000
AXPZ20 KNHC 122151
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC FRI NOV 12 2010

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

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE AXIS IS ANALYZED FROM 09N83W 
TO LOW PRES NEAR 08N87W TO 11N105W TO 11N120W TO 09N138W. 
SCATTERED MODERATE CONVECTION IS NOTED WITHIN 120 NM OF THE AXIS 
BETWEEN 111W AND 120W AND ALSO WITHIN 60 NM OF THE AXIS BETWEEN 
134W AND 138W.

...DISCUSSION...

AN UPPER LEVEL TROUGH EXTENDS FROM THE U.S. GREAT PLAINS REGION 
TO FAR NW MEXICO NEAR 32N114W TO A DEVELOPING CYCLONIC VORTEX 
NEAR 22N138W. DRY AND STABLE AIR UNDER MODERATE TO STRONG 
SUBSIDENCE IS EVIDENT ACROSS THE AREA N OF 20N. AN ELONGATED 
UPPER RIDGE AXIS EXTENDS FROM AN ANTICYCLONE IN THE SW CARIBBEAN 
SEA NEAR 13N82W THROUGH 13N106W TO 15N128W. A WIDE SWATH OF 
ABUNDANT TROPICAL MOISTURE IS BEING DRAWN UP FROM THE ITCZ 
AROUND THE W AND N PERIPHERY OF THE RIDGE AND ACROSS CENTRAL 
MEXICO WITH CONVECTION BEING ENHANCED ALONG THE ITCZ BETWEEN 
104W AND 130W DUE TO MODERATE DIVERGENT FLOW ALOFT.

AT THE SURFACE...STRONG 1039 MB HIGH PRES IS CENTERED WELL N OF 
THE AREA NEAR 43N138W WITH A RIDGE AXIS EXTENDING INTO THE AREA 
NEAR 32N135W AND CONTINUING SE TO NEAR 20N116W. FRESH TO STRONG 
TRADES EXIST N OF 11N AND W OF 125W WITH RESULTANT SEAS OF 8 TO 
11 FT. THESE TRADES WILL PERSIST THROUGH AT LEAST 48 HOURS.

WEAK 1012 MB LOW PRES IS POSITIONED NEAR 08N87W AND IS NEARLY 
STATIONARY. A 1500 UTC ASCAT PASS INDICATED WINDS OF 10 TO 15 KT 
IN THE VICINITY OF THE LOW WITH SATELLITE IMAGERY SHOWING 
SCATTERED MODERATE CONVECTION WITHIN 120 NM OF THE LOW CENTER IN 
THE W QUADRANT. THIS LOW IS EXPECTED TO DISSIPATE THIS WEEKEND. 
A TROUGH EXTENDS FROM NEAR 08N108W TO 14N105W WITH SCATTERED 
MODERATE CONVECTION WITHIN 90 NM E OF THE TROUGH AXIS. MODEL 
GUIDANCE DEVELOPS A LOW ALONG THIS TROUGH BY 24 THROUGH 48 HOURS 
WITH WINDS TO 20 KT IN THE E SEMICIRCLE AND SEAS TO 9 FT. NO 
TROPICAL DEVELOPMENT OF THIS FEATURE IS ANTICIPATED DURING THE
NEXT 48 HOURS.

SOUTHERLY FLOW IS LIKELY TO INCREASE TO 20 KT IN THE FAR SE 
PORTION OF THE AREA ROUGHLY FROM 03N TO 07N BETWEEN 80W AND 86W 
FROM 24 THROUGH 48 HOURS AS LOW PRES ATTEMPTS TO DEVELOP N OF 
THE ISTHMUS OF PANAMA IN THE FAR SW CARIBBEAN SEA.

NW SWELL WITH PEAK WAVE PERIODS OF 16 TO 17 SECONDS CONTINUES TO 
DOMINATE THE MAJORITY OF THE WATERS W OF 110W. THIS SWELL IS 
COMMINGLING WITH SHORTER PERIOD NE SEAS GENERATED BY THE ABOVE 
MENTIONED TRADES. A NEW SET OF N TO NE SWELL GENERATED BY STRONG 
NORTHERLY WINDS OFF OF THE U.S. CALIFORNIA COAST WILL PROPAGATE 
DOWN INTO THE NORTH CENTRAL PORTION OF THE DISCUSSION AREA WITH 
SEAS BUILDING TO 14 FT BY 48 HOURS.

GULF OF CALIFORNIA...
A TIGHT PRES GRADIENT REMAINS OVER THE GULF OF CALIFORNIA REGION 
BETWEEN A RIDGE W OF THE BAJA CALIFORNIA PENINSULA AND TROUGHING 
JUST INLAND OF THE E PORTION OF THE GULF OF CALIFORNIA. AN 
EARLIER ASCAT PASS CAPTURED 25 KT NW TO N WINDS IN THE NORTHERN 
PORTION OF THE GULF WHILE AN EARLIER JASON ALTIMETER PASS 
INDICATED SEAS APPROACHING 8 FT. THESE WINDS WILL SPREAD S TO N 
OF 25N IN 12 HOURS THEN WILL GRADUALLY DIMINISH TO LESS THAN 20 
KT THROUGHOUT THE GULF BY 48 HOURS.

GAP WINDS...
EARLIER WINDSAT AND ASCAT PASSES INDICATED NORTHERLY WINDS OF 
ONLY 15 KT IN THE GULF OF TEHUANTEPEC HOWEVER MORE RECENT LAND 
BASED OBSERVATIONS AT IXTEPEC IN THE STATE OF OAXACA MEXICO 
REPORT THAT WINDS HAVE SINCE INCREASED TO 20 TO 25 KT AND EXPECT 
THESE WINDS TO BE SURGING INTO A SMALL PORTION OF THE GULF OF 
TEHUANTEPEC DOWNWIND TO 15N95W WHICH AGREES WITH THE OPERATIONAL 
GFS AND ECMWF HI-RES SOLUTIONS. THESE WINDS WILL DIMINISH TO 
LESS THAN 20 KT BY 24 HOURS.

$$
LEWITSKY