000
AXPZ20 KNHC 172129
TWDEP 

TROPICAL WEATHER DISCUSSION                                    
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC MON MAR 17 2014

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 
2130 UTC.                           

...SPECIAL FEATURES... 
HIGH PRESSURE IN THE WAKE OF A LATE SEASON COLD FRONT THAT SWEPT
EASTWARD ACROSS THE CENTRAL GULF OF MEXICO THIS AFTERNOON IS 
FORCING COLD AIR THROUGH THE CHIVELAS PASS AND INTO THE GULF OF 
TEHUANTEPEC. 1538 UTC AND 1632 UTC ASCAT PASSES CONFIRMED GALE 
FORCE WINDS...35 KT...HAVE ENTERED THE GULF OF TEHUANTEPEC.  
THESE WINDS ARE EXPECTED TO INCREASE TO 40 KT LATER THIS EVENING
WITH SEAS FORECAST TO BUILD TO 13 FT TONIGHT. THIS GALE EVENT WILL BE 
RATHER SHORT-LIVED AS IT IS EXPECTED TO END BY SUNRISE TUE. WINDS  
WILL QUICKLY DIMINISH TO 15-20 KT AND SEAS WILL SUBSIDE TO LESS THAN 
8 FT BY TUE AFTERNOON. 

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...              
EVIDENCE OF A WEAK MONSOON TROUGH EXTENDS FROM 11N85W TO 05N100W TO 
03N113W. SOME LOW LEVEL WINDS ARE FLOWING INTO THE SEASONAL SOUTHERN 
HEMISPHERIC "SECOND" ITCZ ALONG 04-05S. THE MONSOON TROUGH TRANSITIONS
TO THE ITCZ NEAR 03N113W THROUGH 05N127W TO 04N140W. SCATTERED MODERATE
TO STRONG CONVECTION WAS NOTED FROM 05N TO 08N BETWEEN 83W AND 90W. 

...DISCUSSION... 
A SHARP AND ENERGETIC UPPER TROUGH EXTENDS FROM THE LOWER MS 
RIVER VALLEY SW ACROSS NE MEXICO TO A SHEARED MID LEVEL 
CYCLONE NEAR 21N108W...THEN WNW THROUGH THE MID LEVELS TO A 
WEAKENING MID LEVEL CYCLONE NEAR 23N129W. STRONG SUBSIDENCE IS 
NOTED WITHIN 120-180 NM TO THE S OF THE TROUGH...EXTENDING WELL
SW OF THE S END OF THE BAJA CALIFORNIA PENINSULA. UPPER LEVEL 
RIDGING RESIDES TO THE E AND NW OF THE MAIN MID TO UPPER 
TROUGH. JUST S OF THE AREA OF STRONG SUBSIDENCE LIES A CUT OFF 
LOW...PERSISTING FOR THE PAST SEVERAL DAYS...NEAR 13N117W. THIS 
LOW HAS ACTED IN PHASE WITH ANOTHER UPPER CYCLONE ALMOST DUE S 
AND OCCURRING IN THE SOUTHERN HEMISPHERE NEAR 08S127W...TO 
PRODUCE DEEP LAYERED WLY FLOW ALOFT STRADDLING BOTH SIDES OF THE 
EQUATOR...AND CREATING A ZONE OF STRONG VERTICAL WIND SHEAR AND 
UPPER CONVERGENCE. THE CUT OFF LOW IS WEAKENING AND HAS BEGUN TO 
BE SHUNTED E-SE BY THE UPPER TROUGH ACROSS MEXICO...AND 
ASSOCIATED UPPER FLOW ALONG THE EQUATOR HAS BECOME MORE NW TO 
SE. A LARGE AREA OF UPPER DIVERGENCE PERSISTING WELL TO THE SE 
OF THE CUT OFF LOW THAT PAST FEW DAYS HAS BEEN VENTING DEEP 
CONVECTION N OF THE ITCZ. HOWEVER THIS UPPER DIVERGENCE APPEARS 
TO BE SHIFTING NE AND AWAY FROM THE ITCZ...AND THUS CONVECTION 
HAS WEAKENED THIS AFTERNOON. ACTIVE CONVECTION ALONG THE 
ITCZ HAS SHIFTED EWD OF 95W...AND IS OCCURRING UNDERNEATH 
UPPER LEVEL RIDGING. THIS EASTWARD SHIFT OF ACTIVE ITCZ 
CONVECTION IS LIKELY TO PREVAIL FOR THE NEXT 24 HOURS AS THE CUT 
OFF LOW DIGS SE.

AT THE SURFACE...BROAD RIDGING EXTENDS INTO THE AREA FROM THE NE 
PACIFIC...AND HAS WEAKENED SLIGHTLY DURING THE PAST 24 HOURS AS 
A COLD FRONT HAS MOVED TO ALONG 32N. THE RIDGE EXTENDS SE TO 
NEAR 14N110W...WHERE A NARROW CONVERGENCE LINE HAS DEVELOPED TO 
PRODUCE THE NARROW LINE OF CONVECTION DESCRIBED ABOVE. DIRECTLY 
S OF THE RIDGE...AND ZONE OF 15-20 KT NE TO ENE TRADEWINDS 
PREVAILS FROM THE ITCZ TO NEAR 20N AND W OF 120W...WHERE SEAS 
ARE CURRENTLY 8 TO 10 FT IN MIXED NW SWELL AND ENE TRADEWIND 
SWELL. LARGE PULSES OF NW SWELL CONTINUE TO MOVE THROUGH THE 
REGIONAL WATERS TODAY AND ARE MAINTAINING SEAS ELSEWHERE TO THE 
N AND NW AT 8 TO 11 FT...WITH A RECENT NEW PULSE OF NW SWELL 
CREATING SEAS OF 9 TO 11 FT ACROSS THE NEAR AND OFFSHORE WATERS 
OF NORTHER BAJA CALIFORNIA...WHICH WILL INCREASE 2-3 FT OVER THE 
NEXT 24 HOURS BEFORE DIMINISHING.

GAP WINDS...
THE PRES GRADIENT OVER FAR NW MEXICO AND THROUGH THE GULF OF CALIFORNIA
HAS WEAKENED SIGNIFICANTLY THIS AFTERNOON...ALLOWING WINDS AND SEAS TO
SUBSIDE TO LESS THAN 20 KT AND 8 FT. A 1716 UTC ASCAT PASS CONFIRMED LIGHT 
WINDS OVER THE SOUTHERN GULF OF CALIFORNIA. 

GULF OF PAPAGAYO...HIGH PRES WILL BUILD SE AND S ACROSS THE GULF OF MEXICO 
AND NW CARIBBEAN WITH THE PRES DIFFERENCE BETWEEN IT AND LOWER PRES OVER 
FAR NW COLOMBIA AND THE SW CARIBBEAN SEA FORECAST TO INDUCE AN INITIAL 
SURGE OF NE-E 20-25 KT WINDS THROUGH THE GULF BEGINNING WED MORNING.  

$$
COBB