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AXPZ20 KNHC 282204
TWDEP

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


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

A SURFACE TROUGH EXTENDS FROM 11N87W TO 11N97W TO 08N103W TO 07N110W WHERE SCATTEROMETER DATA SUGGESTS IT THEN TRANSITIONS TO THE ITCZ AXIS FROM THERE TO 09N116W TO 07N126W TO 05N132W TO BEYOND 04N140W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 240 NM S OF THE TROUGH BETWEEN 98W-99W...WITHIN 120 NM OF THE AXIS BETWEEN 120W-123W...AND WITHIN 60 NM N OF THE AXIS BETWEEN 112W-115W. SCATTERED MODERATE CONVECTION IS WITHIN 120 NM N OF THE AXIS BETWEEN 123W-127W...AND BETWEEN 128W-130W. SIMILAR ACTIVITY IS S OF THE TROUGH WITHIN 60 NM OF A LINE FROM 06N89W TO 06N93W...AND N OF THE TROUGH WITHIN 30 NM OF A LINE FROM 11N96W TO 13N93W.


...DISCUSSION...

A LARGE UPPER ANTICYCLONE IS CENTERED OVER THE FAR EASTERN PART OF THE AREA NEAR 12N99W WITH IS BROAD ANTICYCLONIC FLOW NOTED TO THE S OF 21N AND E OF ABOUT 128W. N OF 21N...BROAD UPPER TROUGHING IS PRESENT E OF 128W...AND W OF 128W WITH A MEAN TROUGH AXIS STRETCHING FROM A NEARLY STATIONARY LARGE UPPER LOW OVER SW UTAH SW TO 26N121W TO 20N134W TO SW OF THE AREA AT 16N140W. THE TROUGH SUPPORTS A COLD FRONT THAT EXTENDS FROM SE ARIZONA TO ACROSS NORTHERN BAJA CALIFORNIA...TO 28N120W AND NW TO 29N128W. THE FRONT IS MOVING QUICKLY S AS SEEN ON SATELLITE IMAGERY. A SURGE OF STRONG TO NEAR GALE FORCE NW WINDS WAS CAPTURED BY AN ASCAT PASS FROM THIS AFTERNOON JUST N OF 32N BETWEEN 117W-123W. THE FRONT IS FORECAST TO DISSIPATE OVER INLAND NORTHERN MEXICO ON FRI. A VERY WELL PRONOUNCED SUBTROPICAL JET STREAM BRANCH SEPARATES THE ANTICYCLONIC FLOW WITH THE CYCLONIC FLOW ASSOCIATED WITH THE UPPER TROUGH. THE JET STREAM BRANCH IS ALONG THE POINTS 13N132W TO 21N120W TO 22N110W...AND EASTWARD TO OVER CENTRAL MEXICO. MODERATE TO STRONG WINDS WITH THE JET ARE TRANSPORTING OVERCAST TO BROKEN MID AND HIGH CLOUDS EASTWARD TOWARDS CENTRAL MEXICO FROM NEAR MANZANILLO TO MAZATLAN. THESE CLOUDS ARE WITHIN 350 NM S OF THE JET STREAM W OF 116W...AND WITHIN 180-240 NM S OF THE JET E OF 116W. THE ANTICYCLONIC FLOW OVER THE EASTERN PORTION IS HELPING TO MAINTAIN CONVECTION OCCURRING THERE AS DESCRIBED ABOVE UNDER ITCZ/MONSOON TROUGH.

HIGH PRESSURE OF 1030 MB IS CENTERED NW OF THE AREA NEAR 33N145W WITH A RIDGE EXTENDING SOUTHEASTWARD INTO THE AREA THROUGH 32N140W TO 25N130W 21N119W. THE PRES GRADIENT BETWEEN THE RIDGE AND LOWER PRES IN THE VICINITY OF THE ITCZ IS ALLOWING FOR MODERATE TO FRESH NE TO E TRADES TO EXIST FROM 09N-21N W OF 132W. ANOTHER COLD FRONT IS FORECAST TO SWEEP ACROSS THE FAR NE PART AND NORTHERN BAJA CALIFORNIA SAT NIGHT INTO EARLY SUN. WINDS AHEAD OF THE FRONT OVER THE NORTHERN GULF ARE FORECAST TO BE NEAR GALE FORCE DURING THAT TIME FRAME. THE RIDGE IS FORECAST TO WEAKEN FRI NIGHT INTO SAT ALLOWING FOR THE TRADES TO DIMINISH TO MOSTLY MODERATE INTENSITY.

OTHERWISE...NW SWELL WITH SEAS OF 8-10 FT WILL CONTINUE TO PROPAGATE SE ACROSS MUCH OF THE AREA THROUGH SAT. THE SWELL IS FORECAST TO SUBSIDE SAT NIGHT INTO SUN.

$$ AGUIRRE

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