000
AXPZ20 KNHC 271600
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC THU SEP 27 2007

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

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1530 UTC.
  
...TROPICAL WAVES...

TROPICAL WAVE ALONG 103W S OF 16N MOVING W 10 KT. A 1010 MB LOW 
IS LOCATED ALONG THE WAVE AXIS NEAR 14N. THE WAVE IS UNDER THE 
INFLUENCE OF DEEP EASTERLY SHEAR DUE TO AN UPPER LEVEL HIGH 
CENTERED ALONG THE COAST NEAR ZIHUATANEJO. EVEN THOUGH THE LOW 
IS DEVELOPING BANDED CONVECTION...MUCH OF THE ACTIVITY IS 
DISPLACED WEST OF THE SURFACE LOW DUE TO THE SHEAR. SCATTERED 
MODERATE CONVECTION FROM 12N-16N BETWEEN 101W-109W.

TROPICAL WAVE ALONG 111W S OF 16N MOVING W 10 KT. A WEAK 1009 MB 
LOW IS ALONG THE WAVE AXIS NEAR 12N BUT THIS FEATURE IS MAINLY 
EMBEDDED WITHIN THE ITCZ. THE WAVE HAS VERY LITTLE SIGNATURE AT 
THE MOMENT AND ALL ASSOCIATED CONVECTION IS ORIENTED LINEARLY 
NEAR THE ITCZ AXIS.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 8N77W 14N100W 11N115W 12N135W 
10N140W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION FROM 
6N-11N BETWEEN 92W-101W. SCATTERED MODERATE WITHIN 120 NM OF 
AXIS BETWEEN 108W-128W.

...DISCUSSION...

E OF 110W...
A LARGE AREA OF UPPER LEVEL HIGH PRES IS CENTERED OVER THE 
WESTERN GULF OF MEXICO...MEXICO...AND THE ADJACENT PACIFIC 
WATERS WITH TWO APPARENT CENTERS NEAR 22N96W AND 17N102W. THIS 
EXPANSIVE RIDGE...COUPLED WITH THE MID-LEVEL RIDGE ALONG 
25N...IS PRODUCING STRONG EASTERLY SHEAR OVER THE FAR ERN 
PACIFIC WATERS. HIGH LEVEL MOISTURE ORIGINATING FROM T.D. 
THIRTEEN OVER THE BAY OF CAMPECHE IS ROUNDING THE RIDGE AND 
BEING ADVECTED WESTWARD OVER THE PACIFIC WATERS E OF 110W. AS 
DESCRIBED IN THE TROPICAL WAVE SECTION...AN AREA OF LOW PRES HAS 
DEVELOPED ALONG THE TROPICAL WAVE SW OF ACAPULCO...BUT THE 
EASTERLY SHEAR IS PUSHING THE DEEPEST CONVECTION WEST OF THE 
SURFACE CENTER.

W OF 110W...
AN EXPANSIVE MID/UPPER LEVEL RIDGE AXIS EXTENDS FROM N/CENTRAL 
MEXICO SW TO 16N120W TO 14N140W WITH MODERATE/STRONG SUBSIDENCE 
PRIMARILY FROM 15N-24N. THE ITCZ IS FAIRLY SMOOTH WITH ENHANCED 
AREAS OF CONVECTION E OF 130W IN THE VICINITY OF WEAK LOW-LEVEL 
TROUGHS EMBEDDED WITHIN THE AXIS. A MORE PRONOUNCED SURFACE 
TROUGH IS LOCATED ALONG 134W/135W S OF 18N MOVING W 10-15 
KT...BUT A LACK OF MOISTURE HAS ONLY ALLOWED WIDELY SCATTERED 
SHOWERS/TSTMS TO DEVELOP FROM 13N-16N BETWEEN 131W-137W. FARTHER 
N...A CUT-OFF UPPER LOW IS LOCATED OFF THE NORTHERN CALIFORNIA 
COAST WITH A TROUGH EXTENDING SW...PUTTING THE N PART OF THE 
DISCUSSION AREA N OF 23N UNDER W/SW FLOW ALOFT. A 100 KT UPPER 
LEVEL JET EXTENDS FROM 28N140W TO 28N127W...THEN WEAKENS AS IT 
CONTINUES NE INTO THE SW UNITED STATES.

$$
BERG