000
AXPZ20 KNHC 250923
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC THU SEP 25 2008

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 0845 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 81W N OF 05N MOVING W 10-15 KT. THERE IS 
NO CONVECTION OR ANY EVIDENCE OF THIS FEATURE AT THE MOMENT. 
THEREFORE...ITS CURRENT POSITION IS BASED ON FORWARD 
EXTRAPOLATION.

TROPICAL WAVE IS ALONG 93W N OF 05N MOVING W 10 KT. THE 
INTERACTION WITH A SLIGHT DIFFLUENT UPPER PATTERN IS TRIGGERING 
LARGE CLUSTERS OF DEEP CONVECTION OVER THE N PORTION OF THE GULF 
OF TEHUANTEPEC...SRN MEXICO AND THE BAY OF CAMPECHE. 

TROPICAL WAVE IS ALONG 103W FROM 07N TO 18N MOVING W 10 KT. 
SHORTWAVE IR IMAGES CONTINUE TO SHOW FAIRLY WELL DEFINED 
MID-LEVEL CYCLONIC TURNING ALONG OR JUST E OF THE WAVE AXIS NEAR 
14N. HOWEVER...THERE DOES NOT APPEAR TO BE MUCH OF AN INFLUENCE 
AT THE SFC. GLOBAL MODELS HINT AT SOME WEAK SFC LOW PRESSURE 
DEVELOPMENT OVER THE NEXT COUPLE OF DAYS EITHER FROM THIS WAVE 
OR THE ONE BEHIND IT. 

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 10N85W 13N92W 12N105W 09N120W  
10N130W 08N140W. SCATTERED MODERATE TO STRONG CONVECTION IS N OF 
14N BETWEEN 96W AND 104W. SCATTERED MODERATE CONVECTION IS 
WITHIN 90 NM S OF THE AXIS W OF 129W.

...DISCUSSION...

W OF 110W...
A LOW PRESSURE SYSTEM IS TRACKING W AT 10 KT CURRENTLY CENTERED 
ABOUT 450 NM SSW OF THE SRN TIP OF BAJA CALIFORNIA NEAR 
16N113W...ANALYZED 1008 MB. CONVECTION HAS REDEVELOPED WITHIN 
180 NM NW QUADRANT TONIGHT. HOWEVER...AS THE SYSTEM TRACKS 
FARTHER INTO THE STABLE MID AND UPPER LEVEL AIR THE CONVECTIVE 
BURSTING WILL LIKELY DIMINISH. BOTH ASCAT AND QSCAT MISSED THE 
SYSTEM THIS EVENING...BUT CONSIDERING THE PRES PATTERN WINDS TO 
20 KT ARE LIKELY OVER THE NW SEMICIRCLE...DUE TO THE PRES 
GRADIENT BETWEEN IT AND HIGH PRES N OF THE ZONE. ANOTHER LOW IS 
SITUATED WITHIN THE ITCZ NEAR 10N130W. CONVECTION HAS INCREASED 
MAINLY TO THE W OF THE LOW...BUT IT REMAINS EMBEDDED WITHIN THE 
ITCZ. GLOBAL MODELS SHOW THIS WEAK LOW PRES DRIFTING W WITHIN 
THE ITCZ OVER THE NEXT COUPLE OF DAYS.

IN THE MID AND UPPER LEVELS...RIDGING EXTENDS SW FROM SOUTHERN 
MEXICO ALONG 21N105W 14N132W AND AN UPPER TROUGH CUTS ACROSS THE 
NW WATERS FROM 30N129W TO 22N134W. CONFLUENCE BETWEEN THESE 
FEATURES IS ENHANCING STABILITY. 

E OF 110W...
A MID TO UPPER RIDGE OVER SOUTHERN MEXICO CONTINUES TO PROVIDE 
NE TO E SHEAR OVER THE TROPICAL WAVES LIMITING THE CHANCE OF 
ORGANIZATION. WATER VAPOR IMAGES REVEAL ABUNDANT HIGH LEVEL 
MOISTURE OVER THIS ENTIRE REGION BUT CONVECTION IS CONFINED N OF 
13N BETWEEN 96W AND 104W...ENHANCED BY THE TROPICAL WAVES AS 
MENTIONED ABOVE. 

GAP WINDS...THE COMBINATION OF HIGH PRES BUILDING S OVER MEXICO 
AND LOW PRES OVER THE CAROLINAS WILL LIKELY SET UP N WINDS OF 
20-25 KT IN THE GULF OF TEHUANTEPEC FRI NIGHT AND SAT.

$$
CANGIALOSI