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Eastern North Pacific Tropical Weather Discussion



000
AXPZ20 KNHC 281527
TWDEP 

TROPICAL WEATHER DISCUSSION                                  
NWS NATIONAL HURRICANE CENTER MIAMI FL                      
1605 UTC THU APR 28 2016

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
1300 UTC.

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

A SURFACE TROUGH EXTENDS FROM 11N97W TO 07N105W TO 08N110W. THE
ITCZ STRETCHES FROM 08N110W TO 09N115W TO 07N126W TO BEYOND
04N140W. SCATTERED MODERATE CONVECTION IS PRESENT IN AN AREA
BOUNDED BY A LINE FROM 09N110W TO 03N138W TO 11N127W TO 09N110W.

...DISCUSSION...

N OF 15N E OF 120W...

HIGH PRESSURE OF 1030 MB NEAR 33N145W RIDGES SOUTHEASTWARD INTO
THE AREA TO 12N110W. BROAD SURFACE TROUGHING IS PRESENT OVER
NORTHERN MEXICO. A COLD FRONT CURRENTLY IS ANALYZED FROM
31.5N114W TO 31N115W. THE PRESSURE GRADIENT BETWEEN THE HIGH AND
COLD FRONT AND THE TROUGHING OVER MEXICO IS GENERATING FRESH TO
STRONG NW TO N FLOW OVER THE GULF OF CALIFORNIA BETWEEN 29.5N
AND 30.5N AND ALONG THE NORTHERN BAJA COAST BETWEEN 28N AND 29N.
WINDS WILL DIMINISH IN THE GULF AS THE FRONT DISSIPATES THIS
EVENING AND TONIGHT. ANOTHER COLD FRONT IS FORECAST TO MOVE
ACROSS THE SAME AREA SAT NIGHT THROUGH EARLY SUN. WINDS AHEAD OF
THE FRONT OVER THE NORTHERN GULF ARE FORECAST TO BE NEAR GALE
FORCE DURING THAT TIME FRAME.

OTHERWISE...NW SWELLS OF 6-10 FT WILL CONTINUE TO PROPAGATE
ACROSS THE AREA THROUGH SAT...HIGHEST OFFSHORE OF BAJA
CALIFORNIA. SWELLS ARE STILL EXPECTED TO SUBSIDE SAT NIGHT
THROUGH EARLY NEXT WEEK AS THE PRESSURE GRADIENT DECREASES.

S OF 15N E OF 110W...

A WEAK PRESSURE GRADIENT PREVAILS OVER THE AREA WITH GENTLE TO
LIGHT WINDS. THE LIGHT WIND REGIME IS EXPECTED THROUGH EARLY
NEXT WEEK.

LATEST ALTIMETRY SUGGESTS SOUTHERN HEMISPHERE SWELL IS STILL
TOPPING OUT AT AROUND 12 FEET AS IT CROSSES THE EQUATOR W OF THE
GALAPAGOS. THE ECMWF MODEL IS INITIALIZING WELL WITH THESE SWELL
HEIGHTS SO WILL FAVOR THE ECMWF FOR NEAR TERM SEA HEIGHTS IN
THIS AREA.

ELSEWHERE FROM THE EQUATOR TO 32N E OF 140W...

THE PRESSURE GRADIENT BETWEEN THE RIDGE AND LOWER PRESSURE IN
THE VICINITY OF THE ITCZ IS MAINTAINING MODERATE TO FRESH TRADES
N OF THE ITCZ. COMBINED SEAS IN THE 6 TO 9 FT RANGE PERSIST IN
THIS AREA AS SOUTHERN HEMISPHERE...TRADE-WIND AND NW SWELL ALL
BEGIN TO MERGE. THE SWELL WILL BEGIN TO DECAY TONIGHT AND SAT.
FRESH TO STRONG TRADES ARE STILL ANTICIPATED THROUGH SAT
MORNING...THEN DIMINISHING ON SUNDAY AND MONDAY AS AN
APPROACHING COLD FRONT WEAKENS THE RIDGE. PRESSURE GRADIENT WILL
RETIGHTEN BY THE MIDDLE OF NEXT WEEK AS NEW HIGH PRESSURE BUILDS
IN BEHIND THE FRONT.

$$
MCELROY