000
AXPZ20 KNHC 280331
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SAT JAN 28 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 ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0245 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
MONSOON TROUGH EXTENDS FROM LOW PRES NEAR 07N74W 1007 MB TO 
03N79W TO 05N90W...WHERE IT TRANSITIONS TO ITCZ AXIS... 
CONTINUING ON TO 08N116W TO 06N123W TO BEYOND 06N140W.  
SCATTERED MODERATE ISOLATED STRONG CONVECTION WITHIN 90 NM S AND 
180 NM N OF AXIS BETWEEN 100W AND 115W. SCATTERED MODERATE 
ISOLATED STRONG CONVECTION NOTED FROM 10N TO 13.5N BETWEEN 102W 
AND 115W. SCATTERED MODERATE CONVECTION NOTED WITHIN 240 NM N OF 
AXIS BETWEEN 122W AND 129W.

...DISCUSSION...
A MIDDLE TO UPPER LEVEL ELONGATED CYCLONIC CIRCULATION ALONG THE 
WESTERN BOUNDARY OF THE AREA CONTINUES TO OPEN UP INTO A SHARP 
TROUGH...EXTENDING FROM 21N144W SE TO A BROAD AND FLAT BASE NEAR 
05N131W...WHERE A TROPICAL WLY JET TO 85 KT CAN BE FOUND. UPPER 
LEVEL RIDGING HAS EVOLVED E OF THIS FEATURE IN THE PAST FEW 
DAYS...AIDED BY PERSISTENT DEEP CONVECTION OCCURRING N OF THE 
ITCZ. A WEAK UPPER ANTICYCLONE HAS DEVELOPED DUE TO THIS 
CONVECTION...NEAR 09N113W...EXTENDING NW TO 25N129W. JUST N OF 
THIS LOCATION...A WELL PRONOUNCED UPPER RIDGE CONTINUES TO 
SHARPEN AND SHIFT E...CENTERED ON AN ANTICYCLONE NOW NEAR 
32N132W...EXTENDING N-NW WELL BEYOND 45N138W. TO THE W OF 
THIS...THREE SEPARATE MIDDLE TO UPPER LEVEL TROUGHS ARE COMING 
INTO PHASE BETWEEN 145W AND 160W...AND ACTING TO PUT A SQUEEZE 
ON THE AFOREMENTIONED UPPER RIDGE...AS WELL AS THE UPPER TROUGH 
ALONG 140W. THE NORTHERN STREAM PORTION OF THE UPPER TROUGH TO 
THE W WILL CONTINUE E AND INTO THE W COAST OF N AMERICA OVER THE 
WEEKEND...AND FLATTEN THE RIDGE CURRENTLY TO ITS E. THE SOUTHERN 
STREAM PORTION IS FORECAST TO DIG SE OF THE BIG ISLAND OF HAWAII 
AND EVOLVE INTO A CUT OFF LOW W OF 140W OVER THE WEEKEND. THIS 
WILL KICK THE WEAKENING TROUGH PRESENTLY ALONG 140W TOWARD THE 
E...AND CONTINUE TO PROVIDE UPPER SUPPORT FOR ACTIVE CONVECTION 
FROM THE ITCZ TO 15N AND E OF 120W...WHERE VERY WARM SST'S 
PERSIST.

A SURFACE HIGH PRES RIDGE COVERS THE AREA N OF 18N W OF 119W. NE 
TO E WINDS NEAR 20 KT ARE OBSERVED ALONG THE SOUTHERN PERIPHERY 
OF THE THE RIDGE FROM 08N TO 15N W OF 127W...WHILE NE TO E WINDS 
20-25 KT ARE FOUND N OF 24N BETWEEN 126W AND 134W...BECOMING SE 
WINDS W OF 134W. SEAS ACROSS AREA ARE RUNNING 9 TO 11 FT IN 
MIXED NE AND NW SWELL. N TO NE WINDS OF 20-25 KT PREVAILED N OF 
27N BETWEEN 118W AND 126W. OTHERWISE MODERATE TO LARGE NWLY 
SWELLS DOMINATE MUCH OF THE AREA WATERS N OF 15N W OF 115W 
YIELDING SEAS 8 FT AND GREATER.

A STRONG COLD FRONT HAS STALLED ACROSS THE SE GULF OF MEXICO 
THIS EVENING...WITH HIGH PRES BEHIND THE FRONT PRODUCING A TIGHT 
PRES GRADIENT OVER SOUTHERN MEXICO. THIS RESULTED IN GALE FORCE 
WINDS THROUGH THE GULF OF TEHUANTEPEC SINCE LAST NIGHT...BUT 
WINDS HAVE SINCE DIMINISHED TO JUST BELOW GALE FORCE...AND WILL 
GRADUALLY DIMINISH TO LESS THAN 20 KT SAT AFTERNOON. ANOTHER 
GULF OF MEXICO COLD FRONT WILL LEAD TO ANOTHER GALE EVENT ACROSS 
THE GULF OF TEHAUNTEPEC BY EARLY SUN MORNING.

ELY GAP WINDS TO 20 KT CONTINUE TO BLOW ACROSS NICARAGUA AND 
THROUGH THE GULF OF PAPAGAYO THIS EVENING...AND ARE EXPECTED TO 
PERSIST THROUGH THE WEEKEND.

$$
STRIPLING