000
AXPZ20 KNHC 150923
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SUN AUG 15 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 
0715 UTC.

...TROPICAL WAVE...

A TROPICAL WAVE ALONG 91W N OF 10N IS MOVING W-NW AT 12 KT.  
SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION LIES E OF THE 
WAVE OVER GUATEMALA AND BELIZE WHILE SCATTERED MODERATE 
CONVECTION IS OVER GULF OF TEHUANTEPEC FROM 14N TO 17N BETWEEN 
93W AND 96W.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE IS ANALYZED FROM 11N120W TO 
10N130W TO 10N140W. NO SIGNIFICANT CONVECTION LIES ALONG THE 
ITCZ AT THIS TIME. EAST OF THE ITCZ...SOUTHWESTERLY WINDS CAN BE 
FOUND FROM THE EQUATOR NORTHWARD TO THE MONSOON TROUGH FROM 
22N108W THROUGH 1007 MB LOW PRES AT 17N109W TO 13N114W.

...DISCUSSION...

AN UPPER LEVEL RIDGE EXTENDS FROM THE SOUTHWESTERN U.S. THROUGH 
THE FAR NORTHERN GULF OF CALIFORNIA SOUTHWESTWARD TO NEAR 
23N132W. SUBSIDENT CONDITIONS CAN BE FOUND NW OF THIS RIDGE AXIS 
AND ARE MARKED BY THE DRY AIR ON WATER VAPOR IMAGERY NW OF A 
LINE FROM 30N120W TO 14N135W TO THE ITCZ ALONG 135W. A SHARP 
UPPER TROUGH LIES FROM 15N125W TO 23N120W TO NORTHERN MEXICO 
NEAR 30N107W. UPPER LEVEL DIFFLUENCE BETWEEN THIS TROUGH AND THE 
RIDGE TO ITS NORTH IS ENHANCING THE SCATTERED MODERATE 
CONVECTION OVER THE GULF OF CALIFORNIA AND NW MEXICO N OF 29N. 
AN ANTICYCLONE LIES S OF THE TROUGH OVER MEXICO NEAR 25N104W AND 
EXTENDS A RIDGE TO 17N117W. DIFFLUENCE ALONG THE RIDGE AXIS IS 
ENHANCING SCATTERED MODERATE CONVECTION FARTHER S IN THE GULF OF 
CALIFORNIA FROM 23N TO 26N E OF 110W. AN UPPER LOW OVER THE BAY 
OF CAMPECHE NEAR 20N97W EXTENDS A TROUGH SOUTH TO 10N98W. 
ANOTHER RIDGE AXIS LIES EAST OF THIS TROUGH FROM THE YUCATAN 
PENINSULA TO 13N94W. CONVECTION NEAR THE AFOREMENTIONED TROPICAL 
WAVE IS BEING ENHANCED BY THE DIFFLUENCE ASSOCIATED WITH THIS 
RIDGE ALOFT.

A SURFACE RIDGE LIES FROM 29N140W TO 24N115W. THE PRESSURE 
GRADIENT BETWEEN THIS RIDGE AND TROUGHING IN THE GULF OF 
CALIFORNIA CONTINUES TO RESULT IN NW TO N WINDS TO 20 KT NEAR 
THE W COAST OF BAJA CALIFORNIA N OF 26N. THIS RIDGE AXIS IS 
EXPECTED TO MOVE SOUTHWESTWARD...DECREASING THE PRES GRADIENT 
OVER NE WATERS. THIS AREA OF WINDS WILL SHIFT WEST THROUGH MON 
MORNING AND DIMINISH BELOW 20 KT BY MON AFTERNOON. TROUGHING 
OVER THE SW U.S. WILL DEEPEN TODAY AS A COLD FRONT DIVES SOUTH 
OF THE U.S. FOUR CORNERS. THIS WILL INCREASE THE PRES GRADIENT 
OVER THE NORTHERN GULF OF CALIFORNIA AND INCREASE SOUTHERLY 
WINDS TO 20 KT BY SUNDAY EVENING. SOUTHERLY FLOW THROUGH THE 
GULF OF CALIFORNIA AND ON THE BACKSIDE OF THE LOW PRES SYSTEM 
CURRENTLY NEAR 17N109W 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.

THE MONSOON TROUGH THAT EXTENDS THROUGH THE 1007 MB LOW PRES 
SYSTEM NEAR 17N109W IS DRAWING ITCZ MOISTURE NORTHEASTWARD FROM 
CENTRAL WATERS. THE 0450 ASCAT PASS SHOWS 20-25 KT SOUTHWEST 
WINDS FEEDING INTO THE SOUTH SIDE OF THE LOW AND HELPING KEEP 
SEAS IN THE 8 TO 11 FT RANGE IN SW SWELL. THE LOW IS FORECAST TO 
SHIFT GRADUALLY NORTHWESTWARD OVER THE NEXT FEW DAYS AS THE 
MONSOON TROUGH AXIS SHIFTS EASTWARD AND WINDS AND SEAS BEGIN TO 
DIMINISH.

$$
SCHAUER