000
AXPZ20 KNHC 250412
TWDEP 

TROPICAL WEATHER DISCUSSION     
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC THU JAN 25 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 
0345 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG AXIS 4N77W 7N95W 10N105W 4N125W 
4N140W. SCATTERED MODERATE WITHIN 75 NM OF THE AXIS BETWEEN 82W 
AND 86W.

...DISCUSSION...

OMEGA BLOCK OVER CALIFORNIA/W COAST IS BEGINNING TO BREAK DOWN
AND BECOME PINCHED OFF AS A DEEP CLOSED LOW OVER NRN MEXICO NEAR 
29N109W MOVES WWD 10 KT AND AN UPSTREAM PROGRESSIVE BUT 
NEGATIVELY TILTED TROUGH IMPINGES FROM THE NW. A WELL DEFINED 
CYCLONIC CIRCULATION WAS NOTED NEAR 38N131W. A NEAR ZONAL 
SUBTROPICAL JET IS POSITIONED ALONG 19N/20N WITH CORE SPEEDS OF 
90-100 KT...THEN TURNS SHARPLY NE INTO N/CENTRAL MEXICO ON THE 
SE PERIPHERY OF THE CLOSED LOW. A WEAK COLD FRONT OVER THE 
NORTHWEST CORNER OF THE AREA EXTENDS FROM 30N133W TO 26N140W 
WITH ISOLATED SHOWERS WITHIN THE FRONTAL BAND...AND FURTHER 
WEAKENING IS ANTICIPATED DURING THE NEXT 12 HRS. OVERALL THE 
MIDDLE AND UPPER ATMOSPHERE ARE FAIRLY SUBSIDENT AND HAS THUS 
LIMITED THE VERTICAL EXTENT OF CLOUD COVER EVEN IN THE ITCZ 
MAINLY W OF 95W.

FARTHER E...A SURFACE TROUGH EMBEDDED WITHIN THE ITCZ IS LOCATED 
SW OF ACAPULCO FROM 6N112W TO 15N103W AND PROVIDES THE DIVIDING 
LINE FOR WEAK 5-10 KT WINDS TO THE E...AND STRONGER 15-20 KT NE 
WINDS TO THE W. THIS FEATURE REMAINS WEAK IN TERMS OF 
THE ASSOCIATED LOW-LEVEL CONVERGENCE. WINDS OVER THE GULF OF 
TEHUANTEPEC ARE 20-25 KT BUT ARE EXPECTED TO INCREASE TO GALE 
FORCE WITHIN THE NEXT 12 HOURS AS HIGH PRES BUILDS OVER THE GULF 
OF MEXICO. A 2230 UTC QUIKSCAT PASS INDICATED WINDS IN THE GULF 
OF PAPAGAYO WERE 20-25 KT. THESE WINDS WILL REMAIN STEADY AT 20 
KT OR SO FOR THE NEXT FEW DAYS. WINDS OVER THE GULF OF PANAMA 
HAVE COME DOWN SLIGHTLY TO 20 KT ACCORDING TO THE QUIKSCAT DATA 
FROM THIS EVENING. THESE WINDS WILL CONTINUE FOR 24 HOURS THEN 
WEAKEN BEYOND THAT TIME. 

THE CLOSED LOW OVER NW MEXICO IS FORCING A STRONG 120 KT JET 
CORE OF THE SUBTROPICAL JET ACROSS N/CENTRAL MEXICO WITH A 
PROLIFIC BAND OF MID/UPPER LEVEL CLOUDINESS ACROSS MUCH OF THE 
COUNTRY. A STATIONARY FRONT IS DRAPED ACROSS THE MOUNTAINOUS 
TERRAIN FROM THE W SIDE OF THE CHIVELAS PASS NWWD TO DURANGO AND 
COLD LOW-LEVEL FLOW IS BEING FORCED ONTO THE MEXICAN PLATEAU 
WITH ABNORMALLY COLD TEMPERATURES OF 2 TO 4 DEGREES CELSIUS AND 
LOW STRATUS E OF THE SIERRA MADRE OCCIDENTALS.

$$
COBB