000
AXPZ20 KNHC 242203
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC WED OCT 24 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 
2145 UTC.

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

MONSOON TROUGH EXTENDS FROM 12N86W TO LOW PRES NEAR 12N95W 1008 
MB TO 10N107W TO 08N124W...WHERE IT TRANSITIONS TO ITCZ 
CONTINUING TO 08N135W AND TO BEYOND 08N140W. SCATTERED MODERATE 
ISOLATED STRONG CONVECTION IS WITHIN 240 NM S OF TROUGH E OF 
90W...S OF TROUGH BETWEEN 96W AND 104W AND WITHIN 120 NM S OF 
TROUGH BETWEEN 104W AND 109W. SIMILAR ACTIVITY EXISTS
FROM 09N TO 13N BETWEEN 110W AND 117W.

...DISCUSSION...

A NEARLY STATIONARY LARGE ANTICYCLONE IS CENTERED AT 20N111W 
WITH IS ASSOCIATED ANTICYCLONIC ENVELOP COVERING THE AREA THE 
VAST MAJORITY OF THE SE PORTION. WITH THIS FEATURE IN PLACE...
THE UPPER FLOW REMAINS STAGNANT AS IT CAUSING NORTHERN STREAM  
TO CONTINUE TO LIFT OVER AND ACROSS THE ANTICYCLONE..AND INTO
THE BACK SIDE OF AN UPPER TROUGH OVER THE WESTERN CONUS.
A LARGE POOL OF ABUNDANT TROPICAL MOISTURE PREVAILS ACROSS THE 
TROPICS FROM 06N TO 13N E OF 120W...WITH CONVECTION DESCRIBED 
ABOVE BEING INITIATED BY MODERATE TO FRESH MONSOONAL FLOW S OF 
THE TROUGH. UPPER LEVEL ELY WINDS S OF THE UPPER RIDGE CONTINUE 
TO DIVERT AROUND THE DEEPER CONVECTION S OF THE MONSOON TROUGH. 
THIS UPPER PATTERN WILL CHANGE LITTLE IN THE NEXT 24 HOURS BUT 
WILL BEGIN TO BROADEN AND FLATTEN BY FRI AS UPPER TROUGHING DIGS 
SW ACROSS CENTRAL AMERICA NEAR 90W.

AN AREA OF BUILDING HIGH PRES OVER THE NORTH CENTRAL WATERS 
CENTERED NEAR 30N130W WILL SHIFT E ALONG 31N THROUGH THU. THE 
PRESENCE OF A LOW PRES TROUGH OVER NW MEXICO AND BAJA CALIFORNIA 
WILL TIGHTEN THE P1RES GRADIENT OVER THE NE PORTION...BRINGING 
FRESH TO STRONG N-NW WINDS ACROSS THE NEAR AND OFFSHORE WATERS W 
OF THE BAJA PENINSULA. EXPECT 20-25 KT WINDS TO GRADUALLY EXPAND 
SWD TO NEAR 24N BY THU BETWEEN 115W AND 125W...WITH SEAS BUILDING
TO 10 FT. GLOBAL MODELS ARE HINTING AT THE POSSIBILITY OF WINDS 
INCREASING TO 30 KT N OF 29N ACROSS THE REGION THU...RAISING 
SEAS TO 11 FT. THIS ENHANCED PRES GRADIENT WILL ALSO INDUCE NNW 
WINDS 20-25 KT THROUGH THE NORTHERN TWO-THIRDS OF THE GULF OF 
CALIFORNIA BY THU EVENING CONTINUING THROUGH FRI...WITH SEAS 
BUILDING TO 8 FT BY FRI MORNING.

THE LARGE CYCLONIC CIRCULATION ASSOCIATED WITH HURRICANE SANDY 
IN THE W CENTRAL CARIBBEAN IS STRENGTHENING W-SW WIND FLOW S OF 
THE MONSOON TROUGH EXTENDING INTO THE COASTAL WATERS OF 
NICARAGUA....COSTA RICA...AND PANAMA...WHERE SEAS ARE REACHING 
AT OR NEAR 8 FT. MOIST CONVERGENT MONSOONAL FLOW WILL PRODUCE 
WIDESPREAD AREAS OF RAIN WITH OCCASIONAL MODERATE TO HEAVY 
SQUALLS ACROSS PANAMA AND COSTA RICA...GRADUALLY SHIFTING N INTO 
NICARAGUA THROUGH THU...WITH STRONG GUSTY WINDS POSSIBLE IN 
HEAVIER DOWNPOURS.

SCATTEROMETER DATA FROM THIS AFTERNOON SHOWED FRESHENING N WINDS 
20-25 KT WITH A SMALL AREA TO 30 KT THROUGH THE GULF OF 
TEHUANTEPEC. CYCLONIC FLOW AROUND TROPICAL STORM SANDY IN 
COMBINATION WITH A WEAK RIDGE THAT NOSES SOUTHWEST ACROSS THE SE 
GULF OF MEXICO IS SUPPORTING ENHANCED WINDS THROUGH THE ISTHMUS 
OF TEHUANTEPEC...WHICH ARE EXPECTED TO PULSE BETWEEN 15-30 KT 
THROUGH EARLY THU...THEN PULSE 15-25 KT THROUGH FRI.

THE ASCAT PASS FROM 1612 UTC THIS MORNING REVEALED A COUPLE
OF WEAK CYCLONIC CIRCULATIONS EMBEDDED ALONG THE MONSOON TROUGH
...ONE AT 11N94W AND THE OTHER NEAR 11N117W. THIS FALLS IN LINE
WITH THE LATEST GLOBAL MODEL GUIDANCE...AND THAT FROM THE
PAST FEW DAYS. EXPECT THESE WEAK FEATURES TO PERSIST THROUGH
AT LEAST THE NEXT 48 HRS WITH LITTLE SIGNIFICANT INTENSIFICATION 
EXPECTED. THIS WILL HELP KEEP A CONVERGENCE ZONE OF FAIRLY 
ACTIVE CONVECTION E OF 125W THROUGH THIS PERIOD.

$$
AGUIRRE