000
AXPZ20 KNHC 190218
TWDEP 

TROPICAL WEATHER DISCUSSION      
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC FRI MAY 18 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

...SPECIAL FEATURE...
AT 2100 UTC...TROPICAL DEPRESSION ALETTA CENTERED NEAR 14.4N 
113.5W MOVING NE OR 40 DEG AT 3 KT. ESTIMATED MINIMUM PRES 1006 
MB. MAXIMUM SUSTAINED WINDS 30 KT GUSTS 40 KT. PLEASE REFER TO 
THE LATEST PUBLIC ADVISORY TCPEP1/WTPZ31 KNHC FOR MORE DETAILS. 
SCATTERED MODERATE CONVECTION IS WITHIN 90 NM NE QUADRANT OF 
ALETTA. ALETTA WILL CONTINUE TO WEAKEN THE NEXT 12 TO 24 HOURS.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
MONSOON TROUGH EXTENDS FROM 08N83W TO 09N90W TO 1007 MB LOW PRES 
NEAR 13N101W TO 14N110W. ITCZ EXTENDS FROM 09N120W TO 05N129W TO 
06N140W. SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 120 NM
OF 13N100W. SCATTERED MODERATE ISOLATED STRONG CONVECTION FROM 
03N TO 09N E OF 99W.

...DISCUSSION...
A BROAD AREA OF LOW PRES IS EMBEDDED WITHIN THE MONSOON TROUGH 
AND CENTERED NEAR 13N101W. CONVECTIVE ACTIVITY ASSOCIATED WITH 
THIS DISTURBANCE HAS BECOME MORE CONCENTRATED NEAR THE SYSTEM 
CENTER BUT CONVECTIVE ORGANIZATION CHARACTERIZED BY LOW LEVEL 
CLOUD LINES AND CONVECTIVE BANDING HAS BECOME LESS ORGANIZED. 
THIS DISTURBANCE IS EXPECTED TO SLOWLY DEVELOP AND MAY EVENTUALLY
INTENSIFY INTO A TROPICAL CYCLONE. BUT THERE IS A LOW 20 PERCENT 
CHANCE IT WILL BECOME A TROPICAL CYCLONE IN THE NEXT 48 HOURS.

CONVECTIVE ACTIVITY REMAINS FAIRLY ACTIVE S OF THE MONSOON TROUGH
EAST OF 100W. A WEAK SURFACE RIDGE IS ANALYZED NW OF T.D. ALETTA.
SCATTEROMETER DATA SHOWS WINDS TO 20 KT N OF 29N E OF 123W...WITH
SEAS ABOUT 8 FT IN N-NW SWELL GENERATED N OF THE AREA ALONG THE 
COAST OF CALIFORNIA. AN ASCAT PASS AT 1420 UTC SHOWED 20-30 KT S 
TO SW WINDS IN THE GULF OF PANAMA...BUT SHIP OBS DID NOT INDICATE
WINDS MORE THAN 15 KT. IT APPEARS THE SCAT PASS WAS CONTAMINATED 
BY WIDESPREAD DEEP CONVECTION IN THE AREA AT THE TIME. THEREFORE 
DO NOT EXPECT SIMILAR STRONG WINDS TO SHOW UP ON NEXT SCAT PASS.

EXPECT THE MONSOON TROUGH E OF 115W TO CONTINUE TO BE PRIMARY 
SYNOPTIC FEATURE THROUGH THE WEEKEND. GLOBAL MODEL GUIDANCE 
SHOWS THE LOW CURRENTLY NEAR 100W GRADUALLY BECOMING BETTER 
ORGANIZED SUN AND MON AS ENHANCED N-NE FLOW DOWNSTREAM FROM THE 
GULF OF TEHAUNTEPEC PROVIDES ADDITIONAL LOW LEVEL VORTICITY TO 
THE SYSTEM. GENTLE TO MODERATE TRADE WINDS WILL PREVAIL W OF 
120W WITH SEAS SUBSIDING TO 4-6 FT ACROSS MOST OF THE DISCUSSION 
AREA BY SUN.

$$
MUNDELL