000
AXPZ20 KNHC 110918
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL 
HURRICANE CENTER MIAMI FL
1005 UTC FRI AUG 11 2006

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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0845 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE ALONG 132W N OF 2N WAS MOVING W 10 TO 15 KT.
SOME CLUSTERS OF STRONG CONVECTION ON THE ITCZ MAINLY W OF THE 
WAVE AXIS. NO ORGANIZATION TO THE CONVECTION.

A TROPICAL WAVE N OF 5N ALONG 98W WAS MOVING W 15 TO 20 KT. ONLY 
ISOLATED CONVECTION ALONG THE ITCZ NEAR 98W.  

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 7N78W 9N89W 7N99W 9N112W 14N123W 
7N140W. A CLUSTER OF STRONG CONVECTION NEAR 5N77W. ISOLATED 
MODERATE NEAR 7N94W 6N96W AND 7N98W. SCATTERED MODERATE BETWEEN 
9N AND 14N FROM 116W TO 130W. SCATTERED STRONG BETWEEN 8N AND 
13N FROM 133W TO 140W. 

OTHER ISOLATED MODERATE TO STRONG CONVECTION NEAR THE COAST AT 
7N80W 7N82W 9N85W 10N87W 10N89W 12N90W 11N92W AND 13N93W.

...DISCUSSION...

MID LEVEL LARGE SCALE FEATURES TONIGHT INCLUDE A ANTICYCLONE 
OVER THE NRN PORTION OF MEXICO AND THE SW US WHICH HAS BEEN 
DRIFTING WWD THE PAST FEW DAYS. A DEPARTING CYCLONIC CIRCULATION 
N 0F THE AREA ALONG 125W. MID LEVEL EASTERLIES HAVE BROADENED 
AND TONIGHT ARE AS FAR N AS 26N. A WEAK INVERTED TROUGH IN THE 
EASTERLIES HAS BEEN MOVING SLOWLY WWD THE PAST SEVERAL DAYS AND 
TONIGHT IS ALONG 128W.  WATER VAPOR IMAGERY SHOWS THE SYSTEM 
REMAINS WEAK WITH ONLY HIGH LEVEL MOISTURE DEFINING IT. A VERY 
DRY UPPER ATMOSPHERE IS NOTED BETWEEN 130W AND 140W MOVING 
SLOWLY WWD. ON THE SURFACE TONIGHT THE PACIFIC RIDGE OF HIGH 
PRESSURE IS PRODUCING NE TRADES OF 20 KT MAINLY W OF 130W AND NE 
TO E WINDS TO 20 KT BETWEEN 15N AND 20N W OF 120W. WINDS ALONG 
THE BAJA COAST REMAIN LIGHT AND QUIKSCAT WINDS ARE 10 TO 15 KT. 
WINDS W OF PAPAGUAYO ARE ELY 10 TO 20 KT TONIGHT WHILE CROSS 
EQUATORIAL WINDS ARE MOSTLY 15 TO 20 KT S OF 8N WITH POSSIBLE 
HIGHER GUSTS W OF 130W.

LATER DAY 1 FINDS A WEAKNESS IN THE PRESSURE FIELD AT MID LEVELS 
BETWEEN 115W AND 135W. THE INVERTED TROUGH IN THE EASTERLIES 
BEGINS TO MOVE MORE NWLY ALONG 130W DUE TO THIS WEAKNESS. THE 
MID LEVEL RIDGE OVER NRN MEXICO CONTINUES TO DRIFT SLOWLY WWD. 
ON THE SURFACE LATER DAY 1 LITTLE CHANGE TO THE PACIFIC RIDGE 
AND THE ASSOCIATED NE TRADES. WINDS ALONG THE BAJA COAST REMAIN 
LIGHT NWLY. SO CALLED GAP WINDS ALONG THE MEXICAN AND CENTRAL 
AMERICAN COAST WILL BE MOSTLY LIGHT. CROSS EQUATORIAL WINDS WILL 
REMAIN STRONGEST W OF 110W BUT SLY SWELL TO 8 FT WILL MOVE N OF 
THE EQUATOR TO 6N.

FOR DAY 2 MID LEVEL HEIGHTS FALL SLOWLY AS A TROUGH N OF THE 
AREA OVER THE WRN US SHIFTS SWD ALONG 125W. THE MID LEVEL RIDGE 
DRIFTING WWD THE PAST FEW DAYS WEAKENS BUT GENERALLY LIES ENE TO 
WSW FROM THE SRN PLAINS ACROSS NRN MEXICO..BAJA TO 20N130W. THE 
INVERTED TROUGH MOVES WNW TO NEAR137W AND WEAKENS. A NEW 
INVERTED TROUGH OVER NE MEXICO IS STILL FORECAST TO DRIFT NWD 
INTO SRN TX. OVERALL MID LEVEL EASTERLIES WEAKEN DAY 2 AND ARE 
MAINLY S OF 20N.  ON THE SURFACE DAY 2 THE PACIFIC RIDGE SHOWS 
SIGNS OF STRENGTHENING WITH THE NE TRADES SHIFTING NWD TO 
BETWEEN 15N AND 30N W OF 130W. THE RIDGE IS EXPECTED TO INCREASE 
NLY WINDS TO 20 KT N OF 27N BETWEEN 122W AND 130W WITH N SWELL 
INCREASING TO 8 FT. WINDS ALONG THE BAJA COAST SHOULD REMAIN 
NWLY 10 TO 15 KT. GAP WINDS REMAIN LIGHT DAY 2 WHILE CROSS 
EQUATORIAL WINDS DECREASE TO MOSTLY 15 KT S OF 5N WITH SLY SWELL 
TO 8 FT. 

$$
RRG