000
AXPZ20 KNHC 191007
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC MON MAR 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0930 UTC.

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

THE ITCZ AXIS EXTENDS FROM 03N128W TO BEYOND 01N140W. NO 
SIGNIFICANT DEEP CONVECTION. 

...DISCUSSION...

A STRONG COLD FRONT ASSOCIATED WITH A DEEP LAYERED HIGH 
AMPLITUDE AND VERY ENERGETIC TROUGH ACROSS THE WESTERN U.S. HAS 
CONTINUED TO MOVE SE OVERNIGHT...AND THROUGH THE SOUTH PORTIONS 
OF BAJA CALIFORNIA AND THE ADJACENT SOUTHERN GULF OF CALIFORNIA 
WATERS...TO NEAR MAZATLAN MEXICO EXTENDING SW TO NEAR 17N115W. A 
0413 UTC ASCAT PASS SHOWED STRONG W WINDS TO 30 KT ACROSS FAR N 
PORTIONS OF THE GULF THAT VEERED NWLY TO AROUND 20 KT SOUTHWARD 
TO ABOUT 27N...WITH WINDS S OF THERE MUCH LIGHTER AND VARIABLE. 
MEANWHILE...NW WINDS 20-25 KT WERE DEPICTED ALONG THE W COAST OF 
THE BAJA PENINSULA EXTENDING OUT 90 NM FROM THE W COAST. ACTIVE 
CONVECTION OCCURRING BEHIND THE FRONT AND ACROSS N PORTIONS OF 
THE GULF THIS EVENING HAS SHIFTED E AND NE AND WILL INLAND 
ACROSS MEXICO...LEAVING THE GULF WATERS MOSTLY CLEAR AT THIS 
TIME. THE FRONT WILL BE NUDGED SLIGHTLY SE AND INLAND ACROSS 
MEXICO THIS MORNING AND THE AREA OF FRESH WINDS WILL SHIFT 
SOUTHWARD ALONG THE BAJA PENINSULA AND THE MAINLAND MEXICAN 
COAST TO CABO CORRIENTES BY TUE EVENING. MEANWHILE...A 
REINFORCING COLD FRONT WILL SINK S ACROSS THE FAR NE WATERS AND 
BAJA CALIFORNIA NORTE LATE THIS AFTERNOON AND 
EVENING...ACCOMPANIED BY NW WINDS 20-25 KT JUST AHEAD OF THE 
FRONT. THIS FRONT WILL CONTINUE TO MOVE SE AND REACH BAJA 
CALIFORNIA SUR BY TUE AFTERNOON AND DISSIPATED. NORTHWEST SWELL 
ASSOCIATED WITH THE FIRST FRONT CONTINUES TO PRODUCE SEAS AS 
HIGH AS 17 FEET OFFSHORE OF THE W COAST OF BAJA CALIFORNIA 
NORTE. THESE SEAS WILL SUBSIDE TO LESS THAN 12 FEET BY EARLY TUE 
MORNING. 

THE BROAD SUBTROPICAL RIDGE IS RAPIDLY FILLING IN BEHIND THE 
FIRST FRONT...ANCHORED ON A 1028 MB HIGH PRES CENTER NEAR 
30N146W...AND EXTENDS SE TO 24N114W. THIS RIDGE IS SUPPORTING A 
LARGE AREA OF FRESH TRADE WINDS TO ITS SOUTH ACROSS AN AREA 
BOUNDED BY THE POINTS 24N140W TO 13N117W TO 03N140W. THIS AREA 
OF TRADEWINDS WILL REMAIN RELATIVELY UNCHANGED UNTIL TUE WHEN 
THE SUBTROPICAL HIGH WILL BE WEAKENED AND PUSHED EASTWARD BY AN 
ENCROACHING COLD FRONT. THE AREA OF FRESH TRADES WILL EXPAND TO 
130W BUT THIN OUT FROM NORTH TO SOUTH CONSIDERABLY BY TUE 
EVENING IN RESPONSE TO CHANGES IN THE SUBTROPICAL HIGH.

THE SOUTHERN STREAM UPPER JET IS FOUND ON THE LEADING EDGE OF  
BROAD DEEP-LAYER TROUGH ASSOCIATED WITH THE COLD FRONT OVER NW 
MEXICO. THE JET AXIS LIES FROM 13N123W NEWD TO CENTRAL MEXICO. 
THE JET IS TRANSPORTING TROPICAL MOISTURE IN THE MID AND UPPER 
LEVELS ACROSS CENTRAL MEXICO AND INTO THE W HALF OF THE GULF OF 
MEXICO. 

ACROSS E PORTIONS...LIGHT TO MODERATE WINDS DOMINATED MOST OF 
THE AREA S OF 20N AND E OF 110W. A SURFACE A TROUGH EXTENDS FROM 
08N84W TO 01N102W...AND REMAINS A FOCUS FOR LOW LEVEL MOISTURE 
CONVERGENCE AND CONVECTION. SCATTERED MODERATE CONVECTION WAS 
NOTED WITHIN 240 NM SE OF TROUGH BETWEEN 84W AND 92W. ISOLATED 
TO SCATTERED MODERATE CONVECTION WAS NOTED WITHIN 120 NM EITHER 
SIDE OF TROUGH BETWEEN 92W AND 102W. STRONG NW SHEAR ALOFT HAS 
ACTED TO WEAKEN THIS CONVECTION IN THE PAST SEVERAL HOURS. 

GAP WINDS...
GULF OF PAPAGAYO...ALTHOUGH THE PRES GRADIENT BETWEEN RIDGING 
OVER THE NW CARIBBEAN AND THE AFOREMENTIONED TROUGH HAS WEAKENED 
SLIGHTLY OF RECENT...FRESH NE GAP WIND FLOW CONTINUES TO EXIT 
ACROSS THE GULF OF PAPAGAYO IN A SMALL AND NARROW PLUME. THIS 
AREA OF FRESH WINDS IS EXPECTED TO DISSIPATE AFTER THE PERIOD OF 
PEAK DRAINAGE FLOW TUE MORNING AS THE SUPPORTING RIDGING SHIFTS 
NORTHEASTWARD AND THE PRES GRADIENT RELAXES. 
 
$$
STRIPLING