000
AXPZ20 KNHC 171619
TWDEP 

TROPICAL WEATHER DISCUSSION                                    
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.                           

...SPECIAL FEATURES... 
A LATE WINTER SEASON COLD FRONT SWEEPING EASTWARD ACROSS THE 
CENTRAL GULF OF MEXICO THIS MORNING IS PRODUCING GALE FORCE 
NORTH TO NORTHWEST WINDS ACROSS MUCH OF THE WESTERN HALF OF THE 
BASIN...WHICH HAS BEGUN TO SPILL THROUGH THE CHIVELAS PASS THIS 
MORNING...AND IS NOW ENTERING THE GULF OF TEHUANTEPEC. NLY WINDS 
OF 20-25 KT ARE EXPECTED TO INCREASE TO GALE FORCE JUST BEFORE 
NOON TODAY...AND INCREASE TO 40 KT BY THIS EVENING. SEAS THERE 
ARE FORECAST TO BUILD TO 10 FT BY AROUND NOON...AND TO 14 FT 
THIS EVENING. THIS GALE EVENT WILL BE RATHER SHORT-LIVED AS IT 
IS EXPECTED TO LAST TO NEAR DAYBREAK TUE BEFORE WINDS QUICKLY 
DIMINISH TO 15-20 KT. SEAS WILL SUBSIDE TO LESS THAN 8 FT BY 
EARLY TUE AFTERNOON. 

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...              
MONSOONAL CIRCULATION REMAINS NON-EXISTENT ACROSS THE AREA AS 
LOW LEVEL WINDS ARE FLOWING INTO THE SEASONAL SOUTHERN 
HEMISPHERIC "SECOND" ITCZ ALONG 04-05S. THE ITCZ EXTENDS FROM 
08N87W TO 08N92W TO 04N105W TO 04N114W TO NEAR 02N130W. 
SCATTERED MODERATE TO STRONG CONVECTION NOTED WITHIN 150 NM 
EITHER SIDE OF AXIS E OF 95W. SCATTERED MODERATE TO STRONG 
CONVECTION NOTED WITH 45 NM EITHER SIDE OF LINE FROM 10N114.5W 
TO 07.5N123W.

...DISCUSSION... 
A SHARP AND ENERGETIC UPPER TROUGH EXTENDS FROM THE LOWER MS 
RIVER VALLEY SW ACROSS NE MEXICO TO A WEAKENING MID LEVEL 
CYCLONE NEAR 22N108W...THEN WNW THROUGH THE MID LEVELS TO A 
WEAKENING MID LEVEL CYCLONE NEAR 23N128W. STRONG SUBSIDENCE IS 
NOTED WITHIN AND TO S OF THE TROUGH...EXTENDING FROM THE S TO 
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 14N140W. 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 
THERE HAS WEAKENED THIS MORNING. ACTIVE CONVECTION ALONG THE 
ITCZ HAS THUS 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 35N. THE RIDGE EXTENDS SE TO 
NEAR 16N113W...WHERE A NARROW CONVERGENCE LINE HAS DEVELOPED TO 
PRODUCE THE NARROW LINE OF CONVECTION DESCRIBED ABOVE. DIRECTLY 
S OF THE RIDGE...AND ZONE OF 15-25 KT NE TO ENE TRADEWINDS 
PREVAILS FROM THE ITCZ TO NEAR 20N AND W OF 120W...WHERE SEAS 
ARE CURRENTLY 7 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 12 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 24-26 HOURS BEFORE DIMINISHING.

GAP WINDS...
THE TIGHTENING OF THE PRES GRADIENT OVER FAR NW MEXICO AND 
THROUGH THE GULF OF CALIFORNIA YESTERDAY AND LAST NIGHT 
CONTINUES TO WEAKEN THIS MORNING...ALLOWING WINDS AND SEAS TO 
BEGIN TO SUBSIDE ACROSS THE GULF BASIN...WITH STRONG WINDS NOW 
CONFINED TO THE S HALF OF THE BASIN EXTENDING S TO 21N...WITH 
PEAK SEAS THIS MORNING ESTIMATED AT 8 FT. GUIDANCE SUGGESTS THAT 
THESE WINDS WILL DIMINISH TO AROUND 10-15 KT LATER THIS 
MORNING...AND SEAS LOWER TO 2-4 FT IN THE NORTHERN HALF OF THE 
GULF....AND ABATE MORE GRADUALLY IN THE SOUTHERN 
HALF...DIMINISHING TO AROUND 15 KT AND 4-6 FT BY LATE AFTERNOON. 

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 LATE WED NIGHT. 

$$
STRIPLING