000
AXPZ20 KNHC 191010
TWDEP 

TROPICAL WEATHER DISCUSSION     
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC WED SEP 19 2007

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

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.

...SPECIAL FEATURES...
TROPICAL STORM IVO CENTERED NEAR 14.7N 110.0W AT 19/0900 UTC MOVING 
WNW AT 9 KT. ESTIMATED MINIMUM CENTRAL PRESSURE 997 MB. MAXIMUM 
SUSTAINED WINDS 50 KT WITH GUSTS TO 60 KT. SEE LATEST NHC FORECAST/ 
ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP2/WTPZ22 KNHC FOR MORE 
DETAILS. IVO CONTINUES TO BECOME BETTER ORGANIZED AS IT DEVELOPS A 
CENTRAL DENSE OVERCAST IN INTERLOCKING SPIRAL BANDS. DEEP CONVECTION
HAS EXPANDED WITH INCREASED CURVATURE. SCATTERED MODERATE TO STRONG 
CONVECTION WITHIN 150 NM OF CENTER.

TROPICAL WAVE ALONG 127W FROM 10N TO 20N MOVING W 10 KT. A 1008 MB 
LOW IS EMBEDDED ON THE WAVE AXIS NEAR 16N. ASSOCIATED CONVECTION HAS 
BECOME MORE CONCENTRATED OVER THE PAST 12 HOURS NEAR THE DEVELOPING 
LOW. SCATTERED MODERATE TO STRONG CONVECTION WITHIN 150 NM OF 16.5N 
127.5W. TROPICAL CYCLONE FORMATION IS POSSIBLE WITHIN THE NEXT 24 TO 
48 HOURS.

...TROPICAL WAVES...
WEAK TROPICAL WAVE ALONG 85W N OF 8N MOVING W AT 15 KT WITH ISOLATED 
CONVECTION WITHIN 60 NM OF 10N85W.

...ITCZ...
ITCZ AXIS CENTERED ALONG 10N85W 11N97W 16N106W 12N112W 17N122W 
15N130W 13N140W. SCATTERED MODERATE CONVECTION WITHIN 45 NM OF 
CENTRAL AMERICAN COAST E OF 100W. SCATTERED MODERATE CONVECTION 
WITHIN 75 NM OF AXIS BETWEEN 105W AND 135W.  

...DISCUSSION...
TROPICAL STORM IVO AND A DEVELOPING SYSTEM NEAR 16N127W ARE ANCHORING
AN ACTIVE LOW PRESSURE TROUGH THAT STRETCHES FROM 105W TO 135W. WATER
VAPOR IMAGERY SHOWS DIFFLUENT FLOW ALOFT WHICH IS ENHANCING TROPICAL 
CYCLONE DEVELOPMENT IN THE REGION. THE LARGER SCALE PRESSURE PATTERN 
ACROSS THE SUBTROPICS IS DOMINATED BY A 1034 MB HIGH CENTERED NW OF 
THE AREA NEAR 40N151W. THE TIGHTENED GRADIENT BETWEEN THIS HIGH AND 
LOW PRES TROUGHING ALONG THE ITCZ IS MAINTAINING STRONG NELY TRADES 
W OF ABOUT 125W. 

20 KT NNE WINDS ARE FUNNELING THROUGH THE GULF OF TEHUANTEPEC WITH 
SEAS TO 8 FT EXTENDING ABOUT 60 NM OUT TO SEA. THESE WINDS ARE 
FORECAST TO CONTINUE A COUPLE MORE DAYS.   

IN THE UPPER LEVELS A WEAKENING UPPER LOW IS CENTERED NEAR 33N135W.  
AN UPPER HIGH LIES FURTHER SE NEAR 21N124W. THIS HIGH IS PROVIDING 
ELY SHEAR OVER THE DEEP TROPICS S OF 15N W OF 115W. A SHORT WAVE 
TROUGH EXTENDS SWD INTO THE TROPICS FROM NEW MEXICO TO SOUTHERN 
BAJA. WATER VAPOR IMAGERY SHOWS A MOISTURE PLUME EXTENDING ACROSS 
THE AREA INTO TEXAS. DRY STABLE AIR DOMINATES THE REMAINDER OF THE 
REGION N OF 22N W OF 110W.

$$
MUNDELL