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Eastern North Pacific Tropical Weather Discussion



000
AXPZ20 KNHC 290244
TWDEP 

TROPICAL WEATHER DISCUSSION                                  
NWS NATIONAL HURRICANE CENTER MIAMI FL                      
0405 UTC FRI APR 29 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0215 UTC.

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

A SURFACE TROUGH EXTENDS FROM 11N91W TO 08N102W TO 07N105W TO
09N115W WHERE EARLIER SCATTEROMETER DATA SUGGESTED IT THEN
TRANSITIONS TO THE ITCZ AXIS FROM THERE TO 09N115W TO 07N125W TO
05N134W TO BEYOND 04N140W. SCATTERED MODERATE ISOLATED STRONG
CONVECTION IS WITHIN 300 NM S OF THE TROUGH BETWEEN 91W-
97W...AND WITHIN 180 NM S OF THE TROUGH BETWEEN 102W-108W.
SIMILAR ACTIVITY IS WITHIN 120 NM N OF THE AXIS BETWEEN 119W-
124W. SCATTERED MODERATE CONVECTION IS WITHIN 60 NM OF THE
TROUGH BETWEEN 112W-114W.

...DISCUSSION...

A LARGE UPPER ANTICYCLONE IS CENTERED OVER THE FAR EASTERN PART
OF THE AREA NEAR 11N98W 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 THU 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 34N144W
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.
A LOW PRES SYSTEM IS FORECAST TO APPROACH FAR SOUTHERN ARIZONA
LATE SAT NIGHT WITH ITS ATTENDANT COLD FRONT SWEEPING ACROSS THE
FAR NORTHERN BAJA CALIFORNIA AND THE FAR NE PART OF THE AREA SAT
NIGHT INTO EARLY SUN. A TIGHT PRES GRADIENT S OF THE LOW AND
AHEAD OF THE FRONT IS FORECAST BY THE GFS MODEL TO BRING NEAR
GALE FORCE WINDS OVER THE FAR NORTHERN PART OF THE GULF 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 8-11 FT WILL CONTINUE TO
PROPAGATE SE ACROSS MUCH OF THE AREA THROUGH SAT...WITH THE
HIGHEST OF SEAS CONFINED PRIMARILY TO THE FAR NE PORTION OF THE
AREA. THE SWELL IS FORECAST TO SUBSIDE SAT NIGHT INTO SUN.

$$
AGUIRRE