000
AXPZ20 KNHC 150907
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC FRI MAR 15 2013

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 
0745 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...           
THE ITCZ AXIS WAS ANALYZED FROM 07N86W TO 01N90W THEN CONTINUES 
FROM 03N121W TO 03N140W. SCATTERED MODERATE CONVECTION WAS NOTED 
E OF ITCZ TO 90W AND WITHIN 90 NM EITHER SIDE OF ITCZ BETWEEN 
126W AND 131W. 

...DISCUSSION...                                               
GULF OF TEHUANTEPEC...A GALE WARNING CONTINUES IN THE GULF OF 
TEHUANTEPEC THIS MORNING. WINDS ONSHORE AT SALINA CRUZ HAVE 
DIMINISHED FROM 35 KT AT 0300 UTC TO 25 KT AT 0600 UTC...BUT 
GALES ARE STILL SUSPECTED OFFSHORE. THERE HAVE BEEN NO RECENT 
SCATTEROMETER PASSES OR SHIP OBSERVATIONS IN THE GULF. DRAINAGE 
FLOW FROM THE LAND SHOULD ENHANCE THE WINDS HERE THROUGH THE 
MORNING HOURS ON FRI. WINDS IN THE SW GULF OF MEXICO WILL WEAKEN 
AND SHIFT MORE EASTERLY BY SAT MORNING...CUTTING OFF THE FLOW 
THROUGH THE ISTHMUS OF TEHUANTEPEC AND DIMINISHING THE GALE. NE 
SWELL FROM THE GULF OF TEHUANTEPEC IS MIXING WITH CROSS-
EQUATORIAL SW SWELL TO PRODUCE AN IMPRESSIVE AREA OF 8-12 FT 
SEAS FROM 04N-14N BETWEEN 90W-105W. THIS AREA OF SWELL WILL 
SUBSIDE OVER THE WEEKEND AS THE WINDS IN THE GULF DIMINISH.

GULFS OF FONSECA AND PAPAGAYO...THE 0258 UTC ASCAT PASS SHOWED 
WINDS TO 30 KT IN THE GULF OF FONSECA AND ALONG THE COAST OF EL 
SALVADOR. FRESH TO STRONG WINDS ARE ALSO FOUND IN THE GULF OF 
PAPAGAYO. 26 KT NE WINDS WERE REPORTED AT LIBERIA COSTA RICA 
NEAR THE GULF OF PAPAGAYO AT 0300 UTC AND THE EASTERN SIDE OF 
THE AFOREMENTIONED ASCAT PASS SAW FRESH WINDS TO 10N88W. THE 
WINDS NEAR FONSECA SHOULD SHIFT SOUTHWARD...WITH GAP FLOW 
THROUGH PAPAGAYO EXPECTED TO INCREASE TO 30 KT SAT MORNING 
DURING THE PERIOD OF PEAK DRAINAGE FLOW OFF THE LAND. OVERNIGHT 
SAT NIGHT...WINDS WILL BEGIN TO DIMINISH IN THE GULF OF 
PAPAGAYO. ISOLATED MODERATE CONVECTION WAS NOTED THIS MORNING 
OFF THE COAST OF COSTA RICA AND NW PANAMA FROM 07N TO 10N 
BETWEEN 82W AND 86W.

GULF OF PANAMA...A FRESH N BREEZE WILL CONTINUE IN THE GULF OF 
PANAMA THROUGH AT LEAST EARLY SUN MORNING. SEAS ARE NOT EXPECTED 
TO REACH 8 FT. 

AN UPPER-LEVEL LOW OVER THE MOUTH OF THE GULF OF CALIFORNIA 
SHOULD REMAIN NEARLY STATIONARY THROUGH SAT AND BEGIN TO BE 
PICKED UP BY A WEAK TROUGH ALOFT PASSING THROUGH THE SOUTHWEST 
U.S. BY SUN. PRECIPITABLE WATER IMAGERY SHOWS A WIDE SWATH OF 
LOW-LEVEL TROPICAL MOISTURE EXTENDING NORTHWARD INTO SOUTHERN 
MEXICO ON THE E SIDE OF THE UPPER LOW. SCATTERED SHOWERS LIE 
OVER SOUTHERN MEXICO IN THE AREA FROM 14N TO 24N BETWEEN 97W AND 
108W. ISOLATED THUNDERSTORMS ARE PRIMARILY NOTED OFFSHORE AND 
HAVE BECOME MORE SCATTERED TO NUMEROUS NEAR ACAPULCO OVERNIGHT. 
CONDITIONS SHOULD REMAIN FAVORABLE FOR PRECIPITATION TO CONTINUE 
IN THIS AREA INTO SAT.

THE 1027 MB SUBTROPICAL HIGH LIES NEAR 33N131W. THE PRESSURE 
GRADIENT IS WEAK BETWEEN THE SUBTROPICAL HIGH AND THE ITCZ OVER 
WESTERN WATERS. TRADE WINDS HAVE BEEN REDUCED TO A MODERATE TO 
FRESH E-NE BREEZE OVER NORTHWESTERN WATERS AS A RESULT. THE 
SUBTROPICAL HIGH HAS BEEN COMPROMISED BY THE DISSIPATING FRONT 
TO ITS SW THAT CLIPS THE FAR NW WATERS. THIS FRONT WILL 
DISSIPATE THIS MORNING. A SECOND FRONT IS ALSO IMPEDING OF THE 
HIGH FROM THE NW. THIS BOUNDARY EXTENDS FROM A DEEP LAYER LOW 
FOUND N OF THE HAWAIIAN ISLANDS. THE LOW WILL GRADUALLY EDGE 
EASTWARD...BUT REMAIN W OF THE AREA. THE BOUNDARY WILL SHIFT 
NORTHWARD AS A WARM FRONT WITH THE SUBTROPICAL HIGH REORGANIZING 
N OF THE BOUNDARY BY SUN. THIS WILL KEEP TRADE WINDS IN THE 
MODERATE TO FRESH RANGE. 

$$
SCHAUER