000
AXPZ20 KNHC 300951
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SAT JAN 30 2010

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

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.

...ITCZ...

THE ITCZ AXIS IS ANALYZED ALONG 06N78W TO 04N90W TO 05N104W TO 
05N120W TO 04N140W. ISOLATED MODERATE CONVECTION IS WITHIN 60 NM 
EITHER SIDE OF AXIS FROM 100W TO 103W AND NEAR 07N102W. 

...DISCUSSION...

ALOFT...A RIDGE/TROUGH/RIDGE PATTERN CONTINUES TO DOMINATE THE 
DISCUSSION AREA. A STRONG MIDDLE/UPPER LEVEL TROUGH MOVING 
ASHORE ALONG THE W COAST OF THE UNITED STATES EXTENDS S INTO THE 
AREA TO NEAR 26N BETWEEN 115W AND 125W. TO THE SOUTH...A BROAD 
MIDDLE/UPPER LEVEL TROUGH WITH AXIS ALONG 110W IS SHIFTING 
SLOWLY E APPROACHING THE WEST COAST OF MAINLAND MEXICO. W AND NW 
OF THIS TROUGH AXIS IS A BROAD UPPER RIDGE ANCHORED ON A HIGH 
LOCATED W OF AREA. A JET STREAM BRANCH WITH CORE WINDS OF 90-110 
KT ENTERS THE REGION NEAR 28N140W THEN CONTINUES E AND SE TO 
NEAR 18N118W. ANOTHER BROAD AND FLAT RIDGE IS TO THE E OF THE 
UPPER TROUGH COVERING THE REMAINDER OF THE FORECAST REGION AS 
WELL AS CENTRAL AMERICA. WATER VAPOR IMAGERY SHOWS SUBSIDENCE 
AND THE IMPLIED DRY AIR MASS COVERING MOST OF THE AREA W OF 120W 
S OF 20N. A LARGE PLUME OF MID/UPPER LEVEL MOISTURE IS NOTED 
AHEAD OF THE TROUGH AXIS BETWEEN 95W AND 110W. ALL THIS MOISTURE 
IS BEEN TRANSPORTED NE ACROSS SOUTH-CENTRAL MEXICO AND THE GULF 
OF MEXICO BY STRONG SWLY WINDS.  

AT THE SURFACE...A 1020 MB SURFACE HIGH IS LOCATED NEAR 30N134W 
EXTENDING A RIDGE OVER THE NORTH WATERS MAINLY N OF 18N. FRESH 
TO STRONG TRADE WINDS ON THE SOUTHERN PERIPHERY OF THIS HIGH ARE 
EVIDENT ON AN EARLIER WINDSAT PASS...AND A RECENT ASCAT DATA. 
THIS WEATHER PATTERN IS EXPECTED TO PERSIST DURING THE NEXT 24 
TO 48 HOURS. A COLD FRONT IS CURRENTLY MOVING ACROSS THE N 
WATERS AND EXTENDS FROM 30N126W TO 25N134W. NE WINDS OF 10 KT 
ARE NOTED BEHIND THE FRONT WHICH IS EXPECTED TO DISSIPATE IN 
ABOUT 24 HOURS. LONG PERIOD NW SWELL WITH SIGNIFICANT WAVE 
HEIGHTS AS HIGH AS 17 FT FOLLOWS THE FRONT. ANOTHER COLD FRONT 
IS FORECAST BY THE COMPUTER MODELS TO ENTER THE FAR NW WATERS 
SAT NIGHT. S TO SW WINDS OF 20 TO 25 KT ARE EXPECTED AHEAD 
OF THE FRONT WITH LIGHTER WINDS...BELOW 20 KT...BEHIND IT. 
OUTSIDE OF GAP WINDS DESCRIBED BELOW...THE REMAINDER OF THE AREA 
IS UNDER LIGHT TO MODERATE WIND FLOW. THE LONG PERIOD NW SWELL 
WILL CONTINUE TO PROPAGATE SE ACROSS THE REGIONAL WATERS RAISING 
SEAS BETWEEN 8 AND 12 FT. A COUPLE OF WEAK TROUGHS ARE NOTED 
WITHIN THE ITCZ MOVING WWD. THE FIRST IS ALONG 105W FROM 1N TO 
8N WITH ISOLATED MODERATE CONVECTION. THE SECOND RUNS FROM 
9N119W TO 2N122W.  

GAP WINDS...
NEXT GULF OF TEHUANTEPEC GALE EVENT IS FORECAST TO BEGIN BY 00Z 
SUNDAY AS HIGH PRES BUILDS SWD INTO THE FAR WRN GULF OF MEXICO 
AND ALONG THE ERN SLOPES OF THE SIERRA MADRE MOUNTAINS IN THE 
WAKE OF A COLD FRONT CURRENTLY MOVING ACROSS THE CENTRAL GULF 
REGION.   

WINDS ARE EXPECTED TO PULSE UP AND DOWN THROUGH THE GULF OF 
PAPAGAYO AND THEN DOWNSTREAM TO NEAR 92W DURING THE NEXT COUPLE 
OF DAYS. 

N WINDS THROUGH THE GULF OF PANAMA ARE EXPECTED TO DIMINISH 
BELOW 20 KT BY THIS AFTERNOON.

FOR ADDITIONAL INFORMATION PLEASE VISIT 
HTTP://WWW.HURRICANES.GOV/MARINE

$$
GR