000
AXPZ20 KNHC 130903
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC FRI OCT 13 2006

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS 
BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND 
METEOROLOGICAL ANALYSIS.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0730 UTC.
     
...TROPICAL WAVES...

TROPICAL WAVE HAS ENTERED THE AREA ALONG 82W N OF 3N MOVING W 15 
KT. THE WAVE HAS VERY LITTLE SIGNATURE EXCEPT FOR A RECENT 
FLARE-UP OF CONVECTION ALONG THE ITCZ JUST S OF PANAMA AND COSTA 
RICA. SCATTERED MODERATE CONVECTION FROM 5N-9N BETWEEN 79W-86W.

TROPICAL WAVE ALONG 101W/102W S OF 17N MOVING W 15 KT. A 0108 
UTC QUIKSCAT PASS NICELY INDICATED THE WAVE POSITION WITH A WEAK 
CYCLONIC WIND FIELD N OF THE ITCZ. THIS POSITION PUTS THE WAVE 
ALONG THE ERN FRINGE OF A MUCH LARGER CIRCULATION DEVELOPING UP 
TO 600 NM TO ITS W. AS THE WAVE MOVES INTO THIS CIRCULATION...A 
CENTER OF CIRCULATION APPEARS TO BE DEVELOPING AS THE WHOLE 
SYSTEM LIFTS SLOWLY N OUT OF THE ITCZ. GLOBAL MODELS CONTINUE TO 
FORECAST AN AREA OF LOW PRES TO CONSOLIDATE FROM THIS SYSTEM 
WITHIN THE NEXT 24-48 HRS...THEN LIFT NW TOWARDS THE BAJA 
PENINSULA BY MON AND TUE. MOST OF THE DEEP CONVECTION IS LOCATED 
W OF THE WAVE AXIS...SEE ITCZ AND DISCUSSION BELOW FOR FURTHER 
INFORMATION.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 8N77W 15N105W 10N122W 13N133W 
12N140W. SCATTERED MODERATE CONVECTION N OF 5N BETWEEN 79W-86W. 
NUMEROUS MODERATE/STRONG FROM 9N-18N BETWEEN 102W-115W. 
SCATTERED MODERATE/STRONG FROM 8N-14N W OF 133W.

...DISCUSSION...

THE DEEP-LAYERED LOW PRES SYSTEM WHICH HAS BEEN OFF THE CA COAST 
OVER THE PAST FEW DAYS HAS NOW SUNK S TO 32N122W...ABOUT 245 NM 
W OF SAN DIEGO. A SURFACE TROUGH EXTENDS S OF THE LOW TO 30N118W 
27N120W 24N130W AND ACTUALLY APPEARS TO BE USHERING DRIER AIR 
INTO THE AREA...SEEN IN SATELLITE IMAGERY AS AN EVAPORATION OF 
THE USUAL LOW-LEVEL STRATUS/STRATOCUMULUS. UPPER LEVEL W/SWLYS 
LIE OVER THE REGION N OF 18N W OF BAJA CALIFORNIA...AND THERE IS 
ONLY A SMALL PATCH OF CIRRUS AHEAD OF A SHORTWAVE TROUGH LOCATED 
ALONG 30N135W 26N140W. AN AREA OF LOW PRES HAS DEVELOPED ALONG 
THE ITCZ NEAR 12N139W AND IS LOCATED BENEATH THE DIFFLUENT 
REGIME OF AN UPPER RIDGE AXIS ALONG 15N120W 12N140W. CONVECTION 
NEAR THE LOW STILL APPEARS ASSOCIATED WITH ITCZ CONVERGENCE AND 
NOT REALLY TIED TO THE CENTER OF CIRCULATION.

FARTHER E...FORMER T.D. OLIVIA HAS STOPPED SPOUTING OCCASIONAL 
TSTMS AND IS NOW LOCATED NEAR 17N119W MOVING ESE 5-10 KT. FORMER 
T.D. NORMAN IS ALSO IN THE REGION NEAR 15N111W AND DOES HAVE 
CONVECTION LOOSELY TIED TO THE ITCZ. OLIVIA AND NORMAN BOTH 
APPEAR TO BE BECOMING ENTRAINED INTO THE MUCH LARGER CIRCULATION 
DEVELOPING TO THEIR E AND WILL LIKELY LOSE THEIR IDENTITIES 
WITHIN THE NEXT 24-48 HRS. THE NEW DEVELOPING SYSTEM APPEARS TO 
HAVE A ROUGH CENTER OF CIRCULATION NEAR 15N104W ALTHOUGH IT IS 
BEING INFLUENCED BY AN APPROACHING TROPICAL WAVE NOW NEAR 101W. 
SEE TROPICAL WAVES SECTION FOR FURTHER DISCUSSION. ASIDE FROM 
CONVECTION ASSOCIATED WITH THE ITCZ...A CLUSTER OF SCATTERED 
MODERATE/STRONG CONVECTION IS ALSO LOCATED N OF 16N BETWEEN 
104W-107W...REACHING INTO W/CENTRAL MEXICO BETWEEN MANZANILLO 
AND MAZATLAN. THE CONVECTION IS BEING ENHANCED BY A BROAD AREA 
OF UPPER LEVEL DIFFLUENCE LOCATED ON THE W SIDE OF A LARGE UPPER 
HIGH OVER THE ISTHMUS OF TEHUANTEPEC. THIS HIGH IS ALSO 
PRODUCING MODERATE UPPER LEVEL EASTERLIES OVER THE FAR E 
PACIFIC...CONTRIBUTING TO STRONG VERTICAL SHEAR SINCE THE 
LOW-LEVEL WIND FIELD IS PRIMARILY WESTERLY.

$$
BERG