000
AXPZ20 KNHC 120924
TWDEP 

TROPICAL WEATHER DISCUSSION      
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SUN AUG 12 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 97W MOVING W 10 TO 15 KT WITH A WEAK 1009 MB 
LOW NEAR 10.9N96.3W. SCATTERED CONVECTION ALONG THE ITCZ AND A 
CLUSTER OF STRONG CONVECTION OFF THE MEXICAN COAST BUT NONE IS 
ORGANIZED INTO ANY TYPE OF BAND THEREFORE WAVE REMAINS WEAK.

TROPICAL WAVE ALONG 109W MOVING W AT 10-15 KT. SCATTERED 
MODERATE TO STRONG CONVECTION ON EITHER SIDE OF WAVE AXIS BUT NO 
ORGANIZATION.

TROPICAL WAVE ALONG 123W MOVING W 15 KT WITH A WEAK LOW 1009 MB 
NEAR 14N123W. THIS WAVE HAS ALL BUT FIZZLED OUT. ONLY ISOLATED 
WEAK CONVECTION NOTED AT THIS TIME. 

...ITCZ...
ITCZ AXIS ALONG 11N86W 11N96W 12N109W 15N118W 11N131W 15N140W. 
SCATTERED MODERATE AND ISOLATED STRONG CONVECTION WITHIN 45 NM 
EITHER SIDE OF A LINE FROM 5N79W TO 8N85W TO 13N89W TO 10N99W TO 
13N105W TO 10N110W. AREA OF STRONG CONVECTION WITHIN 60 NM OF 
13N111W. SCATTERED MODERATE NEAR 11N118W AND FROM 11N133W TO 
15N140W.

AREA OF STRONG CONVECTION NEAR THE MEXICAN COAST AT 15N99W AND 
AT 22N106W. ISOLATED MODERATE IN GULF OF CORTEZ AT 25N109W.

...DISCUSSION...

TWO STRONG MID LEVEL FEATURES TONIGHT. ONE IS AN OLD RIDGE THAT 
COVERS THE SRN CONUS AND HAS BEEN SHIFTING BACK TO THE W THE 
PAST FEW DAYS. THE CENTER OF THE RIDGE IS NEAR 35N100W BUT 
EXTENDS WSW TO 22N130W. THE OTHER FEATURE IS A TROUGH ALONG 135W 
THAT EXTENDS S TO 25N. W OF THE TROUGH IS ANOTHER RIDGE JUST W 
OF 140W. LATEST WATER VAPOR IMAGERY SHOWS A NEW SURGE OF COLD 
AIR HEADING S ALONG 140W NEAR 45N WHICH WILL MAINTAIN THE TROUGH 
DOWN TO OUR REGION. AND EMBEDDED SHORTWAVE WAS NEAR 26N120W 
MOVING NW. DEEP MOISTURE COVERS THE AREA E OF 125W AND ALONG THE 
ITCZ OTHERWISE VERY DRY CONDITIONS W OF 125W N OF 14N. ON THE 
SURFACE TONIGHT HRCN FLOSSIE IS W OF OUR REGION AND STILL LOOKS 
IMPRESSIVE ON SATELLITE IMAGERY. SEE HONOLULU FORECAST OFFICE 
FOR FURTHER DETAILS. OTHERWISE THE PACIFIC RIDGE EXTENDS SE TO 
20N110W. STRONGEST NE TRADES ARE BETWEEN 15N AND 25N W OF 130W 
AND SSMI SHOWS WINDS 20 TO 25 KT. WINDS ALONG THE BAJA COAST ARE 
LIGHT AND QUIKSCAT SHOWS 10 TO 15 KT. GAP WINDS ARE LIGHT 
TONIGHT BUT CROSS EQUATORIAL SLY WINDS OF 20 KT ARE EVIDENT S OF 
10N BETWEEN 95W AND 125W ACCORDING TO SSMI.

LATER DAY 1 MID LEVEL HEIGHTS FALL SOME ALONG 138W AS THE COLD 
AIR SPILLS SWD IN THE TROUGH. THE STRONG RIDGE DRIFTS W TO 
35N102W. A SECOND SHORTWAVE IS NOTED ON THE S SIDE OF THE RIDGE 
OVER CENTRAL MEXICO ALONG 103W MOVING WNW. ON THE SURFACE LATER 
DAY 1 LITTLE CHANGE TO THE PACIFIC RIDGE BUT NE TRADES PICK UP N 
OF 17N BETWEEN 120W AND 130W AS LOW PRES DEVELOPS ALONG THE ITCZ 
NEAR 12N126W. BAJA WINDS REMAIN LIGHT AS DO GAP WINDS. CROSS 
EQUATORIAL SLY WINDS TO 20 KT MAINLY BETWEEN 100W AND 130W.

FOR DAY 2 STRONG SHORTWAVE DIVING S IN THE MID LEVEL TROUGH 
SIGNIFIES COLD AIR ALOFT HEADING S TO 35N. THIS WILL MAINTAIN 
TROUGH FOR A FEW MORE DAYS. STRONG MID LEVEL RIDGE HOLDS FIRM 
OVER SW CONUS EXTENDING WSW TO 22N138W. RIDGE MAINTAINS WWD 
MOVEMENT OF DISTURBANCES ALONG ITCZ. ON THE SURFACE DAY 2 THE 
GFS MODEL ONLY SHOWS ONE DISTURBANCE OLONG THE ITCZ NEAR 
11N113W. BUBBLE OF HIGH PRES WITH PACIFIC RIDGE MOVES TO 31N131W 
WILL TIGHTEN THE GRADIENT ALONG THE BAJA COAST AND INCREASE 
WINDS TO 20 KT. GAP WINDS REMAIN LIGHT ALTHOUGH SOME NLY WINDS 
TO 15 KT THROUGH TEHUANTEPEC. CROSS EQUATORIAL SLY WINDS MAINLY 
S OF 10N BETWEEN 105W AND 125W.

$$
RRG