000
AXPZ20 KNHC 192134 RRA
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC MON NOV 19 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.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
MONSOON TROUGH EXTENDS FROM 09N79W TO 06N92W THEN THE ITCZ AXIS 
CONTINUES TO 08.5N111W TO 06N130W TO 08N140W. SCATTERED MODERATE 
CONVECTION CAN BE FOUND FROM 06N TO 10N BETWEEN 111W AND 115W... 
AND FROM 05N TO 09N W OF 120W.

...DISCUSSION...
ALOFT...AN UPPER LEVEL TROUGH EXTENDS FROM NORTHERN BAJA 
CALIFORNIA TO NEAR 20N123W. STRONG NW JET TO 80 KT IS DIVING SE 
THROUGH BASE OF THE TROUGH. STRONG SW FLOW TO 70 KT IS NOTED 
AHEAD OF THE TROUGH AXIS N OF 22N THROUGH CENTRAL BAJA 
CALIFORNIA AND NW MEXICO INTO THE SW CONUS WHERE WINDS INCREASE 
TO 110 KT. THESE STRONG WINDS ARE ADVECTING ABUNDANT MID/UPPER 
LEVEL MOISTURE. SATELLITE IMAGERY CONTINUES TO SHOWS A WIDE BAND 
OF TRANSVERSE HIGH CLOUDS IN ASSOCIATION WITH THIS JET. 
DOWNSTREAM UPPER RIDGE HAS SHIFTED SLIGHTLY EWD DUE TO DIGGING 
UPPER TROUGH...AND REMAINS CENTERED ON ANTICYCLONE NEAR 
15N100W...AND COVERS THE AREA N OF 10N BETWEEN 90W AND 115W. 
TO THE E OF THE RIDGE...PERSISTENT UPPER TROUGH EXTENDS FROM A 
CUT-OFF LOW JUST OFF THE SE U.S. COAST...S-SW ACROSS THE NW 
BAHAMAS AND THE NW CARIBBEAN TO CENTRAL AMERICA NEAR 14N90W. A 
LINGERING TUTT AXIS STRETCHES FROM 10N89W TO A CYCLONIC 
CIRCULATION NEAR 04N111W. SW FLOW IS NOTED E OF 90W FROM THE 
EQUATOR ACROSS COSTA RICA AND PANAMA INTO THE CARIBBEAN SEA. 
MODERATE TO STRONG SUBSIDENCE OCCURRING N OF THE TUT AXIS 
CONTINUES TO DOMINATE THE AREA E OF 110W...AND IS LIMITING 
CONVECTION ALONG THE MONSOON TROUGH AND THE ITCZ AXIS.  

AT THE SURFACE...A 1025 MB HIGH PRES CENTER HAS DEVELOPED OVER 
THE N WATERS NEAR 29N124W...AND EXTENDS A RIDGE SE TO NEAR 
19N111W. PRES GRADIENT BETWEEN THE RIDGE A LOWER PRES ALONG THE 
ITCZ IS PRODUCING A BELT OF TRADE WINDS 20-25 KT FROM 09N TO 20N 
W OF 120W. THIS WEATHER PATTERN WILL PERSIST OVER THE NEXT 
COUPLE OF DAYS...WHICH WILL MAINTAIN A FAIRLY BROAD ZONE OF 
FRESH TO STRONG TRADE WITH SEAS OF 8 TO 10 FT ACROSS THIS AREA. 

LONG PERIOD NW SWELL CONTINUES TO INVADE THE REGIONAL WATERS 
MAINLY W OF 110W AND NOW ARE RAISING SEAS TO 10 FT N OF 20N W OF 
116W. THESE SWELLS WILL COMBINE WITH NE WIND WAVES DEVELOPING 
WITHIN THE TRADE WIND ZONE TO MAINTAIN COMBINED SEAS OF 8 TO 10 
FT WITHIN THE TRADE WIND BELT. THE NEXT COLD FRONT IS FORECAST 
TO REACH THE FAR NW PORTION OF THE AREA LATE TUE THEN MOVE BACK 
N OF AREA AND DISSIPATE BY WED AS ANOTHER STRONGER COLD FRONT 
MOVES ACROSS THE NE PACIFIC. NW SWELL IN THE WAKE OF THE FRONT 
WILL THEN SPREAD E AND SE ACROSS THE NW WATERS RAISING SEAS TO 
12 FT BY EARLY WED.

GAP WINDS...
PERSISTENT NORTHERLY WINDS OF 25-30 KT ARE BLOWING THROUGH THE 
GULF OF TEHUANTEPEC...AS MODERATE NLY WINDS CONTINUE ACROSS THE 
SW GULF OF MEXICO. WINDS EXITING THE CHIVELAS PASS CONTINUE TO 
BE ENHANCED BY NOCTURNAL DRAINAGE FLOW ACROSS THE GULF OF 
TEHUANTEPEC...AND HAVE BEEN REACHING MINIMAL GALE FORCE ROUGHLY 
BETWEEN 0600 AND 1200 UTC EACH OF THE PAST FEW DAYS. GLOBAL 
MODELS SUGGEST THAT THIS PATTERN WILL CONTINUE THROUGH WEDNESDAY 
BEFORE WINDS ACROSS THE SW GULF BEGIN TO TURN MORE E AND 
DIMINISH INFLUENCE ACROSS THE CHIVELAS PASS. A GALE WARNING 
THEREFORE REMAINS IN EFFECT FOR THE GULF TEHUANTEPEC THROUGH 
WEDNESDAY MORNING...WITH WINDS LIKELY AT OR JUST BELOW GALE 
FORCE OCCURRING DURING THE AFTERNOON HOURS. SEE LATEST NHC HIGH 
SEAS FORECAST UNDER AWIPS/WMO HEADERS HSFEP2/FZPN03 KNHC FOR 
DETAILS. 

PULSING OF NOCTURNAL WINDS ARE ALSO EXPECTED TO CONTINUE ACROSS 
THE GULF OF PAPAGAYO...WITH NOCTURNAL WINDS FORECAST TO REACH 
AROUND 20 KT FROM 0600 TO 1200 UTC...WITH SEAS OF 6-7 FT THROUGH 
AND DOWNWIND OF THE GULF.  

$$
GR