000
AXPZ20 KNHC 270301
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC THU AUG 27 2009

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

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0315 UTC.

...SPECIAL FEATURES...

TROPICAL STORM IGNACIO WAS CENTERED NEAR 23.4N 125.4W OR ABOUT   
985 NM W OF THE SOUTHERN TIP OF BAJA CALIFORNIA AT 27/0300 
UTC...MOVING NW OR 320 DEGREES AT 12 KT. MAXIMUM SUSTAINED WINDS 
REMAIN 35 KT WITH GUSTS TO 45 KT AND THE ESTIMATED MINIMUM 
PRESSURE WAS 1003 MB. IGNACIO IS SHEARED FROM THE SW WITH 
SCATTERED MODERATE CONVECTION NOTED WELL NE OF CENTER WITHIN 90 
NM OF 24N123W. IGNACIO IS EXPECTED TO WEAKEN TO A REMNANT LOW 
THU AS THE CENTER CONTINUES TO TRACK OVER COOLER WATER. 
ADDITIONAL INFORMATION CAN BE FOUND UNDER AWIPS/WMO HEADERS 
MIATCMEP3/WTPZ23 KNHC.
  
A LOW LEVEL TROUGH IS ANALYZED FROM 05N113W TO 13N108W WITH A 
SHARP WIND SHIFT NOTED ALONG THE TROUGH AXIS. WITHIN ABOUT 360 
NM SE OF THE TROUGH THE SURFACE WINDS ARE S TO SW WINDS AT 15 TO 
20 KT WITH SEAS TO 9 FT. N OF 08N WITHIN 150 NM W OF TROUGH NE 
WINDS ARE 15 TO 20 KT WITH SEAS TO 8 FT. TROPICAL CYCLONE 
FORMATION IS POSSIBLY AS THE TROUGH MOVES WESTWARD WITH A BROAD 
SURFACE LOW EXPECTED TO DEVELOP LATE THU NEAR 09N117W AT ABOUT 
1008 MB. 

...TROPICAL WAVES...
A TROPICAL WAVE IS N OF 05N ALONG 94W AND IS MOVING W AT 17 KT 
OVER THE PAST 24 HOURS. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION IS NOTED TO THE N OF 06N BETWEEN 90W AND 98W.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS ALONG 09N84W TO 
09N97W TO 11N104W TO 07N113W TO 15N127W TO 13N140W. SCATTERED 
MODERATE ISOLATED STRONG CONVECTION IS NOTED FROM 05N TO 11N 
BETWEEN 85W AND 98W...AND FROM 05N TO 13N BETWEEN 105W AND 117W 
ASSOCIATED WITH THE SURFACE TROUGH PREVIOUSLY MENTIONED...AND 
ALSO WITHIN 60 NM LINE 14N126W TO 06N136W TO 09N140W.

...DISCUSSION...

AN UPPER ANTICYCLONE NEAR 19N1119W HAS A RIDGE SW TO NEAR 
13N137W AND A RIDGE N TO BEYOND 34N118W. UPPER MOISTURE FROM 
IGNACIO AND ITCZ CONVECTION BETWEEN 116W AND 132W...IS ADVECTED 
N BUT REMAINS UNDER THE RIDGE TO NEAR 31N120W. AN UPPER TROUGH 
HAS MOVED E OVER THE NW PORTION OF THE AREA ROUGHLY ALONG 
32N137W TO 23N142W AND IS ACCOMPANIED BY UPPER MOISTURE W OF ITS 
AXIS. ANOTHER SHARP UPPER TROUGH EXTENDS S INTO THE AREA ALONG 
32N111W TO 24N110W AND INTO A UPPER CYCLONE AT 22N104W. DRY 
UPPER DOMINATES THE AREA N OF 15N W OF 126W AND ALONG THE 
EASTERN UPPER TROUGH BETWEEN 108W AND 112W.

ANOTHER UPPER ANTICYCLONE OVER THE CARIBBEAN NEAR 18N88W HAS ITS 
ENVELOPE OF ANTICYCLONIC FLOW EXTENDING S OVER THE TROPICAL 
PACIFIC E OF 104W AND IS ENHANCING CONVECTION ALONG THE TROPICAL 
WAVE MENTIONED ABOVE.

ELSEWHERE AT THE SURFACE...A RIDGE EXTENDS ALONG 32N117W TO 
17N113W. 

GULF OF TEHUANTEPEC...N TO NE WINDS AT 20 TO 25 KT CONTINUE TO 
SURGE THROUGH THE GULF OF TEHUANTEPEC. ELSEWHERE N OF 10N E OF 
94W NE TO E WINDS ARE AT 15 TO 20 KT. THESE ELY WINDS ARE 
EXPECTED TO CONTINUE FOR A COUPLE MORE DAYS AND SPREAD W TO 
ALONG 98W AS THE NLY WINDS IN THE GULF OF TEHUANTEPEC DIMINISH.

$$
NELSON