Home


000
AXPZ20 KNHC 010230
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC WED JUL 01 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 0230 UTC.


...TROPICAL WAVES...

TROPICAL WAVE ALONG 90W/91W FROM 05N TO 12N. SCATTERED MODERATE CONVECTION IS NOTED FROM 06N TO 08N BETWEEN 86W AND 90W. POSITION IS BASED ON CONTINUITY AS THE TROPICAL WAVE IS POORLY REPRESENTED IN LATEST DATA AND SATELLITE IMAGERY.

TROPICAL WAVE ALONG 100W/101W FROM 09N TO 15N SHOWS UP RELATIVELY WELL IN THE LOWER TO MID LEVELS OF THE ATMOSPHERE BASED ON GOES HIGH DENSITY WINDS AND ANIMATED PRECIPITABLE WATER IMAGERY. IT ALSO HAS A REASONABLE PRESENTATION IN GOES IMAGERY AND THE POSITION MATCHES CONTINUITY. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS NOTED E OF THE WAVE AXIS FROM 09N TO 14N BETWEEN 95W AND 100W. THESE SHOWERS AND THUNDERSTORMS ARE ENHANCED TO A LARGE DEGREE BY A NEGATIVELY TILTED UPPER TROUGH POSITIONED TO THE NW OF THE TROPICAL WAVE.

TROPICAL WAVE ALONG 125W/126W FROM 07N TO 14N. THE WAVE IS POSITIONED TO THE SOUTH OF A LARGE UPPER LOW. DRY SUBSIDENT FLOW ON THE WESTERN SIDE OF THE UPPER LOW IS SUPPRESSING CONVECTIVE DEVELOPMENT N OF THE WAVE. CONVERSELY DIVERGENCE ALOFT SOUTH OF THE UPPER LOW ALONG WITH WEAK TRADE WIND CONVERGENCE IN THE LOWER LEVELS IS ENHANCING AREAS OF CONVECTION SEVERAL HUNDRED MILES TO THE EAST AND WEST OF THE TROPICAL WAVE. WHILE THE WAVE REMAINS INDISTINCT WHILE EMBEDDED IN THIS AREA OF CONVECTION...IT PRESUMED TO HAVE A FAIRLY LOW AMPLITUDE SOUTH OF THE SUBTROPICAL RIDGE.

TROPICAL WAVE ALONG 135W/136W FROM 07N TO 15N. THE WAVE SHOWS UP WEAKLY ON GOES DERIVED HIGH DENSITY WINDS AND IN VISIBLE IMAGERY. NO SIGNIFICANT CONVECTION IS NOTED WITH THE WAVE. EARLIER SCATTEROMETER DATA INDICATED THERE IS SOME ENHANCEMENT TO TRADE WIND FLOW NW OF THE WAVE BETWEEN THE WAVE AND THE SUBTROPICAL RIDGE TO THE NORTH.


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

NO MONSOONAL CIRCULATION IS EVIDENT ACROSS THE REGION. THE ITCZ EXTENDS FROM 09N102W TO 07N105W TO 10N115W TO BEYOND 06N140W. SCATTERED MODERATE CONVECTION NOTED WITHIN 180 NM EITHER SIDE OF AXIS BETWEEN 115W AND 135W.


...DISCUSSION...

N OF 15N E OF 120W...A MID LATITUDE UPPER LEVEL BLOCKING PATTERN CONTINUES TO SPAN THE WESTERN STATES AND THE ADJACENT OCEANIC AREAS TODAY. TO THE SOUTH OF THIS RIDGE...A LARGE MIDDLE/UPPER LEVEL CYCLONIC CIRCULATION CENTERED NEAR 22N120W WITH A SHARP NEGATIVELY TILTED TROUGH REACHING TOWARD 19N105W. A FEW SHOWERS AND THUNDERSTORMS WERE NOTED MOVING ACROSS NW MEXICO AND THE CENTRAL GULF OF CALIFORNIA IN THE DIVERGENT FLOW ALOFT BETWEEN THESE FEATURES...BUT THIS HAS DIMINISHED OVER THE GULF. A WEAK SUBTROPICAL RIDGE TO THE WEST IS MAINTAINING FAIRLY LIGHT SURFACE WINDS ACROSS THE REGION. SUCCESSIVE ALTIMETER PASSES FROM THE MORNING INDICATED ONLY 3 TO 5 FT SEAS IN MOST AREAS. NO CHANGES ARE EXPECTED THROUGH THU IN THE PATTERN. LOOKING AHEAD TO LATE IN THE WEEK...WINDS WILL INCREASE SLIGHTLY OFF THE COAST OF BAJA CALIFORNIA NORTE AND NORTHERN PORTIONS OF BAJA CALIFORNIA SUR BETWEEN THE RIDGE TO THE WEST AND LOWER PRES OVER NW MEXICO.

S OF 15N E OF 110W...STRONG TRADE WIND FLOW THROUGH THE SW CARIBBEAN IS PUSHING INTO THE EASTERN PACIFIC THROUGH THE GULF OF PAPAGAYO AND OTHER LOCATIONS ALONG THE COAST OF NICARAGUA TO THE GULF OF FONSECA. OVERNIGHT ASCAT DATA INDICATED 20 TO 25 KT THIS MORNING...AND THIS WILL PERSIST THROUGH THE NEXT 24 TO 36 HOURS WITH SEAS BUILDING AS HIGH AS 11 FT. FRESH NORTHERLY GAP WINDS WERE ALSO NOTED INTO THE GULF OF PANAMA. CONVECTION ADJACENT TO A PAIR OF WEAK TROPICAL WAVES NEAR 89W AND 100W IS RELATED IN PART TO AN UPPER TROUGH NORTH OF THE AREA. OTHERWISE FAIRLY LIGHT AND DISORGANIZED FLOW IN THE DEEP TROPICS IS NOTED IN TOGA BUOY OBSERVATIONS AND EARLIER ASCAT DATA. THE WINDS AND SEAS ARE EXPECTED TO DIMINISH TO 20 KT OR LESS AND LESS THAN 8 FT THROUGH 36 HOURS. ALTIMETER DATA IS INDICATING GENERALLY 4 TO 5 FT SEAS OUTSIDE OF AREA OF GAP WIND INFLUENCE.

ELSEWHERE...THE SUBTROPICAL RIDGE N OF 20N IS MAINTAINING GENERALLY MODERATE TRADE WIND FLOW INTO THE DEEP TROPICS...EXCEPT FOR NEAR THE TROPICAL WAVE AT 135W...WHERE SATELLITE DERIVED DATA INDICATES FRESH TRADES AND SEAS TO 8 FT FROM 11N TO 15N W OF 133W. ASIDE FROM THE CONVECTION NOTED ALONG THE ITCZ...SUBSIDENT FLOW ON THE WEST SIDE OF THE UPPER LOW IS INHIBITING CONVECTIVE DEVELOPMENT. NO MAJOR CHANGES EXPECTED THROUGH THE NEXT 48 HOURS AT THE SURFACE. LOOKING AHEAD...GLOBAL MODELS INDICATE FAVORABLE FLOW ALOFT ALLOWING WEAK LOW PRES FORMING IN THE DEEP TROPICS BETWEEN 135W AND 140W BY THIS WEEKEND.

$$ CHRISTENSEN

Home