000
AXPZ20 KNHC 300344
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC MON JAN 30 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 
0315 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
MONSOON TROUGH EXTENDS FROM LOW PRES NEAR 06N76W 1008 MB TO 
03N78W TO 05N85W TO 03N94W...WHERE IT TRANSITIONS TO ITCZ 
AXIS...CONTINUING ON TO 02N98W TO 05N112W TO BEYOND 04N140W. 
SCATTERED MODERATE CONVECTION NOTED WITHIN 180 NM S OF AXIS FROM 
83W AND 87W. 

...DISCUSSION...
A SHARP MIDDLE TO UPPER LEVEL TROUGH HAS BECOME WELL ESTABLISHED 
ACROSS W PORTIONS OF THE AREA DURING THE PAST 12 TO 18 
HOURS...CURRENTLY EXTENDING FROM 33N133W TO A DEEP LAYERED 
CYCLONE CENTERED NEAR 12N149W...WITH BROAD TROUGH EXTENDING S 
ACROSS THE EQUATOR. THE DEEP LAYERED CYCLONE HAS BECOME CUT OFF 
FROM THE MEAN FLOW WITH A LOW AMPLITUDE RIDGE DOWNSTREAM TO THE 
E...S OF 20N CENTERED ALONG 129W. DOWNSTREAM OF THIS FLAT 
RIDGE...A BROAD AND NEGATIVELY TILTED TROUGH EXTENDS FROM THE 
REMNANTS OF A SHEARED AND STRETCHED TROUGH NEAR 22N130W TO A 
SHARP BASE NEAR 08N106W. THIS TROUGH WILL CONTINUE TO DRIFT NE 
THROUGH MONDAY NIGHT AND ACT TO VENTILATE CONVECTION OCCURRING 
TO ITS E...AS THE COUPLED CONVECTION SHIFTS N AND NE WITH THE 
TROUGH. TO THE N OF THIS... A SHARP MIDDLE TO UPPER LEVEL TROUGH 
EXTENDS FROM A MIDDLE LEVEL CYCLONE NEAR 25N107W TO 
19N120W...WITH A 60-70 KT JET SEGMENT TO THE S OF THE TROUGH 
HELPING TO MAINTAIN FAVORABLE ANTICYCLONIC SHEAR ACROSS THE 
AFOREMENTIONED CONVECTION. 

AT LOWER LEVELS...A LARGE POOL OF ABUNDANT TROPICAL MOISTURE 
CURRENTLY EXTENDS FROM THE ITCZ N TO AS FAR N AS 17N BETWEEN 99W 
AND 123W...TRAPPED BETWEEN THE EPAC HIGH PRES RIDGE...THE 
ITCZ...AND GAP WIND FLOW SPILLING OUT OF THE GULF OF TEHUANTEPEC 
AND MERGING WITH THE WEAK NE TRADEWINDS. THE INCREASING LOW 
LEVEL FLOW UPSTREAM COMING FROM THE GULF OF TEHUANTEPEC HAS 
INCREASED THE LOW LEVEL FORCING ACROSS THIS UNSTABLE AREA THIS 
AFTERNOON AND EVENING...RESULTING IN A CONTINUED BURST OF DEEP 
CONVECTION FROM 11N TO 15N BETWEEN 101W AND 109W...WITH FREQUENT 
LIGHTNING STRIKES INDICATED BY THE GLOBAL LIGHTNING 
NETWORK...AND CLOUD TOPS TO -64 C. AS MENTIONED ABOVE...THIS 
AREA OF ACTIVE CONVECTION IS EXPECTED TO SHIFT SLIGHTLY N AND NE 
DURING THE NEXT 36 HOURS.

THE WEAKENING EPAC SURFACE HIGH PRES RIDGE COVERS THE AREA N OF 
16N W OF 120W...AND WILL SHIFT W DURING THE NEXT 24 HOURS. A 
SMALL AREA OF NE TRADES AT 20 KT ARE OBSERVED ALONG THE SOUTHERN 
PERIPHERY OF THE THE RIDGE FROM 07N TO 12N W OF 136W...WITH SEAS 
TO 8 FT.

STRONG HIGH PRES BUILDING OVER THE SOUTHERN U.S. HAS ONCE AGAIN 
TIGHTENED THE PRES GRADIENT ACROSS SOUTHERN MEXICO RESULTING IN 
GALE FORCE WINDS TO 40 KT THROUGH THE GULF OF TEHUANTEPEC THIS 
EVENING. GALE CONDITION ARE EXPECTED TO CONTINUE THROUGH EARLY 
MON AFTERNOON...THEN DECREASE TO BELOW GALE FORCE.

ELY WINDS OF 20 TO 25 KT CONTINUE TO BLOW THROUGH THE GULF OF 
PAPAGAYO AND EXTEND DOWNSTREAM TO 92W...AND ARE AIDING IN 
INITIATING SHOWERS AND TSTMS ALONG THE MONSOON THROUGH THERE. 
THIS STRONG GAP WIND FLOW IS EXPECTED TO PERSIST THROUGH TUE AND 
EXPAND DOWNSTREAM TO BEYOND 100W...WITH SEAS BUILDING TO 9 FT.

$$
STRIPLING