000
AXPZ20 KNHC 120925
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC TUE JUN 12 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.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM 09N84W TO 09N92W TO 14N110W TO 
06N106W. THE ITCZ EXTENDS FROM 06N106W TO 06N140W. SCATTERED TO 
NUMEROUS MODERATE ISOLATED STRONG CONVECTION IS WITHIN 200 NM S 
OF THE MONSOON TROUGH BETWEEN 85W AND 94W. SCATTERED MODERATE 
ISOLATED STRONG CONVECTION FROM 06N TO 09N BETWEEN 99W AND 106W. 
SCATTERED MODERATE CONVECTION IS NEAR 14N117W.

...DISCUSSION...
SCATTEROMETER COVERAGE OVER THE PAST SIX HOURS SHOWS FRESH WINDS 
TO 20 KT IN NORTH-CENTRAL PORTION N OF 28N BETWEEN 125W AND 135W
WITH WINDS GENERALLY 15 KT OR LESS ACROSS THE REST OF THE BASIN. 
THE PRES GRADIENT ASSOCIATED WITH THE SUBTROPICAL RIDGE ANCHORED 
BY 1030 MB HIGH NEAR 36N140W HAS RELAXED THE PAST 24-48 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 9N BETWEEN 82W-112W IS FOSTERING ACTIVE CONVECTION 
ALONG THE MONSOON TROUGH E OF 110W. THE MOST ACTIVE AREA OF DEEP 
CONVECTION ASSOCIATED WITH A TROPICAL DISTURBANCE CENTERED NEAR 
7N87W. ANIMATED SATELLITE IMAGERY SHOWS BROADLY CURVED CONVECTIVE
BANDS STARTING TO FORM SOUTH AND WEST OF THE CIRCULATION CENTER. 
A WELL DEFINED AREA OF LOW PRES IS NOT EVIDENT FROM SURFACE OBS 
AND SCAT DATA...BUT WILL LIKELY DEVELOP IF THE DEEP CONVECTION 
PERSISTS IN A FAVORABLE ENVIRONMENT OF LOW LEVEL CONVERGENT FLOW 
S OF THE TROUGH AXIS AND BROAD SCALE DIVERGENCE ALOFT.

GFS MODEL GUIDANCE SHOWS SLOW DEVELOPMENT OF THIS DISTURBANCE IN 
THE NEXT 24-48 HOURS FOLLOWED BY MORE RAPID INTENSIFICATION WED 
NIGHT AND THU...TRACKING THE LOW NW INTO SOUTHERN MEXICO NEAR 
TEHUANTEPEC AS A TROPICAL CYCLONE. THE UKMET IS VERY SIMILAR IN 
TRACKING THE LOW...THOUGH NOT AS STRONG WITH WINDS TOPPING OUT AT
MINIMAL TROPICAL STORM PRIOR TO LANDFALL. THE ECMWF MODEL IS THE 
OUTLIER WITH BROAD TROUGHING ACROSS THE DEEP TROPICS E OF 110W 
THROUGH THE END OF THE WEEK. HAVE USED A STRAIGHT 1-1 BLEND OF 
GFS AND UKMET GUIDANCE THROUGH WED FOR SHORT-TERM GRID FORECAST.

STRONG ELY WINDS OVER WRN CARIBBEAN FUNNELING ACROSS NICARAGUA 
INTO GULF OF PAPAGAYO WILL BRING FRESH E WINDS FROM 10N TO 12N E 
OF 90W THROUGH WED. ADDITIONAL CYCLONIC VORTICITY PROVIDED FROM 
THE ENHANCED EASTERLY WINDS WILL AID INITIAL SPIN-UP OF ANY LOW 
PRES AREAS THAT MAY DEVELOP AROUND THE GFS HOT SPOT NEAR 07N87W.

A TIGHT PRES GRADIENT SHOULD DEVELOP OVER SE MEXICO BETWEEN HIGH 
PRES OVER INTERIOR MEXICO AND LOWER PRES IN THE BAY OF CAMPECHE 
ARE EXPECTED TO DEVELOP TONIGHT AND PERSIST THROUGH WED EVENING.

$$
MUNDELL