000
AXPZ20 KNHC 260937
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC THU APR 26 2012

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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
MONSOON TROUGH FROM 05N76W TO 02N84W. ITCZ FROM 06N88W TO 05N99W 
TO LOW PRES NEAR 05N110W 1012 MB TO 02.5N127W TO BEYOND 03N140W. 
SCATTERED MODERATE TO STRONG CONVECTION NOTED WITHIN 60 NM S OF 
MONSOON TROUGH E OF 81W. SCATTERED MODERATE TO STRONG CONVECTION 
NOTED WITHIN 120 NM EITHER SIDE OF ITCZ BETWEEN 89W AND 113W.

...DISCUSSION...
DEEP LAYER CYCLONE JUST N OF AREA NEAR 32N120W...WITH 1009 MB 
SURFACE LOW...IS EMBEDDED IN BROAD UPPER LEVEL TROUGH EXTENDING 
SW TO NEAR 14N136W...AND TRAILS A SURFACE COLD FRONT THROUGH 
30N117.5W TO AROUND 18N127W. ABUNDANT MID-UPPER LEVEL MOISTURE 
PLUME E OF THE TROUGH AXIS IS SPREADING DEEP LAYER MOISTURE OVER 
S HALF OF BAJA CALIF AND NW MEXICO. LOW PRES AND TROUGH TO MOVE 
E AND INLAND TODAY AND GRADUALLY DRAG FRONTAL BOUNDARY NE ACROSS 
N PORTIONS OF BAJA CALIFORNIA AND INTO NW MEXICO BEFORE 
DISSIPATING OVER NW MEXICO FRI NIGHT. SHALLOW CONVECTION IS 
LIKELY TO OCCUR ALONG FRONT AS IT MOVES E ACROSS N HALF OF BAJA 
CALIFORNIA TODAY. UPPER LEVEL RIDGE PERSISTS E OF THIS 
TROUGH...EXTENDING FROM NEAR 08N112W NE BEYOND 30N103W. 
MIDDLE-UPPER TROUGH FROM SE GULF OF MEXICO TO DIGGING MID LEVEL 
LOW OVER GULF OF TEHUANTEPEC SPREADING SUBSIDENCE SWD ACROSS SE 
MEXICO AND INTO ADJACENT PORTIONS OF TROPICAL EPAC. TO THE 
E...UPPER RIDGE CENTERED OVER NRN S AMERICA YIELDING SWLY JET 
ALOFT ACROSS CENTRAL AMERICA E OF 90W. VERY ACTIVE CONVECTION 
ALONG ITCZ AND WARM SST'S AIDING IN MAINTAINING A NARROW 
TROPICAL RIDGE OVER ITCZ ALONG 06N-08N E OF 120W.

SEVERAL RECENT OBSERVATIONS BY SHIPS "ZCDD6" AND "A8IF5" VERIFY 
COMPUTER MODEL GUIDANCE...WHERE W TO NW WINDS 20 TO 25 KT 
PREVAIL N OF 28N W OF THE COLD FRONT TO 125W. THESE WINDS WILL 
SHIFT E INTO BAJA CALIFORNIA NORTE TODAY. HIGH PRES BEHIND THE 
FRONT WILL INDUCE A STRONG PRES GRADIENT ALONG THE W COAST OF 
THE ENTIRE BAJA PENINSULA TO PRODUCE NWLY WINDS 20 KT WITHIN 150 
NM OF THE W COAST BY TONIGHT AND CONTINUE THROUGH FRI NIGHT. AT 
THE SAME TIME...NWLY WINDS WILL INCREASE TO 20 KT INSIDE THE 
GULF OF CALIFORNIA S OF 26N AND PERSIST THROUGH FRI AFTERNOON. 
STRONG HIGH PRES...AROUND 1032 MB...WILL RESIDE JUST NW OF THE 
AREA FRI AND SAT...AND ALSO BEGIN TO STRENGTHEN THE PRES 
GRADIENT TO ITS S AND ACT TO GREATLY ENHANCE THE NE TRADEWIND 
FLOW. NELY TRADEWINDS 20-25 KT ARE EXPECTED TO EXPAND FROM 05N 
TO 17N W OF 120W BY LATE TONIGHT AND THEN FROM FROM 05N TO 23N W 
OF 130W BY FRI NIGHT...WITH SEAS REMAINING 8-9 FT IN MIXED NW 
SWELL. 
LIGHT TO MODERATE WINDS CONTINUE ACROSS THE AREA E OF 110W WITH 
WEAKENING GAP WIND FLOW DESCRIBED BELOW. WEAK SWLY MONSOON FLOW 
HAS BEEN PULSING ON AND OFF FOR THE PAST SEVERAL DAYS...AND IS 
FORECAST TO BECOME WELL ESTABLISHED S OF 06N E OF 125W BY SAT.

GAP WINDS...
AN 0550 UTC OSCAT SCATTEROMETER PASS SHOWED NLY WINDS 20-25 KT 
FUNNELING THROUGH THE CHIVELA PASS INTO GULF OF TEHUANTEPEC S TO 
NEAR 14N. SELY FLOW DEVELOPING ACROSS THE SW GULF OF MEXICO WILL 
END THE NLY SUPPORT FOR THIS GAP WIND FLOW TODAY...AND WINDS AND 
SEAS WILL DIMINISH BELOW 20 KT AND 8 FT BY AFTERNOON.

THIS SAME OSCAT SCATTEROMETER PASS SHOWED A SMALL PLUME OF FRESH 
TO STRONG NE WINDS IN THE GULF OF PAPAGAYO...AND SIMILAR NLY  
WINDS IN THE GULF OF PANAMA. WEAKENING INFLUENCE OF HIGH PRES 
ACROSS THE W CARIBBEAN THIS AFTERNOON AND EVENING IS EXPECTED TO 
DIMINISH WINDS TO LESS THAN 20 KT ACROSS BOTH OF THESE AREAS 
BEFORE SUNSET TODAY.

$$
STRIPLING