000
AXPZ20 KNHC 140938
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC THU FEB 14 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 
0700 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
THE MONSOON TROUGH WAS ANALYZED FROM 06N91W TO 07N94W TO 04N101W 
TO 06N106W. ITCZ AXIS WAS ANALYZED FROM 06N106W TO 09N110W TO 
106N120W TO 07N135W TO 05N1340W. SCATTERED MODERATE CONVECTION 
WAS N OF THE ITCZ TO 17N W OF 129W.

...DISCUSSION...
A SURFACE TROUGH JUST W OF THE AREA FROM 27N150W TO 22N146W TO 
14N149W IS THE REFLECTION OF AN UPPER LOW NEAR 23N143W. A 
100-120 KT UPPER JET EXTENDS ON THE E SIDE OF THE LOW FROM 
10N135W TO 25N130W EASTWARD INTO NW MEXICO. STRONG UPPER LEVEL 
DIFFLUENCE BETWEEN THE REAR RIGHT QUADRANT OF THIS JET AND A 
WEST-NORTHWESTERLY UPPER JET THAT EXTENDS INTO THE FORECAST AREA 
FROM 03N140W TO 00N132W IS LIFTING MOISTURE POOLED NEAR A 
PERTURBATION ALONG THE ITCZ OVER WESTERN WATERS. AN AREA OF 
SHOWERS AND THUNDERSTORMS CAN BE FOUND N OF THE ITCZ TO 17N W OF 
129W AS A RESULT. THE INCREASED PRESSURE GRADIENT BETWEEN THE 
ITCZ PERTURBATION AND THE SUBTROPICAL RIDGE IS CURRENTLY 
GENERATING AN AREA OF FRESH TO STRONG TRADE WINDS N OF THE ITCZ 
TO 18N W OF 125W. THESE TRADES ARE EXPECTED TO INTENSIFY TO 30 
KT OVERNIGHT TONIGHT AS THE SUBTROPICAL RIDGE SHIFTS SLIGHTLY 
WESTWARD AND WILL DIMINISH TO A STRONG BREEZE AGAIN BY EARLY SAT 
AS THE RIDGE WEAKENS. THE AFOREMENTIONED UPPER LOW WILL 
DISSIPATE AND THE JET WILL SHIFT EASTWARD OVER THE NEXT FEW DAYS.

A POSITIVELY TILTED SPOKE IN THE MEAN UPPER TROUGH OVER THE 
CENTRAL U.S. EXTENDS FROM THE SOUTHERN U.S. PLAINS THROUGH THE 
MOUTH OF THE GULF OF CALIFORNIA INTO NE FORECAST WATERS. THIS 
SPOKE WILL SHIFT E TODAY...BUT THE WESTERN PORTION OF THE MEAN 
TROUGH WILL BE RELOADED WITH BOTH NORTHERN STREAM ENERGY MOVING 
THROUGH THE INTERIOR WESTERN U.S. AND ENERGY EJECTED FROM THE 
AFOREMENTIONED UPPER LOW CURRENTLY JUST W OF NORTHERN FORECAST 
WATERS NEAR 23N143W. AT THE SURFACE...THE STRONG PRESSURE 
GRADIENT BETWEEN THE SUBTROPICAL RIDGE OVER NE WATERS AND 
TROUGHING OVER NORTHERN MAINLAND MEXICO ASSOCIATED WITH THE MEAN 
TROUGH ALOFT IS FORCING FRESH TO STRONG N-NW WINDS DOWN THE 
LENGTH OF THE GULF OF CALIFORNIA. EARLIER SCATTEROMETER PASSES 
CAPTURED THESE WINDS IN THE SOUTHERN PORTION AND THE MOUTH OF 
THE GULF. THE LONG FETCH DOWN THE GULF HAS LIKELY ALLOWED SEAS 
TO BUILD TO 9 FT. WINDS WILL DIMINISH S OF 25N OVER THE NEXT FEW 
DAYS AS THE SUBTROPICAL RIDGE SHIFTS W...BUT THE RELOADING OF 
THE UPPER TROUGH WILL STRENGTHEN THE SURFACE TROUGHING OVER 
MAINLAND MEXICO...ALLOWING THE PRES GRADIENT TO REMAIN STRONG. A 
FRESH TO STRONG BREEZE IS FORECAST TO CONTINUE THROUGH AT LEAST 
EARLY SAT. 

GAP WINDS...
GULF OF TEHUANTEPEC...NORTHERLY WINDS BEHIND A COLD FRONT MOVING 
THROUGH THE SW GULF OF MEXICO TODAY WILL SQUEEZE THROUGH THE 
CHIVELA PASS AND BEGIN TO GENERATE FRESH TO STRONG N WINDS IN 
THE GULF OF TEHUANTEPEC ON FRI MORNING. HIGH PRESSURE BUILDING 
ACROSS THE GULF OF MEXICO FRI NIGHT AND SAT WILL STRENGTHEN THE 
GAP WINDS THROUGH TEHUANTEPEC...WITH GALES EXPECTED BY SAT 
AFTERNOON OR EVENING. 

$$
SCHAUER