000
AXPZ20 KNHC 262143
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC THU JUL 26 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 14N114W TO 21N113W MOVING W-NW AT 15 
KT. THE WAVE REMAINS EMBEDDED WITHIN AN AREA OF DEEP LAYER 
MOISTURE AS DEPICTED ON THE MIMIC-TPW ANIMATION. SCATTERED 
MODERATE CONVECTION IS NOTED NEAR THE NORTHERN END OF THE WAVE 
AXIS. COMPUTER MODEL GUIDANCE CONTINUES TO SUGGEST NO TROPICAL 
CYCLONE DEVELOPMENT WITH THIS FEATURE.

TROPICAL WAVE EXTENDS FROM 08N134W TO 15N128W WITH A 1009 MB LOW 
PRES ALONG THE WAVE AXIS NEAR 11N132W. THIS FEATURE IS MOVING W 
AT 16 KT. THE WAVE COINCIDES WITH A BULGE OF MOISTURE IN THE 
TOTAL PRECIPITABLE WATER PRODUCT. SHOWER AND THUNDERSTORM 
ACTIVITY HAS DIMINISHED IN ASSOCIATION WITH THE WEAK AREA OF LOW 
PRESSURE. LATEST SATELLITE IMAGERY INDICATES ONLY SCATTERED 
MODERATE CONVECTION FROM 08N TO 12N BETWEEN 127W AND 135W. 
SIGNIFICANT DEVELOPMENT OF THIS SYSTEM IS NOT ANTICIPATED AS IT 
MOVES WESTWARD OR WEST-NORTHWESTWARD AT AROUND 10 TO 15 KT. THIS 
SYSTEM HAS A LOW CHANCE OF BECOMING A TROPICAL CYCLONE DURING 
THE NEXT 48 HOURS WHEN THE TROPICAL WAVE WITH THE ASSOCIATED LOW 
PRES IS FORECAST TO MOVE W OF THE FORECAST AREA.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
THE MONSOON TROUGH IS ALONG 08N78W TO 10N88W. THE INTERTROPICAL 
CONVERGENCE ZONE AXIS EXTENDS FROM 10N88W TO 10N100W TO 07N112W 
TO 12N126W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS  
WITHIN 120 NM S OF ITCZ AXIS BETWEEN 97W AND 101W...AND BETWEEN 
110W AND 115W.

...DISCUSSION...
WATER VAPOR IMAGERY INDICATES AN UPPER LEVEL ANTICYCLONIC 
CIRCULATION CENTERED NEAR 15N126W THAT EXTENDS A RIDGE AXIS 
NORTH-NORTHWESTWARD TO BEYOND 32N140W. TO THE EAST OF THIS RIDGE 
AXIS...THERE IS A SHORTWAVE TROUGH EXTENDING ALONG 125W N OF 
20N. MODERATE TO STRONG SUBSIDENCE AND IMPLIED DRY AIR MASS 
DOMINATES MUCH OF THE NORTHERN FORECAST WATERS MAINLY N OF 18N W 
OF 115W. ANOTHER ANTICYCLONIC CIRCULATION IS CENTERED OVER NW 
MEXICO NEAR 28N109W WITH A RIDGE ALONG THE PACIFIC COAST OF 
MEXICO TO NEAR 16N98W. AN INVERTED TROUGH OVER THE GULF OF 
MEXICO EXTENDS INTO THE EPAC THROUGH THE GULF OF TEHUANTEPEC. 
THE REMAINDER OF THE DISCUSSION AREA E OF 120W IS UNDER THE 
INFLUENCE OF PRIMARILY EASTERLY WINDS ALOFT.  

A SURFACE RIDGE EXTENDS FROM A 1032 MB HIGH PRESSURE CENTERED 
NEAR 38N148W TO 23N115W. THE PRESSURE GRADIENT BETWEEN THE 
SURFACE RIDGE AND LOWER PRESSURE IN THE VICINITY OF THE ITCZ IS 
MAINTAINING FRESH TRADE WINDS FROM 11N TO 17N W OF 127W. THE 
AREA OF FRESH TRADES WILL SHIFT WESTWARD WITH THE TROPICAL WAVE 
ALONG 08N134W TO 15N128W.

FRESH 20 TO OCCASIONALLY 25 KT GULF OF PAPAGAYO GAP WINDS 
CONTINUE. THIS WEATHER PATTERN WILL PERSIST FOR THE NEXT FEW 
DAYS. THE WINDS WILL PEAK DURING THE LATE NIGHT AND EARLY 
MORNING HOURS WITH THE AID OF NOCTURNALLY DRIVEN DRAINAGE FLOW. 

$$
GR