000
AXPZ20 KNHC 202140
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC THU OCT 20 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 
2100 UTC.

...ITCZ/MONSOON TROUGH...

MONSOON TROUGH EXTENDS FROM 13N90W TO 1013 MB LOW NEAR 13N103W 
TO 13N111W TO 08N122W THEN AS ITCZ AXIS FROM 07N121W TO 09N140W.
SCATTERED MODERATE CONVECTION WITHIN 90 NM N OF TROUGH BETWEEN 
100W AND 106W.

...DISCUSSION...

TEHUANTEPEC GAP WIND EVENT IS ONGOING...BUT LACK OF IN-SITU OVER
WATER OBSERVATIONS MAKE IT DIFFICULT TO DETERMINE IF GALE FORCE 
WINDS ARE PRESENT. LATEST GFS MODEL FORECAST INDICATES GALES ARE 
NO LONGER PRESENT...SO BASED ON EXPECTED CONDITIONS...WILL LET 
THE GALE WARNING EXPIRE WHILE MAINTAINING 20-30 KT WINDS FOR 3 
OR 4 MORE DAYS. FORCING SHOULD DIMINISH SLIGHTLY AS THE SURFACE 
HIGH ALONG THE MEXICAN GULF OF MEXICO COAST MOVES E AND WEAKENS. 
REINFORCING COLD AIR ADVECTION ACROSS THE GULF OF MEXICO AND THE 
CHIVELA PASS SATURDAY WILL CONTINUE THE N WINDS IN THE GULF OF 
TEHUANTEPEC THROUGH THE WEEKEND...POSSIBLY BACK UP TO GALE FORCE 
BY MONDAY. SIGNIFICANT WAVE HEIGHTS AROUND 12 FEET TODAY WILL 
DIMINISH TO 9 FEET BY FRIDAY.

WEAK 1013 MB LOW EMBEDDED WITHIN THE MONSOON TROUGH NEAR 13N103W 
IS EVIDENT FROM ANIMATED SAT IMAGERY AND SCATTEROMETER. MODERATE 
VERTICAL SHEAR ALONG WITH A LACK OF SIGNIFICANT DEEP CONVECTION 
SUGGEST DEVELOPMENT INTO A TROPICAL CYCLONE IS NOT LIKELY IN THE 
SHORT-TERM. ALL OF THE GLOBAL MODELS MAINTAIN A VERY WEAK BROAD 
LOW NEAR 15N113W WITHIN THE MONSOON TROUGH.

NO SIGNIFICANT COLD FRONT INCURSIONS ARE EXPECTED INTO THE NW 
PORTION THROUGH TUESDAY. LONG-PERIOD SWELL WITH WAVE HEIGHTS OF 
8-10 FEET SHOULD BEGIN REACHING NW PORTION BY MONDAY MORNING.

$$
MUNDELL