000
AXPZ20 KNHC 200330
TWDEP 

TROPICAL WEATHER DISCUSSION      
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SUN MAY 20 2012

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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0300 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
MONSOON TROUGH EXTENDS FROM 16N94W TO LOW PRES NEAR 11N99W 1005 
MB TO 07N126W. ITCZ EXTENDS FROM 07N126W TO 03N140W. SCATTERED 
MODERATE TO STRONG CONVECTION WITHIN 120 NM SW SEMICIRCLE OF LOW.

...DISCUSSION...
THE MONSOON TROUGH THAT STRETCHES EASTWARD FROM SOUTH OF REMNANT 
LOW ALETTA NEAR 13.5N 112.6W THROUGH A BROAD AREA OF LOW PRES 
CENTERED NEAR 11N99W TO THE PACIFIC COAST OF CENTRAL AMERICA 
REMAINS VERY ACTIVE CONVECTIVELY E OF 102W. SATELLITE IMAGERY 
SHOWS MODERATE TO STRONG CONVECTION WITHIN 120 NM SW OF THE 
ANCHOR MONSOON LOW NEAR 11N99W. ASCAT PASS AT 1540 UTC SHOWS 
CONVERGENT S-SW WINDS TO 20-25 KT ALTHOUGH MOST OF THE WIND 
BARBS ARE RAIN FLAGGED DUE TO HEAVY CONVECTION. A BROAD UPPER 
LEVEL ANTICYCLONE CENTERED NEAR 11N93W IS PROVIDING EXCELLENT 
DIFFLUENCE ALOFT AND ENHANCING CONVECTIVE ACTIVITY ALONG AND S 
OF THE MONSOON TROUGH AXIS E OF 102W.

EXPECT THE BROAD AREA OF LOW PRES NEAR 11N99W TO REMAIN NEARLY 
STATIONARY NEAR 10N100W THE NEXT 24-48 HOURS WHILE THE CENTRAL 
PRES GRADUALLY DEEPENS AND THE OUTER WIND FIELD STEADILY GROWS 
AND STRENGTHENS. THIS WILL ALLOW THE MONSOON TROUGH TO BECOME 
MORE FIRMLY ENTRENCHED ACROSS THE E PACIFIC E OF 110W. EXPECT TO 
SEE ENHANCED N-NE WINDS SPILLING ACROSS THE CHIVELA PASS INTO 
THE GULF OF TEHUANTEPEC SUN MORNING THROUGH TUE NIGHT BASED ON 
GFS AND ECMWF MODELS. A KEY FACTOR WILL BE FORMATION OF SURFACE 
TROUGH OVER THE YUCATAN PENINSULA WHILE HIGH PRES BUILDS S ALONG 
THE GULF COAST OF MEXICO. WINDS DOWNSTREAM FROM THE GULF OF 
TEHUANTEPEC WILL SUPPLY POSITIVE VORTICITY TO THE BROAD AREA OF 
LOW PRES EMBEDDED IN THE MONSOON TROUGH...AND MAY ALLOW TROPICAL 
CYCLOGENESIS TO EVENTUALLY OCCUR. GFS AND ECMWF GLOBAL MODELS 
ARE IN FAIRLY GOOD AGREEMENT REGARDING DEVELOPMENT AND MOVEMENT 
OF THE LOW OVER THE NEXT FEW DAYS. ONLY SIGNIFICANT DIFFERENCE 
WAS TIMING...WITH THE GFS ABOUT 6 HRS AHEAD OF THE ECMWF.

GENTLE TO MODERATE TRADE WINDS PREVAIL ELSEWHERE W OF 110W WITH 
SEAS ANALYZED AT 5-6 FT OVER MOST OF THE DISCUSSION AREA OUTSIDE 
OF THE CONVECTIVELY ACTIVE MONSOON TROUGH REGION.

$$
MUNDELL