000
AXPZ20 KNHC 290336
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SAT JAN 29 2011

CORRECTED W OF 130W TO READ W OF 120W

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0315 UTC.

...ITCZ...

AXIS IS CENTERED ALONG 4N77W 3N94W 8N112W 6N130W 7N140W. 
SCATTERED MODERATE CONVECTION IS WITHIN 30 NM OF THE AXIS 
BETWEEN 108W-110W.

...DISCUSSION...

E OF 120W...A FAIRLY AMPLIFIED UPPER PATTERN REMAINS IN PLACE N 
OF 20N. AN UPPER LEVEL LOW MOVING E IS JUST W OF NORTHERN BAJA
CALIFORNIA WITH A TROUGH SW TO NEAR 22N120W. MODERATE SUBSIDENCE 
AND ASSOCIATED DRY AIR IS NOTED FROM 21N TO 27N. ELSEWHERE S OF 
THE LOW BROAD SW UPPER LEVEL FLOW DOMINATES THE AREA WITH WITH 
ABUNDANT CENTRAL PACIFIC UPPER LEVEL MOSITURE BEING ADVECTED 
NORTHEASTWARD IN THIS FLOW TO ACROSS MEXICO AND INTO THE GULF OF 
MEXICO. DIFFLUENCE ALOFT BETWEEN 105W AND 112W IS AIDING ITCZ 
CONVECTION BETWEEN 107W-110W. THE ONLY EXCEPTION TO THE MOSITURE 
IS AN AREA OF MODERATE SUBSIDENCE NOTED S OF 14N E OF 100W 
INDUCING A RATHER DRY AND STABLE ATMOSPHERIC ENVIRONMENT WITH 
ONLY SCATTERED LOW CLOUDS WITH POSSIBLE ISOLATED SHOWERS WITHIN 
THIS AREA. OVER THE FAR EASTERN PORTION...A WEAK MID LEVEL 
TROUGH EMBEDDED IN THE ZONAL FLOW IS JUST INLAND COLOMBIA. 
EARLIER CONVECTION NOTED ALONG THE COAST OF COLOMBIA HAS 
WEAKENED OVER THE PAST FEW HOURS.

W OF 120W...
A LARGE MID/UPPER CUT-OFF UPPER LEVEL LOW THAT FORMED OFF THE 
TAIL END OF A TROUGH IS W OF THE REGION NEAR 12N145W MOVING E
ABOUT 12 KT. TO ITS N...A RATHER VIGOROUS DEEP LAYER TROUGH IS 
QUICKLY MOVING E. ITS ASSOCIATED SURFACE COLD FRONT IS ABOUT 300 
NM NW OF THE AREA. MID/UPPER LEVEL RIDGING IS PRESENT TO THE E 
OF THIS TROUGH OVER THIS SECTION OF THE DISCUSSION REGION. THE 
ASSOCIATED 1026 MB SURFACE HIGH IS ANALYZED N OF THE AREA AT 
30N136W WITH A RIDGE SE TO 25N123W TO NEAR 20N110W. THE HIGH IS 
FORECAST TO MOVE A LITTLE TO THE W OVER THE NEXT 24 HOURS 
BLOCKING THE FRONT FROM ENTERING THE AREA. THE HIGH WILL THEN 
BEGIN TO WEAKEN AS IT MOVES E AFTER 24 HOURS ALLOWING THE COLD 
FRONT TO MAKE A MOVE TOWARDS THE FAR NE CORNER BY 48 HOURS. NE 
TO E TRADES OF 20 KT ARE CONFINED FROM 15N TO 20N W OF 135W AS 
THE RIDGE TO THE N INTERACTS WITH A WEAK SURFACE TROUGH JUST W 
OF THE AREA ALONG 145W. AS THE HIGH NEAR 30N136W BEGINS TO SHIFT 
EWD AFTER 24 HOURS...THE GRADIENT WILL THEN RELAX SOME. MAX SEAS 
OF 11 FT IN NW SWELL OVER THE FAR WESTERN PORTION ARE FORECAST TO
SUBSIDE TO 8 FT IN 48 HOURS. BROKEN TO SCATTERED MID AND HIGH 
LEVEL CLOUDS ARE STREAMING NNE AHEAD OF THE UPPER LEVEL LOW W OF 
THE AREA CROSSING 140W FROM 10N TO 24N REACHING EWD TO BEYOND
120W. POSSIBLE WIDELY SCATTERED SHOWERS COULD BE UNDERNEATH 
THESE CLOUDS.

GAP WINDS...
THE 00 UTC SURFACE ANALYSIS FROM TONIGHT SHOWS A WEAKER PRES
GRADIENT ACROSS SOUTHEASTERN MEXICO AS THE HIGH CENTER OVER
THE WESTERN GULF OF MEXICO HAS WEAKENED. RECENT SURFACE
OBSERVATION REPORTS FROM MEXICAN REPORTING STATION...IXTEPEC... 
JUST INLAND THE NW SIDE OF THE ISTHMUS OF TEHUANTEPEC SHOW 
N WINDS NOW DOWN TO 20 TO 25 KT...SO THE CURRENT GALE WARNING
FOR THE GULF OF TEHUANTEPEC IS SET TO EXPIRE IN ABOUT 6 HOURS.
WINDS THROUGH THE GULF THEN DECREASE TO 20 TO 25 KT...AND TO 
LESS THAN 20 KT BY SAT EVENING. SEAS UP TO 10 FT ARE FORECAST
TO SUBSIDE TO LESS THAN 8 FT BY 24 HOURS.

NE WINDS OF 20 KT THROUGH THE GULF PAPAGAYO WILL INCREASE TO
20 TO 25 KT IN ABOUT 24 HOURS...WHILE EXPANDING W TO NEAR 90W
...THEN DECREASE TO 20 KT IN 48 HOURS.


$$
AGUIRRE