000 AXPZ20 KNHC 212151 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC MON APR 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... THE MONSOON TROUGH IS DIFFICULT TO LOCATE. SCATTEROMETER WINDS INDICATE AN ITCZ FORMS FROM 08N92W TO 06N100W TO 06N132W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED WITHIN 180 NM EITHER SIDE OF A LINE FROM 06N78W TO 07N83W TO 04N89W. SIMILAR CONVECTION IS OBSERVED ALONG THE ITCZ WITHIN THE AREA BOUNDED BY 02-12N BETWEEN 105-133W. ...DISCUSSION... AN UPPER SHORTWAVE TROUGH HAS MOVED OVER THE NW PORTION OF THE DISCUSSION AREA WITH ITS MEAN AXIS FROM 32N131W TO 25N140W. THIS TROUGH IS PRECEDED BY A BAND OF UPPER MOISTURE ABOUT 480 NM E OF THE TROUGH AXIS...AND IS CURRENTLY MOVING E ACROSS THE CALIFORNIA COAST TO THE N OF 33N. A SECOND UPPER TROUGH OVER THE CENTRAL CONUS CONTINUES SW ACROSS MEXICO AND THE SOUTHERN GULF CALIFORNIA TO A BASE OVER THE EPAC NEAR 15N113W. A 300 NM WIDE BAND OF UPPER MOISTURE...ORIGINATING FROM ITCZ CONVECTION BETWEEN 110W-140W...CONTINUES E OF THE TROUGH AXIS FROM 12N111W TO ACROSS CENTRAL MEXICO AT 20N110W...THEN FANS OUT AS IT SPREADS NE ACROSS THE CENTRAL GULF OF MEXICO. AN UPPER ANTICYCLONE IS OVER THE DEEP TROPICS NEAR 08N131W WITH A SHORTWAVE RIDGE EXTENDING NE BETWEEN THE TWO UPPER TROUGHS... JUST DESCRIBED...TO A CREST AMPLIFYING N ACROSS ARIZONA. EXCEPT AS MENTIONED...THE UPPER LEVELS APPEAR VERY DRY TO THE N OF 17N WITHIN THE ANTICYCLONIC ENVELOPE. AN UPPER RIDGE EXTENDS E FROM THE TROPICAL ANTICYCLONE AT 08N131W TO A CREST NEAR 07N110W AND CONTINUES TO ENHANCE CONVECTION ALONG THE WESTERN SEGMENT OF THE ITCZ AS PREVIOUSLY DESCRIBED. ANOTHER UPPER ANTICYCLONE IS CENTERED AT 08N98W WITH AN UPPER RIDGE EXTENDING NE ACROSS THE YUCATAN PENINSULA AND THE EASTERN GULF OF MEXICO TO A GENTLE CREST OVER SOUTHERN GEORGIA. UPPER MOISTURE IS OBSERVED OVER THE W PERIPHERY OF THE RIDGE ORIGINATING FROM ITCZ CONVECTION BETWEEN 100-110W. A WEAK ILL-DEFINED UPPER TROUGH EXTENDS SW FROM OVER NICARAGUA TO A BASE OVER THE DEEP TROPICS AT 02N94W...AND EFFECTIVELY SEPARATES THE UPPER ANTICYCLONIC FLOW JUST DESCRIBED FROM THE FLOW ASSOCIATED WITH ANOTHER E TO W UPPER RIDGE EXTENDING W OFF THE COAST OF COLOMBIA ALONG 08N TO THE E OF 92W. WEAK DIFFLUENCE ALONG THIS EASTERN RIDGE IS SUPPORTING THE PREVIOUSLY DESCRIBED CONVECTION ALONG THE MONSOON TROUGH AND ITCZ TO THE E OF 90W. SOME OF THE DEBRIS MOISTURE FROM THIS CONVECTION IS ADVECTED NE ACROSS PANAMA...COSTA RICA AND THE SW CARIBBEAN...THE TURNS E ACROSS THE CENTRAL CARIBBEAN. DRY UPPER AIR IS SUPPRESSING CONVECTION OVER CENTRAL AMERICA FROM THE YUCATAN PENINSULA TO NICARAGUA...AS WELL AS THE EPAC TO THE N OF 08N BETWEEN 85-96W. A WEAK COLD FRONT HAS MOVED INTO THE NW DISCUSSION WATERS FROM 32N130W TO 28N140W. A SURFACE RIDGE IS ALREADY BRIDGING THROUGH THE WEAKENING FRONTAL BOUNDARY FROM NEAR 30N140W TO 19N110W. NE TRADES AT 15-20 KT CONTINUE S OF THE RIDGE ACROSS THE WATERS FROM 08-22N W OF 125W...WITH SEAS OF 7-8 FT IN MIXED NE WIND WAVES...AND NOW REINFORCED LONG PERIOD NW SWELL STILL MIXING WITH LONG PERIOD CROSS-EQUATORIAL S SWELL. THE REINFORCING NW SWELL HAS REACHED THE NW COAST OF THE BAJA PENINSULA IN THE FORM OF COMBINED SEAS OF 6-10 FT...WITH THESE CONDITIONS EXPECTED TO SPREAD S ALONG THE BAJA PENINSULA N OF 25N TONIGHT. THE NW SWELL WILL GRADUALLY SUBSIDE ACROSS THE DISCUSSION WATERS N OF ON TUE. HOWEVER...THE PRESSURE GRADIENT WILL TIGHTEN ON TUE NIGHT WITH NW WINDS INCREASING TO 20-25 KT ACROSS THE WATERS N OF 28N E OF 120W TO BAJA PENINSULA. THESE WINDS WILL DIMINISH AND THE SEAS WILL SUBSIDE ON THU. ATTENTION THEN TURNS TO THE S AS CROSS EQUATORIAL SOUTHERLY SWELL PROPAGATES N TO ALONG 25N ON FRI. $$ NELSON