000
AXPZ20 KNHC 210936
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SUN FEB 21 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 AXIS IS CENTERED ALONG 03N78W TO 06N100W TO 06N109W TO 
06N125W TO 08N140W. SCATTERED MODERATE WITHIN 100 NM N OF AXIS 
BETWEEN 120W AND 125W. 

...DISCUSSION...

AN UPPER-LEVEL TROUGH IS OVER THE NW CORNER OF THE FORECAST 
REGION AND EXTENDS SW TO JUST EAST OF THE HAWAIIAN ISLANDS. A 
SUBTROPICAL JET STREAM ROUNDS THE BASE OF THIS TROUGH AND 
CONTINUES MAINLY EWD ACROSS THE REGIONAL WATERS CROSSING 
SOUTHERN BAJA CALIFORNIA PENINSULA WITH CORE WINDS OF 130-150 
KT. IN ADDITION TO MAINTAINING MAINLY A ZONAL FLOW PATTERN 
ACROSS MOST OF THE AREA...THIS JET ALSO CONTINUES TO ADVECT 
PLENTIFUL MID TO UPPER LEVEL MOISTURE FROM THE DEEP CENTRAL 
TROPICAL PACIFIC NE TO E ACROSS CENTRAL AND SOUTHERN MEXICO AND 
INTO THE BAY OF CAMPECHE AND NW CARIBBEAN SEA. THE UPPER TROUGH 
WILL WEAKEN AS IS MOVE EWD DURING THE NEXT 24 TO 48 HOURS. THE 
ATTENDANT COLD FRONT CLIPS THE FAR NW WATERS WITH NW WINDS OF 20 
KT BEHIND IT. THIS FRONTAL SYSTEM WILL BE N OF AREA IN 24 
HOURS...AND A 1024 MB SURFACE HIGH PRES CURRENTLY LOCATED 
26N138W WILL REMAIN IN CONTROL OF THE WEATHER PATTERN ACROSS THE 
MAJORITY OF THE FORECAST REGION DURING THE NEXT COUPLE OF DAYS. 
THE PRES DIFFERENCE BETWEEN THE HIGH AND LOWER PRES ASSOCIATED 
WITH THE ITCZ IS ALLOWING FOR AN AREA OF NE TO E 20 TO 25 KT 
TRADE WINDS FROM 08N TO 18N W OF 120W. BOTH...AN EARLIER WINDSAT 
PASS AND A RECENT ASCAT DATA CORROBORATED THESE WINDS SPEEDS. 
MODEL GUIDANCE AGREES THAT THE HIGH WILL SHIFT MAINLY E TO NEAR 
26N132W IN 24 HRS. AS A RESULT THE AREA OF TRADES IS EXPECTED TO 
EXPAND EASTWARD TO NEAR 110W IN 24 HOURS. WINDS ARE ALSO 
EXPECTED TO INCREASE NEAR THE BAJA CALIFORNIA PENINSULA IN ABOUT 
24 HOURS AND ACROSS THE GULF OF CALIFORNIA IN APPROXIMATE 48 
HOURS AS PRES GRADIENT TIGHTENS BETWEEN THE HIGH AND LOWER PRES 
OVER NORTHERN MEXICO.

ELSEWHERE A NEARLY STATIONARY UPPER LEVEL ANTICYCLONE IS NOTED 
NEAR 08N115W WITH AN UPPER RIDGE AXIS EXTENDING FROM THERE TO 
18N114W. BROAD MID TO UPPER LEVEL ANTICYCLONIC FLOW COVERS THE 
AREA SOUTH OF THE ABOVE MENTIONED JET STREAM AND W OF 100W. A 
MID TO UPPER LEVEL TROUGH EXTENDS FROM NEAR THE GULF OF 
TEHUANTEPEC TO 06N96W. A DIFFLUENT PATTERN ALOFT BETWEEN THESE 
TWO UPPER LEVEL FEATURES IS HELPING TO INDUCE SCATTERED MODERATE 
TO STRONG CONVECTION EITHER SIDE OF A SURFACE TROUGH EMBEDDED IN 
THE ITCZ THAT EXTENDS FROM 09N102W TO 04N103W. 

A WEAK 1011 MB LOW IS ALSO EMBEDDED IN THE ITCZ NEAR 06N111W. A 
RECENT ASCAT PASS ONLY SHOWED WINDS OF 10 TO 15 KT AROUND THE 
LOW CENTER. HOWEVER...MARINE GUIDANCE INDICATES A SMALL AREA OF 
S TO SW WINDS OF 20 KT WITHIN 120 NM OF LOW CENTER IN ABOUT 24 
HOURS. THIS LOW WILL DRIFT NE DURING THE NEXT FEW DAYS. 

GAP WINDS...
WINDS WILL CONTINUE TO PULSE TO 20 KT IN THE GULF OF PAPAGAYO 
DURING THE NEXT 24 HOURS WITH THE STRONGEST WINDS EXPECTED TO 
OCCUR DURING THE EARLY MORNING HOURS WHEN DRAINAGE FLOW OFF THE 
CENTRAL AMERICA LANDMASS PEAKS.

LOOKING AHEAD...THE NEXT TEHUANTEPEC EVENT IS FORECAST TO BEGIN 
BY THE COMPUTER MODELS LATE WED...WITH WINDS LIKELY REACHING 
GALE FORCE THU.

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

$$
GR