000
AXPZ20 KNHC 270940
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SAT JUN 27 2009

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 
0730 UTC.

...TROPICAL WAVE....
A TROPICAL WAVE LIES ALONG 86W N OF 05N WITH SCATTERED MODERATE 
CONVECTION WITHIN 120 NM OF ITS AXIS FROM 05N TO 07N. THE 
TROPICAL WAVE WILL CONTINUE MOVING W AT APPROXIMATELY 10 KT 
THROUGH THE WEEKEND.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 07N78W TO 09N85W TO 07N99W TO 
12N117W TO 07N140W. SCATTERED MODERATE CONVECTION LIES WITHIN 75 
NM OF THE AXIS E OF 83W. NUMEROUS STRONG CONVECTION LIES WITHIN 
90 NM W SEMICIRCLE OF LOW PRES EMBEDDED IN THE ITCZ NEAR 
11N122W. SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION CAN 
BE FOUND ELSEWHERE WITHIN 75 NM OF THE ITCZ BETWEEN 118W AND 
125W.

...DISCUSSION...
MODERATE SUBSIDENCE WITH STABLE ENVIRONMENTAL CONDITIONS 
REMAINS PRESENT OVER THE MAJORITY OF THE DISCUSSION AREA NW OF A 
LINE FROM THE SOUTHERN TIP OF BAJA CALIFORNIA SW TO 20N120W TO 
10N140W. AN UPPER LEVEL RIDGE LIES ALONG 19N W OF 120W WITH 
SURFACE HIGH PRES DOMINATING WATERS N OF 18N W OF 120W. ANOTHER 
UPPER-LEVEL HIGH CENTERED NEAR THE TX/OK BORDER HAS A RIDGE 
EXTENDING SW ACROSS NORTH-CENTRAL MEXICO. EASTERLY FLOW ALOFT 
ACROSS CENTRAL MEXICO S OF THIS HIGH IS DIRECTING THE REMNANTS 
OF THE AFTERNOON CONVECTION OVER THE MAINLAND TO THE COASTAL 
REGIONS...WITH ISOLATED MODERATE CONVECTION FOUND WITHIN 120 NM 
OF COAST S OF 20N W OF 97W. UPPER DIFFLUENCE BETWEEN THIS RIDGE 
AND AN UPPER LEVEL LOW OVER THE SW GULF OF MEXICO IS PROVIDING 
THE MOST ORGANIZED CONVECTION WITHIN THIS AREA...PRIMARILY S OF 
18N BETWEEN 100W AND 102W. TO THE E OF THE UPPER LOW...A 
TROPICAL WAVE LIES ALONG 86W N OF 05N WITH SCATTERED MODERATE 
CONVECTION WITHIN 120 NM OF ITS AXIS FROM 05N TO 07N. DEEP LAYER 
MOISTURE E OF THE WAVE AND A BROADLY DIFFLUENT PATTERN ALOFT IS  
SUPPORTING THE CONVECTION WITHIN 75 NM OF THE ITCZ E OF 83W.

AT THE SURFACE...THE DEEP LAYERED RIDGE OVER NW WATERS IS 
EXPECTED WEAKEN OVER THE NEXT FEW DAYS AS THE INVERTED MID TO 
UPPER LEVEL TROUGH CENTERED NEAR 118W S OF 20N IS FORCED 
NORTHWARD INTO THE LEADING EDGE OF AN AMPLIFYING MID LATITUDE 
TROUGH PASSING NE OF HAWAII SUN NIGHT AND PICKING UP THE UPPER 
LOW CURRENTLY N OF HAWAII. TRADE WINDS OVER W WATERS SHOULD 
DIMINISH BELOW 20 KT AS THE SURFACE PRES GRADIENT RELAXES SUN.  
MEANWHILE...THE SURFACE LOW PRES SYSTEM EMBEDDED IN THE ITCZ 
NEAR 11N122W ASSOCIATED WITH THIS INVERTED TROUGH ALOFT SHOULD 
WEAKEN AS THE ENERGY ASSOCIATED WITH THE TROUGH MOVES NORTHWARD 
AWAY FROM THE ITCZ AND THE UPPER LEVEL FLOW BECOMES LESS 
DIFFLUENT NEAR THE LINGERING SURFACE TROUGH. THE QUIKSCAT PASS 
FROM 0206 UTC SHOWED WINDS IN THE 20 TO 25 KT RANGE WITHIN 150 
NM NW QUADRANT OF THE LOW. THE SURFACE LOW CURRENTLY LIES IN A 
REGION OF MODERATE UPPER LEVEL DIFFLUENCE BETWEEN THE RIDGE AXIS 
TO ITS NW AND THE INVERTED TROUGH ALOFT....ALLOWING FOR NUMEROUS 
STRONG CONVECTION WITHIN 90 NM W SEMICIRCLE OF THE SFC LOW.

LONG PERIOD SWELL FROM THE SOUTH PACIFIC IS CROSSING THE 
EQUATOR RAISING SEAS TO 8 FT S OF 04N BETWEEN 94W AND 102W. 
EXPECT THE LARGEST SIGNIFICANT WAVE HEIGHTS ASSOCIATED WITH THIS 
SWELL EVENT TO SHIFT W OVER THE WEEKEND.
 
$$
SCHAUER CLARK/GR