000
AXPZ20 KNHC 160929
TWDEP 

TROPICAL WEATHER DISCUSSION     
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC FRI FEB 16 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 IS CENTERED ALONG 3N78W 3N83W 2N90W 5N113W 1N132W 
1N140W. SCATTERED MODERATE CONVECTION WITHIN 20 NM OF A LINE 
FROM 1N89W TO 4N97W. SCATTERED MODERATE WITHIN 60 NM OF 5N118W.

ISOLATED MODERATE CONVECTION NEAR THE COAST OF COLOMBIA AT 5N78W 
AND NEAR THE ECUADORIAN COAST NEAR 1N81W.

...DISCUSSION...

IN THE MID LEVELS TONIGHT A REX BLOCK HAS SET UP ALONG 130W 
WHERE THE WRN END OF A MID LEVEL TROUGH CENTERED NEAR 20N130W 
HAS SEPARATED FROM IT'S PARENT TROUGH OVER N CENTRAL MEXICO. THE 
CUTOFF CENTER IS TRAPPED S OF A CUTOFF RIDGE CENTERED NEAR 
33N130W. THIS IS A RELATIVELY STABLE PATTERN NAMED AFTER AN OLD 
BRITISH METEOROLOGIST THAT FIRST IDENTIFIED THIS PATTERN. A 
SUBTROPIC JET SEGMENT CONTINUES FROM 10N BETWEEN 115W AND 130W 
TURNS NE AND ACCELERATES ENE OVER CENTRAL MEXICO. A STRONG POLAR 
JET IS WELL NW OF THE AREA AND CURVES NWD OVER THE RIDGE. ON THE 
SURFACE TONIGHT A STRONG HIGH 1034 MB CENTERED BENEATH THE MID 
LEVEL CENTER COVERS THE REGION N OF 5N AND W OF 105W. THE RIDGE 
IS PRODUCING STRONG NE TRADES TO 30 KT BETWEEN 6N AND 22N W OF 
120W WITH SEAS 10 TO 15 FT. STRONG NWLY WINDS ARE ALSO OCCURING 
THROUGH THE SEA OF CORTEZ ACCORDING TO SSMI AND QUIKSCAT. WINDS 
ARE EXPECTED TO INCREASE TONIGHT THROUGH TEHUANTEPEC AS HIGH 
PRESSURE BUILDS OVER THE WRN GULF OF MEXICO. 

LATER DAY 1 VERY LITTLE CHANGE TO THE MID LEVEL PATTERN EXCEPT 
FOR STRONG SWLY FLOW WORKING IT'S WAY SE TOWARD 30N140W. ON THE 
SURFACE LATER DAY 1 LOOK FOR GALE CONDITIONS TO DEVELOP THROUGH 
TEHUANTEPEC AS HIGH PRESSURE MOVES S ALONG THE WRN GULF OF 
MEXICO COAST. THE PACIFIC RIDGE IS FORECAST TO WEAKEN SLIGHTLY 
BUT REMAIN IN PLACE LATER DAY 1 AND NE TRADES SHOULD DECREASE 
SOME. SEA OF CORTEZ WINDS ARE ALSO FORECAST TO DIMINISH LATER 
DAY 1. 

FOR DAY 2 THE STRONG MID LEVEL SWLY WINDS WILL TURN MORE WLY AS 
A STRONG SHORTWAVE TROUGH MOVES E TO 138W JUST N OF THE AREA. 
THE WLY FLOW WILL WEAKEN THE MID LEVEL RIDGE WHICH WILL IN TURN 
DISLODGE THE CUTOFF LOW CENTER. THUS THE ONCE STABLE PATTERN IS 
NO MATCH FOR THE STRONG WLY FLOW N OF 30N. ON THE SURFACE DAY 2 
A COLD FRONT WILL BRUSH BY THE NW PORTION AND WEAKEN THE PACIFIC 
RIDGE. THE FRONT IS ASSOCIATED WITH THE SHORTWAVE ALOFT. NE 
TRADES CONTINUE TO DIMINISH TO 15 TO 20 KT WITH SEAS 9 TO 11 FT. 
WINDS ALONG THE BAJA COAST WILL BE MOSTLY N TO NE 10 KT WITH 
SEAS 4 TO 6 FT. WINDS TEMPORARILY DROP BELOW GALE FORCE IN THE 
GULF OF TEHUANTEPEC AS HIGH PRESSURE WEAKENS OVER THE SW GULF OF 
MEXICO. GAP WINDS W OF NICARAGUA AND EL SALVADOR WILL INCREASE 
OUT OF THE NE TO 20 KT AS PRESSURE BUILDS OVER THE NW CARIBBEAN. 

$$
RRG