000
AXPZ20 KNHC 220955
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SUN APR 22 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.

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

MONSOON TROUGH FROM 06N77W TO 06N95W. ITCZ EXTENDS FROM 05N97W 
TO 03N115W TO 06N125W TO 03N140W. SCATTERED MODERATE TO STRONG 
CONVECTION NOTED WITHIN 210 NM S OF ITCZ BETWEEN 97W TO 105W. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION NOTED FROM 06N TO 
10N BETWEEN 107W AND 124W.

...DISCUSSION...

ALOFT...A STRONG BLOCKING RIDGE PERSISTS ACROSS THE NE PORTIONS 
OF THE AREA THIS MORNING...CENTERED ON AN UPPER ANTICYCLONE OVER 
NEW MEXICO NEAR 35N114W...WITH SHARP TROUGHS TO THE E AND W OF 
THIS FEATURE. NEARLY ZONAL FLOW PREVAILS FROM 10N TO 20N. A 
TROPICAL UPPER JET IS FOUND TO THE S OF THE SHARP UPPER TROUGH 
APPROACHING NW PORTIONS...FROM ABOUT 10N TO 15N BETWEEN 135W AND 
160W.   

THE MAIN ISSUE FOR THE NEXT 48 HOURS CONTINUES TO BE THE 
DEVELOPMENT OF GALE FORCE WINDS THROUGH THE GULF OF TEHUANTEPEC 
WHICH HAS RECENTLY BEGUN...DUE TO A UNSEASONABLY STRONG COLD 
FRONT PUSHING THROUGH THE GULF OF MEXICO. HIGH PRES WILL BUILD 
OVER THE SOUTHERN PLAINS AND NW GULF AS A DEEP LAYERED LOW PRES 
SYSTEM PUSHES E ACROSS THE EXTREME NE GULF IN THE NEXT FEW 
HOURS. STRONG GAP WIND FLOW BEHIND THE FRONT HAS SURGED SOUTH 
THROUGH THE CHIVELA PASS AND THE GULF OF TEHUANTEPEC. A 0406 UTC 
ASCAT PASS DEPICTED AN UNUSUALLY WIDE PLUME OF NLY WINDS 
SPILLING DUE S ACROSS THE GULF OF TEHUANTEPEC TO 14N...WITH GALE 
FORCE WINDS ACROSS W PORTIONS. THESE WINDS MAY DIMINISH SLIGHTLY 
BELOW GALE FORCE LATER TODAY...BUT WILL INCREASE AGAIN IN EXCESS 
OF GALE FORCE SUN NIGHT DUE TO STRONG HIGH PRES BUILDING BEHIND 
THE FRONT OVER THE WESTERN GULF OF MEXICO AS WELL AS NOCTURNAL 
DRAINAGE INFLUENCES. THE STRONG GAP FLOW WILL PERSIST THROUGH 
MON...CREATING A LONG PLUME OF NE TO E WINDS WITH FRESH NE SWELL 
WITH HEIGHTS OF 8 TO 11 FT REACHING AS FAR AS 800 NM SW OF THE 
GULF OF TEHUANTEPEC. 

ELSEWHERE S OF 20N...WEAK HIGH PRES CENTERED ACROSS NE PORTIONS 
OF THE AREA WILL MAINTAIN GENERALLY LIGHT TO MODERATE TRADE WIND 
FLOW FROM ROUGHLY 06N TO 20N W OF 110W THROUGH EARLY NEXT WEEK. 
LIGHT SW TO W MONSOONAL FLOW WILL REMAIN E OF 95W AND PROVIDE 
ENOUGH LOW LEVEL CONVERGENCE TO SUPPORT SCATTERED S OF THE ILL 
DEFINED MONSOON TROUGH. 

N OF 20N...THE SHARP UPPER TROUGH APPROACHING NW PORTIONS 
CONTINUES TO MAKE VERY SLOW AND MODEST PROGRESS EASTWARD DUE TO 
THE BLOCKING UPPER RIDGE. AN ASSOCIATED COLD FRONT HAS MOVED 
INTO THE AREA FROM 30N137.5W TO 28N140W AND WILL CONTINUE TO 
SHIFT VERY SLOWLY EASTWARD AS IT PUSHES INTO A 1017 MB SURFACE 
HIGH NEAR 38N129W ASSOCIATED WITH THE BLOCKING MID/UPPER RIDGE.  
SURFACE RIDGING EXTENDS TO THE SE ALONG THE COAST OF MEXICO NEAR 
15N105W. THE FRONT WILL REACH FROM 30N128W TO 24N135W BY 18Z MON 
BEFORE STARTING TO STALL AND WEAKEN FROM 35N127W TO 23N130W BY 
18Z TUE. THE HIGH PRES WILL ALSO ALLOW WINDS TO REMAIN FAIRLY 
LIGHT N OF 20N INTO EARLY NEXT WEEK. GLOBAL MODEL CONSENSUS 
SHOWS FRESH TO STRONG NW FLOW WILL FOLLOW THE COLD FRONT OVER 
THE FAR NW PORTION OF THE DISCUSSION AREA BY LATE MON... 
ACCOMPANIED BY NW SWELL YIELDING SEAS OF 8 TO 12 FT.

$$
STRIPLING