Tropical Weather Discussion
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000
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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