000
AXPZ20 KNHC 211604
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC FRI SEP 21 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.

...SPECIAL FEATURE...
THE CENTER OF HURRICANE IVO AT 21/1500 UTC IS NEAR 19.5N 113.4W
OR 300 NM SOUTHWEST OF CABO SAN LUCAS MEXICO. HURRICANE IVO IS
MOVING NORTH-NORTHWEST 6 KT. THE MAXIMUM SUSTAINED WIND SPEEDS 
ARE 65 KT WITH GUSTS TO 80 KT. THE ESTIMATED MINIMUM CENTRAL 
PRESSURE IS 987 MB. PLEASE READ THE LATEST NHC FORECAST/ADVISORY 
UNDER AWIPS/WMO HEADERS MIATCMEP2/WTPZ22 KNHC FOR MORE DETAILS. 
BROAD UPPER LEVEL ANTICYCLONIC FLOW COVERS THE WESTERN GULF OF 
MEXICO AND INTERIOR MEXICO AT LEAST TO 104W. A DEEP LAYER TROUGH 
IS MOVING FROM CALIFORNIA TO THE AREA TO THE NORTH OF IVO. 
WARMING CLOUD TOP TEMPERATURES AND REMNANT SHOWERS AND POSSIBLE 
THUNDERSTORMS COVER THE WATERS FROM 18N TO 22N BETWEEN 112W AND 
114W. PRECIPITATION ASSOCIATED WITH IVO HAS BEEN SHOWING WIDE 
SWINGS IN INTENSITY EVERY FEW HOURS FOR THE LAST 6 TO 8 HOURS.
  
...TROPICAL WAVES...
TROPICAL WAVE ALONG 95W/96W SOUTH OF 17N MOVING WEST 10-15 KT.
NUMEROUS STRONG SHOWERS AND THUNDERSTORMS ARE FROM 11N TO 12N
BETWEEN 91.5W AND 93.5W. SCATTERED MODERATE TO STRONG SHOWERS
AND THUNDERSTORMS ARE IN THE ITCZ FROM 8.5N TO 10N BETWEEN 96W 
AND 100W. CLOUD TOP TEMPERATURES HAVE BEEN WARMING AND COOLING
IN ALTERNATING UP AND DOWN PERIODS DURING THE LAST 4 TO 5 HOURS.

...ITCZ...
8N80W 12N89W 13N83W 12N100W 14N107W 14N113W 12N118W 18N127W
14N133W 12N140W. SCATTERED MODERATE SHOWERS TO ISOLATED STRONG 
THUNDERSTORMS FROM 11N TO 12N BETWEEN 108W AND 109W...AND FROM 
10N TO 11N BETWEEN 118W AND 123W. SCATTERED MODERATE TO STRONG 
SHOWERS AND THUNDERSTORMS ARE IN THE ITCZ FROM 8.5N TO 10N 
BETWEEN 96W AND 100W. CLOUD TOP TEMPERATURES HAVE BEEN WARMING 
AND COOLING IN ALTERNATING UP AND DOWN PERIODS DURING THE LAST
4 TO 5 HOURS. WARMING CLOUD TOP TEMPERATURES AND POSSIBLY 
REMNANT SHOWERS FROM 12N TO 20N BETWEEN 121W AND 125W...AND 
WITHIN 30 NM ON EITHER SIDE OF 17N132W 12N138W 12N140W.

...DISCUSSION...

A DEEP LAYER TROUGH EXTENDS FROM A 33N121W CYCLONIC CIRCULATION 
CENTER TO 26N124W 23N130W AND 20N130W. A SURFACE TROUGH EXTENDS
FROM A 1008 MB LOW PRESSURE CENTER NEAR 33N122W TO 33N120W 
31N120W AND 27N125W. ISOLATED SHOWERS MAY BE IN A CLOUD BAND 
WITHIN 30 TO 45 NM ON EITHER SIDE OF 27N127W 27N124W 29N120W
31N120W BEYOND 32N120W. DRY AIR/SUBSIDENCE COVERS THE AREA
FROM 20N130W 23N120W 27N115W TO 30N.

BROAD UPPER LEVEL DIFFLUENT FLOW IS TAKING PLACE NEAR 16N131W.
THE EASTERN PACIFIC OCEAN WEST OF 131W IS UNDER THE INFLUENCE
OF BROAD UPPER LEVEL ANTICYCLONIC FLOW FROM WEST OF 140W.
THE AREA EAST OF 131W IS FEELING THE EFFECTS OF THE 33N121W- 
20N130W DEEP LAYER TROUGH.

UPPER LEVEL ANTICYCLONIC OUTFLOW MOVES AWAY FROM HURRICANE IVO
AND GAINS A CYCLONIC SENSE AS IT MOVES ACROSS MEXICO AND 100W...
ACROSS THE ISTHMUS OF MEXICO AND FINALLY ACROSS THE YUCATAN 
PENINSULA. PRECIPITATION IN THE ITCZ HAS INCREASED EAST OF 105W
AS THIS SITUATION PROVIDES AN EFFICIENT OUTFLOW CHANNEL FOR 
THUNDERSTORM ACTIVITY. SCATTERED MODERATE TO STRONG SHOWERS AND 
THUNDERSTORMS ARE IN THE ITCZ FROM 8.5N TO 10N BETWEEN 96W AND 
100W. CLOUD TOP TEMPERATURES HAVE BEEN WARMING AND COOLING IN 
ALTERNATING UP AND DOWN PERIODS DURING THE LAST 4 TO 5 HOURS.

THE 33N121W CYCLONIC CENTER HAS DRAGGED A LARGE AREA OF DRY AIR 
SOUTHWARD...TO BE WEST OF 125W INTO THE REMNANT CIRCULATION
OF T.D. 13-E. THE REMNANT LOW OF 1010 MB IS NEAR 17N131W.
THIS SYSTEM IS STRUGGLING TO SURVIVE...WITH INTERMITTENT BURSTS
OF CONVECTIVE PRECIPITATION. THE ENVIRONMENT AROUND THE REMNANT
LOW OF T.D. 13-E IS HOSTILE FOR TROPICAL CYCLONES TO REGENERATE.

$$
MT