000
AXPZ20 KNHC 271558
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC WED FEB 27 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1545 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
MONSOON TROUGH FROM 06N77W TO 04N90W TO 03N105W. ITCZ FROM 
03N105W TO 05N115W TO 03N140W. SCATTERED MODERATE ISOLATED 
STRONG FROM 03N TO 07N BETWEEN 83W AND 86W...AND FROM 08N TO 10N 
BETWEEN 126W AND 129W.

...DISCUSSION...
NEARLY STATIONARY SHARP UPPER LEVEL TROUGH REMAINS OVER THE FAR 
NW PORTION OF THE DISCUSSION AREA WITH AXIS FROM SOUTHERN 
CALIFORNIA THROUGH 32N130W SW THROUGH 24N140W TO A BASE NEAR 
12N145W. A BROAD FLAT UPPER LEVEL RIDGE COVERS THE REMAINDER OF 
THE AREA E OF THE TROUGH AND N OF 10N. SATELLITE DERIVED WINDS 
DEFINE A VERY STRONG SUBTROPICAL JETSTREAM WHICH ENTERS THE AREA 
NEAR 22N140W SLICES NE THROUGH 30N130W THEN TURNS EAST ALONG 
31N/32N TO THE SOUTHWEST CONUS. CORE SPEEDS WERE ABOUT 150-160 
KT OVER MEXICO AND BAJA CALIFORNIA BETWEEN 110W AND 130W. THIS 
POWERFUL JET WAS ADVECTING COPIOUS MID AND UPPER LEVEL MOISTURE 
ACROSS BAJA CALIFORNIA TOWARD MEXICO...WITH THE MOISTURE 
CONFINED TO WITHIN 660 NM S OF THE JET. IN THE DEEP TROPICS AN 
UPPER LEVEL TROUGH EXTENDS FROM 10N118W SE TO A SMALL CLOSED LOW 
2N105W. MODERATE TO STRONG SUBSIDENCE WITH DRY AND STABLE AIR AT 
THE MIDDLE AND UPPER LEVELS IS FROM 5N-15N E OF 110W.

SURFACE RIDGE IS N OF 15N W OF 110W. THE PRES GRADIENT ALONG THE 
SOUTHERN PERIPHERY OF THE RIDGE IS STRONG ENOUGH TO SUPPORT NE 
WINDS OF 20-30 KT FROM 9N-12N W OF 132W. THESE WINDS WERE 
CONFIRMED BY A 0650 UTC HIGH RESOLUTION ASCAT PASS. A SEPARATE 
AREA OF 20-25 KT WINDS WERE NOTED FROM 16N TO 27N W OF 135W. 
THE RIDGE IS FORECAST TO STRENGTHEN SOME THU WITH THE AREAS OF 
WINDS FORECAST TO MERGE WITH OVERALL COVERAGE OF THE 20-25 KT 
WINDS STRETCHING FROM 12N-25N W OF 128W.

THE GRADIENT BETWEEN THE RIDGE AND LOWER PRESSURES OVER MEXICO 
HAS RESULTED IN NLY WINDS OF 20-25 KT IN THE GULF OF CALIFORNIA 
N OF 25N. THESE WINDS ARE FORECAST TO INCREASE TO 30 KT AND 
SPREAD SOUTHWARD THROUGH THE REMAINDER OF THE GULF WITH SEAS 
BUILDING TO 10 FT WITH THE HIGHEST SEAS EXPECTED AT THE SOUTHERN 
END OF THE GULF.   

STRONG HIGH PRES BUILDING SOUTHWARD BEHIND A COLD FRONT MOVING 
THROUGH THE GULF OF MEXICO WILL TIGHTEN THE PRES GRADIENT ACROSS 
SOUTHERN MEXICO. AS A RESULT NLY WINDS INCREASE TO 20-25 KT IN 
THE GULF OF TEHUANTEPEC EARLY THU. NWP MODELS ARE IN AGREEMENT 
IN TIGHTENING THE GRADIENT FURTHER WITH GALE FORCE WINDS 
COMMENCING LATE FRI OR FRI NIGHT. THE POTENTIAL EXISTS FOR STORM 
FORCE WINDS BY LATE SAT INTO SUN.  

$$
COBB