000
AXPZ20 KNHC 262115
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SUN SEP 26 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 
2100 UTC.

...SPECIAL FEATURE...

EAST SHEAR OVER THE LOW PRES SYSTEM NEAR 15N108W IS DISPLACING 
THE CONVECTION NEAR THIS LOW TO WITHIN 120 NM OF ITS W 
SEMICIRCLE. EASTERLY SHEAR IS EXPECTED TO CONTINUE OVER THE 
SYSTEM FOR THE NEXT 24 HOURS...BUT THEN AN ANTICYCLONE IS 
EXPECTED TO SHIFT SW OVER THIS NEARLY STATIONARY AREA OF LOW 
PRES AT THE SURFACE WHICH WOULD MAKE CONDITIONS MORE FAVORABLE 
FOR THE SYSTEM TO POSSIBLY BECOME A TROPICAL CYCLONE WITHIN THE 
NEXT 48 HOURS. THE ASCAT PASS FROM 1612 UTC ALREADY SHOWS 20-25 
KT SW WINDS BUILDING IN THE S SEMICIRCLE OF THE LOW. PLEASE SEE 
THE LATEST TROPICAL WEATHER OUTLOOK FROM THE NATIONAL HURRICANE 
CENTER FOR MORE DETAILS.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE IS ANALYZED FROM 13N93W TO 
14N104W THEN RESUMES AT 08N112W TO 12N131W TO 10N140W. NO 
SIGNIFICANT CONVECTION CAN BE FOUND ALONG THE ITCZ AT THIS TIME.

...DISCUSSION...

E OF 115W....
AN UPPER-LEVEL ANTICYCLONE IS CENTERED OVER CENTRAL MEXICO NEAR 
20N100W AND A RIDGE EXTENDS FROM THIS ANTICYCLONE TO ANOTHER 
ANTICYCLONE NEAR 29N122W. EAST WINDS ON THE SOUTH SIDE OF THIS 
RIDGE ARE RESPONSIBLE FOR THE EASTERLY SHEAR OVER THE SURFACE 
LOW AT 15N108W AS DESCRIBED ABOVE. TROUGHING ALOFT ASSOCIATED 
WITH AN UPPER LOW OVER NW MEXICO NEAR 30N109W EXTENDS FROM THE 
LOW TO JUST N OF THE RIDGE AXIS ALONG 109W. THIS UPPER LOW IS 
FORECAST TO SHIFT W TO THE NORTHERN BAJA PENINSULA AS THE RIDGE 
ALOFT CONSOLIDATES TO ITS S NEAR THE SURFACE LOW DESCRIBED ABOVE 
DURING THE NEXT FEW DAYS. THIS FORECAST PATTERN SHOULD ALLOW FOR 
SOME DEVELOPMENT OF THE LOW PRES SYSTEM AND...ALONG WITH THE 
WESTWARD MOVEMENT OF THE REMNANTS OF MATTHEW THROUGH SOUTHERN 
MEXICO...MAINTAIN THE 20-25 KT SW SURFACE FLOW E OF THIS 
SURFACE LOW FROM ROUGHLY 05N TO 16N. THE 1612 UTC ASCAT PASS 
ALREADY SHOWS AN EXPANDING AREA OF S TO SW WINDS AROUND 25 KT 
OFF THE COAST OF CENTRAL AMERICA AS COMPARED TO THE PASS 
OVERNIGHT. SCATTERED MODERATE CONVECTION CAN BE FOUND WITHIN 30 
NM OF A LINE FROM 13N87W TO 08N95W...NEAR THIS AREA OF STRONG 
WINDS.

W OF 115...
WITH THE BULK OF THE EASTERN PACIFIC MOSITURE TRAPPED E OF 
115W...CONVECTION REMAINS HARD TO COME BY IN WESTERN WATERS 
ALONG THE ITCZ. A QUASI-STATIONARY 1012 MB SURFACE LOW PRES 
SYSTEM IS NOTED ALONG THE ITCZ NEAR 11N123W. AN ASCAT PASS FROM 
1745 UTC SHOWED WINDS REMAIN LESS THAN 20 KT NEAR THIS LOW. 
MEANWHILE...15-17 SECOND PERIOD SWELL IS PUSHING INTO THE NW 
PORTION OF THE DISCUSSION AREA FROM THE N CENTRAL ATLANTIC. SEAS 
ARE CURRENTLY AS HIGH AS 13 FT WITH THIS SWELL TRAIN. THE 
FORECAST CALLS FOR NW SWELL OF 10 TO 13 FT TO SPREAD SE THROUGH 
THE AREA AND GRADUALLY SUBSIDE...WITH THE LEADING EDGE OF THIS 
SWELL REACHING THE SOUTHERN TIP OF THE BAJA PENINSULA TUE. A 
SECOND SURGE OF NW SWELL WILL REACH NW WATERS TUE AND BRING THE 
SEAS BACK TO THE 8 TO 13 FT RANGE.

$$
SCHAUER