000
AXPZ20 KNHC 091606
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC FRI NOV 09 2007

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. 

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1545 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 9N85W 8N90W 7N100W 7N110W 7N120W
8N130W 9N140W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS 
WITHIN 60 NM OF THE AXIS BETWEEN 94W-100W AND WITHIN 30 NM OF 
THE AXIS BETWEEN 104W-107W. SCATTERED MODERATE CONVECTION WITHIN
30 NM OF THE AXIS BETWEEN 110W-113W.

...DISCUSSION...

E OF 110W...
PERSISTENT ELONGATED MID/UPPER LEVEL RIDGING STRETCHES ALONG THE 
SPINE OF MEXICO FROM A MID/UPPER LEVEL ANTICYCLONE LOCATED OVER
NW COLOMBIA. THE RIDGE CONTINUES TO NW TO A CREST NW OF THE 
DISCUSSION AREA TO E ARIZONA. A MID/UPPER LEVEL CYCLONE MOVING 
SLOWLY W IS NOTED NEAR 7N94W ON WATER VAPOR IMAGERY. 
ANTICYCLONIC UPPER LEVEL FLOW COVERS MUCH OF THE AREA...EXCEPT 
FOR THE FAR WESTERN EDGE WHERE MID/UPPER CYCLONIC FLOW IS 
EVIDENT AHEAD OF AN APPROACHING SHORTWAVE TROUGH. MOSTLY BROKEN 
CIRRUS CLOUDS ARE SEEN RIDING NORTHEASTWARD AROUND THE NORTHERN 
PERIPHERY OF THE RIDGE AXIS MOVING INTO SOUTHERN CALIFORNIA AND 
NORTHERN BAJA. MODERATE SUBSIDENCE AND ASSOCIATED DRY AIR COVERS 
THE AREA S OF THE ITCZ...AND ALSO N OF THE ITCZ E OF 90W. ITCZ 
CONVECTION HAS INCREASED BETWEEN 93W-108W WHICH IS UNDER THE 
SOUTHERN PERIPHERY OF THE RIDGE WHERE GENERALLY LIGHT ELY FLOW 
EXISTS. CLUSTERS OF SCATTERED MODERATE TO STRONG CONVECTION HAVE 
ALSO INCREASED FROM 4N-8N E OF 80W TO JUST INLAND THE COLOMBIAN 
COAST PRIMARILY DUE TO TYPICAL LOW PRES OVER NW COLOMBIA WITH 
SOME FURTHER ENHANCEMENT BY SURFACE TROUGHING OVER THE FAR SW 
CARIBBEAN SEA...AND UPPER LEVEL DIFFLUENT FLOW OVER THE GULF OF 
PANAMA AND FAR NW CORNER OF COLOMBIA.

WINDS LESSENED TO JUST BELOW THE GALE FORCE THRESHOLD OVER THE 
GULF OF TEHUANTEPEC SHORTLY AFTER 0900 UTC AS CONFIRMED BY A 
QUIKSCAT PASS FROM AROUND 1244 UTC THIS MORNING THAT SHOWED 
WINDS N-NE WINDS IN THE 20-30 KT RANGE ACROSS A SWATH OF ABOUT 
100 NM IN DIAMETER. THIS IS IN RESPONSE TO WEAKENING HIGH PRES
OVER MEXICO. NE WINDS TO 20 KT ARE STILL POSSIBLE FROM 8N-12N
E OF 88W THROUGH THE NEXT 48 HRS BEFORE DIMINISHING.

W OF 110W...
A MID/UPPER LEVEL TROUGH EXTENDS INTO THE AREA THROUGH 32N125W
TO 25N130W AND SW TO 19N135W WHERE IT BECOMES A SHEAR AXIS TO 
W OF THE AREA AT 19N140W AND W TO A MID LEVEL CYCLONIC 
CIRCULATION NEAR 20N142W. A JET STREAM BRANCH WITH MAXIMUM WINDS 
IN THE RANGE OF 50-60 KT ENTERS THE AREA THROUGH 13N140W AND 
TURNS NE AROUND THE BASE OF THE AFOREMENTIONED TROUGH. AMPLE 
MID/UPPER LEVEL MOISTURE IS ADVECTED NE WITHIN 360 NM SE OF THE 
JET STREAM BRANCH. ISOLATED SHOWERS ARE POSSIBLE UNDERNEATH 
THESE CLOUDS...CLUSTERS OF SCATTERED MODERATE TO STRONG 
CONVECTION ARE OCCURRING S OF THE JET STREAM JUST W OF 
140W...AND CONTINUING FURTHER W FOR A GOOD DISTANCE ALONG THE 
ITCZ. MODERATE SUBSIDENCE AND ASSOCIATED DRY AIR IS PRESENT 
WITHIN 350 NM S OF THE TROUGH W OF 132W. MID/UPPER LEVEL
MOISTURE IS SEEN SPILLING SWD INTO THE AREA BEHIND THE TROUGH IN 
MODERATE TO STRONG N FLOW. AN UPPER WEAK ANTICYCLONE CENTER
MOVING NW 10-15 KT IS NOTED NEAR 6N127W WITH A RIDGE EXTENDING
NORTHEASTWARD TO 16N121.5W.

AT THE SURFACE...A 1021 MB HIGH IS NEAR 28N138W WITH A RIDGE SE 
TO 24.5N116W. HIGH PRES COVERS THE AREA N OF 19N AND W OF 114W. 
SCATTERED TO BROKEN STRATOCUMULUS CLOUDS MOVING WESTWARD WITH 
ISOLATED SHOWERS ARE NOTED N OF 20N W OF 132W.

$$
AGUIRRE