000
AXPZ20 KNHC 310340
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SUN JAN 31 2010

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 
0215 UTC.

...ITCZ...

THE ITCZ AXIS IS ANALYZED ALONG 06N77W TO 04N85W TO 06N105W TO 
04N112W TO 05N127W TO 03N134W TO 03N140W.  SCATTERED MODERATE 
CONVECTION WAS OCCURRING WITHIN A 60 NM RADIUS OF 03N135W. 
ISOLATED TO SCATTERED MODERATE CONVECTION WAS OCCURRING ALONG 
AND UP TO 120 NM S OF A CONVERGENCE LINE FROM 05N88W TO 07N83W. 

...DISCUSSION...

A STRONG UPPER LEVEL WLY FLOW BETWEEN 18N AND 34N PERSISTS 
TONIGHT FROM THE CENTRAL PACIFIC TO THE W COAST OF N AMERICA AND 
MEXICO. THIS CONTINUES TO INDUCE A NEGATIVE NW TO SE TILT TO S/W 
TROUGHS MOVING EWD ACROSS THE N PACIFIC.  

A VERY BROAD AND FLAT MIDDLE/UPPER LEVEL RIDGE EXTENDS FROM THE 
CENTRAL PACIFIC S OF THE HAWAIIAN ISLANDS N AND NE TO 30N W OF 
120W. A FEW S/W TROUGH COULD BE SEEN EMBEDDED IN THIS BROAD W TO 
WNW UPPER FLOW APPROACHING W PORTIONS OF THE AREA. A S/W RIDGE 
WAS N OF 28N MOVING E AND NEARING THE W COAST. DOWNSTREAM OF THE 
FLAT RIDGE...A MIDDLE/UPPER LEVEL TROUGH WAS TILTED NORTH 
NORTHWEST TO SOUTH SOUTHEAST WITH THE AXIS LOCATED THROUGH 
25N111W TO 08N105W...AND APPEARS ON WATER VAPOR IMAGERY THAT IT 
IS BEGINNING TO LIFT NE OVER THE DOWNSTREAM RIDGE OVER THE GULF 
OF MEXICO. AN UPPER CYCLONE OVER N NEVADA WITH TROUGH EXTENDING 
S INTO FAR NE PORTIONS OF THE AREA WAS BEGINNING TO COME IN 
PHASE WITH N PORTIONS OF THE AFOREMENTIONED TROUGH...N OF 25N. A 
70 KT JET DIVES INTO THE BACKSIDE OF THE SRN TROUGH AND THEN 
ACCELERATES E OF THE TROUGH ACROSS MEXICO... WITH UPPER LEVEL 
WIND MAXIMUMS TO 100 KT ACROSS THE NW AND N GULF OF MEXICO. 
WATER VAPOR IMAGERY INDICATES STRONG SUBSIDENCE OVER A VAST AREA 
S OF 13N TO THE ITCZ W OF 118W. AT THE SURFACE A 1018 MB HIGH 
WAS LOCATED NEAR 35N128W AND IS FORECAST TO DISSIPATE IN 24 
HOURS. THE PRESSURE GRADIENT TO THE S OF THIS WEEK RIDGE WAS 
PRODUCING NORTHEAST TRADES FROM 20 TO 25 KNOTS CONFINED TO S OF 
16N W OF 122W...AND WILL SINK TO S OF 13N AND CONTINUE OUT TO 48 
HOURS. SURFACE TROUGHS/PERTURBATIONS EMBEDDED WITHIN THE ITCZ 
WERE LOCATED ALONG 105W/106W S OF 08N AND ALONG 126W/127W S OF 
09N. A DISSIPATING FRONTAL TROUGH WAS LOCATED THROUGH 30N121W TO 
24N133W. SEAS CONTINUE TO BE DOMINATED BY NWLY SWELL...AND WERE 
RUNNING IN THE 12 TO 14 FOOT RANGE N OF 24N W OF 120W. 
ADDITIONAL PULSES OF NW SWELL WILL PROPAGATE THROUGH THE AREA 
WATERS THROUGHOUT THE UPCOMING WEEK...WITH HIGHEST SEAS 
GENERALLY REMAINING N OF 26N.

MINIMAL GALE CONDITIONS ARE EXPECTED TO BEGIN THROUGH THE GULF 
OF TEHUANTEPEC BETWEEN 0300-0600 UTC AND DROP BELOW GALE FORCE 
BY 36 HOURS. GAP WINDS IN THE GULF OF PAPAGAYO ARE 20 TO 25 
KNOTS AND WILL PULSE UP AND DOWN OVER THE NEXT 48 HOURS...WHILE 
NLY FLOW THROUGH THE GULF OF PANAMA WILL PULSE UP AND DOWN AT OR 
BELOW 20 KT THROUGHOUT THE NEXT FEW DAYS. 

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

$$
STRIPLING