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Eastern North Pacific Tropical Weather Discussion (Text)



000
AXPZ20 KNHC 290923
TWDEP 

TROPICAL WEATHER DISCUSSION                                  
NWS NATIONAL HURRICANE CENTER MIAMI FL                      
1005 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0900 UTC.

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

A SURFACE TROUGH EXTENDS FROM 10N95W TO 06N105W TO 07N113W TO
05N119W WHERE IT THEN TRANSITIONS TO THE ITCZ AXIS FROM THERE TO
05N130W TO BEYOND 06N140W. SCATTERED MODERATE CONVECTION IS FROM
05N TO 08N BETWEEN 91W AND 95W. SIMILAR CONVECTION IS FROM 07N
TO 10N BETWEEN 121W AND 123W. SCATTERED MODERATE ISOLATED STRONG
CONVECTION CAN BE FOUND WITHIN 180 NM S OF TROUGH BETWEEN 103W
AND 108W.

...DISCUSSION...

A VERY WELL PRONOUNCED SUBTROPICAL JET STREAM BRANCH IS LOCATED
BETWEEN A LARGE UPPER ANTICYCLONE CENTERED S OF THE GULF OF
TEHUANTEPEC NEAR 13N95W AND AN UPPER LEVEL TROUGH LOCATED OVER
THE N WATERS. STRONG SW WINDS WITH THE JET ARE TRANSPORTING
ABUNDANT MID TO UPPER LEVEL MOISTURE EASTWARD TOWARDS BAJA
CALIFORNIA SUR AND NORTH-CENTRAL MEXICO. A DIFFLUENT PATTERN
ALOFT IS HELPING TO INDUCE SOME CONVECTIVE ACTIVITY ALONG THE
ITCZ MAINLY BETWEEN 100W AND 110W AS DESCRIBED ABOVE UNDER
ITCZ/MONSOON TROUGH SECTION.

A SURGE OF STRONG TO NEAR GALE FORCE NW WINDS IS NOTED PER
SCATTEROMETER DATA JUST N OF THE FORECAST AREA BETWEEN 117W-123W
WHILE FRESH TO STRONG WINDS ARE BLOWING OVER THE NE WATERS N OF
27N E OF 117W. SEAS GENERATED BY THESE WINDS ARE PROPAGATING
ACROSS THE FORECAST REGION...PARTICULARLY N OF 22N E OF 120W TO
THE W COAST OF BAJA CALIFORNIA. THESE MARINE CONDITIONS WILL
PERSIST OVER THE NEXT 24-48 HOURS WITH SEAS BUILDING TO AROUND
11 FT.

HIGH PRESSURE OF 1030 MB IS CENTERED NW OF THE AREA NEAR 34N144W
WITH A RIDGE EXTENDING SOUTHEASTWARD TO NEAR THE REVILLAGIGEDO
ISLANDS. THE PRES GRADIENT BETWEEN THE RIDGE AND LOWER PRES IN
THE VICINITY OF THE ITCZ IS ALLOWING FOR FRESH TO LOCALLY STRONG
NE TO E TRADES TO EXIST FROM 08N TO 22N W OF 130W. THE RIDGE IS
FORECAST TO WEAKEN TONIGHT INTO SAT ALLOWING FOR THE TRADES TO
DIMINISH TO MOSTLY MODERATE INTENSITY.  

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 OF
CALIFORNIA DURING THAT TIME FRAME. CURRENTLY...THE FORECAST
CALLS FOR SW TO W WINDS IN THE 20 TO 30 KT RANGE AND SEAS
BUILDING TO AROUND 8 FT S OF THE FRONT TO 29.5N. MAINLY FRESH NW
WINDS ARE EXPECTED IN THE WAKE OF THE FRONT.

OTHERWISE...NW SWELL WITH SEAS OF 8-11 FT WILL CONTINUE TO
PROPAGATE SE ACROSS MUCH OF THE AREA THROUGH SAT...MERGING WITH
CROSS EQUATORIAL SOUTHERLY SWELL ACROSS THE WATERS W OF 110W
TODAY. THIS SWELL EVENT IS FORECAST TO SUBSIDE SAT NIGHT INTO
SUN. LARGE SW SWELL FROM THE SOUTHERN HEMISPHERE WILL CONTINUE
TO DOMINATE THE FORECAST WATERS E OF 110W. THE SWELL TRAIN WITH
A LEADING EDGE PERIOD OF 18-19 SECONDS IS FORECAST TO REACH THE
COASTS OF MEXICO AND CENTRAL AMERICA LATE TODAY.

$$
GR

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Page last modified: Friday, 29-Apr-2016 09:23:21 UTC