000
AXPZ20 KNHC 150945
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC FRI APR 15 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 
0900 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE AXIS WAS ANALYZED FROM 03N78W 
TO LOW PRES NEAR 05N91W TO LOW PRES NEAR 04N117W TO 02N129W. 
SCATTERED MODERATE TO STRONG CONVECTION WAS WITHIN 180 NM OF THE 
FIRST LOW. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION WAS 
WITHIN 90 NM OF THE SECOND LOW AND ALSO WITHIN 90 NM EITHER SIDE 
OF THE AXIS BETWEEN 120W AND 125W.

...DISCUSSION...

AN UPPER LEVEL ANTICYCLONE IS CENTERED OVER THE NORTHERN WATERS 
NEAR 24N123W WITH VERY DRY AIR UNDER SUBSIDENCE INDICATED BY 
WATER VAPOR IMAGERY ACROSS THE MAJORITY OF THE AREA N OF 20N. 
THE EXCEPTION IS IN THE E PORTION WHERE A MID TO UPPER SHORTWAVE 
TROUGH REACHES FROM THE SOUTHERN BAJA CALIFORNIA PENINSULA SE 
THROUGH 17N110W TO 08N107W. A 30 TO 45 KT JET IS ADVECTING MID 
LEVEL MOISTURE FROM ACROSS THE SOUTHERN BAJA AND INTO CENTRAL 
MEXICO. 

A PAIR OF UPPER LEVEL ANTICYCLONES RESIDE ON EITHER SIDE OF THE 
TROUGH. THE EASTERN ANTICYCLONE IS POSITIONED OVER 08N90W WITH 
VERY DRY AIR NOTED N OF 08N E OF 107W WHILE CONVECTION IS BEING 
ENHANCED OVER THE SOUTHERN PERIPHERY OF THE ANTICYCLONE ALONG 
THE ITCZ AS DESCRIBED ABOVE. THE WESTERN ANTICYCLONE LIES OVER 
08N125W WITH CLUSTERS OF CONVECTION EXISTING ALONG THE ITCZ S OF 
UPPER RIDGING ALONG 08N W OF THE TROUGH AXIS.

AT THE SURFACE...A 1010 MB AREA OF LOW PRES IS EMBEDDED WITHIN 
THE ITCZ NEAR 05N91W. THE CLOUD FIELD SHOWS SOME CYCLONIC 
TURNING AND EARLIER ASCAT PASSES INDICATED A BROAD CYCLONIC 
CIRCULATION. CONVECTION ASSOCIATED WITH THIS LOW IS AS DESCRIBED 
IN THE ITCZ SECTION ABOVE. COMPUTER MODELS SHOW THIS SYSTEM 
PERSISTING OVER THIS REGION WHILE NOT MOVING MUCH DURING THE 
NEXT SEVERAL DAYS. A WEAKER 1011 MB AREA OF LOW PRES IS NEAR 
04N117W WITH CONVECTION AS DESCRIBED IN THE ITCZ SECTION ABOVE. 
A TROUGH IS JUST N OF THIS LOW EXTENDING FROM 12N118W TO 
07N115W. SCATTERED MODERATE CONVECTION WAS WITHIN 90 NM OF THE 
TROUGH.

MEANWHILE 1031 MB HIGH PRES IS CENTERED NEAR 32N129W WITH 
RIDGING EXTENDING SE TO 15N110W. FRESH TRADES ARE BEING ENHANCED 
W OF THE LOW AND TROUGH OVER THE W CENTRAL WATERS ALONG WITH 8 
TO 11 FT SEAS IN MIXED NW AND FRESHER NE SWELLS. N TO NE 20 KT 
WINDS ALSO EXIST W OF THE BAJA CALIFORNIA PENINSULA AS CAPTURED 
BY A RECENT 0426 UTC ASCAT PASS. THE AREA OF 20 KT WINDS WILL 
SHRINK DURING THE NEXT 24 HOURS AS THE HIGH WEAKENS TO 1026 MB 
AND RETREATS MORE TO THE W. TRADES WILL WEAKEN TO LESS THAN 20 
KT BY SUN NIGHT WHILE SEAS DECAY TO 9 FT OR LESS WITH HIGH PRES 
CONTINUING TO WEAKEN TO 1024 MB BY 48 HOURS.

ELSEWHERE...20 TO 25 KT NW TO N WINDS ARE EXPECTED IN THE GULF 
OF CALIFORNIA WITH 20 KT WINDS SPILLING OUT TO THE S ALONG THE 
MEXICAN COAST N OF 18N E OF 108W...DUE TO A TIGHT PRES GRADIENT 
BETWEEN THE ABOVE MENTIONED RIDGING W OF THE BAJA CALIFORNIA 
PENINSULA AND TROUGHING LOCATED OVER MEXICO JUST E OF THE GULF 
OF CALIFORNIA. THE PRES GRADIENT WILL WEAKEN THROUGH TONIGHT AS 
THE HIGH RETREATS W AND TROUGHING BECOMES CENTERED OVER THE GULF 
OF CALIFORNIA WITH WINDS DIMINISHING TO LESS THAN 20 KT BY SUN 
MORNING.

GAP WINDS...
GULF OF PANAMA...NLY WINDS TO 20 KT ARE BLOWING THROUGH THE GULF 
OF PANAMA. HOWEVER...THE PRES GRADIENT IS EXPECTED TO RELAX AND 
THE WINDS WILL DIMINISH TO LESS THAN 20 KT BY THE EARLY 
AFTERNOON.

$$
LEWITSKY