000
AXPZ20 KNHC 110920
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC THU OCT 11 2007

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.

...ITCZ...

INTERTROPICAL CONVERGENCE ZONE...AXIS ALONG 15N90W 12N105W 
13N115W 9N130W 9N140W. SCATTERED STRONG CONVECTION FROM 13N91W 
TO 13N96W TO 12N102W TO 16N103W. ISOLATED MODERATE NEAR 9N132W 
AND 10N139W. 

SCATTERED MODERATE TO STRONG CONVECTION NEAR THE COAST AT 4N78W 
TO 7N79W AND FROM 8N83W TO 9N85W. SCATTERED MODERATE TO STRONG 
NEAR 12N88W TO 14N92W. 

...DISCUSSION...

A BROAD MID LEVEL RIDGE EXTENDS E AND SE ACROSS THE AREA TO NW 
MEXICO TONIGHT. ONE CENTER OF THIS RIDGE IS JUST W OF THE LOWER 
BAJA PENINSULA. A STRONG TROUGH IN THE WESTERLIES ALONG 133W 
CONTINUES TO LOWER MID LEVEL HEIGHTS AS A POLAR JET DIGS SSE 
ALONG 140W N OF THE AREA. A WEAK SHORTWAVE ALONG 130W NEAR 23N 
IS MOVING NE IN RESPONSE TO THE DIGGING JET. ON THE SURFACE 
TONIGHT THE MONSOONAL TROUGH OF SUMMER TIME HAS RE-ORIENTED 
ITSELF OFF THE MEXICAN COAST FROM SE OF THE BAJA PENINSULA SE TO 
NEAR 13N93W THEN INLAND OVER CENTRAL AMERICA TO A LOW IN THE WRN 
CARIBBEAN. THE LOWER PRESSURE IN THE TROUGH IS ENHANCING SWLY 
WINDS S OF 10N E OF 110W. THE PACIFIC RIDGE IS WEAK WITH LITTLE 
SUPPORT ALOFT. A 1020 MB CENTER NEAR 24N137W EXTENDS NE TO 
31N129W. PRESSURE GRADIENT BETWEEN THE RIDGE AND TROUGH OVER THE 
SEA OF CORTEZ IS PRODUCING NLY WINDS ALONG THE BAJA COAST TO 20 
KT ACCORDING TO SSMI AND QUIKSCAT. GAP WINDS THROUGH TEHUANTEPEC 
TO 20 KT THE RESULT OF WEAK HIGH PRES OVER SRN MEXICO AND THE 
LOW PRES OVER THE WRN CARIBBEAN. 

LATER DAY 1 WITH APPROACH OF THE STRONG UPPER TROUGH ALONG 130W 
THE RIDGE OVER NW MEXICO BUILDS NWD SLOWING THE FORWARD MOTION 
OF THE TROUGH..THUS THE WEAK SHORTWAVE ALONG 130W MAKES LITTLE 
HEADWAY. ON THE SURFACE LATER DAY 1 A COLD FRONT ASSOCIATED WITH 
THE UPPER TROUGH BRUSHES BY THE NRN PORTION OF THE AREA WITH 
SOME INCREASE IN SW TO WINDS TO 20 KT AND NWLY SWELL TO 8 FT. 
THE PACIFIC RIDGE WEAKENS SOME AND NE TRADES ARE MOSTLY 10 TO 15 
KT. EVEN THE NLY WINDS ALONG THE BAJA COAST DIMINISH TO 15 KT AS 
THE GRADIENT WEAKENS. LITTLE CHANGE TO THE GUSTY SWLY WINDS S OF 
12N E OF 110W WITH SW SWELL OF 8 TO 10 FT EXPANDING BETWEEN 8N 
AND 10N E OF 108W.

FOR DAY 2 WHATS LEFT OF THE WEAK MID LEVEL TROUGH ALONG 130W 
EITHER DISSIPATES OR GETS PICKED UP BY A NEW JET SURGE AROUND 
THE BASE OF THE UPPER TROUGH WHICH MOVES SLOWLY E TO 120W. THE 
MID LEVEL RIDGE HOLDS IT'S OWN OVER NW MEXICO REFUSING TO BUDGE. 
FLAT MID LEVEL PATTERN W OF 120W. ON THE SURFACE DAY 2 WHATS 
LEFT OF THE COLD FRONT SLIPS INTO OUR REGION TO 28N W OF 130W 
BUT THE GRADIENT IS WEAK AND WINDS REMAIN ONLY 10 TO 15 KT WITH 
NW SWELL TO 9 FT. THE PACIFIC RIDGE PUSHED S TO 25N BULGES NE TO 
THE SRN CA COAST. THE PRES GRADIENT BETWEEN THE RIDGE AND LOW 
PRES OVER THE SEA OF CORTEZ WILL MAINTAIN NWLY WINDS ALONG THE 
BAJA COAST TO 20 KT WITH NWLY SWELL TO 8 FT. GUSTY SWLY WINDS OF 
20 KT WILL CONTINUE S OF 12N E OF 110W WITH SWLY SWELL TO 10 FT.

$$
RRG