000
AXPZ20 KNHC 200925
TWDEP 

TROPICAL WEATHER DISCUSSION      
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC FRI JUL 20 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 95W N OF 2N MOVING W 10 KT. SCATTERED CONVECTION 
MAINLY WITHIN 6 DEGREES W OF THE AXIS BUT NO ORGANIZATION AT THIS 
TIME.
  
TROPICAL WAVE ALONG 118W FROM 4N TO 18N MOVING W 10 TO 15 KT. NO 
EVIDENCE OF THIS WAVE NOTED. CONVECTION ORIENTED NE/SW AND 
ASSOCIATED WITH AN INVERTED TROUGH IN THE MID LEVELS.

TROPICAL WAVE ALONG 136W FROM 2N TO 17N MOVING W 15 KT. A CIRCULAR 
AREA OF CONCENTRATED CONVECTION WITHIN 90 NM OF 11N139W OTHERWISE NO 
OTHER EVIDENCE OF THIS WAVE.

...ITCZ...
AXIS ALONG 8N78W 10N95W 17N105W 10N118W 7N128W 12N137W 10N140W. 
SCATTERED MODERATE CONVECTION NEAR 4N78W 7N81W 8N87W 7N90W 8N91W AND 
11N88W. SCATTERED MODERATE TO STRONG CONVECTION FROM 8N TO 15N 
BETWEEN 95W AND 104W. SCATTERED MODERATE WITHIN 60 NM OF A LINE FROM 
19N107W TO 7N132W AND WITHIN 60 NM OF 10N114W AND WITHIN 90 NM OF 
11N139W.

...DISCUSSION...

THE UPPER TROUGH THAT WAS ALONG 130W LAST NIGHT HAS SHIFTED E 
TONIGHT TO 124W AS THE ONCE DIGGING JET HAS REORIENTED ITSELF MORE W 
TO E. THUS MID LEVEL HEIGHTS ARE SLOWLY RISING N OF 28N BETWEEN 120W 
AND 130W. MID LEVEL RIDGES STILL PRESENT W OF THE AREA ALONG 30N AND 
OVER THE SW CONUS. AN INVERTED MID LEVEL TROUGH ALONG 110W IS 
STATIONARY DIVERTING THE MID LEVEL EASTERLIES S OF 20N SW TO 
10N110W. ON THE SURFACE TONIGHT AN ACTIVE AREA OF CONVECTION 
CONTINUES FROM 16N109W TO 10N120W ASSOCIATED WITH THE INVERTED 
TROUGH. QUIKSCAT SHOWS SLY WINDS TO 25 KT FEEDING INTO THIS REGION 
OF CONVECTION. OTHERWISE THE PACIFIC RIDGE IS CENTERED NW OF THE 
AREA BUT EXTENDS SE TO 20N120W. THE RIDGE IS PRODUCING NE WINDS OF 
15 KT N OF 20N W OF 120W ACCORDING TO SSMI IMAGERY. WINDS ALONG THE 
BAJA COAST N OF 25N ARE NWLY 15 TO 20 KT ACCORDING TO QUIKSCAT AND 
IN GOOD AGREEMENT WITH THE GFS MODEL FOR 06Z. GAP WINDS ARE LIGHT 
AND CROSS EQUATORIAL SLY WINDS ARE STRONGEST BETWEEN 88W AND 100W 
AND BETWEEN 110W AND 125W ACCORDING TO BOTH MICROWAVE IMAGES.

LATER DAY 1 MID LEVEL PATTERN WILL CHANGE LITTLE WITH THE FEATURES 
REMAINING IN PLACE. THE UPPER TROUGH CONTINUES TO WEAKEN ALONG OUR 
30N BORDER WHILE THE INVERTED TROUGH DRIFTS W TO ALONG 115W. ON THE 
SURFACE LATER DAY 1 THE PACIFIC RIDGE AXIS REMAINS ALONG 30N 
EXTENDING SE TO 20N115W. LITTLE CHANGE IN NE TRADES. TRPL WAVES 
REMAIN WEAK ALTHOUGH THE GFS MODEL WANTS TO SLOWLY DEVELOP A LOW 
CENTER NEAR 10N100W. WINDS ALONG THE BAJA COAST REMAIN LIGHT AS WILL 
GAP WINDS. CROSS EQUATORIAL WINDS DECREASE SOME TO MOSTLY 10 TO 15 
KT. 

FOR DAY 2 THE MID LEVEL RIDGE OVER THE SW CONUS SHIFTS NE ALLOWING 
THE INVERTED TROUGH TO SLIDE NW SLIGHTLY TO A LINE FROM NRN BAJA SW 
TO 15N130W. THE UPPER TROUGH CONTINUES NWD AND IS NO LONGER A PLAYER 
IN OUR REGION S OF 30N. THE MID LEVEL RIDGE ALONG 30N APPEARS 
SOMEWHAT WEAKER DAY 2. ON THE SURFACE DAY 2 THE PACIFIC RIDGE AXIS 
WILL REMAIN ALONG 30N AND EXTEND SE TO 20N115W. NE TRADES TO 20 KT 
WILL PREVAIL FROM 10N TO 20N W OF 130W. WINDS ALONG THE BAJA COAST 
WILL REMAIN LIGHT AS WILL GAP WINDS. CROSS EQUATORIAL SLY WINDS 
INCREASE SOME TO 20 KT BETWEEN 100W AND 110W. 

$$
RRG