000
AXPZ20 KNHC 231004
TWDEP 

TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL                        
0405 UTC SAT MAR 23 2013

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 
0945 UTC.

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

MONSOON TROUGH AXIS IS NOT PRESENTLY IDENTIFIABLE. THE ITCZ AXIS 
EXTENDS FROM 04N102W TO 05N110W TO 04N124W TO 01N140W. SCATTERED 
MODERATE TO STRONG CONVECTION IS WITHIN 120 NM N OF THE ITCZ 
AXIS BETWEEN 124W AND 127W. SCATTERED MODERATE/ISOLATED STRONG 
CONVECTION EXISTS WITHIN 45 NM OF LINE FROM 03N83W TO 05N86W.

...DISCUSSION... 

ALOFT...A LONGWAVE TROUGH EXTENDS FROM THE CENTRAL U.S. SSW TO 
THE NRN BAJA CALIFORNIA...AND CONTINUES SW TO AN UPPER LOW 
MOVING SE AT 21N130W. A TROUGH EXTENDS FROM THE LOW SSE TO S OF 
THE EQUATOR AT 126W. HIGHLY AMPLIFIED RIDGING COVERS THE FAR 
WESTERN PORTION OF THE AREA. ATMOSPHERIC MOISTURE REMAINS VERY 
LIMITED AS ABUNDANT DEEP MOISTURE W OF THE AREA OVER THE CENTRAL 
PACIFIC IS SHUNTED NEWD ON THE BACK SIDE OF THE RIDGE TO WELL N 
OF THE REGION. SATELLITE WATER IMAGERY SHOWS STRONG SUBSIDENCE 
PREVAILING OVER JUST ABOUT THE ENTIRE DISCUSSION AREA...WITH THE 
EXCEPTION OF THE BASE OF THE LONGWAVE TROUGH WHERE SLIGHT 
DIFFLUENCE THERE IS AIDING CONVECTION DESCRIBED ABOVE UNDER 
ITCZ. THE UPPER LOW WILL CONTINUE SE THROUGH TONIGHT...THEN BE 
FORCED ENE TOWARD CENTRAL BAJA CALIFORNIA SUN AND SUN NIGHT AS 
THE RIDGE OVER THE WESTERN PORTION SHIFTS EWD IN REACTION TO A 
MORE VIGOROUS UPPER LOW CURRENTLY WELL W OF THE AREA N OF THE 
HAWAIIAN ISLANDS THAT TRACKS NEWD. 

BROAD SCALE RIDGING COVERS JUST ABOUT THE ENTIRE SE PORTION OF 
THE AREA WITH AN ASSOCIATED ANTICYCONE AT 01N96.5W. ONLY 
CONVECTION NOTED OVER THIS PORTION OF THE AREA IS OF THE 
SCATTERED MODERATE/ISOLATED STRONG INTENSITY WITHIN 30 NM OF 
04N84W.
 
AT THE SURFACE...A 1032 MB HIGH CENTER WELL N OF THE AREA AT 
42N130W EXTENDS A RIDGE SSW THROUGH 32N138W...AND TO SW OF THE 
AREA JUST E OF THE HAWAIIAN ISLANDS. HIGH PRES COVERS THE 
AREA N OF 18N AND W OF ABOUT 117W. THE TIGHT PRES GRADIENT 
NOTED THE PAST 2-3 DAYS OVER THE FAR NE WATERS HAS WEAKEN
SINCE YESTERDAY...AND WINDS THERE ARE NORTHERLY AT 20 KT OR 
LESS. SEAS ARE 8-10 FT IN A NW SWELL NW OF A LINE FROM 30N117W 
TO 24N130W TO 16N140W...AND HIGHER SEAS OF 9-13 FT IN A NW TO N 
SWELL ARE N OF 28N BETWEEN 120W-129W. THESE SWELLS ARE FORECAST 
BY WAVEWATCH MODEL GUIDANCES TO GRADUALLY SUBSIDE TO 9 FT BY 48 
HRS...AND GENERALLY BE LOCATED N OF 19N W OF 117W.

CROSS EQUATORIAL SW SWELLS WITH PERIODS IN THE RANGE OF 15-18 
SECONDS ARE ALREADY IMPACTING THE COAST OF CENTRAL 
AMERICA...MAINLAND MEXICO AND MUCH OF THE COAST OF BAJA 
CALIFORNIA. THE WAVEWATCH AND SWELL GUIDANCES SUGGEST THAT THESE 
SWELLS AND RESULTANT SEAS WILL SUBSIDE SUN THROUGH MON.
 
GAP WINDS...THE NEXT GAP WIND EVENT IS EXPECTED TO TAKE PLACE 
THOUGH THE GULF OF TEHUANTEPEC BEGINNING LATE MON NIGHT INTO TUE 
WITH POSSIBLE MINIMAL GALE FORCE WINDS. GLOBAL MODELS INDICATE 
THAT THESE WINDS MAY LAST INTO THU.

$$
AGUIRRE