000
AXPZ20 KNHC 181500
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1430 UTC.

...SPECIAL FEATURE...

TROPICAL DEPRESSION MIRIAM IS CENTERED NEAR 20.1N 113.8W...OR 
270 NM SW OF THE SOUTHERN TIP OF BAJA CALIFORNIA...AT 18/1500 
UTC MOVING NNW AT 4 KT. MAXIMUM SUSTAINED WIND SPEED IS 25 KT 
WITH GUSTS TO 35 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1005 
MB. MIRIAM NO LONGER HAS ANY DEEP CONVECTION AND IS DEGENERATING 
INTO A REMNANT SWIRL. A 1302 UTC QUIKSCAT PASS INDICATED THAT 
MAXIMUM WINDS HAVE DECREASED TO 25 KT...WHICH IS THE ADVISORY 
INTENSITY. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO 
HEADERS MIATCMEP4/WTPZ24 KNHC FOR MORE DETAILS. THIS IS THE LAST 
ADVISORY ISSUED BY THE NATIONAL HURRICANE CENTER ON MIRIAM. 

...TROPICAL WAVES...

TROPICAL WAVES ALONG 91W/92W AND 100W/101W HAVE BEEN DROPPED 
FROM THE SURFACE ANALYSIS IN FAVOR OF A 1010 MB LOW WHICH IS 
CENTERED BETWEEN THE TWO NEAR 10N93W. THE ENVIRONMENT IS MOSTLY 
CLEAR IN THE VICINITY OF THE LOW...AND WIDELY SCATTERED MODERATE 
CONVECTION LIES UP TO 250 NM AWAY ALONG THE ITCZ AND WITHIN 150 
NM OF THE CENTRAL AMERICAN COAST BETWEEN COSTA RICA AND PUERTO 
ESCONDIDO MEXICO.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 8N78W 7N100W 8N110W 12N123W 8N131W 
12N140W. SCATTERED MODERATE CONVECTION WITHIN 75 NM OF THE AXIS 
BETWEEN 91W-99W. ISOLATED SHOWERS/TSTMS FROM 5N-11N BETWEEN 
106W-117W...AND FROM 9N-13N BETWEEN 120W-126W.

...DISCUSSION...

A SHARP SHORTWAVE TROUGH ALONG 36N127W 24N131W...AND AN 
ASSOCIATED MID-LEVEL LOW NEAR 29N127W...ARE SKIRTING ACROSS THE 
NW PORTION OF THE DISCUSSION AREA WITH CONVERGENCE AT THE BASE 
OF THE TROUGH CAUSING STRONG SUBSIDENCE N OF 20N W OF 125W. AN 
UPPER RIDGE IS LOCATED DOWNSTREAM OF THE TROUGH N OF 20N ALONG 
117W AND IS ALSO CAUSING MODERATE/STRONG SUBSIDENCE OVER NW 
MEXICO AND THE BAJA PENINSULA. T.D. MIRIAM HAS BECOME EMBEDDED 
BENEATH THIS SUBSIDENCE AND IS NO LONGER ABLE TO GENERATE DEEP 
CONVECTION. FARTHER S...AN EXTENSIVE UPPER RIDGE EXTENDS FROM 
THE SRN BAJA PENINSULA SW TO 17N140W WITH BROAD NELY UPPER LEVEL 
FLOW TRANSPORTING MOISTURE FROM CENTRAL MEXICO SW INTO THE 
TROPICS. AN INVERTED UPPER TROUGH IS MOVING TOWARDS THIS FLOW 
ALONG 112W...CAUSING A SPECKLING OF ISOLATED TSTMS NEAR THE ITCZ.

OVER THE FAR E PACIFIC...THE UPPER FLOW IS MAINLY EASTERLY WITH 
ONE NOTABLE RIDGE LOCATED JUST OFF THE MEXICAN COAST ALONG 105W. 
A WEAK LOW HAS DEVELOPED S OF THE THE GULF OF TEHUANTEPEC...BUT 
THE CONVECTION IS FAR-FLUNG FROM THE CENTER AND THE UPPER LEVEL 
EASTERLIES ARE TOO STRONG AT THE MOMENT TO FOSTER DEVELOPMENT.

$$
BERG