000
AXPZ20 KNHC 181603
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC MON NOV 18 2013

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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1545 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... 

THE MONSOON TROUGH AXIS AXIS EXTENDS FROM 08N79W TO 09N89W TO 
08N100W TO 07N112W WHERE WHERE LOW LEVEL WINDS SUGGEST A 
TRANSITION TO ITCZ AXIS EXTENDS TO 06N122W TO 10N130W.TO 07N105W 
WHERE LOW LEVEL WINDS SUGGEST A TRANSITION TO ITCZ WHICH EXTENDS 
TO 07.5N121W TO 12N128W TO BEYOND 08N140W. SCATTERED 
MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 120 M N OF THE 
MONSOON TROUGH BETWEEN 94W-98W. 

...DISCUSSION... 

AN UPPER TROUGH EXTENDS FROM CENTRAL CALIFORNIA SW TO A SMALL 
UPPER LEVEL LOW NEAR 20N135W MOVING S...AND TO W OF THE AREA 
NEAR 10N142W. THE ASSOCIATED SURFACE COLD FRONT IS JUST W OF THE 
DISCUSSION AREA THROUGH 32N143W TO 27N150W WHERE IT BECOMES A 
STATIOANRY FRONT TO JUST NW OF THE HAWAIIAN ISLANDS. THE TROUGH 
IS TAPPING DEEP TROPICAL CENTRAL PACIFIC MOISTURE NOTED AS 
MOSTLY BROKEN MID/UPPER LEVEL CLOUDS STREAMING NEWD WITHIN ABOUT 
330 NM SW OF THE TROUGH. WITHIN THIS MOISTURE PLUME SCATTERED 
SHOWERS AND ISOLATED TSTMS ARE NOTED. ELSWHERE OVER THE AREA E 
OF THE TROUGH...GENERALLY BROAD RIDGING COVERS THE AREA WITH 
RESULTANT MODERATE TO STRONG SUBSIDENCE NOTED ALOFT. THIS IS 
KEEPING A FAIRLY DRY AND STABLE ATMOSPHERIC ENVIRONMENT IN 
PLACE. THE EXCEPTION IS OVER THE FAR EASTERN PORTION WHERE ELY 
FLOW ALOFT S OF AN ANTICYCLONE CENTERED OVER NE GUATEMALA IS 
ADVECTING UPPER LEVEL DEBRIS SCATTERED TO BROKEN CLOUDS FROM 
MONSOON TROUGH CONVECTION MENTIONED ABOVE AS WELL AS FROM 
SCATTERED MODERATE/ISOLATED STRONG CONVECTION OVER THE FAR 
EASTERN PORTION FROM 04N-08N BETWEEN 79W-83W.

THE UPPER TROUGH WILL SHIFT EWD TO THE FAR NE PORTION OF THE 
AREA BY TUE EVENING WITH THE UPPER LEVEL LOW HANGING BACK NEAR 
19N135W. THE SURFACE COLD FRONT SHOULD REACH APPROACH THE FAR NW 
CORNER OF THE AREA LATE TUE NIGHT INTO WED...BUT SHOULD BE IN A 
WEAKENED STATE WITH THE UPPER SUPPORT WELL TO THE NE. 
PRESENTLY... MODEL GUIDANCE ONLY DEPICTS SW WINDS OF ABOUT 15-20 
KT TO MOVE INTO THE FAR NW CORNER BY THAT TIME WITH SEAS OF 
ABOUT 4-6 FT.

ELSEWHERE AT THE SURFACE...A 1023 MB HIGH CENTER IS ANALYZED 
NEAR 31N124W WITH A RIDGE EXTENDING SEWD TO NEAR 31N112W. 
DESPITE THE PROXIMITY OF THE AREA OF HIGH PRES TO THE ITCZ...THE 
PRES GRADIENT BETWEEN THESE FEATURES IS ONLY ALLOWING FOR GENTLE 
TO MODERATE TRADES N OF THE ITCZ AS WAS DETECTED BY ASCAT DATA 
FROM OVERNIGHT LAST NIGHT. AN ALTIMETER PASS FROM 1530 UTC THIS 
MORNING REVEALED SEAS IN THE RANGE OF 5-7 FT OVER THE MAJORITY 
OF THE CENTRAL PORTION OF THE AREA.

THE 1023 MB HIGH IS FORECAST TO MOVE SW TO NEAR 28N128W IN 24 
HRS WHILE WEAKENING SOME MAINTAINING A RATHER LOOSE PRES GRADIENT 
OVER JUST ABOUT ENTIRE THE ENTIRE DISCUSSION DOMAIN. WITH THE 
WEAK PRESSURE GRADIENT AND NO SIGNIFICANT SWELLS OR GAP WIND 
EVENTS OVER THE NEXT COUPLE OF DAYS...WINDS AND SEAS WILL REMAIN 
BELOW ADVISORY CRITERIA OVER THE MAJORITY OF THE FORECAST AREA. 
THE ONE EXCEPTION WILL RESULT FROM A DEEPENING TROUGH OVER 
MEXICO WHICH WILL TIGHTEN THE PRESSURE GRADIENT OFF THE BAJA 
COAST AND STRENGTHEN THE NW-N WINDS N OF 28N E OF 117W BY EARLY 
WED WITH SEAS THERE GRADUALLY BUILDING TO 8 FT.

$$
AGUIRRE