000
AXPZ20 KNHC 152204
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC WED SEP 15 2010

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2145 UTC.

...ITCZ...

AXIS ALONG 15N95W 13N104W 11N112W 11N121W 9N130W 10N140W. 
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 120 NM S 
OF THE AXIS BETWEEN 98W-104W. SCATTERED MODERATE CONVECTION IS 
WITHIN 120 NM S OF THE AXIS BETWEEN 108W-114W...AND ALSO WITHIN 
60 NM OF THE AXIS BETWEEN 119W-123W. 

...DISCUSSION...

ALOFT...
A VERY SHARP UPPER LEVEL TROUGH ENTERS THE FAR NE PORTION OF
THE AREA FROM SOUTHERN CALIFORNIA SW TO NEAR 27N126W. A 
MID/UPPER LEVEL RIDGE IS FOLLOWING IN ITS WAKE TO THE N OF
29N BETWEEN 124W-130W. WATER VAPOR IMAGERY SHOWS MODERATE
SUBSIDENCE AND VERY STABLE AIR COVERING THE AREA TO THE 
S OF THE TROUGH AND RIDGE TO NEAR THE ITCZ REGION. THE TROUGH
IS FORECAST TO MOVE INLAND ACROSS THE WESTERN CONUS OVERNIGHT
INTO THU AS THE RIDGE SLIDES TO THE NE PORTION. AN ANTICYCLONE
SLOWLY NE IS LOCATED TO THE W OF SOUTHERN BAJA CALIFORNIA NEAR
25N115W WITH A RIDGE S TO NEAR 18N117W. ANOTHER ANTICYCLONE IS
OVER CENTRAL MEXICO NEAR 22N100W WITH A RIDGE W TO 22N107W. A 
SHEAR ZONE BETWEEN BOTH ANTICYCLONES CONTINUES TO ADVECT AMPLE 
TROPICAL MOISTURE FROM THE DEEP TROPICS...MOSTLY DEBRIS 
CLOUDINESS FROM ITCZ CONVECTION N AND NE TO ACROSS NORTHERN 
MEXICO AND INTO SECTIONS OF THE SOUTHERN U.S. THE FLOW PATTERN S 
OF THE ANTICYCLONES IS RATHER STRONG WHILE IT ACTS TO ADVECT 
EXTENSIVE OF MOISTURE WESTWARD TO A LINE FROM SOUTHERN BAJA 
CALIFORNIA TO 10N130W. CONVECTION WITHIN THIS MOISTURE AREA HAS 
INCREASED SOME DURING THE PAST 24 HOURS...BUT AT THE SAME TIME 
IS BEING SHEARED UNDER THE ELY FLOW.

SURFACE...
HIGH PRES OF 1023 MB EXTENDS A RIDGE ENE TO N OF THE AREA AT 
32N127W. A WEAK FRONTAL BOUNDARY WELL N OF THE AREA APPROACHING 
NRN CALIFORNIA IS PRESSING THE HIGH S ALLOWING FOR THE PRES
GRADIENT OVER THE FAR EASTERN PORTION OF THE AREA NEAR THE 
BAJA CALIFORNIA COAST TO BEGIN TO TIGHTEN SHORTLY RESULTING IN
NW WINDS OF 20 KT TO FILTER ACROSS THE WATERS N OF 25N AND WITHIN
120 NM W OF THE BAJA CALIFORNIA COAST. AS THE GRADIENT WEAKENS 
WITHIN THE NEXT 24-36 HRS...THE WINDS WILL ALSO DIMINISH.

SCATTEROMETER DATA ALONG WITH VISIBLE SATELLITE IMAGERY FROM 
THROUGHOUT THE DAY DEPICTED A STRONG E-W SHEAR VORTICITY FROM 
10N TO 13N...AND BETWEEN 107W AND 116W. A SURFACE LOW OF 1009 MB 
IS ANALYZED NEAR 12N111W. SCATTERED MODERATE/ISOLATED STRONG 
CONVECTION IS WITHIN 45 NM OF 13N113W. SCATTERED MODERATE 
CONVECTION IS WITHIN 120 NM OF THE LOW IN THE SOUTHERN 
SEMICIRCLE.

GLOBAL MODEL GUIDANCE SUGGESTS THAT THIS LOW...OR ANOTHER NEAR 
IT WILL LIKELY DEVELOP FURTHER OVER THE NEXT 24-48 HOURS...
WITH FRESH TO STRONG SW WINDS DEVELOPING IN ITS S SEMICIRCLE 
ALONG WITH SEAS UP TO 10 FT IN LATEST WAVEWATCH GUIDANCE.

MARINE...
CROSS EQUATORIAL LONG PERIOD SWELLS SPREADING NORTHWARD ARE 
EXPECTED TO REACH AS FAR NORTH AS 16N. LARGE SURF ALONG EXPOSED 
COASTS IS POSSIBLE THE NEXT FEW DAYS FROM SEAS UP TO 12 FT. HIGH 
SEAS AND STRONG SW WINDS ASSOCIATED WITH LOW DEVELOPMENT IN THE 
MONSOON TROUGH INDICATED BY NOAA WAVEWATCH GUIDANCE FROM 8N TO 
13N BETWEEN 101W AND 115W.

$$
AGUIRRE