000
AXPZ20 KNHC 212151
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC WED MAY 21 2014

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 
2145 UTC. 
  
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
 
A 1010 MB SURFACE LOW IS ANALYZED ON THE NW COAST OF COLOMBIA AT 
10N75W WITH THE MONSOON TROUGH EXTENDING WSW FROM THE LOW ACROSS 
EASTERN PANAMA AND THE GULF OF PANAMA...AND CONTINUING W ACROSS 
THE PACIFIC COAST AT THE PANAMA AND COSTA RICA BORDER. THE 
MONSOON TROUGH CONTINUES W THROUGH 10N92W TO A 1011 MB SURFACE 
LOW EMBEDDED WITHIN THE THE MONSOON TROUGH AT 11N105W...THEN 
TURNS NW TO A SECOND 1011 MB EMBEDDED LOW PRES AT 13N117W. 
SCATTEROMETER WINDS INDICATE AN ITCZ AXIS FORMS SW OF THE LOW AT 
13N117W AND CONTINUES SW THROUGH 08N123W TO BEYOND 07N140W.
 
SCATTERED MODERATE CONVECTION IS OBSERVED ALONG THE EASTERN 
SEGMENT OF THE MONSOON TROUGH WITHIN 75 NM EITHER SIDE OF A LINE 
FROM 09N78W TO 10N88W. SIMILAR CONVECTION IS NOTED OVER AND TO 
THE S OF THE ITCZ AXIS WITHIN 75 NM EITHER SIDE OF A LINE FROM 
04N126W TO 07N133W TO 07N140W. SCATTERED MODERATE ISOLATED 
STRONG CONVECTION IS OBSERVED WELL S OF THE MONSOON TROUGH 
WITHIN 120 NM EITHER SIDE OF A LINE FROM 06N90W TO 03N103W. 
SIMILAR CONVECTION IS OBSERVED OVER THE SW SEMICIRCLE OF THE 
EMBEDDED SURFACE LOW AT 11N105W. ISOLATED STRONG CONVECTION WITH 
FREQUENT LIGHTNING IS NOTED N OF THE MONSOON TROUGH BETWEEN 89W 
AND 101W.

THE LOW PRESSURE AT 11N105W IS EXPECTED TO DRIFT W-NW THROUGH 
THE WEEKEND WITH GUIDANCE SUGGESTING DEEPENING OF THE LOW NEAR 
12N113W ON MON NIGHT INTO TUE. THE LOW PRESSURE NEAR 13N117W IS 
EXPECTED TO REMAIN QUASI-STATIONARY AND GRADUALLY LOSE IDENTITY 
IN THE MONSOON TROUGH.

...DISCUSSION...                                       

AN UPPER ANTICYCLONE IS OVER THE DEEP TROPICS AT 04N128W WITH AN 
UPPER RIDGE EXTENDING N THROUGH 22N138W TO BEYOND 32N138W. UPPER 
DIFFLUENCE IS ENHANCING CONVECTION ALONG THE ITCZ TO THE W OF 
125W AS PREVIOUSLY DESCRIBED. THE DEBRIS MOISTURE IS BEGINNING 
TO SPREAD NE ACROSS THE TROPICS TO THE S OF 22N W OF 130W. SOME 
DEBRIS MOISTURE IS ALSO SPILLING E ACROSS THE RIDGE TO THE N OF 
30N BETWEEN 130-138W.   
 
AN UPPER ANTICYCLONE IS OVER THE TROPICS AT 14N101W WITH AN UPPER
RIDGE EXTENDING N ACROSS THE WESTERN GULF OF MEXICO THROUGH 
ANOTHER ANTICYCLONE OVER SE LOUISIANA...WITH THE RIDGE 
CONTINUING N ACROSS THE CENTRAL CONUS. CONVECTION IS ENHANCED 
UNDER THE ANTICYCLONIC ENVELOPE OVER THE PACIFIC BETWEEN 90-110W 
AND PREVIOUSLY MENTIONED...WITH THE DEBRIS MOISTURE REMAINING 
WITHIN THE SAME AREA. AN UPPER TROUGH IS POSITIONED BETWEEN 
THESE UPPER RIDGES WITH ITS MEAN AXIS FROM 32N118W TO 20N121W TO 
A BASE OVER THE DEEP TROPICAL PACIFIC AT 07N122W. A NARROW BAND 
OF UPPER MOISTURE IS NOTED JUST E OF THE UPPER TROUGH AXIS 
WITHIN 45 NM EITHER SIDE OF A LINE EXTENDING NE FROM 27N115W TO 
ACROSS EASTERN ARIZONA. OTHERWISE...THE UPPER LEVELS APPEAR VERY 
DRY N OF 18N W OF 110W. DEBRIS MOISTURE COVERS THE UPPER LEVELS 
S OF 10N TO THE E OF 88W.
  
A SURFACE RIDGE EXTENDS FROM 32N130W TO 17N112W. ANTICYCLONIC 
SURFACE WINDS ARE FORECAST AT 15-20 KT AROUND THE PERIPHERY OF 
THIS RIDGE THROUGH THE UPCOMING WEEKEND.

GULF OF TEHUANTEPEC...THE NOCTURNAL NORTHERLY DRAINAGE FLOW WILL 
MAX AT 15 KT TONIGHT AND EACH NIGHT THROUGH FRI NIGHT...THEN 
WEAKEN TO A 10 KT MAX ON SAT NIGHT.

$$
NELSON