000
AXPZ20 KNHC 282138
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SUN JUN 28 2009

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 
2115 UTC.

...TROPICAL WAVE...

TROPICAL WAVE IS ALONG 97W N OF 06N MOVING W NEAR 15 KT. A WEAK 
AREA OF LOW PRES FORMED ALONG THE N PORTION OF THE WAVE A FEW 
DAYS AGO...NOW LOCATED JUST N OF THE YUCATAN PENINSULA. THE 
REMAINING SOUTHERN PORTION IS WEAK WITH LITTLE SIGNATURE NOTED 
IN SATELLITE IMAGERY OR AVAILABLE SFC DATA. 

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 11N86W TO 13N96W TO 11N110W TO 
14N121W TO 09N140W. NUMEROUS MODERATE SCATTERED STRONG 
CONVECTION IS FROM 05N TO 12N E OF 90W. SCATTERED MODERATE 
CONVECTION IS WITHIN 180 NM N AND 240 NM S OF THE AXIS BETWEEN 
102W AND 107W. SCATTERED MODERATE CONVECTION IS FROM 07N TO 13N 
BETWEEN 112W AND 117W. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION IS FROM 06N TO 09N W OF 130W.

...DISCUSSION...

SUBTROPICS...
LIGHT SFC WINDS EXIST ACROSS MUCH OF THE SUBTROPICS DUE TO A 
WEAK HIGH SITUATED NEAR 23N125W. HOWEVER...THERE ARE A FEW AREAS 
OF MARGINAL 20 KT WINDS TO MENTION. NE WINDS NEAR 20 KT ARE 
OCCURRING OVER THE FAR NW CORNER...AS INDICATED BY AN EARLIER 
QUIKSCAT PASS...ON THE SRN PERIPHERY OF A 1032 MB HIGH NEAR 
43N138W. THESE WINDS ARE EXPECTED TO DIMINISH OVER THE NEXT 
24-48 HOURS AS THE HIGH MOVES N AND A WEAK TROUGH DEVELOPS IN 
THAT REGION. NW WINDS ARE LIKELY STILL NEAR 20 KT NEAR THE N 
BAJA COAST BASED ON LOW-LEVEL CLOUD MOTIONS. THESE WINDS ARE 
ALSO FORECAST TO DIMINISH ON MON AS THE AFOREMENTIONED HIGH 
MOVES N. DESPITE THE LIGHT WINDS ACROSS THE REGION...SEAS ARE 
ELEVATED TO 6-9 FT DUE PRIMARILY TO N SWELL PROPAGATING S FROM 
GALE FORCE WINDS OFF THE CALIFORNIA COAST. 

ALOFT...A MID-UPPER TROUGH EXTENDS FROM 30N137W TO A LOW NEAR 
23N129W WITH RIDGING LOCATED BOTH E AND W OF THE TROUGH. 
WIDESPREAD DRY AIR IS NOTED ACROSS THE ENTIRE REGION ABOVE THE 
LOW-MID LEVEL CLOUD DECK. A SHORTWAVE TROUGH NEAR 33N144W IS 
EXPECTED TO AMPLIFY THE TROUGH OVER THE DISCUSSION ZONE MON AND 
TUE.

TROPICS...
THE TROPICS ARE QUIET ACROSS THE EAST PACIFIC AS THERE ARE NO 
WELL DEFINED AREAS OF SFC LOW PRESSURE. CONVECTION IS SPREAD OUT 
ACROSS THE ENTIRE BELT MAINLY NEAR THE ITCZ (OUTLINED ABOVE). 
THERE ARE A COUPLE OF OTHER WEATHER FEATURES PROVIDING 
ENHANCEMENT TO THE CONVECTION OR WINDS. ONE OF THESE IS A SFC 
TROUGH ALONG 16N127W 10N132W. THIS TROUGH HAS TIGHTENED THE 
PRESSURE GRADIENT PRODUCING NE 20 KT WINDS FROM 11N-16N W OF 
122W. THIS FEATURE IS EXPECTED TO CONTINUE ITS W-NW DRIFT 
ALLOWING THE ENHANCED AREA OF WINDS TO SHIFT W AS WELL. AN AREA 
OF SCATTERED MODERATE CONVECTION IS LOCATED N OF 15N BETWEEN 
101-105W SUPPORTED BY UPPER DIFFLUENCE S OF AN UPPER LOW OVER 
CENTRAL MEXICO. 

CROSS-EQUATORIAL SLY WINDS ARE NEAR 20 KT NEAR THE 
AFOREMENTIONED SFC TROUGH S OF 06N BETWEEN 127W AND 134W. THESE 
WINDS ARE EXPECTED TO PERSIST OVER THE NEXT DAY OR SO AS THE 
PRESSURE GRADIENT REMAINS TIGHT BETWEEN THE SRN HEMISPHERE 
SUBTROPICAL RIDGE AND THE ITCZ. 

$$
CANGIALOSI