000
AXPZ20 KNHC 170909
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SUN FEB 17 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 
0830 UTC.

...SPECIAL FEATURE...
WINDS TO STORM FORCE PERSIST THROUGH THE GULF OF TEHUANTEPEC 
THIS MORNING. REPORTS OVER THE PAST SEVERAL HOURS FROM SALINA 
CRUZ OAXACA ON THE COAST SHOW MAXIMUM WINDS TO 45 KT...AND IT IS 
LIKELY STRONGER OVER ADJACENT WATERS WHERE HIGH MOMENTUM WINDS 
IN THE LOWER LEVELS OF THE ATMOSPHERE ARE MIXING TO THE SURFACE. 
AN ASCAT PASS FROM 0330 UTC CAUGHT THE EDGE OF DOWNSTREAM PLUME 
OF THE STORM EVENT...WITH 20 TO 25 KT AS FAR WEST AS 12N98W. THE 
WINDS ARE THE RESULT OF STRONG 1030 MB HIGH PRES NEAR TAMPICO 
MEXICO ACCOMPANIED BY A PUSH OF COLD AIR THROUGH THE CHIVELA 
PASS IN THE ISTHMUS OF TEHUANTEPEC. THE HIGH PRES SHIFTS WELL 
EAST ACROSS THE NORTHERN GULF OF MEXICO THROUGH THIS 
AFTERNOON...ALLOWING WINDS OVER THE SW GULF OF MEXICO TO VEER 
MORE TO THE E AND SE. THIS WILL ALLOW STORM CONDITIONS TO 
DIMINISH TO GALE FORCE THROUGH THE MORNING. THE COMBINATION OF A 
STILL HIGH PRES GRADIENT ALONG WITH LINGERING COLDER AIR 
DRAINING INTO THE GULF OF TEHUANTEPEC WILL ALLOW THE GALE 
CONDITIONS TO LAST INTO THE EARLY EVENING...WITH WINDS TO 30 KT 
THROUGH SUN NIGHT INTO MON MORNING. SEAS WILL BUILD AS HIGH AS 
20 FT THROUGH AFTERNOON GIVEN THE LONG FETCH AND PERSISTENCE OF 
THE STORM EVENT.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
MONSOON TROUGH AXIS NOT DISCERNIBLE.  ITCZ EXTENDS FROM 02N98W 
TO 07N112W TO 08N127W TO 04N140W.  ISOLATED MODERATE CONVECTION 
WITHIN 90 NM S OF AXIS FROM 128W TO 133W.

...DISCUSSION...
A DEEP LAYER RIDGE WILL REMAIN ANCHORED N THROUGH NE OF THE 
HAWAIIAN ISLANDS THROUGH MID WEEK...WEST OF AN ELONGATED 
MID/UPPER TROUGH EXTENDING FROM THE COAST OF NORTHERN CALIFORNIA 
TO A DEVELOPING UPPER CYCLONE CENTERED NE OF THE BIG ISLAND NEAR 
20N152W. 

FARTHER SOUTH...A WELL DEFINED SURFACE TROUGH BREAKS THE ITCZ 
NEAR 128W AND IS MIGRATING W AT 10 TO 15 KT. THE TROUGH WILL 
GRADUALLY DAMPEN OUT AS IT SHIFTS W OF THE AREA THROUGH MID 
WEEK. SCATTEROMETER AND ALTIMETER DATA FROM THE PREVIOUS 24 
HOURS HAVE INDICATED A BROAD AREA OF 20 TO 25 KT TRADE WINDS N 
OF THE ITCZ W OF 125W. ALTIMETER DATA ALSO SHOW SEAS TO 11 FT IN 
THIS AREA...LIKELY A MIX OF FRESH NE SWELL AND LONGER PERIOD NW 
SWELL. 

A SHARP AND ELONGATED UPPER TROUGH EXTENDS W OF THE DEEP LAYER 
RIDGE FROM CENTRAL CALIFORNIA TO 30N140W TO A STATIONARY UPPER 
LOW NE OF THE BIG ISLAND OF HAWAII NEAR 22N149W. A PAIR OF UPPER 
DISTURBANCES WILL MIGRATE SE ACROSS CENTRAL AND SOUTHERN 
CALIFORNIA THROUGH MID WEEK...SUPPORTING THE ARRIVAL A WEAK COLD 
FRONT INTO THE WATERS N OF 25N E OF 130W AS WELL AS NORTHERN 
BAJA CALIFORNIA AND THE NORTHERN PORTION OF THE GULF OF 
CALIFORNIA BY WED. WHILE THE STRONGER WINDS WILL LIKELY REMAIN N 
OF THE AREA BEHIND THIS FRONT...WW3 AND ECWAVE GUIDANCE 
INDICATES ANOTHER TRAIN OF NW SWELL WILL FOLLOW THE FRONT AND 
SWEEP THE WATERS W OF 115W BY EARLY WED AND BRINGING SEAS OF 8 
TO 11 FT N OF 20N W OF 115W.

FARTHER TO THE SOUTHEAST...THE DOWNSTREAM PLUME OF STRONG WINDS 
FROM THE STORM EVENT IN THE GULF OF TEHUANTEPEC WILL PUSH SEAS 
OF 8 TO 10 FT IN MAINLY NE TO E SWELL FAR INTO THE 
PACIFIC...REACHING AS FAR W AS 110W BETWEEN 05N TO 12N BY LATE 
MON. THIS PLUME OF NE TO E SWELL WILL GRADUALLY DECAY BY MIDWEEK 
BUT ALSO BE OVERTAKEN BY THE SUCCESSIVE TRAINS OF NW SWELL.

ALONG THE CENTRAL AMERICAN COAST...THE STRONG HIGH PRES BUILDING 
BEHIND THE COLD FRONT IN THE GULF OF MEXICO RESPONSIBLE FOR THE 
CURRENT STORM EVENT IN THE GULF OF TEHUANTEPEC WILL ALSO PROVIDE 
THE IMPETUS FOR PULSES OF FRESH TO STRONG WINDS THROUGH THE GULF 
OF PAPAGAYO THIS MORNING THROUGH MID WEEK...WITH THE STRONGEST 
PULSES DURING THE LATE NIGHT AND EARLY MORNING HOURS. SIMILARLY 
ADDITIONAL PULSES OF FRESH TO STRONG WINDS WILL PUSH FROM THE SW 
CARIBBEAN INTO THE GULF OF PANAMA LATE TONIGHT INTO TUE.

$$
CHRISTENSEN