000
AXPZ20 KNHC 160912
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC MON AUG 16 2010

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 
0700 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE IS N OF 10N ALONG 98W MOVING W-NW AT 5 KT. 
SCATTERED MODERATE CONVECTION LIES BETWEEN 75 NM AND 330 NM W OF 
THE WAVE AXIS FROM 09N TO 12N AND WITHIN 45 NM OF THE COAST OF 
THE GULF OF TEHAUNTEPEC E OF THE WAVE TO 93W. CONVECTION 
WITHIN 360 NM E OF THE WAVE BECOMES SCATTERED MODERATE TO STRONG 
INLAND OVER MEXICO.

A TROPICAL WAVE HAS MOVED INTO THE GULF OF PANAMA ALONG 78W. 
THIS WAVE IS MOVING W AT 15 KT. SCATTERED CONVECTION WITH THE 
WAVE LIES OVER EASTERN PANAMA.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE AXIS IS ANALYZED INLAND OVER 
WESTERN CENTRAL AMERICA E OF 93W. SOUTHWESTERLY MONSOON FLOW 
DOMINATES PACIFIC WATERS GENERALLY S OF 15N TO THE E OF 120W. 
THE ITCZ CONTINUES FROM 13N120W TO 12N130W TO 09N136W TO 10N140W 
WITH NO SIGNIFICANT CONVECTION FOUND ALONG ITS AXIS.

...DISCUSSION...

A SHARP UPPER TROUGH LIES ALONG 104W N OF 14N TO THE 
MEXICO/TEXAS BORDER. THIS TROUGH IS EMBEDDED IN UPPER LEVEL 
RIDGING STEMMING PRIMARILY FROM AN ANTICYCLONE WELL NE OF THE 
AREA NEAR 29N94W. THIS ANTICYCLONE EXTENDS A RIDGE SOUTHWARD TO 
15N99W. UPPER LEVEL DIFFLUENCE ASSOCIATED WITH THIS RIDGE AXIS 
IS ENHANCING THE CONVECTION OVER MEXICO NOTED WITH THE TROPICAL 
WAVE ALONG 98W. ANOTHER ANTICYCLONE IS BEGINNING TO BREAK OFF 
FROM THE LARGER SCALE UPPER RIDGE NEAR 20N120W S TO 04N126W. AN 
UPPER LOW LIES N OF THIS NEW ANTICYCLONE NEAR 25N125W. THIS LOW 
IS SIPHONING SOME UPPER LEVEL MOISTURE FROM SOUTHEAST.

A SURFACE RIDGE LIES FROM 30N133W TO 26N120W. THE PRESSURE 
GRADIENT BETWEEN THIS RIDGE AND TROUGHING IN THE NORTHERN GULF 
OF CALIFORNIA AND SOUTHWEST U.S. CONTINUES TO RESULT IN NW TO N 
WINDS TO 20 KT OVER NE WATERS...BUT THESE WINDS WILL DIMINISH 
BELOW 20 KT EARLY TODAY AS A FRONT WELL NW OF THE AREA 
ENCROACHES ON THIS RIDGE. THE TROUGHING OVER THE SW U.S. HAS 
INCREASED THE PRES GRADIENT OVER THE NORTHERN GULF OF CALIFORNIA 
AND INCREASED SOUTHERLY WINDS TO 20 KT. SOUTHERLY FLOW THROUGH 
THE GULF OF CALIFORNIA AND ON THE BACKSIDE OF THE LOW PRES 
SYSTEM CURRENTLY NEAR 19N108W IS TRANSPORTING MOISTURE NORTHWARD 
THROUGH THE GULF INTO THE SW U.S. AND NE MEXICO ACCORDING TO 
SATELLITE PRECIPITABLE WATER IMAGERY. THIS INCREASE IN AVAILABLE 
MOSITURE WILL HELP FEED SHOWERS AND TSTMS IN THAT AREA.

A TROUGH EXTENDS FROM THE 1008 MB LOW PRES SYSTEM NEAR 19N108W 
TO 13N117W. THE SOUTHWESTERLY FLOW SOUTH OF THE TROUGH AXIS IS 
DRAWING ITCZ MOISTURE NORTHEASTWARD FROM CENTRAL WATERS. 
SCATTERED MODERATE CONVECTION LIES WITHIN 210 NM NW AND 90 NM NE 
QUADRANTS OF THE LOW. SHIPS MTFH5...WITH NW WINDS NEAR 
20N108W...AND V7FE9...WITH SE WINDS NEAR 19N105W...HELPED PLACE 
THE LOW CENTER AT 0600 UTC AND SHOW THAT WINDS TO 25 KT REMAIN E 
OF THE LOW NEAR THE MEXICAN COAST. HOWEVER...THE 0430 UTC ASCAT 
PASS SHOWS THAT WINDS OVER 20 KT WITH THIS SYSTEM HAVE SHRUNK IN 
AREA SIGNIFICANTLY SINCE THIS TIME YESTERDAY. THE LOW LIES UNDER 
AT LEAST 20 KT OF EASTERLY SHEAR THAT IS EXPECTED TO BECOMING 
SOUTHEASTERLY AT 25-30 KT OVERNIGHT TONIGHT AFTER THE UPPER 
TROUGH CURRENTLY ALONG 104W PASSES TO ITS W. THE LOW IS EXPECTED 
TO DIMINISH UNDER THIS SHEAR ON TUE.

CROSS EQUATORIAL SWELL IS EXPECTED TO REACH 8 FT OVER S CENTRAL 
WATERS BY TUE MORNING AND EXPAND NORTHEAST TO 07N W OF THE 
GALAPAGOS ISLANDS BY EARLY WED MORNING.

$$
SCHAUER