000
AXPZ20 KNHC 060319
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC FRI APR 06 2007

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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0300 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 6N77W 11N85W 5N110W 3N130W 6N140W. 
NUMEROUS MODERATE/STRONG CONVECTION FROM 5N-9N BETWEEN 84W-95W. 
ISOLATED SHOWERS/TSTMS WITHIN 150 NM OF THE AXIS BETWEEN 
100W-116W.

...DISCUSSION...

SUBTROPICAL PACIFIC...
AN AMPLIFIED UPPER RIDGE AXIS LIES ALONG 110W RUNNING UP ALONG 
THE BAJA PENINSULA AND NW MEXICO...THEN NW ACROSS CALIFORNIA AND 
OREGON. A CUT-OFF MID/UPPER LOW IS EMBEDDED WITHIN THE RIDGE 
NEAR 32N121W BUT STILL HAS SIGNIFICANT EWD MOVEMENT DUE TO 
VIGOROUS WESTERLY FLOW N OF THE HAWAIIAN ISLANDS. A DANGLING 
UPPER TROUGH EXTENDS FROM 30N121W SW TO 20N140W AND IS 
SURROUNDED BY MODERATE/STRONG SUBSIDENCE. THE SUBTROPICAL JET 
RUNS ON THE S SIDE OF THE TROUGH FROM 16N140W TO 20N126W THEN TO 
30N116W WITH A TROPICAL MOISTURE FIELD STREAMING INTO NRN 
MEXICO. A 1018 MB HIGH IS CENTERED NEAR 29N127W AND IS PRODUCING 
MOSTLY TRANQUIL WEATHER...ALTHOUGH WINDS AND SEAS ARE JUST 
BEGINNING TO INCREASE OVER THE FAR NW PORTION OF THE AREA IN 
ADVANCE OF A LARGE STORM SYSTEM. THE ASSOCIATED COLD FRONT IS 
EXPECTED TO MOVE INTO THE AREA FRI AFTERNOON ALTHOUGH IT WILL 
HAVE LOST MUCH OF ITS STEAM IN TERMS OF WIND. A FEW SHOWERS WILL 
BE POSSIBLE WITHIN THE FRONTAL BAND BEGINNING EARLY FRI THROUGH 
WHEN THE FRONT BECOMES STATIONARY LATE SAT.

TROPICAL PACIFIC...
THE SUBTROPICAL JET ENTERS THE AREA ALONG 14N WITH WESTERLY FLOW 
EXTENDING E TO 120W. THE FLOW BECOMES DIFFLUENT AT THAT 
POINT...WITH PART OF IT STREAMING NE INTO THE RIDGE OVER WRN 
MEXICO...AND THE OTHER PART STREAMING SE INTO AN UPPER TROUGH 
ALONG 16N100W EQ114W. MODERATE/STRONG SUBSIDENCE LIES BETWEEN 
97W-115W AT THE BASE OF THE RIDGE AND THE CONFLUENCE INTO THE 
TROUGH AND THIS IS HELPING TO PRODUCE BEAUTIFUL WEATHER ALONG 
THE MEXICAN AND CENTRAL AMERICAN COAST TO EL SALVADOR. TO THE 
E...THE UPPER SHEAR AXIS IS PRODUCING SOME UPPER DIFFLUENCE S OF 
CENTRAL AMERICA...AND THE ITCZ IS BEING PERTURBED NWD INTO COSTA 
RICA TO INITIATE NUMEROUS MODERATE CONVECTION BETWEEN 84W-95W. 
EARLIER CONVECTION OVER COSTA RICA AND PANAMA IS CURRENTLY ON 
THE DOWNWARD TREND.

A 0028 UTC QUIKSCAT PASS JUST ARRIVED AND SHOWS THAT WINDS OVER 
THE GULF OF TEHUANTEPEC HAVE INCREASED TO MINIMAL GALE FORCE 
WITHIN ABOUT 60 NM OF THE COAST. THE GALE WARNING GOES INTO 
EFFECT NOW AND WILL LAST FOR 18 HOURS...WITH THE HIGHEST WIND 
FIELD EXPANDING A BIT TO THE SW AS THE SURGE CONTINUES FROM THE 
SW GULF OF MEXICO. THE MODELS AGREE THAT THIS WILL BE A 
SHORT-LIVED EVENT WITH WINDS DIMINISHING BELOW GALE FORCE BY FRI 
AFTERNOON THEN BELOW 20 KT BY SAT EVENING.

$$
BERG