000
AXPZ20 KNHC 252155
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC WED MAY 25 2011

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2045 UTC.
 
...ITCZ...
THE INTERTROPICAL CONVERGENCE ZONE IS FROM 06N77W TO 06N82W TO 
12N96W TO 07N120W TO 05N140W. SCATTERED MODERATE CONVECTION IS 
FROM 05N TO 10N BETWEEN 79W AND 90W...AND FROM 06N TO 12N 
BETWEEN 95W AND 103W. SCATTERED MODERATE TO ISOLATED STRONG 
CONVECTION IS FROM 08N TO 13N BETWEEN 105W AND 111W.

...DISCUSSION...
THE SUBTROPICAL RIDGE IS CURRENTLY BEING COMPROMISED BY A 
RAPIDLY WEAKENING COLD FRONT. HOWEVER...THE PRESSURE GRADIENT 
BETWEEN THE SUBTROPICAL RIDGE AND TROUGHING OVER THE 
SOUTHWESTERN UNITED STATES AND CENTRAL MEXICO IS STILL STRONG 
ENOUGH TO SUPPORT FRESH NW WINDS WITHIN 180 NM OF THE W COAST OF 
BAJA CALIFORNIA. THE AREA OF FRESH NW WINDS WILL EXPAND WESTWARD 
BY THU AS THE PRES GRADIENT BETWEEN THE RIDGE AND TROUGHING OVER 
THE INTERIOR WESTERN UNITED STATES BUILDS. WINDS ARE EXPECTED TO 
BECOME STRONG OFF THE BAJA CALIFORNIA NORTE COAST BY EARLY FRI 
MORNING. 

FRESH TRADE WINDS LIE OVER CENTRAL WATERS W OF 130W. THE AREA OF 
FRESH TRADES WILL EXPAND NORTHEASTWARD AS THE SUBTROPICAL HIGH W 
OF THE AFOREMENTIONED DISSIPATING COLD FRONT MOVES EASTWARD. 
THIS FRONT WILL BRING A BATCH OF NW SWELL WITH SEAS TO 9 FT INTO 
THE NW PORTION OF THE FORECAST AREA BEGINNING THU MORNING...BUT 
WINDS WILL REMAIN BELOW ADVISORY CRITERIA. CURRENTLY...A 40-50 
KT SOUTHWESTERLY UPPER JET LIES OVER THE REGION OF TRADE WINDS 
AND IS TRANSPORTING UPPER MOSITURE MANIFESTED AS CIRRUS CLOUDS 
THAT OVERLAY THE DENSE STRATOCUMULUS THAT EXTENDS OVER MUCH OF 
THE AREA N OF 15N W OF 115W.

CONVECTION ALONG THE ITCZ IS STRONGEST W OF THE 1010 MB EMBEDDED 
LOW PRES SYSTEM NEAR 12N97W. NORTHEASTERLY SHEAR ALOFT IS 
FORCING THE CONVECTION DOWNWIND OF THE LOW LEVEL CENTER. THE LOW 
IS EXPECTED TO DISSIPATE TO A TROUGH BY THU MORNING.

CROSS-EQUATORIAL S SWELL WITH SEAS TO 8 FT ARE OVER S CENTRAL 
WATERS S OF 7N W OF 95W. THIS SWELL WILL MAKE ITS WAY NORTHWARD 
TO 12N BY FRI.

AN UPPER LEVEL LOW IS CENTERED NEAR 20N127W. DIFFLUENCE E OF THE 
CENTER IS PRODUCING SCATTERED SHOWERS FROM 17N-24N BETWEEN 
125W-135W.

$$
FORMOSA