000
AXPZ20 KNHC 270319
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC MON SEP 27 2010

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 
0300 UTC.

...SPECIAL FEATURE...

EAST SHEAR OVER LOW PRES SYSTEM NEAR 15N107W IS DISPLACING MOST 
CONVECTION NEAR THIS LOW W OF ITS CENTER. 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 SHOULD MAKE CONDITIONS 
MORE FAVORABLE FOR THE SYSTEM TO POSSIBLY BECOME A TROPICAL 
CYCLONE. THE ASCAT PASS FROM 1612 UTC ALREADY SHOWS 20 KT SW 
WINDS IN S SEMICIRCLE. REFER TO THE LATEST TROPICAL WEATHER 
OUTLOOK FROM THE NATIONAL HURRICANE CENTER FOR MORE DETAILS.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE IS ANALYZED 13N93W TO 15N104W 
THEN RESUMES AT 8N108W TO 12N131W TO 10N139W. 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 
20N101W AND A RIDGE EXTENDS FROM THIS ANTICYCLONE TO ANOTHER 
ANTICYCLONE NEAR 28N123W. EAST WINDS ON THE SOUTH SIDE OF THIS 
RIDGE ARE RESPONSIBLE FOR THE EASTERLY SHEAR OVER THE SURFACE 
LOW AT 15N107W AS DESCRIBED ABOVE. TROUGHING ALOFT ASSOCIATED 
WITH AN UPPER LOW DIGGING S OVER NW MEXICO NEAR 28N110W EXTENDS 
FROM THE LOW TO JUST N OF THE RIDGE AXIS ALONG 110W. 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 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 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 45 NM OF A LINE FROM 
13N88W TO 10N100W...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 TUE AFTERNOON AND EVENING.

$$
MUNDELL