000
AXPZ20 KNHC 110938
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC MON JUN 11 2012

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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.

...SPECIAL FEATURE...
LOW PRES 1008 MB CENTERED NEAR 11N111W REMAINS EMBEDDED IN THE 
MONSOON TROUGH UNDER AN INCREASINGLY LESS FAVORABLE ENVIRONMENT. 
SATELLITE IMAGERY SHOWS THE SYSTEM IS LOCATED IN A NARROW BUFFER 
ZONE BETWEEN UPPER LEVEL WINDS THAT ARE WESTERLY W OF 118W AND 
EASTERLY E OF 109W. THIS IS ALLOWING DEEP CONVECTION TO PERSIST 
DUE TO DIVERGENT FLOW ALOFT...BUT THE WINDOW OF OPPORTUNITY TO 
DEVELOP INTO A TROPICAL CYCLONE IS RAPIDLY CLOSING. SCATTERED 
MODERATE-STRONG CONVECTION IS WITHIN 150 NM OF THE CENTER WITH 
CLUSTERS OF MODERATE CONVECTION WITHIN 240 NM NW AND SE OF LOW.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM 09N84W TO LOW PRES 1010 MB NEAR 
11N93W TO 13N104W TO LOW PRES 1008 MB NEAR 11N111W TO 08N127W. 
THE ITCZ AXIS EXTENDS FROM 08N127W TO 07N140W. SCATTERED MODERATE
TO STRONG CONVECTION IS WITHIN 150 NM OF THE LOW NEAR 11N111W. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION IS WITHIN 90 NM OF 
THE MONSOON TROUGH E OF 95W.

...DISCUSSION...
ASCAT SCATTEROMETER COVERAGE OVER THE PAST SIX HOURS SHOWS WINDS 
20 KT OR LESS ACROSS THE ENTIRE BASIN...EXCEPT FOR 20-25 KT WINDS
WITHIN 45-60 NM OF THE LOW CENTER NEAR 11N111W. THE PRES GRADIENT
ASSOCIATED WITH THE SUBTROPICAL RIDGE ANCHORED BY 1030 MB HIGH AT
35N140W HAS RELAXED OVER THE PAST 12-24 HOURS...ALLOWING N TO NE 
WINDS W OF NORTHERN BAJA TO DIMINISH AS WELL AS E-NE TRADE WINDS 
NORTH OF THE ITCZ AXIS. DIFFLUENT UPPER LEVEL WINDS ALONG 10N 
BETWEEN 95W AND 105W IS ALLOWING ACTIVE CONVECTION TO PULSE UP 
AND DOWN ALONG THE MONSOON TROUGH.

GFS MODEL GUIDANCE HAS SEEN LESS RUN-TO-RUN VARIABILITY SINCE 12Z
AND THE GFS IS TRENDING TOWARD SLOW DEVELOPMENT OF LOW PRES AREA 
CENTERED NEAR 9N90W THROUGH WED MORNING THEN MORE RAPID INTENSITY
RATE WED NIGHT AND THU...TRACKING THE LOW NW INTO SOUTHERN MEXICO
NEAR TEHUANTEPEC AS A TROPICAL CYCLONE. THE GFS WEAKENS THE LOW 
NEAR 11N111W AND EVENTUALLY MERGES IT WITH THE STRONGER SYSTEM TO
THE EAST. BY COMPARISON...THE ECMWF AND UKMET MODELS MAINTAIN AN 
ACTIVE MONSOON TROUGH WITH MODERATE TO FRESH W-SW WINDS S OF THE 
TROUGH BUT NEITHER MODEL DEVELOPS A SIGNIFICANT LOW THAT EMERGES 
OUT OF THE TROUGH. OBVIOUSLY A BLEND OF THE GFS AND ECMWF WOULD 
BE A POOR APPROACH BECAUSE BOTH CANNOT BE CORRECT...SO WILL NEED 
TO SELECT THE BEST MODEL FOR LONG-TERM GUIDANCE. AT THIS POINT 
WILL CONTINUE TO USE A TONED-DOWN VERSION OF THE GFS WHICH SHOWS 
DEVELOPMENT OF A WEAKER LOW AND SLOW DEVELOPMENT TO MINIMAL TS.

STRONG ELY WINDS OVER WRN CARIBBEAN SEEPING ACROSS NICARAGUA 
INTO GULF OF PAPAGAYO WILL BRING FRESH E WINDS LATER TODAY FROM 
10N TO 12N E OF 90W THROUGH TUE NIGHT OR WED. CYCLONIC VORTICITY 
FROM THE ENHANCED EASTERLY WINDS WILL AID INITIAL SPIN-UP OF ANY 
LOW PRES AREAS THAT MAY DEVELOP NEAR THE GFS HOT SPOT NEAR 9N90W.

$$
MUNDELL