000
AXPZ20 KNHC 120333
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC WED JAN 12 2011

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0300 UTC.

...ITCZ...

AXIS IS CENTERED ALONG 05N83W TO 04N91W TO 09N117W TO 07N140W. 
SCATTERED MODERATE CONVECTION IS WITHIN 60 NM EITHER SIDE OF THE 
AXIS BETWEEN 133W AND 138W. A SURFACE TROUGH IS EMBEDDED WITHIN 
THE ITCZ AXIS ANALYZED FROM 13N114W TO 06N118W WITH SCATTERED 
MODERATE CONVECTION FROM 11N TO 14N BETWEEN 111W AND 119W.

...DISCUSSION...

WATER VAPOR IMAGERY INDICATES AN UPPER LEVEL SHORTWAVE TROUGH 
PROGRESSING EASTWARD AND MOVING INLAND ACROSS THE CENTRAL 
CALIFORNIA COAST THIS EVENING WITH THE ASSOCIATED TROUGH AXIS 
EXTENDING SW FROM 36N123W TO 30N130W. THIS FEATURE IS PROVIDING 
MARGINAL SUPPORT FOR A COLD FRONT THAT CONTINUES TO BECOME MORE 
DIFFUSE ALONG THE NORTHERN FORECAST WATERS BORDER NEAR 31N131W. 
SEAS BEHIND THIS FEATURE REMAIN TO 8 FT IN NW SWELL AND THESE 
SEAS ARE EXPECTED TO SUBSIDE BELOW 8 FT WITHIN 12 TO 18 HOURS. 
SOUTHERLY WINDS WILL AGAIN PICK UP ON THE WESTERN PERIPHERY OF A 
SURFACE RIDGE ALONG 127W BY WEDNESDAY AS ANOTHER COLD FRONT IS 
EXPECTED TO APPROACH THE FAR NORTHWESTERN CORNER OF THE AREA 
INTO WEDNESDAY INCREASING WINDS TO 20 KT IN THE FAR NW CORNER 
AND SEAS BUILDING TO 13 FT IN NW SWELL.

SURFACE ANTICYCLONIC WIND FLOW MOVES AROUND A 1021 MB HIGH 
PRESSURE CENTERED NEAR 28N125W. AN AREA OF NE TO E TRADES EXISTS 
ON THE SOUTHERN PERIPHERY OF THE RIDGE FROM GENERALLY 08N TO 20N 
W OF 115W. RECENT ASCAT PASSES DEPICTED THIS LARGE AREA OF 
TRADES THAT IS EXPECTED TO COMPRESS WESTWARD SLIGHTLY AND EXPAND 
NORTHWARD THROUGH THE PERIOD AS THE SURFACE RIDGE MOVES NE. AS 
THE RIDGE SHIFTS NORTHEASTWARD...A TIGHT PRESSURE GRADIENT IS 
EXPECTED TO SET UP BETWEEN THE RIDGE AND TROUGHING OVER THE 
SIERRA MADRE OCCIDENTALS OF WESTERN MEXICO PRODUCING STRONG 20 
TO 25 KT NW WINDS IN THE GULF OF CALIFORNIA THROUGH THE PERIOD.

GAP WINDS...
WITH A STRONG ARCTIC HIGH PRESSURE BUILDING IN ACROSS EASTERN 
TEXAS AND EASTERN MEXICO...GALE FORCE CONDITIONS ARE CURRENTLY 
OCCURRING OVER THE GULF OF TEHUANTEPEC AREA WITH NORTHERLY WINDS 
UP TO 40 KT. OVER THE PAST 6 HOURS...IXTEPEC MEXICO HAS REPORTED 
SUSTAINED N WINDS AT 30 TO 35 KT WITH GUSTS TO 45 KT...SO 
THEREFORE HAVE INCREASED THE SYNOPSIS CONDITIONS TO REFLECT THIS 
DATA. THIS EVENT IS EXPECTED TO INCREASE TO STORM FORCE BY 
12/0600 UTC...AS DRAINAGE FLOW REACHES A DIURNAL MAXIMUM 
OVERNIGHT AND THE MAIN SURGE OF NORTHERLY WINDS FROM THE WESTERN 
GULF OF MEXICO MAKES IT WAY THROUGH THE CHIVELA PASS AND EXITS 
THROUGH THE ISTHMUS INTO THE GULF OF TEHUANTEPEC BY EARLY 
WEDNESDAY MORNING.

WINDS ACROSS THE GULF OF PAPAGAYO ARE EXPECTED TO INCREASE TO 25 
KT THROUGH WEDNESDAY AS EASTERLY SURGES IN THE SOUTHWESTERN 
CARIBBEAN SEA BLOW THROUGH THE PASSES THE NEXT FEW DAYS.

$$
HUFFMAN