000
AXPZ20 KNHC 061001
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC FRI NOV 06 2009

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

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0845 UTC.

...TROPICAL LOWS...

LOW PRES IS NEARLY STATIONARY NEAR 11N92W ESTIMATED AT 1008 MB. 
THE SYSTEM IS ENCOUNTERING SOUTHWESTERLY WIND SHEAR. CONVECTION 
HAS DIMINISHED WITH THE SYSTEM OVER THE LAST FEW HOURS. 
CURRENTLY...SCATTERED MODERATE CONVECTION CAN ONLY BE FOUND 
WITHIN 90 NM N QUADRANT.

1010 MB LOW PRES IS NEAR 13N114W. SCATTERED MODERATE ISOLATED 
STRONG CONVECTION LIES WITHIN 180 NM W QUADRANT AND SCATTERED 
MODERATE CONVECTION CAN BE FOUND ELSEWHERE WITHIN 120 NM N AND 
60 NM S SEMICIRCLE OF THE LOW. THIS LOW PRES SYSTEM CURRENTLY 
LIES UNDER AN UPPER LEVEL ANTICYCLONE WHICH IS PROVIDING A 
DIFFLUENT UPPER ENVIRONMENT TO SUPPORT CONVECTION. OVER THE NEXT 
24-48 HOURS...THE LOW WILL ENCOUNTER 30-40 KT WESTERLY UPPER 
LEVEL FLOW THAT WILL INHIBIT DEVELOPMENT.

...ITCZ...

THE ITCZ AXIS EXTENDS ALONG 12N86W TO 08N110W TO 12N115W TO 
09N125W TO 08N140W. SCATTERED MODERATE CONVECTION LIES WITHIN 75 
NM EITHER SIDE OF THE ITCZ AXIS BETWEEN 99W AND 108W.

...DISCUSSION...

N OF 20N...
AN UPPER LEVEL ANTICYCLONE IS CENTERED NEAR 12N112W WITH A RIDGE 
AXIS EXTENDING N ACROSS THE SOUTHERN TIP OF BAJA CALIFORNIA TO 
THE AZ/NM BORDER WITH OLD MEXICO. AN UPPER LOW NEAR 30N121W IS 
APPROACHING THIS RIDGE FROM THE W. SATELLITE PRECIPITABLE WATER 
IMAGERY SHOWS A THINNING MOISTURE PLUM EXTENDING FROM THE ITCZ 
NEAR 140W NORTHEASTWARD INTO SOUTHERN CALIFORNIA WITH SCATTERED 
MODERATE CONVECTION FOUND WITHIN 75 NM OF LINE FROM 30N118W TO 
26N119W. THIS TROUGH IS EXPECTED TO QUICKLY PASS E INTO MEXICO 
AND THE SW U.S. CONVECTION SHOULD WANE TODAY OVER FORECAST 
WATERS AS THE LOW BECOMES DETACHED FROM THE TROPICAL MOISTURE 
PLUME. THE UPPER PATTERN IS AMPLIFIED OVER THE REST OF N WATERS. 
THIS IS REFLECTED AT THE SURFACE WHERE A 1022 MB HIGH PRES 
SYSTEM CAN BE FOUND AT 27N124W. THE PRES GRADIENT BETWEEN THIS 
HIGH AND LOW PRES OVER THE GULF OF CALIFORNIA HAS BROUGHT 20 TO 
25 KT NORTHERLY WINDS OFF THE W COAST OF BAJA CALIFORNIA. THESE 
WINDS SHOULD DISSIPATE OVER THE NEXT FEW DAYS AS THE HIGH PRES 
REORGANIZES FARTHER W AS A RESULT OF THE COLD FRONT CURRENTLY 
BEARING DOWN ON IT FROM THE NW. WHILE THIS FRONT IS EXPECTED TO 
DISSIPATE BEFORE IT CAN REACH FORECAST WATERS...LONG PERIOD NW
SWELL FROM THE SYSTEM WILL PUSH INTO NW WATERS BY SAT WITH 
SIGNIFICANT WAVE HEIGHTS INCREASING TO 18 FT OVER NW AND N 
CENTRAL WATERS. 

S OF 20N...
ASIDE FROM THE AFOREMENTIONED LOW PRES SYSTEMS AND THE GAP WINDS 
DESCRIBED BELOW...EASTERLY TRADE WINDS ARE THE DOMINANT FEATURE 
OF NOTE. THE TRADES ARE CURRENTLY LIMITED TO BETWEEN 10N AND 20N 
W OF 128W...WITH A SMALL AREA OF 20 TO 25 KT WINDS ASSOCIATED 
WITH A WEAKENING LOW PRES SYSTEM NEAR 10N134W. THE AREA OF 
TRADES WILL SHIFT W IN RESPONSE TO THE REORGANIZATION OF THE 
HIGH PRES SYSTEM TO THE NORTH. 

GAP WINDS...
GALE FORCE WINDS ARE EXPECTED TO CONTINUE THROUGH THE GULF OF 
TEHUANTEPEC THROUGH FRI DIMINISHING BELOW GALE FRI NIGHT. SOME 
UNCERTAINTY IN THE FORECAST AS GUIDANCE SUGGESTS ANOTHER GALE N 
OF THE AREA IN THE BAY OF CAMPECHE AND DEPENDING ON THE 
ORIENTATION OF THE GALE CENTER IT MAY CONTRIBUTE TO ANOTHER   
N SURGE IN THE GULF OF TEHUANTEPEC OR ACTUALLY IMPEDE N FLOW 
INTO THE ISTHMUS OF TEHUANTEPEC. TO FURTHER COMPLICATE THE 
FORECAST IS CONSIDERABLY UNCERTAINTY WITH THE FUTURE OF TROPICAL 
CYCLONE IDA.

$$
SCHAUER