000
AXPZ20 KNHC 170915
TWDEP 

TROPICAL WEATHER DISCUSSION     
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SAT FEB 17 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0845 UTC.

...ITCZ...

ITCZ AXIS ALONG ALONG 1N80W 4N99W 6N115W 1N140W. ISOLATED 
MODERATE CONVECTION ALONG A LINE FROM 3N86W TO 4N90W. ISOLATED 
MODERATE NEAR 6N106W 6N109W 7N117W 6N119W 7N121W AND 5N128W. 

OTHER ISOLATED MODERATE CONVECTION NOTED NEAR EQ88W 6N85W 9N86W 
AND 1N92W. 

...DISCUSSION...

IN THE MID LEVELS TONIGHT A BLOCKING PATTERN KNOWN AS A REX 
BLOCK CONTINUES ALONG 128W WITH A RIDGE CENTER NEAR 34N128W AND 
A LOW CENTER NEAR 25N128W. THE WHOLE PATTERN IS BEING NUDGED EWD 
BY A STRONG WLY FLOW JUST NW OF THE AREA. ON THE SURFACE TONIGHT 
THE PACIFIC HIGH CENTER 1031 MB WAS NEAR 31N135W AND WAS STILL 
PRODUCING NE TRADES TO 25 KT S OF 25N AND W OF 120W. A GALE 
CONDITION EXISTS IN THE GULF OF TEHUANTEPEC AND SSMI CONFIRMS 
THIS. NO QUIKSCAT AVAILABLE. WINDS ALONG THE BAJA COAST WERE 
LIGHT NWLY. OTHER GAP WINDS WERE ALSO LIGHT. 

LATER DAY 1 THE STRONG MID LEVEL WLY FLOW WILL ERODE THE RIDGE 
CENTER AND ALSO BEGIN MOVING THE CUTOFF LOW NE. ON THE SURFACE 
LATER DAY 1 WITH MOVEMENT OF THE MID LEVEL LOW CENTER 
NE..SURFACE PRESSURES FALL W OF BAJA KEEPING WINDS LIGHT ALONG 
THE BAJA COAST. NE TRADES WEAKEN SOME AS THE PACIFIC RIDGE 
WEAKENS WITH MOVEMENT OF THE MID LEVEL CENTER. WINDS THROUGH 
TEHUANTEPEC WEAKEN BELOW GALE FORCE TEMPORARILY WHILE GAP WINDS 
W OF NICARAGUA AND EL SALVADOR BEGIN TO INCREASE TO 20 KT. S OF 
PANAMA NLY WINDS ALSO INCREASE TO 20 KT. 

FOR DAY 2 RAPID MOVEMENT OF A SHORTWAVE TROUGH EWD ALONG 35N 
WILL DISLODGE THE OLD CUTOFF LOW AT MID LEVELS AND LIFT IT NE. 
MID LEVEL TROUGHING WILL CONTINUE FROM THE NRN BAJA AREA SW TO 
20N140W WITH THE MID LEVEL FLOW BECOMING NWLY NW OF THE TROUGH 
AXIS. MID LEVEL RIDGING DEVELOPS ALONG 100W NWD OVER MEXICO 
AHEAD OF THE TROUGH. ON THE SURFACE DAY 2 A WEAK TROUGH PERSISTS 
JUST W OF THE BAJA COAST KEEPING WINDS LIGHT E OF 120W AND N OF 
15N. N AND NE WINDS INCREASE W OF 120W AS THE PACIFIC RIDGE 
BUILDS UNDER THE NWLY FLOW. N TO NE WINDS TO 25 KT WITH SEAS 
INCREASING 9 TO 12 FT SHOULD BE THE RULE W OF 124W. WINDS 
INCREASE TO STORM FORCE THROUGH TEHUANTEPEC DAY 2 AS HIGH 
PRESSURE BUILDS OVER THE WRN GULF OF MEXICO. SEAS WILL ALSO 
INCREASE TO 15 FT. OTHER GAP WINDS W OF THE CENTRAL AMERICAN 
COAST WILL ALSO INCREASE TO 25 KT AS HIGH PRESSURE BUILDS OVER 
THE NW CARIBBEAN. 

$$
RRG