000
AXPZ20 KNHC 180920
TWDEP 

TROPICAL WEATHER DISCUSSION      
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC TUE SEP 18 2007

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 
0900 UTC.

...SPECIAL FEATURE...
AREA OF LOW PRES 1009 MB NEAR 13N106W MOVING W 10 KT...ASSOCIATED 
WITH TROPICAL WAVE ALONG 106W FROM 8N TO 17N. SCATTERED MODERATE 
CONVECTION IS FROM 9N TO 15N BETWEEN 102W AND 111W.  A TROPICAL 
DEPRESSION MAY FORM IN THIS AREA WITHIN 24-48 HOURS.

...TROPICAL WAVES...
TROPICAL WAVE ALONG 118W FROM 10N TO 19N MOVING W 5-10 KT. LITTLE OR 
NO CONVECTION ASSOCIATED WITH THIS WAVE.

...ITCZ...
ITCZ AXIS CENTERED ALONG 10N85W 11N97W 13N102W 15N126W 11N134W 
10N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION WITHIN 120 NM 
OF AXIS BETWEEN 119W AND 137W. SCATTERED MODERATE CONVECTION WITHIN 
90 NM S OF AXIS W OF 132W. 

...DISCUSSION...
THE SFC LOW NEAR 13N106W DOES DISPLAY SLIGHTLY BETTER CONVECTIVE 
ORGANIZATION...BUT IS STRUGGLING TO INTENSIFY. ANIMATED VISUAL DATA 
MONDAY SHOWED AN ORGANIZED LOW LEVEL CIRCULATION WITH ANTICYCLONIC 
OUTFLOW ALOFT. WHILE THIS FAVORS INTENSIFICATION...GLOBAL FORECAST 
MODELS SHOW ONLY TEPID SUPPORT FOR TROPICAL CYCLOGENESIS. THE ITCZ 
REMAINS SOMEWHAT ACTIVE WITH LOWS ANALYZED ALONG THE ITCZ AXIS NEAR 
106W...118W AND 129W. A BROAD LOW LEVEL CYCLONIC CIRCULATION EVIDENT 
BETWEEN 120W AND 130W IS PRODUCING SCATTERED SHOWERS AND ISOLATED 
THUNDERSTORMS ALONG THE ITCZ AXIS. A 1029 MB SFC HIGH CENTERED NEAR 
38N150W IS TIGHTENING THE PRESSURE GRADIENT W OF 125W...ENHANCING 20 
TO 25 KT TRADES N OF 15N. QUIKSCAT DATA ALSO SHOWED A SMALL AREA OF 
20-25 KT WINDS IN THE GULF OF TEHUANTEPEC WHICH MAY PERSIST ANOTHER 
12-24 HOURS...PRODUCING SEAS TO 8 FT NEAR THE COAST THROUGH WED. 

IN THE MID AND UPPER LEVELS...AN UPPER LOW CENTERED NEAR 30N139W IS 
DRIFTING W. AN UPPER RIDGE FURTHER E ROUGHLY ALONG 21N IS PROVIDING 
NE/ELY SHEAR OVER THE TROPICS E OF 130W. A SHORT WAVE TROUGH EXTENDS 
SWD INTO THE TROPICS FROM NEW MEXICO TO SOUTHERN BAJA. WATER VAPOR 
IMAGERY SHOWS A MOISTURE PLUME EXTENDING FROM 8N TO 20N BETWEEN 80W 
AND 110W. DRY STABLE AIR DOMINATES THE REMAINDER OF THE REGION N OF 
20N AND W OF 110W.

$$
MUNDELL