000
AXPZ20 KNHC 201014
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC THU SEP 20 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...

HURRICANE IVO CENTERED NEAR 16.5N 112.5W...OR 450 NM SSW OF CABO 
SAN LUCAS MEXICO...AT 20/0900 UTC MOVING NNW AT 6 KT. MAXIMUM 
SUSTAINED WINDS ARE 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 THE PAST 6-12 HOURS...BUT MICROWAVE 
IMAGERY SHOWED AN IRREGULAR EYE 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 129.8W AT 20/0900 
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. VERTICAL SHEAR APPEARS TO BE HAMPERING THE DEVELOPMENT 
OF THE DEPRESSION WITH THE LOW-LEVEL CENTER MOVING SLOWLY W AS THE 
MID-LEVEL CIRCULATION MOVES NW. DEEP CONVECTION NEAR THIS MID-LEVEL 
CIRCULATION IS DISSIPATING...AND THE SYSTEM IS MOVING INTO AN AREA 
OF WIDESPREAD STRATOCUMULUS CLOUDS INDICATIVE OF COOLER WATERS. 
SCATTERED MODERATE CONVECTION FROM 18N-21N BETWEEN 123W-129W.

...TROPICAL WAVES...

TROPICAL WAVE ALONG 90W N OF 10N MOVING W 10-15 KT. THE WAVE IS 
TRIGGERING SOME ITCZ RELATED CONVECTION OFF THE COASTS OF NICARAGUA 
AND EL SALVADOR.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 8N78W 11N90W 10N100W 17N108W 17N128W 
12N140W. SCATTERED MODERATE CONVECTION FROM 9N TO 11N BETWEEN 92W 
AND 100W. SCATTERED MODERATE CONVECTION WITHIN 90 NM OF AXIS W OF 
115W.

...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...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 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 CENTERED BETWEEN THE TWO SYSTEMS ALONG 117W 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.

$$
MUNDELL