000
AXPZ20 KNHC 182128
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SUN MAR 18 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 
2000 UTC.

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

THE ITCZ IS S OF THE EQUATOR. THERE IS NO SIGNIFICANT DEEP 
CONVECTION

...DISCUSSION...

A STRONG COLD FRONT HAS MOVED THROUGH MUCH OF BAJA CALIFORNIA 
AND SONORA MEXICO. THE OBSERVATION STATION AT HERMOSILLO MEXICO 
HAS DROPPED TO 66 DEGREES FAHRENHEIT AT 2000 UTC TODAY AFTER THE 
FRONTAL PASSAGE COMPARED TO 88 DEGREES AT THE SAME TIME 
YESTERDAY. INFRARED SATELLITE IMAGERY SHOWS SCATTERED MODERATE 
CONVECTION WITHIN 120 NM EITHER SIDE OF THE FRONT N OF 26N. 
FRESH TO STRONG NW WINDS CAN BE FOUND BEHIND THE FRONT AS 
OBSERVED BY SHIP VRBH4 WHICH REPORTED 25 KT NEAR 27N122W AT 1800 
UTC. THIS FRONT WILL SWEEP EASTWARD INTO MAINLAND MEXICO ON MON. 
FRESH TO STRONG WINDS CAN ALSO BE FOUND IN THE NORTHERN GULF OF 
CALIFORNIA. THESE WINDS MAY BE LOCALLY STRONGER AS THEY FUNNEL 
THROUGH THE MOUNTAIN PASSES IN BAJA CALIFORNIA NORTE OVERNIGHT 
TONIGHT. THE AREA OF FRESH WINDS WILL SHIFT SOUTHWARD ALONG THE 
BAJA PENINSULA AND ALONG THE MAINLAND MEXICAN COAST TO CABO 
CORRIENTES THROUGH TUE AFTERNOON. NORTHWEST SWELL ASSOCIATED 
WITH THIS FRONT HAS BROUGHT SEAS AS HIGH AS 20 FT OFF THE W 
COAST OF BAJA CALIFORNIA NORTE. 

THE SUBTROPICAL RIDGE IS RAPIDLY FILLING IN BEHIND THIS FRONT. 
THE RIDGE STEMS FROM 1030 MB HIGH PRES NEAR 31N145W AND EXTENDS 
TO 20N107W. THIS RIDGE IS SUPPORTING A LARGE AREA OF FRESH TRADE 
WINDS FROM 05N TO 22N W OF 130W AND FROM 08N TO 17N BETWEEN 125W 
AND 130W ACCORDING TO THE 1844 UTC ASCAT PASS. THIS AREA OF 
TRADE WINDS WILL EXPAND EASTWARD 120W THROUGH THE END OF THE 
PERIOD TUE AFTERNOON. 

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 10N120W TO SOUTH TEXAS. THE JET 
IS TRANSPORTING TROPICAL MOISTURE IN THE MID AND UPPER LEVELS 
THROUGH THE SOUTHERN GULF OF CALIFORNIA INTO CENTRAL MEXICO AND 
THE RIO GRANDE VALLEY. THIS MOISTURE IS MANIFESTED AS A BAND OF 
MULTI-LAYERED CLOUDS ALONG THE JET AXIS. THIS BAND OF CLOUDS HAS 
DIMINISHED SOMEWHAT SINCE YESTERDAY AS THE JET HAS WEAKENED. 
THIS TREND WILL CONTINUE THROUGH TUE AFTERNOON.

A SURFACE TROUGH LIES FROM 10N85W TO 07N85W TO 02N93W. SCATTERED 
MODERATE CONVECTION CAN BE FOUND WITHIN 240 NM SE OF THE TROUGH 
BETWEEN 85W AND 89W. THIS CONVECTION IS BEING ENHANCED BY UPPER 
LEVEL DIFFLUENCE ASSOCIATED WITH THE REAR RIGHT QUADRANT OF THE 
SOUTHWESTERLY UPPER JET OVER THE CARIBBEAN SEA.

GAP WINDS...
GULF OF PAPAGAYO...THE PRES GRADIENT BETWEEN RIDGING OVER THE NE 
CARIBBEAN AND THE AFOREMENTIONED TROUGH FROM 10N85W TO 07N85W TO 
02N93W CONTINUES TO SUPPORT FRESH NE GAP FLOW WELL DOWNWIND OF 
THE GULF OF PAPAGAYO AS SEEN BY THE 1524 UTC ASCAT PASS. THE 
AREA OF FRESH WINDS IS EXPECTED TO DISSIPATE BY MON EVENING AS 
THE SUPPORTING RIDGING SHIFTS NORTHEASTWARD AND THE PRES 
GRADIENT RELAXES. 
 
$$
SCHAUER