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AXPZ20 KNHC 212143
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC FRI NOV 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 2115 UTC.


...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... MONSOON TROUGH AXIS EXTENDS FROM 9N83W ALONG 10N91W TO 1010 MB LOW NEAR 9N97W ALONG 7N101W TO 1009 MB LOW NEAR 11N118W TO 7N124W WHERE THE ITCZ BEGINS AND CONTINUES ALONG 9N133W TO 8N140W. SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 180 NM N AND 90 NM S OF MONSOON TROUGH BETWEEN 92W-95W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS WITHIN 180 NM S OF MONSOON TROUGH BETWEEN 86W-92W...WITHIN 210 NM S OF MONSOON TROUGH BETWEEN 115W-120W...AND WITHIN 75 NM OF THE ITCZ W OF 137W. SCATTERED MODERATE CONVECTION IS WITHIN 120 NM S OF MONSOON TROUGH BETWEEN 100W-105W...WITHIN 120 NM N OF MONSOON TROUGH BETWEEN 104W-106W...AND WITHIN 150 NM N OF ITCZ BETWEEN 127W-130W.


...DISCUSSION...

ALOFT...AN UPPER-LEVEL TROUGH IS SHIFTING EASTWARD EXTENDING SW FROM AN UPPER LOW OVER ARIZONA ACROSS N BAJA CALIFORNIA TO NEAR 20N120W. AN UPPER RIDGE IS ANCHORED NEAR 30N138W WITH A RIDGE AXIS STRETCHING SE IN THE WAKE OF THE TROUGH TO NEAR 25N126W. AS A RESULT...FLOW INTO THE BASE OF THE TROUGH IS BRINGING SUBSIDENT CONDITIONS WITH RELATED DRY AND STABLE AIR ACROSS THE AREA N OF 19N. S OF 19N THE ATMOSPHERE REMAINS VERY MOIST WITH ASSOCIATED ACTIVE CONVECTION ALONG AND NEAR THE ITCZ AND MONSOON TROUGH AS DESCRIBED ABOVE.

AT THE SURFACE...A RIDGE EXTENDS FROM A 1026 MB HIGH LOCATED NEAR 30N140W WITH A RIDGE AXIS EXTENDING SE TO 22N115W. THE PRESSURE GRADIENT BETWEEN THE SURFACE RIDGE AND LOWER PRESSURE IN THE VICINITY OF THE ITCZ IS INDUCING AN AREA OF FRESH TO STRONG TRADE WINDS OVER THE AREA DESCRIBED FROM 9N-25N W OF 134W. THESE WINDS WILL EXPAND NORTHWARD AND SLIGHTLY EASTWARD THROUGH EARLY SAT AS HIGH LIFTS NORTHWARD WITH THE ASSOCIATED RIDGE BUILDING MORE FIRMLY S-SE OVER THE AREA. THESE WINDS THEN DIMINISH EARLY ON SUN AS THE HIGH AND RIDGE WEAKEN. BY SUN EVENING MOST OF THE AREA W OF 115W WILL HAVE SEAS OF 8 FT OR GREATER.

A SURFACE TROUGH IS ANALYZED FROM 14N115W TO THE 1009 MB LOW NEAR 11N118W GENERATING SCATTERED MODERATE TO STRONG CONVECTION FROM 13N-15N BETWEEN 112W-115W. SCATTERED MODERATE ISOLATED STRONG CONVECTION COVERS THE REMAINDER OF THE AREA FROM 11N-16N BETWEEN 107W-115W. THIS TROUGH AND LOW WILL MOVE WESTWARD WITH THE LOW DISSIPATING IN 36 TO 48 HOURS. THE WINDS AND SEAS WILL BECOME INTERMIXED WITH THE TRADE WINDS ABOVE.

LONG PERIOD NW SWELL IS MOVING THROUGH THE CENTRAL PORTION OF THE AREA WITH A SECOND SURGE MOVING INTO THE NW PORTION OF THE AREA W OF 124W. THESE SWELLS WILL CONTINUE SE MERGING WITH A S SWELL EXPECTED TO MOVE ACROSS THE EQUATOR SAT AFTERNOON AS A THIRD SWELL EVENT MOVES INTO THE NW SECTION. THIS WILL KEEP MOST OF THE BASIN IN THE 14 TO 16 SEC PERIOD THROUGH THE WEEKEND.

LOOKING FURTHER AHEAD...THE NEXT GULF OF TEHUANTEPEC IS FORECAST TO BE A STRONGER ONE. SOME MODELS SUGGEST THAT WINDS MAY POSSIBLY REACH MINIMAL STORM FORCE BY EARLY ON WED MORNING. WAVEWATCH GUIDANCE SUGGESTS BUILDING SEAS UP TO 20-24 FT WITH THIS EVENT. EDITS WILL BE MADE TO THE NDFD GRIDS AS NECESSARY PRIOR TO THIS UPCOMING EVENT.

$$ PAW

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