRIEF STRONG PULSES WITH LIMITED FETCH SHOULD ONLY ALLOW SEAS TO BUILD TO A MAXIMUM OF 7 FT.

$$ NELSON

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