000
AXPZ20 KNHC 082221
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC TUE OCT 08 2013

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

...SPECIAL FEATURE... TROPICAL STORM NARDA AT 16.3N 127.4W AT 
2100 UTC MOVING W-NW OR 295 DEG AT 11 KT.  MAXIMUM SUSTAINED 
WIND CONTINUE TO DIMINISH NOW AT 35 GUSTING TO 45 KT AND CENTRAL
PRES OF 1007 MB.  CONVECTION HAS DIMINISHED SIGNIFICANTLY IN 
LAST 12 HRS WITH ONLY SCATTERED MODERATE CONVECTION WITHIN 30 NM
N SEMICIRCLE.  NARDA APPROACHING VERY DRY AIR MASS AND LOSING
ITS UPPER LEVEL ORGANIZED OUTFLOW AS IT DRIFT W.  IT IS EXPECTED
NARDA WILL BECOME A TROPICAL DEPRESSION THEN A POST TROPICAL LOW
PRES WITHIN THE NEXT 24-48 HRS. REFER TO FORECAST ADVISORY UNDER
WMO/AWIPS HEADERS WTPZ24 KNHC/MIATCMEP4 FOR ADDITIONAL DETAILS. 

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...           
MONSOON TROUGH EXTENDS FROM 10N86W TO 11N92W TO LOW PRES 1009 MB
AT 11N98W TO LOW PRES 1010 MB AT 12N108W TO 11N113W TO 16N121W
THEN RESUME FROM 13N130W TO BEYOND 09N140W.  SCATTERED MODERATE
TO STRONG CONVECTION WITHIN 210 NM N AND 150 S OF AXIS FROM 91W
TO 103W.  SCATTERED MODERATE ISOLATED STRONG CONVECTION WITHIN
150 NM N OF AXIS FROM 108W TO 114W.

...DISCUSSION...
STRONG UPPER TROUGH FROM 32N128W TO BEYOND 31N140W BRINGS A ZONAL
AND VERY DRY AND STABLE AIR MASS INTO BASIN N OF 14N W OF 105W...
INCLUDING EFFECTS OVER NARDA.  BROAD UPPER LEVEL RIDGE CENTERED
AT 18N114W BRINGS ABUNDANT TROPICAL MOISTURE INTO E PAC S OF 14N
E OF 118W...ENOUGH TO SUSTAIN PLENTY OF MODERATE TO STRONG
CONVECTION ALONG MONSOON TROUGH. 

...ELSEWHERE AT LOWER LEVELS...
BROAD AND HEALTHY 1035 MB HIGH PRES CENTER AT 40N144W EXTEND
SURFACE RIDGE TO 25N118W AND SUPPORT FRESH NE TRADES N OF 15N
W OF 125W.  HIGH PRES MOVES W AND TIGHTENS PRES GRADIENT WITH
WEAK SURFACE TROUGH OVER CENTRAL CALIFORNIA INCREASING WINDS AND 
BRINGING NW SWELLS INTO N PART OF BASIN.  

MODEL GUIDANCE PAYS ATTENTION TO INTENSITY OF CURRENT LOW PRES 
1009 MB EMBEDDED IN MONSOON TROUGH THAT EVENTUALLY BREAKS OFF AND 
MOVES W-NW.  UPPER LEVEL CONDITIONS ARE FAVORABLE FOR SLOW
INTENSIFICATION AND WILL BE MONITORED FOR SIGNS OF TROPICAL
ORGANIZATION. 

GULF OF TEHUANTEPEC...WINDS DIMINISHING SIGNIFICANTLY AS COLD
FRONT OVER GULF OF MEXICO MOVES FURTHER E AND WINDS VEER E-SE 
OVER BAY OF CAMPECHE.  WINDS EXPECTED TO BECOME UNDER 20 KT WED.  
 
GULF OF CALIFORNIA...LIGHT SW WINDS EXPECTED TO INCREASE LATE
WED OR THU BUT DIMINISH BY END OF FORECAST PERIOD.

WALLY BARNES