000
AXPZ20 KNHC 170924
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC MON MAY 17 2010

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. 

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.

...TROPICAL WAVES...

A WEAK TROPICAL WAVE IS ALONG 81W FROM 02N TO 10N MOVING W 
AROUND 10 KT. NO SIGNIFICANT CONVECTION. THE TOTAL PRECIPITABLE 
WATER PRODUCT SHOWS A MODEST SURGE OF MOISTENED AIR ASSOCIATED 
WITH THIS WAVE.

THE TROPICAL WAVE THAT WAS PREVIOUSLY ANALYZED ALONG 100W ON THE 
00Z SURFACE MAP IS RELOCATED ALONG 95W BASED ON LATEST SATELLITE 
IMAGERY AND THE TOTAL PRECIPITABLE WATER PRODUCT WHERE A NWD 
BULGE OF MOISTURE IS NOTED. SCATTERED MODERATE CONVECTION IS 
EITHER SIDE OF THE WAVE AXIS MAINLY S OF 9N. 

...ITCZ...

THE ITCZ AXIS IS ALONG 10N85W TO 08100W TO 10N111W THEN RESUMES 
FROM 09N116W TO 07N140W. CLUSTER OF SCATTERED MODERATE TO STRONG 
CONVECTION FROM 10N TO 11.5N BETWEEN 115W AND 118W. SCATTERED 
MODERATE TO ISOLATED STRONG CONVECTION WITHIN 130 NM N OF AXIS 
BETWEEN 121W AND 123W.

...DISCUSSION...

AN UPPER LEVEL TROUGH EXTENDS FROM 31N118W TO 21N124W THEN WWD 
TO 21N140W. ABUNDANT MID TO UPPER LEVEL MOISTURE IS NOTED BEHIND 
THE TROUGH AXIS N OF 22N WHILE VERY DRY AIR IS SEEN E OF THE 
TROUGH AXIS TO NORTHERN BAJA CALIFORNIA PENINSULA. 

AN UPPER ANTICYCLONE CENTERED NEAR 10N101W HAS A RIDGE AXIS 
EXTENDING TO THE E ALONG 09-10N ACROSS CENTRAL AMERICA AND INTO 
THE NW CARIBBEAN SEA. ANOTHER RIDGE AXIS ALSO EXTENDS TO THE W 
TO NEAR 10N132W. THIS RIDGE ALOFT COVERS THE TROPICS AND IS 
HELPING TO INDUCE CONVECTION ALONG THE ITCZ PARTICULARLY BETWEEN 
110W AND 125W. A JETSTREAM BRANCH WITH CORE WINDS OF 70-90 KT 
ENTERS THE FORECAST AREA NEAR 18N140W AND CONTINUES TO THE ENE 
TO CENTRAL MEXICO. THIS SYSTEM IS ADVECTING MID TO UPPER LEVEL 
MOISTURE FROM THE DEEP TROPICS S OF THE HAWAIIAN ISLANDS TO THE 
ENE AROUND THE NORTHERN PERIPHERY OF THE AFOREMENTIONED 
ANTICYCLONE AND RIDGE. 

AT THE SURFACE...A TROUGH...REMNANTS OF A WEAK LOW PRES... 
EXTENDS FROM 12N111W TO 6N114W. WEAK CYCLONIC TURNING IS NOTED 
IN THE CLOUD FIELD ALONG THE TROUGH AXIS NEAR 9N. CONVECTION HAS 
INCREASE AHEAD OF THE TROUGH WITH SATELLITE PICTURES SHOWING A 
CLUSTER OF SCATTERED MODERATE TO STRONG CONVECTION FROM 10N TO 
11.5N BETWEEN 115W AND 118W. THIS FEATURE WHICH IS WELL DEPICTED 
IN THE MOISTURE PRODUCT WILL CONTINUE TO MOVE WWD DURING THE 
NEXT 24-48 HOURS. 

ALSO AT THE SURFACE...A RIDGE EXTENDING W TO E ALONG 25N/26N 
DOMINATES THE N WATERS. NE TRADES OF 20 KT EXIST ON THE SOUTHERN 
PERIPHERY OF THE RIDGE FROM 09N TO 16N W OF 120W AS NOTED PER AN 
ASCAT PASS FROM 0552 UTC. THE TRADES ARE EXPECTED TO INCREASE 
AGAIN IN ABOUT 48 HOURS AS A HIGH PRES BUILDS OVER THE NW CORNER 
OF THE AREA. 

A COLD FRONT IS APPROACHING THE FAR NW PORTION OF THE DISCUSSION 
AREA. THIS FRONT WILL SKIRT ACROSS THE NORTHERN WATERS N OF 29N 
DURING THE NEXT 48 HOURS EVENTUALLY DISSIPATING BY LATE TUE AS 
IT NEARS BAJA CALIFORNIA. A TIGHT PRES GRADIENT NEAR THE FRONTAL 
REMNANTS WILL PRODUCE NW WINDS AT 20 KT ALONG THE W BAJA 
CALIFORNIA COAST BY 42 HOURS AND BEYOND.

NE SWELL GENERATED BY THE TRADES IS MIXING WITH CROSS EQUATORIAL 
SW SWELL WITH COMBINED SEAS BETWEEN 8-10 FT. ADDITIONAL PULSES 
OF SW SWELL WILL CONTINUE TO PROPAGATE ACROSS THE REGIONAL 
WATERS DURING THE NEXT 24-48 HOURS.  

$$
GR