000
AXPZ20 KNHC 180313
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC WED NOV 18 2009

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 
0300 UTC.

...ITCZ...
AXIS IS ALONG 6N78W 7N100W 6N110W 10N125W 7N140W. SCATTERED 
MODERATE ISOLATED STRONG CONVECTION WITHIN 90 NM S OF AXIS FROM 
120W-124W. SCATTERED MODERATE TO STRONG CONVECTION WITHIN 150 NM 
N OF AXIS FROM 132W-140W.

...DISCUSSION...
WEAKENING MIDDLE TO UPPER LEVEL TROUGH EXTENDS FROM 32N134W TO 
26N140W. A BROAD UPPER LEVEL RIDGE IS E OF THE TROUGH WITH 
ANTICYCLONIC FLOW COVERING A LARGE PORTION OF THE DISCUSSION 
AREA N OF 15N BETWEEN 105W-130W. AN 80-95 KT JETSTREAM THROUGH 
THE MIDDLE OF THE RIDGE EXTENDS FROM 23N140W TO 25N120W THEN 
ACROSS SOUTHERN BAJA CALIFORNIA AND INTO CENTRAL MEXICO. THE JET 
IS ADVECTING HIGH LEVEL MOISTURE FROM THE ITCZ NE TO 21N W OF 
130W. AN UPPER LEVEL CYCLONIC CIRCULATION IN THE DEEP TROPICS IS 
CENTERED NEAR 9N113W. MODERATE TO STRONG SUBSIDENCE WITH DRY 
STABLE AIR AT THE MID/UPPER LEVELS IS WITHIN 300 NM E OF 
CYCLONIC CIRCULATION. UPPER LEVEL DIFFLUENT FLOW IS ENHANCING 
CONVECTIVE ACTIVITY ALONG THE ITCZ W OF 132W.

STRONG HIGH PRES MOVING THROUGH THE WESTERN GULF OF MEXICO
IS PRODUCING GALE FORCE WINDS THROUGH THE GULF OF TEHUANTEPEC.
THE GALE CONDITIONS ARE EXPECTED TO PERSIST THROUGH TONIGHT THEN 
GRADUALLY DIMINISH EARLY WED AS HIGH PRES SHIFTS E ACROSS THE 
GULF OF MEXICO. A COLD FRONT IS MOVING INTO THE FAR NW PORTION 
OF THE DISCUSSION AREA FROM 32N132W TO 28N140W. OVERCAST LOW TOP 
CLOUDS ARE W OF THE FRONT AND WITHIN 60 NM E OF THE FRONT. A 
SURFACE HIGH PRES RIDGE IS SE OF THE FRONT. THE HIGH IS 
PRODUCING STRONG ENOUGH GRADIENT FOR WINDS TO REACH 20 TO 25 KT 
FROM 8N TO 22N W OF 120W. BROKEN TO OVERCAST STRATOCUMULUS 
CLOUDS COVER THE AREA N OF 20N BETWEEN 118W-130W.

A COUPLE OF SURFACE TROUGHS ARE ANALYZED ALONG THE ITCZ. ONE 
FROM 11N104W TO 4N103W. SCATTERED MODERATE CONVECTION THAT WAS 
ASSOCIATED WITH THE TROUGH EARLIER HAS DISSIPATED. ANOTHER 
TROUGH EXTENDS FROM 14N128W TO 7N128W. ISOLATED SHOWERS ARE 
ALONG THE TROUGH AXIS.

$$
DGS