000
AXPZ20 KNHC 141602
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC THU FEB 14 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0700 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
THE MONSOON TROUGH WAS ANALYZED FROM THE COLOMBIAN COAST AT 
06N77W TO ACROSS SOUTHERN PANAMA...THEN TURNS SW TO 08N88W TO 
06N108W WHERE LOW LEVEL WINDS INDICATE A TRANSITION TO AN ITCZ. 
THE ITCZ CONTINUES NW TO 08N115W TO 05N128W TO 08N136W. ISOLATED 
MODERATE CONVECTION IS CURRENTLY FLARING ALONG THE MONSOON 
TROUGH TO THE S OF PANAMA. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION IS OBSERVED WITHIN 120 NM EITHER SIDE OF A LINE FROM 
07N127W TO 10N134W.  

...DISCUSSION...
A MID TO UPPER CYCLONE IS FILLING NEAR 32N141W WITH AN UPPER 
TROUGH EXTENDING S TO BASE AT 14N141W. UPPER MOISTURE IS 
ROTATING AROUND THE CYCLONE OVER THE AREA N OF 25N BETWEEN 136W 
AND 142W. A SECOND UPPER TROUGH IS DIVING S INTO THE NORTHERN 
PORTION OF THE AREA...ROUGHLY TO THE N OF 31N BETWEEN 120W AND 
130W...AND IS ACCOMPANIED BY DRY UPPER AIR. A LONGWAVE UPPER 
TROUGH DOMINATING N AMERICA HAS ITS MEAN AXIS EXTENDING S ACROSS 
OLD MEXICO FROM 32N100W TO 20N106W TO A BASE OVER THE PACIFIC AT 
16N112W...AND IS ALSO ACCOMPANIED BY VERY DRY UPPER AIR. TO THE 
S...AND SOMEWHAT SEPARATING THESE UPPER TROUGHS...IS UPPER RIDGE 
EXTENDING N FROM AN UPPER ANTICYCLONE AT 12N112W TO A CREST AT 
31N126W. UPPER DIFFLUENCE BETWEEN THE WESTERN TROUGH AND THE 
RIDGE IS ENHANCING CONVECTION ALONG THE ITCZ AS PREVIOUSLY 
DESCRIBED. THE RESULTANT DENSE DEBRIS MOISTURE IS ADVECTED N AND 
NE WITHIN 420 NM EITHER SIDE A LINE FROM 06N134W TO 22N128W TO 
26N118W. ANOTHER UPPER ANTICYCLONE IS OVER THE TROPICS AT 15N98W 
WITH A RIDGE EXTENDING W TO A CREST AT 14N106W. THE UPPER LEVELS 
APPEAR VERY DRY S OF 20N E OF 112W.

AT THE LOW LEVELS...A RIDGE EXTENDS FROM 32N132W TO 14N102W. NE 
TRADES ARE ENHANCED TO 20 TO 25 KT S OF THE RIDGE FROM 07N TO 
16N W OF 125W...WITH SEAS OF 9 TO 12 FT IN MIXING NE AND NW 
SWELL. THIS ENHANCED AREA WILL SHRINK OVER THE NEXT COUPLE OF 
DAYS. NORTHERLY FLOW E OF THE SURFACE RIDGE IS MAINTAINING NW TO 
N WINDS AT 20 TO 25 KT ACROSS THE GULF OF CALIFORNIA TO THE S OF 
26N AND OVER THE FAR E PACIFIC WATERS N OF 17N E OF 110W. THE 
AREA OF ENHANCED WINDS WILL SHIFT N ACROSS THE CENTRAL GULF OF 
CALIFORNIA ON FRI AND ACROSS THE NORTHERN GULF ON SAT.     

GAP WINDS...
GULF OF TEHUANTEPEC...NORTHERLY WINDS BEHIND A COLD FRONT MOVING 
THROUGH THE SW GULF OF MEXICO TODAY WILL SQUEEZE THROUGH THE 
CHIVELA PASS AND BEGIN TO GENERATE FRESH TO STRONG N WINDS IN 
THE GULF OF TEHUANTEPEC AROUND SUNRISE FRI MORNING. HIGH 
PRESSURE BUILDING ACROSS THE GULF OF MEXICO FRI NIGHT WILL 
STRENGTHEN THE GAP WINDS THROUGH TEHUANTEPEC...WITH A MINIMAL 
GALE EXPECTED BY SUNRISE SAT...STRENGTHENING TO A STRONG GALE 
SAT NIGHT...AND CONTINUING THROUGH SUNRISE ON SUN. 

$$
NELSON