000
AXPZ20 KNHC 210936
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC MON AUG 21 2006

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS 
BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND 
METEOROLOGICAL ANALYSIS.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0845 UTC.

...SPECIAL FEATURES...
TS HECTOR NEAR 21.2N 135.1W 1005 MB AT 0900 UTC AUG 21 MOVING NW 
OR 310 DEG AT 6 KT. MAXIMUM SUSTAINED WINDS 35 KT GUSTS 45 KT.   
ONLY ISOLATED MODERATE CONVECTION REMAINS IN THE N QUADRANT OF 
HECTOR..OTHERWISE MOSTLY STRATAFORM LOW AND MID CLOUDS SURROUND 
HECTOR. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS 
MIATCMEP4/WTPZ24 KNHC FOR MORE DETAILS. 

WEAK LOW PRES IS NEAR 11N101W MOVING WNW 5 TO 10 KT. THE 
ESTIMATED PRES IS 1008 MB. CONVECTION HAS BEEN INCREASING THE 
PAST SEVERAL HOURS AND APPEARS TO BE GETTING BETTER ORGANIZED.  

...TROPICAL WAVES...
A TROPICAL WAVE N OF 4N ALONG 85W MOVING W AT 10 TO 15 KT. 
ISOLATED CONVECTION OVER COSTA RICA OTHERWISE LITTLE EVIDENCE OF 
WAVE PRESENCE.

A TROPICAL WAVE ALONG 126W FROM 3N TO 15N MOVING W AT 10 TO 15 
KT. 
SOME EVIDENCE OF A POSSIBLE LOW PRES CENTER ALONG THE ITCZ. 
SCATTERED MODERATE CONVECTION MOSTLY DISORGANIZED BUT EVIDENCE 
OF ANTICYCLONIC OUTFLOW PRESENT WHICH COULD AID DEVELOPMENT.

...ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 8N77W 11N96W 7N114W 12N140W. 
SCATTERED MODERATE TO STRONG CONVECTION WITHIN 90 NM OF 5N79W. 
ISOLATED MODERATE NEAR 7N89W AND 8N91W. SCATTERED MODERATE 
WITHIN 30 NM OF A LINE FROM 10N103W TO 8N109W. SCATTERED 
MODERATE WITHIN 90 NM OF A LINE FROM 8N123W TO 11N129W. 
SCATTERED MODERATE WITHIN 45 NM OF 15N138W. 

SCATTERED STRONG CONVECTION NEAR THE COAST AT 13N90W 16N94W AND 
16N101W.

...DISCUSSION...

IN THE MID LEVELS TONIGHT A LARGE RIDGE OF HIGH PRESSURE REMAINS 
STATIONARY OVER THE SRN PLAINS WITH AN AXIS EXTENDING W AND SW 
ACROSS NRN MEXICO AND BAJA TO NEAR 20N125W. MID LEVEL EASTERLIES 
ARE CONFINED TO S OF 20N WITH A WEAK INVERTED TROUGH ALONG 
20N108W TO 10N102W. A SHORTWAVE TROUGH IN THE WESTERLIES JUST N 
OF THE AREA ALONG 125W WAS MOVING ENE TOWARD CENTRAL CA. THE 
FLOW BEHIND THE TROUGH BECOMES W AND SW JUST N OF 30N. A WEAK 
IMPULSE IN THE WESTERLIES IS ALONG 145W S OF 30N MOVING ENE 
TONIGHT. ON THE SURFACE TONIGHT T.S. HECTOR WAS NEAR 21N135W 
MOVING NW AT 8 KT AND ENCOUNTERING COOLER WATER AND THUS LOOSING 
ALL OF ITS CONVECTION. THE STORM CONTINUES TO PUSH AGAINST THE 
PACIFIC RIDGE PRODUCING A LARGE AREA OF STRONG NE WINDS BETWEEN 
20N AND 27N W OF 130W. WINDS ALONG THE BAJA COAST ARE NWLY 15 KT 
ACCORDING TO THE GFS MODEL. THERE ARE NO SSMI OR QUIKSCAT 
IMAGERY TO CONFIRM THIS. GAP WINDS REMAIN LIGHT TONIGHT WHILE 
CROSS EQUATORIAL SLY WINDS TO 20 KT ARE STRONGEST BETWEEN 95W 
AND 120W ACCORDING TO GFS AND A PARTIAL PASS OF SSMI CONFIRMS 
THIS.

LATER DAY 1 LITTLE CHANGE TO THE MID LEVEL RIDGE OVER THE SRN US 
AND MEXICO. THE INVERTED TROUGH IN THE EASTERLIES DRIFTS WWD 
WITH THE GFS MODEL SHOWING SOME STRENGTHENING OF VORTICITY ALONG 
11N WHERE A POSSIBLE TROPICAL CYCLONE IS TRYING TO FORM. MID 
LEVEL WESTERLIES DIP A LITTLE FURTHER S CROSSING THE CORNER OF 
THE AREA WITH A WEAK SHORTWAVE APPROACHING THE CORNER OF THE 
REGION. ON THE SURFACE LATER DAY 1 THE GFS MODEL PERSISTS TO 
DEVELOPING A TROPICAL LOW NEAR 11N103W AND MOVING IT WNW. HECTOR 
CONTINUES TO WEAKEN TO 25 TO 35 KT AS IT MOVES NW. LITTLE CHANGE 
TO THE PACIFIC RIDGE WHICH WILL NOSE SE TO 20N125W. WINDS ALONG 
THE BAJA COAST WILL REMAIN LIGHT TO MODERATE WITH SEAS TO 6 FT. 
GAP WINDS WILL REMAIN LIGHT AND CROSS EQUATORIAL SLY WINDS ARE 
FORECAST TO STRENGTHEN S OF 10N BETWEEN 95W AND 115W AS THE 
TROPICAL LOW DEVELOPS.

FOR DAY 2 THE GFS MODEL SHOWS THE MID LEVEL RIDGE OVER THE SRN 
PLAINS SHIFTING WWD SLOWLY AND THE RIDGE AXIS LIFTING N TO ALONG 
30N. THE MODEL INCREASES THE VORTICITY NEAR 13N107W INDICATIVE 
OF A DEVELOPING TROPICAL LOW. THE MODEL SHOWS THE WEAK SHORTWAVE 
TROUGH OVER THE NW CORNER OF THE AREA CAPTURING THE REMAINS OF 
HECTOR AND MOVING IT NWD.  A CLOSED MID LEVEL LOW APPEARS JUST W 
OF THE REGION NEAR 33N150W. ON THE SURFACE DAY 2 HECTOR IS 
FORECAST TO BE JUST A REMNANT LOW NEAR 23N139W WITH WINDS 20 TO 
25 KT. THE PACIFIC RIDGE WILL REMAIN W OF 120W WITH ONLY A WEAK 
PRES GRADIENT ALONG THE BAJA COAST THUS WINDS REMAIN LIGHT. THE 
GFS MODEL CONTINUES TO STRENGTHEN THE TROPICAL LOW..THUS IT WILL 
HAVE TO WATCHED AS IT TRACKS WNW. GAP WINDS WILL REMAIN LIGHT 
WHILE CROSS EQUATORIAL SLY WINDS REMAIN BRISK TO 20 KT BETWEEN 
100W AND 120W WITH SLY SWELL OF 8 FT. 

$$
RRG