000
AXPZ20 KNHC 140914
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC THU APR 14 2011

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 
0645 UTC.

...ITCZ...
THE INTERTROPICAL CONVERGENCE ZONE AXIS IS ANALYZED FROM 03N97W 
TO 06N105W TO 02N111W TO 04N124W TO 01N131W. SCATTERED MODERATE 
CONVECTION IS WITHIN 120 NM S OF THE ITCZ AXIS BETWEEN 104W AND 
109W AS WELL AS WITHIN 150 NM N OF THE ITCZ AXIS BETWEEN 116W 
AND 124W AND WITHIN 180 NM S OF ITCZ AXIS BETWEEN 118W AND 123W.


...DISCUSSION...

A NORTHERN STREAM UPPER TROUGH EXTENDS FROM THE U.S. 
INTERMOUNTAIN WEST THROUGH NE MEXICO AND THE NORTHERN GULF OF 
CALIFORNIA TO 21N128W. THIS TROUGH IS ASSOCIATED WITH A COLD 
FRONT CURRENTLY MOVING THROUGH THE WESTERN CONUS. AS THIS DEEP 
LAYER TROUGH MOVES EASTWARD...LOOK FOR FRESH TO STRONG NW WINDS 
TO SWEEP SOUTHWARD THROUGH THE GULF OF CALIFORNIA LATER THIS 
MORNING AND BEGIN TO DIMINISH BY SAT MORNING. A 1030 MB 
SUBTROPICAL HIGH PRES SYSTEM NEAR 32N128W BEHIND THE FRONT WILL 
EXPAND NORTHEASTWARD AND BREAK OFF A NEW HIGH THAT WILL MOVE 
INTO CALIFORNIA TODAY WHILE THE REMAINING SUBTROPICAL HIGH WILL 
WEAKEN AND SHIFT WESTWARD JUST N OF THE AREA FRI INTO SAT 
MORNING. THE PRES GRADIENT BETWEEN THIS SUBTROPICAL RIDGING AND 
TROUGHING OVER WESTERN MEXICO AND THE U.S. INTERMOUNTAIN WEST 
HAS INCREASED THE WINDS OFF THE COAST OF BAJA CALIFORNIA TO 25 
KT. THESE WINDS ARE EXPECTED TO DECREASE TO 20 KT OVERNIGHT 
TONIGHT AS THE HIGH PRES WEAKENS AND SHIFTS W. 

FRESH TO STRONG TRADE WINDS LIE OVER MUCH OF THE CENTRAL PORTION 
OF THE FORECAST AREA W OF 120W ACCORDING TO THE 0624 UTC ASCAT 
PASS. BY FRI MORNING...THIS AREA OF TRADES WILL WEAKEN A NOTCH 
AND BEGIN TO SHIFT WESTWARD IN TANDEM WITH THE SUBTROPICAL HIGH.

AN ANTICYCLONE ALOFT LIES NEAR 26N130W NW OF THE AFOREMENTIONED 
UPPER TROUGH. DRY AIR ALOFT SEEN ON WATER VAPOR IMAGERY SUGGESTS 
SUBSIDENCE OVER THE REGION. AN AREA OF FAIR WEATHER 
STRATOCUMULUS LIES FROM 15N TO 25N W OF 114W AS WELL AS N OF 25N 
BETWEEN 117W AND 125W.

THE 0300 UTC ASCAT PASS SHOWS A SURFACE LOW LIES NEAR 05N90W. 
SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION IS WITHIN 330 
NM SE SEMICIRCLE OF THE LOW AS WELL AS FROM 02N TO 04N BETWEEN 
81W AND 85W. THIS LOW COINCIDES WITH A MAXIMUM IN LOW TO MID 
LEVEL MOSITURE ACCORDING TO PRECIPITABLE WATER SATELLITE 
IMAGERY. THE LOW ALSO LIES UNDER A REGION A DIFFLUENT LIGHT 
WINDS ALOFT...MAKING CONDITIONS FAVORABLE FOR THE DEVELOPMENT OF 
CONVECTION. 

AN ANTICYCLONE ALOFT NEAR 17N97W EXTENDS A RIDGE TO 13N113W. 
SCATTERED MODERATE TO STRONG CONVECTION LIES UNDER THIS 
ANTICYCLONE N OF 15N TO THE GULF OF TEHUANTEPEC COASTAL AREA 
BETWEEN 93W AND 95W. ELSEWHERE IN THIS REGION...WATER VAPOR 
IMAGERY SUGGESTS SUBSIDENCE ASSOCIATED WITH THE ANTICYCLONE 
EXTENDS OVER MUCH OF CENTRAL AMERICA. 

ANOTHER ANTICYCLONE ALOFT NEAR 07N132W EXTENDS A RIDGE TO 
08N120W. DIFFLUENT FLOW BETWEEN THIS RIDGE AXIS AND A CYCLONIC 
CIRCULATION TO THE SOUTHEAST CENTERED NEAR 01S106W COINCIDES 
WITH ANOTHER MAXIMUM IN PRECIPITABLE WATER ALONG THE ITCZ 
BETWEEN 115W AND 125W. CONVECTION DESCRIBED IN THE ITCZ SECTION 
ABOVE LIES IN THIS REGION. 

GAP WINDS...
GULF OF PAPAGAYO...WINDS TO 20 KT WILL CONTINUE THROUGH THE 
TODAY AND DISSIPATE BY EVENING WITH SEAS REMAINING JUST BELOW 8 
FT.

GULF OF PANAMA...THE 0300 UTC ASCAT PASS SHOWS AN AREA OF FRESH 
N WINDS IN THE GULF OF PANAMA. THESE WINDS ARE EXPECTED TO 
DIMINISH FRI MORNING. 

$$
SCHAUER