000
AXPZ20 KNHC 182156
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC MON SEP 18 2006

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2145 UTC.

...TROPICAL LOWS...

THE REMNANT LOW OF TROPICAL CYCLONE MIRIAM IS NEAR 20N113.5W 
1006 MB DRIFTING NW AND FORECAST TO DISSIPATE BY 48 HOURS.

BROAD LOW PRES HAS MEAN CENTER NEAR 13N95W 1010 MB UNDER AN 
UPPER RIDGE DESCRIBED BELOW. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION IS CURRENTLY ENHANCED TO N OF 11N BETWEEN 91W AND 
101W. MODELS ARE NOT SUGGESTING CONTINUED DEVELOPMENT.
 
...ITCZ...

ITCZ AXIS IS CENTERED ALONG 9N84W 10N94W 8N105W 12N118W 11N140W. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION WITHIN 60 NM 
EITHER SIDE LINE 8N83W 7N101W 4N110W AND LINE 10N107W 9N122W.

...DISCUSSION...

AN UPPER CYCLONE IS NEAR 50N131W WITH A SHORTWAVE TROUGH 
EXTENDING S THROUGH A SMALL UPPER CYCLONE AT 32N126W WITH THE 
TROUGH CONTINUING SW TO BASE NEAR 23N132W. 

AN UPPER ANTICYCLONE IS CENTERED AT 22N116W WITH A RIDGE 
EXTENDING E TO CREST OVER OLD MEXICO AT 26N103W. JUST TO THE N 
OF THE RIDGE OVER N CENTRAL OLD MEXICO...A TROUGH IS NOTED 
EXTENDING S ACROSS THE CENTRAL CONUS FROM A PARENT CYCLONE AT 
46N91W.

A BAND OF VERY DRY UPPER AIR IS INDICATED WITHIN 60 NM EITHER 
SIDE OF LINE 28N125W 23N134W...AND IS SURROUNDED BY RELATIVELY 
DRY AIR OVER THE DISCUSSION AREA NW OF LINE 12N140W 21N124W 
22N112W 25N102W.

A SMALL MID TO UPPER CYCLONE THAT SPUN OFF FROM TROPICAL CYCLONE 
MIRIAM IS STILL EVIDENT NEAR 17N125W AND CONTINUES WESTWARD.

AN INVERTED UPPER TROUGH THAT APPEARS TO HAVE CUT OF FROM AN 
ATLC TUTT IS STILL EVIDENT ALONG 17N103W 11N114W AND ACROSS THE 
EQUATOR AT 125W. TO THE E...A LARGE ANTICYCLONE IS CENTERED OVER 
THE N CENTRAL GULF OF MEXICO. ITS ENVELOPE OF ANTICYCLONIC FLOW 
DOMINATES THE DISCUSSION AREA N OF 13N E OF THE INVERTED TROUGH 
TO ABOUT 90W.

A LARGE UPPER ANTICYCLONE IS OVER S AMERICA NEAR 11S61W WITH A 
RIDGE EXTENDING NW ACROSS THE EQUATOR AT 77W TO A CREST AT 
9N85W.

ELSEWHERE AT THE SURFACE A RIDGE EXTENDS ALONG 32N138W 18N122W. 

$$
NELSON