000
AXPZ20 KNHC 200317
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC THU SEP 20 2007

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.

...SPECIAL FEATURES...

HURRICANE IVO CENTERED NEAR 16.1N 112.4W...OR 430 NM SSW OF CABO 
SAN LUCAS MEXICO...AT 20/0300 UTC MOVING NW AT 8 KT. MAXIMUM 
SUSTAINED WIND SPEED IS 65 KT WITH GUSTS TO 80 KT. ESTIMATED 
MINIMUM CENTRAL PRESSURE IS 987 MB. SEE LATEST NHC FORECAST/ 
ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP2/WTPZ22 KNHC FOR MORE 
DETAILS. IVO DEVELOPED A LARGE BURST OF DEEP CONVECTION WHICH 
OBSCURED MUCH OF THE CENTER OF CIRCULATION A LITTLE BEFORE 0000 
UTC...BUT AN SSM/I PASS NEAR 0100 UTC SHOWED A WELL-DEVELOPED 
EYE HAD FORMED BENEATH THE CONVECTIVE CANOPY. THE HURRICANE HAS 
TWO SPIRAL BANDS ATTEMPTING TO FORM TO THE NE AND SW OF THE 
CENTER...BUT THE CENTRAL DENSE OVERCAST IS RATHER AMORPHOUS. 
NUMEROUS MODERATE/STRONG CONVECTION WITHIN 150 NM OF CENTER.

TROPICAL DEPRESSION THIRTEEN-E CENTERED NEAR 17.8N 129.3W...OR 
1130 NM WSW OF CABO SAN LUCAS MEXICO...AT 20/0300 UTC MOVING WNW 
5 KT. MAXIMUM SUSTAINED WIND SPEED IS 30 KT WITH GUSTS 40 KT. 
ESTIMATED MINIMUM CENTRAL PRESSURE IS 1007 MB. SEE LATEST NHC 
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP3/WTPZ23 KNHC 
FOR MORE DETAILS. EASTERLY SHEAR APPEARS TO BE HAMPERING THE 
DEVELOPMENT OF THE DEPRESSION WITH THE LOW-LEVEL CENTER MOVING 
SLOWLY W AS THE MID-LEVEL CIRCULATION SHOOTS AWAY TO THE NW. 
DEEP CONVECTION NEAR THIS MID-LEVEL CIRCULATION IS 
DISSIPATING...AND THE ONLY OTHER DEEP CONVECTION LEFT IS WELL NE 
AND WELL S OF THE ACTUAL CENTER. SCATTERED MODERATE CONVECTION 
FROM 18N-21N BETWEEN 123W-131W.

...TROPICAL WAVES...

TROPICAL WAVE ALONG 88W/89W N OF 8N MOVING W 10-15 KT. THE WAVE 
IS SEEN AS A NWD INFLECTION OF THE ITCZ OFF THE COASTS OF 
NICARAGUA AND EL SALVADOR. CONVECTION IS ALIGNED ALONG THE ITCZ 
AXIS...AND SCATTERED TSTMS HAVE DEVELOPED ACROSS COASTAL AREAS 
BETWEEN GUATEMALA AND NICARAGUA.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 7N77W 11N92W 14N110W 17N128W 
13N140W. SCATTERED MODERATE FROM 7N-10N BETWEEN 81W-87W. 
SCATTERED MODERATE FROM 9N-16N BETWEEN 115W-124W. SCATTERED 
MODERATE WITHIN 60 NM OF AXIS W OF 128W.

...DISCUSSION...

E OF 110W...
BROKEN MID/UPPER LEVEL RIDGING EXTENDS ACROSS NORTHERN 
MEXICO...INTERRUPTED BY TWO CLOSED UPPER LOWS OVER THE EASTERN 
GULF OF MEXICO AND OVER CENTRAL MEXICO. IN ADDITION...HURRICANE 
IVO W OF 110W IS PRODUCING UPPER LEVEL OUTFLOW WHICH IS 
SPREADING NE OF THE SYSTEM TOWARDS COASTAL MEXICO. AS A 
RESULT...THE UPPER LEVEL FLOW E OF 110W HAS BECOME LESS STRONGLY 
EASTERLY. THE STRONGEST UPPER LEVEL EASTERLIES ARE NOW PRIMARILY 
S OF 10N WITH MORE VARIABLE FLOW N OF 10N.

W OF 110W...
HURRICANE IVO AND TROPICAL DEPRESSION THIRTEEN-E DOMINATE THE 
ACTIVITY W OF 110W...BOTH STORMS LOCATED ON THE S SIDE OF A 
STRONG MID/UPPER LEVEL RIDGE RUNNING FROM NW MEXICO TO 17N140W. 
A MID/UPPER LEVEL INVERTED TROUGH IS CENTERED BETWEEN THE TWO 
SYSTEMS ALONG 117W WHICH IS PRODUCING AN AREA OF MODERATE/STRONG 
SUBSIDENCE N OF 15N BETWEEN 110W-122W. FARTHER N...A STRONG 
UPPER LOW IS DIGGING S ALONG THE COAST OF CALIFORNIA WITH 
WESTERLY FLOW NOW OVER THE REGION N OF 24N. THE SURFACE RIDGE IS 
FAIRLY STRONG N OF THE AREA AND IS ADVECTING A LARGE AREA OF 
STABLE STRATOCUMULUS OVER THE SUBTROPICAL WATERS N OF 20N W OF 
115W.

$$
BERG