000
AXPZ20 KNHC 111014
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL                           
1005 UTC SAT JAN 11 2014

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 
0900 UTC.                              

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...  
THE MONSOON TROUGH EXTENDS FROM 09N74W TO 06N78W TO 09N87W TO 
06N91W WHERE IT TRANSITIONS TO ITCZ...CONTINUING ON TO 06N100W 
TO 04N108W TO 06N128W TO BEYOND 05N140W. SCATTERED MODERATE TO   
STRONG CONVECTION NOTED WITHIN 180 NM N AND 60 NM S OF ITCZ W OF 
124W. A CLUSTER OF MODERATE CONVECTION WITH ISOLATED STRONG 
WAS NOTED FROM 11N TO 13.5W BETWEEN 112W AND 116W.
 
...DISCUSSION...
ALOFT...A RIDGE/TROUGH/RIDGE PATTERN GENERALLY PREVAILS ACROSS 
THE FORECAST WATERS THIS MORNING. A MIDDLE TO UPPER LEVEL 
SHORTWAVE WAS NOTED IN SATELLITE IMAGERY APPROACHING 142W THIS 
MORNING AND ABUTTING THE W SIDE OF A SHARP UPPER RIDGE BETWEEN 
130W AND 140W. WIDESPREAD BROKEN MIDDLE AND HIGH CLOUDS PREVAIL 
WITHIN THE RIDGE AXIS...WHEN VEERS NORTHEASTWARD ALONG 130W N OF 
30N. A BROAD UPPER LEVEL TROUGH EXTENDS FROM DEEP LAYERED 
TROUGHING ACROSS THE CENTRAL U.S. THROUGH W TEXAS AND NW MEXICO 
TO A SLOWLY WEAKENING UPPER CYCLONE NEAR 22N111W...THEN 
CONTINUES TO BROAD BASE NEAR 15N118W. A SHORTWAVE TO THE SE OF 
THE CYCLONE YESTERDAY HAS BECOME ABSORBED IN THE BROAD TROUGHING 
AND IS APPROACHING THE SW COAST OF MEXICO...EMBEDDED IN SW FLOW 
ALOFT. THE BROAD TROUGH IS FORECAST TO MOVE SLOWLY E ACROSS 
MEXICO AND WEAKEN THROUGH THE WEEKEND...WITH NEARLY ZONAL FLOW 
DEVELOPING N OF 25N BY LATE SUNDAY. UPPER RIDGING TO THE E OF 
THIS TROUGH EXTENDS FROM THE EQUATOR ALONG 94W ACROSS CENTRAL 
AMERICA AND INTO THE SW N ATLANTIC....AND IS PRODUCING FAIR 
WEATHER. 
 
AT LOWER LEVELS...WEAKENING HIGH PRESSURE HAS SHIFTED SW TONIGHT 
AND IS NEAR 31N133W...NOW AT 1028 MB. A MODEST RIDGE EXTENDS SE 
FROM THE HIGH TO NEAR 17N108W. THE PRESSURE GRADIENT BETWEEN 
THIS HIGH AND LOWER PRESSURE ACROSS THE SIERRA MADRE 
OCCIDENTALES OF MEXICO WAS PRODUCING NW TO N WINDS AROUND 15 KT 
THROUGH CENTRAL PORTIONS OF THE GULF OF CALIFORNIA 
OVERNIGHT...WHERE SEAS ARE LIKELY AROUND 4 FT. RECENT 
SCATTEROMETER PASSES SHOWED N WINDS 15 KT OR LESS ACROSS THE 
PACIFIC WATERS W OF BAJA...WHERE SEAS WERE 4-6 FT IN NW SWELL. 
TO THE S OF THE RIDGE...NE TO E TRADES OF 20-25 KT WERE DEPICTED 
BY SCATTEROMETER PASSES FROM 07N TO 12N W OF 127W. ELSEWHERE W 
OF 120W...SEAS WERE 8 TO 9 FT IN PRIMARILY NW SWELL.

A DEEP LAYERED UPPER TROUGH MOVING ACROSS THE NE CENTRAL PACIFIC 
HAS DRAGGED A COLD FRONT TOWARDS THE REGION...AND WAS 
APPROACHING NW PORTIONS...MEANDERING SW ACROSS NW PORTIONS OF 
THE HAWAIIAN ISLANDS. THE FRONT WILL BARELY DIP INTO THE NW 
CORNER OF THE AREA BY 00Z TONIGHT...THEN WEAKEN AS IT SWEEPS SE 
ACROSS N AND NE PORTIONS OF THE AREA AND REACH FAR N PORTIONS OF 
BAJA CALIFORNIA BY SUN EVENING. A 1035 MB HIGH IS FORECAST TO 
BUILD BEHIND THE FRONT AND ACT TO FRESHEN THE TRADES W OF 
130W...WITH N TO NE WINDS BEHIND THE FRONT ON SUNDAY. SEAS 
BEHIND THE FRONT ARE FORECAST TO BUILD 10 TO 15 FT ACROSS N 
CENTRAL AND NE PORTIONS SUN. THE HIGH IS THEN EXPECTED TO SLOWLY 
WEAKEN OFFSHORE OF CALIFORNIA MON. THIS WILL ACT TO FRESHEN NW 
WINDS INSIDE THE GULF OF CALIFORNIA TO AROUND 25 KT MON THROUGH 
MON NIGHT.  

GAP WINDS...                                                     
WITH WEAKENING HIGH PRES ACROSS THE REGION AND SOUTHERLY RETURN 
FLOW ACROSS THE GULF OF MEXICO...GAP WINDS ACROSS THE GULF OF 
TEHUANTEPEC HAVE DIMINISHED TO 15 KT OR LESS IN THE PAST 12 
HOURS...BUT WILL QUICKLY INCREASE FROM THE N TO 20-30 KT THIS 
EVENING AND TONIGHT AS A COLD FRONT MOVES ACROSS THE GULF OF 
MEXICO. THIS EVENT IS EXPECTED TO END BY LATE SUNDAY. ANOTHER 
COLD FRONT MOVING INTO THE GULF OF MEXICO MON IS EXCEPTED TO 
INDUCE NORTHERLY GALE THROUGH TEHUANTEPEC BY EARLY TUE THAT IS 
EXPECTED TO LAST THROUGH LATE THU. WINDS COULD APPROACH 50 KT 
THERE WED EVENING AND NIGHT.

FRESH ELY TRADES ACROSS THE CENTRAL CARIBBEAN ARE SPILLING 
ACROSS CENTRAL AMERICA TO PRODUCE A SMALL AREA OF 20-25 KT WINDS 
EXITING THE GULF OF PAPAGAYO THIS MORNING...AND WILL WEAKEN 
TODAY ONLY TO PULSE AGAIN TONIGHT TO 20-25 KT THROUGH SUN 
MORNING. ELSEWHERE E OF 110W...LIGHT TO MODERATE TRADES OF 15 KT 
OR LESS PREVAIL N OF THE MONSOON TROUGH AND ITCZ...WITH LITTLE 
CHANGE EXPECTED THROUGH SUN.

$$
STRIPLING