000
AXPZ20 KNHC 020920
TWDEP 

TROPICAL WEATHER DISCUSSION      
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC THU AUG 02 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...

TROPICAL STORM ERICK IS CENTERED NEAR 13.3N 130.0W AT 0900 UTC 
WITH A CENTRAL PRESSURE OF 1005 AND MOVING WEST AT 12 KT. 
MAXIMUM SUSTAINED WINDS ARE 35 KT WITH GUSTS TO 45 KT. ERICK 
CONTINUES TO BE ATTACHED TO THE ITCZ WHERE ABUNDANT MOISTURE IS 
AVAILABLE FOR PRODUCTION OF CONVECTION. WATER VAPOR IMAGERY 
SHOWS A VERY DRY MID AND UPPER ATMOSPHERE JUST W AND N OF THE 
STORM. ERICK CONTINUES WWD ON THE S SIDE OF A LARGE MID LEVEL 
ANTI-CYCLONE. A SMALL AREA OF STRONG CONVECTION NW OF THE CENTER 
HAS PERSISTED FOR SEVERAL HOURS. SMALL BANDS ARE EVIDENT TYING 
IN THE STORM CIRCULATION WITH THE ITCZ. SEE LATEST NHC 
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP3/WTPZ23 KNHC 
FOR ADDITIONAL DETAILS.

...TROPICAL WAVE...

A TROPICAL WAVE IS LOCATED ALONG 114W FROM 7N TO 20N AND IS  
MOVING WEST 10 TO 15 KT. CONVECTION WITH THIS WAVE IS MAINLY 
ALONG THE ITCZ AND SHOWS NO ORGANIZATION AT THIS TIME.

...ITCZ...

ITCZ AXIS IS ALONG THE LINE...8N76W 10N95W 15N114W 13N125W 
8N140W. SCATTERED MODERATE AND STRONG CONVECTION WITHIN 90 NM OF 
A LINE FROM 7N80W TO 9N96W TO 15N111W TO 12N123W. SCATTERED 
MODERATE WITHIN 30 NM OF A LINE FROM 10N132W TO 8N140W.

ISOLATED STRONG CONVECTION NEAR THE COAST AT 13N90W AND 15N94W.

...DISCUSSION...

A BIG MID LEVEL RIDGE COVERS THE REGION N OF 20N INCLUDING THE 
SW CONUS TONIGHT. AN INVERTED MID LEVEL TROUGH HAS MIGRATED 
SLOWLY NW INTO THE RIDGE AND HAS CLOSED OFF TONIGHT NEAR 
33N124W. WATER VAPOR IMAGERY SHOWS THE CIRCULATION EMBEDDED IN 
THE VERY DRY RIDGE. ON THE SURFACE TONIGHT TRPL ST0RM ERICK 
CONTINUES MOVING WNW SLOWLY AND STILL ATTACHED TO THE ITCZ WHICH 
IS PROBABLY GOOD FOR IT SINCE VERY DRY AIR LIES W AND NW OF THE 
CIRCULATION. THE PACIFIC RIDGE EXTENDS SE OVER THE AREA N OF 10N 
W OF 110W.  NE TRADES TO 20 KT ARE PRIMARILY W OF 130W. WINDS 
ALONG THE BAJA COAST ARE MOSTLY LIGHT NWLY. GAP WINDS ARE LIGHT 
AND CROSS EQUATORIAL SLY WINDS ARE 15 TO 20 KT ACROSS THE ENTIRE 
AREA S OF 10N. 

LATER DAY 1 LITTLE CHANGE TO THE OVERALL MID LEVEL PATTERN. THE 
BROAD RIDGE WILL CONTINUE TO PUT THE SQUEEZE ON THE EMBEDDED 
CYCLONIC CIRCULATION AND HOLD IT NEARLY STATIONARY. ON THE 
SURFACE LATER DAY 1 TRPL STORM ERICK WILL CONTINUE WNW WITH SLOW 
DEVELOPMENT. LITTLE CHANGE ELSEWHERE.

FOR DAY 2 THE GFS MODEL SHOWS HELP IS ON THE WAY FOR THE 
EMBEDDED CYCLONIC CIRCULATION IN THE FORM OF A SHORTWAVE TROUGH 
DIVING SE TO 33N130W AND HELPING THE CIRCULATION LIFT NWD. 
ANOTHER INVERTED TROUGH OVER MEXICO AT MID LEVELS IS MOVING 
SLOWLY WWD ON THE S SIDE OF THE RIDGE AND IS POISED TO TAKE THE 
EMBEDDED ONE'S POSITION. ON THE SURFACE DAY 2 TRPL STORM ERICK 
IS FORECAST TO STAY AT TRPL STORM STRENGTH WHILE IT LUMBERS WNW. 
LITTLE CHANGE TO THE OTHER FEATURES..EXCEPT THE GFS MODEL SHOWS 
SOME INCREASE IN CROSS EQUATORIAL SLY WINDS OF 20 TO 25 KT 
BETWEEN 100W AND 110W S OF A LOW CENTER ON THE ITCZ. 

$$
RRG