000
AXPZ20 KNHC 041012 AAA
TWDEP 

TROPICAL WEATHER DISCUSSION      
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SAT AUG 04 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.

...SPECIAL FEATURES...
LOW PRES 1010 MB 10N108W MOVING W 10 TO 15 KT. AREA OF NUMEROUS 
STRONG CONVECTION WITHIN 90 NM OF THE LOW CENTER. 

...TROPICAL WAVE...
TROPICAL WAVE ALONG 92W MOVING W 10 KT. ISOLATED CONVECTION OFF 
THE COAST OF EL SALVADOR OTHERWISE THIS WAVE HAS WEAKENED SINCE 
MOVING INLAND DURING THE PAST 24 HR.

TROPICAL WAVE ALONG 106W MOVING W 10 TO 15 KT. LITTLE CONVECTION 
OF CONSEQUENCE IN THE VICINITY OF THE WAVE AXIS. 

TROPICAL WAVE ALONG 119W WITH A 1010 MB LOW NEAR 16N119W MOVING 
W 10-15 KT. A SMALL AREA OF MODERATE TO STRONG CONVECTION HAS 
CONTINUED NEAR 17N121W. STRONG UPPER LEVEL ELY WINDS OVER THE 
AREA ARE KEEPING THE CONVECTION SHEARED FROM THE LOW LEVEL 
CENTER WHICH IS NEAR 16N119W.

...ITCZ...
ITCZ AXIS IS CENTERED ALONG...8N81W 10N105W 17N119W 9N130W 
10N140W. SCATTERED MODERATE TO STRONG CONVECTION FROM 4N TO 8N E 
OF 81W. CLUSTER OF STRONG CONVECTION WITHIN 90 NM OF 10N109W. 
SCATTERED MODERATE FROM 12N113W TO 9N118W. SCATTERED MODERATE TO 
STRONG WITHIN 60 NM OF 17N121W. ISOLATED MODERATE NEAR 13N140W.

ISOLATED MODERATE TO STRONG CONVECTION NEAR THE COAST AT 10N88W 
13N89W 15N96W 16N100W 18N106W AND 23N107W.

...DISCUSSION...

TWO MID LEVEL RIDGES DOMINATE THE SCENE OVER THE REGION TONIGHT. 
ONE REMAINS OVER THE SW CONUS AND THE OTHER JUST NW OF 140W 
WHICH RIDGES SE INTO OUR REGION TO 25N132W. IN BETWEEN THE TWO 
WAS AN EMBEDDED TROUGH BUT THE TROUGH HAS BEEN ABSORBED BY A 
SHORTWAVE THAT DROPPED DOWN ALONG 130W AND HAS RESCUED THE 
EMBEDDED TROUGH. MID LEVEL EASTERLIES REMAIN S OF 20N WITH ONE 
VORTICITY CENTER ALONG 120W WHERE A TRPL DISTURBANCE ON THE 
SURFACE IS LOCATED. A NEW EMBEDDED SHORTWAVE IS OVER NRN MEXICO 
TONIGHT MOVING SLOWLY WWD. ON THE SURFACE TONIGHT THE PACIFIC 
RIDGE REMAINS CENTERED NW OF THE AREA AND RIDGES SE TO NEAR 
20N110W. STRONGEST NE TRADES ARE N OF 25N W OF 130W AT 20 KT. 
WINDS ALONG THE BAJA COAST REMAIN LIGHT NWLY. GAP WINDS ARE ALSO 
LIGHT. CROSS EQUATORIAL SLY WINDS TO 20 KT ARE BETWEEN 100W AND 
110W S OF A CONVECTIVE AREA ON THE ITCZ. 

LATER DAY 1 THE TWO MID LEVEL RIDGES REMAIN IN PLACE WITH A 
TROUGH ALONG 128W IN BETWEEN THE TWO. THE EMBEDDED SHORTWAVE 
OVER NW MEXICO CONTINUES MOVING W TO ALONG 109W. ON THE SURFACE 
LATER DAY 1 WEAK LOW PRES NEAR 17N121W IS PRESSING AGAINST THE 
PACIFIC RIDGE PRODUCING NE WINDS TO 20 KT AND SEAS TO 8 FT. 
CROSS EQUATORIAL SLY WINDS TO 20 KT WILL BE FOUND BETWEEN 100W 
AND 120W..OTHERWISE LITTLE CHANGE ELSEWHERE. 

FOR DAY 2 THE MID LEVEL RIDGE OVER THE SW CONUS THE PAST SEVERAL 
DAYS APPEARS TO BE WEAKENING AND MOVING SLOWLY EWD..THUS 
RELAXING IT'S GRIP ON THE EMBEDDED SHORTWAVE OVER NW MEXICO. THE 
SHORTWAVE MOVES TO 115W AND BEGINS TO FEEL THE INFLUENCE OF THE 
FAIRLY STRONG TROUGH ALONG 125W. THE OTHER MID LEVEL RIDGE NW OF 
THE AREA SHOWS SIGNS OF WEAKENING TOO AND BARELY EXTENDS INTO 
OUR REGION E OF 140W. ON THE SURFACE DAY 2 WITH WEAKENING MID 
LEVEL SUPPORT..THE PACIFIC RIDGE ALSO WEAKENS AND NE TRADES 
SHIFT TO MAINLY W OF 135W. THE OLD DISTURBANCE ALONG 120W MOVES 
TO 126W AND WEAKENS ACCORDING TO THE GFS MODEL. A SECOND 
DISTURBANCE ON THE ITCZ MOVES SLOWLY W TO NEAR 11N115W. THIS 
WILL ENHANCE SLY CROSS EQUATORIAL WINDS WHICH COULD REACH 20 TO 
25 KT JUST S OF THE LOW CENTER. SLY SWELL TO 8 FT WILL MOVE INTO 
THE AREA S OF 10N. OTHERWISE GAP WINDS AND BAJA WINDS REMAIN 
LIGHT. 

$$
RRG