000
AXPZ20 KNHC 140938
TWDEP 

TROPICAL WEATHER DISCUSSION      
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SAT JUL 14 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.

...TROPICAL WAVES...

TROPICAL WAVE ALONG 92W N OF 3N HAS MOVED W 10 TO 15 KT. 
SCATTERED CONVECTION BUT NO ORGANIZATION. 

TROPICAL WAVE IS ALONG 101W N OF 5N MOVING W AT 10 TO 15 KT. 
SCATTERED MODERATE CONVECTION ALONG THE ITCZ WITH NO 
ORGANIZATION. 

LOW PRES NEAR 14.5N112W 1007 MB ACCOMPANIES THE WAVE ALONG 112W 
N OF 6N. STRONG CONVECTION WELL W AND SW OF AN APPARENT LOW 
LEVEL CENTER. NO CONVECTION NEAR CENTER.

LOW PRES ANALYZED NEAR 11N127W MOVING W 10 TO 15 KT. THIS SYSTEM 
HAS BECOME BETTER ORGANIZED DURING THE NIGHT AND HAS A BALL OF 
STRONG CONVECTION NEAR THE CENTER. A BAND OF MODERATE TO STRONG 
CONVECTION ALSO HAS DEVELOPED SE OF THE CENTER. 

...ITCZ...

ITCZ AXIS IS CENTERED ALONG AXIS 9N80W 9N93W 14N112W 9N130W 
8N140W. SCATTERED MODERATE CONVECTION FROM 7N TO 13N BETWEEN 90W 
AND 106W. SCATTERED MODERATE TO STRONG CONVECTION WITHIN 120 NM 
OF A LINE FROM 13N113W TO 9N135W. 

.SCATTERED MODERATE TO STRONG CONVECTION WITHIN 90 NM OF THE 
COAST FROM 8N82W TO 11N87W AND FROM 13N91W TO 15N99W.

...DISCUSSION...

A VIGOROUS UPPER TROUGH CONTNUES MAINLY NW OF THE REGION TONIGHT 
BUT IT IS HAVING SOME AFFECT ON OUR REGION S OF 30N. ALSO A MID 
LEVEL RIDGE REMAINS STATIONARY OVER THE SW CONUS AND IS 
PRODUCING MODERATE ELY WINDS ALOFT S OF 20N. AN EMBEDDED TROUGH 
IS ALONG 117W MOVING SLOWLY NW. ON THE SURFACE TONIGHT THE UPPER 
TROUGH IS RESPONSIBLE FOR SENDING WEAK COLD FRONTS INTO OUR NW 
CORNER BUT THEY DON'T PACK MUCH PUNCH. THE TROUGH IS ALSO 
RESPONSIBLE FOR A WEAKENED PACIFIC RIDGE THAT TONIGHT HAS A 1020 
MB CENTER NEAR 30N128W AND IS PRODUCING NE TRADES S OF 20N W OF 
120W TO 20 KT. WINDS ALONG THE BAJA COAST ARE MOSTLY NWLY 10 TO 
15 KT ACCORDING TO QUIKSCAT AND SSMI IMAGERY. GAP WINDS ARE 
MOSTLY LIGHT TONIGHT. CROSS EQUATORIAL SLY WINDS ARE 15 TO 20 KT 
WHERE CONVECTION IS ACTIVE ALONG THE ITCZ.

LATER DAY 1 MID LEVEL HEIGHTS WILL BE SLOWLY RISING OVER THE NW 
CORNER OF THE AREA AS THE UPPER TROUGH LIFTS NE. THE MID LEVEL 
RIDGE HOLDS FIRM OVER THE SW CONUS AND THE INVERTED TROUGH LIMPS 
ALONG TOWARD THE NW ALONG 120W. GFS MODEL SHOWS WEAK VORTICITY 
AT MID LEVELS ALONG THE ITCZ IN COORIDNATION WITH CONVECTION. ON 
THE SURFACE LATER DAY 1 THE COLD FRONT WASHES OUT OVER THE 
EXTREME NW CORNER OF THE AREA. LITTLE CHANGE TO THE PACIFIC 
RIDGE REMAINING STATIONARY NEAR 30N128W. NE TRADES CONFINED TO 
10N TO 21N W OF 125W NEAR 20 KT. GAP WINDS REMAIN LIGHT WHILE 
CROSS EQUATORIAL SLY WINDS TO 20 KT CHANGE LITTLE.

FOR DAY 2 UPPER TROUGH SHIFTS N OF 30N WHILE MID LEVEL RIDGE 
HOLDS FIRM OVER SW CONUS. MID LEVEL EASTERLIES S OF 20N WITH 
WEAK AREAS OF VORTICITY ALONG 100W..115W AND 130W STIRRING UP 
THE USUAL CONVECTION ALONG THE ITCZ. ON THE SURFACE DAY 2 
ANOTHER WEAK COLD FRONT POKES INTO THE NW CORNER OF THE AREA BUT 
QUICKLY DISSIPATES. NO CHANGE TO THE PACIC RIDGE WITH THE 1020 
MB CENTER STATIONARY. NE TRADES MAINLY FROM 10N TO 20N W OF 120W 
WHERE GRADIENT BETWEEN RIDGE AND LOW PRES ON THE ITCZ WILL 
PRODUCE WINDS OF 20 KT. BAJA WINDS MOSTLY NEAR 15 KT WHILE GAP 
WINDS REMAIN LIGHT. CROSS EQUATORIAL SLY WINDS STRONGEST BETWEEN 
90W AND 105W AND W OF 120W WHERE LOW PRES ON THE ITCZ ENHANCES 
CONVECTION.

$$
RRG