000 AXPZ20 KNHC 271601 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC TUE AUG 27 2013 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 1545 UTC. ...SPECIAL FEATURES... A 1006 MB LOW PRES IS NEAR 13N104W MOVING SLOWLY N NE. THIS FEATURE IS PART OF A BROAD AREA OF LOW PRES THAT EXTENDS FROM ROUGHLY FROM COAST OF MEXICO FROM 17N TO 21N ACROSS THE PACIFIC TO NEAR 112W AND EASTWARD TO NEAR 98W. THIS AREA OF BROAD LOW PRES CONSISTS OF MULTIPLE LOW PRES SWIRLS...WITH ONE NEAR 18N105W...AND A WEAKER ONE NEAR 13N107. SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 60 NM OF THE LOW CENTER...EXCEPT WITHIN 75 NM IN THE SW QUADRANT. CLUSTERS OF SCATTERED MODERATE TO STRONG CONVECTION ARE NOTED ELSEWHERE WITHIN THIS AREA FROM 09N TO 15N BETWEEN 101W-110W. SCATTERED MODERATE TO STRONG CONVECTION IS ALSO NOTED FROM 17N TO 21N E OF 108W TO ALONG THE COAST OF MEXICO. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 45 NM OF A LINE FROM 16N100W TO 18N105W...AND ALSO WITHIN 45 NM OF 13N99W. SATELLITE-DERIVED WINDS SUGGEST THAT THIS AREA OF BROAD LOW PRES IS PRESENTLY BEING AFFECTED BY UPPER LEVEL NELY SHEAR. GLOBAL MODELS IN PRETTY GOOD AGREEMENT THAT THE PRES GRADIENT WILL TIGHTEN TO THE NE AND E OF THIS AREA OF LOW PRES THROUGH THE NEXT 48 HOURS ALLOWING FOR WINDS TO INCREASE INTO THE 20-30 KT RANGE TONIGHT OR TUE WILL SEAS BUILDING TO 8-10 FT...AND TO 25-35 KT WITH SEAS TO 12 FT OR POSSIBLY HIGHER BY WED AFTERNOON OR MAYBE SOONER DEPENDING ON TIMING OF CONSOLIDATION OF THE ARE OF LOW PRES AREA. THERE IS A MEDIUM POSSIBILITY OF TROPICAL CYCLONE FORMATION OF THIS AREA OF LOW PRES WITHIN THE NEXT 48 HOURS. EXPECT LOCALLY HEAVY RAINFALL IS EXPECTED TO CONTINUE OVER PORTIONS OF SOUTHWESTERN MEXICO AND OVERSPREAD THE SOUTHERN BAJA PENINSULA DURING THE NEXT FEW DAYS IN ASSOCIATION WITH THIS AREA OF LOW PRES. INTERESTS IN THAT AREA SHOULD MONITOR THE PROGRESS OF THIS SYSTEM. ..INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... MONSOON TROUGH AXIS EXTENDS FROM NORTHERN COSTA RICA TO 09N94W. IT RESUMES FROM WEAK LOW PRES OF 1007 MB AT 15N110W TO 1009 MB LOW PRES AT 12N131W TO ANOTHER LOW OF 1009 MB AT 14N132W TO 11N140W. SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 180- 210 NM S OF THE AXIS BETWEEN 117W-124W. SCATTERED STRONG CONVECTION IS WITHIN 90 NM OF THE AXIS BETWEEN 130W-134W...AND WITHIN 60 NM OF THE AXIS BETWEEN 134W-135.5W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION EXISTS FROM 04N-10N E OF 86W. ...DISCUSSION... SATELLITE WATER VAPOR IMAGERY SHOWS AN UPPER LEVEL ANTICYCLONE W OF BAJA CALIFORNIA PENINSULA NEAR 26N117W WITH A RIDGE NE TO FAR NW MEXICO AND ARIZONA...AND ANOTHER RIDGE SW TO NEAR 14N133W. A BROAD UPPER TROUGH TROUGH IS LOCATED NW OF THE AREA WITH AN AXIS THROUGH 32N130W TO WSW OF THE AREA AT 28N140W. SW FLOW IS PRESENT BETWEEN THE TROUGH AND THE ANTICYCLONE/RIDGE. WITHIN THE SW FLOW MODERATE TO STRONG SUBSIDENCE IS NOTED KEEPING RATHER DRY AND STABLE CONDITIONS NW AND W OF THE RIDGE/ANTICYCLONE. SCATTERED TO BROKEN LOW CLOUDS ARE OVER THE FAR NW PART OF THE AREA W OF 132W. TO THE SE OF THE RIDGE/ANTICYCLONE THE ATMOSPHERE BECOMES SIGNIFICANTLY MOIST AND UNSTABLE WITH ABUNDANT DEEP ATMOSPHERIC NOTED THERE...MAINLY DUE TO THE BROAD AREA OF LOW PRES AND ASSOCIATED LOWS THERE. SATELLITE WATER VAPOR IMAGERY SHOWS AN INVERTED UPPER TROUGH NEAR 112W FROM 14N TO 21N. ANOTHER INVERTED UPPER TROUGH EXTENDS FROM 21N112W TO ACROSS SOUTHERN BAJA CALIFORNIA...AND GULF OF CALIFORNIA AND N TO EASTERN ARIZONA. AN UPPER LEVEL ANTICYCLONE IS SEEN OVER FAR NE MEXICO WITH A RIDGE SSW TO NEAR 16N103W. THE UPPER FLOW PATTERN BETWEEN THIS RIDGE AND THE INVERTED TROUGHS IS NE TO E...AND IS WHAT IS HELPING TO SPREAD UPPER LEVEL MOISTURE ASSOCIATED WITH CONVECTION IN THE BROAD AREA OF LOW PRES WESTWARD TO NEAR 113W BEFORE IT THINS OUT IN DRIER AIR ALOFT. A 100 MILE WIDE STREAM OF UPPER LEVEL MOISTURE IS BETWEEN THE NORTHERN MOST INVERTED TROUGH AND THE NORTHERN CREST OF THE ANTICYCLONE AT 26N117W. THIS MOISTURE STREAM IS CHANNELING NWD TO ACROSS NW MEXICO AND WESTERN ARIZONA. AT THE SURFACE...THE 1007 MB AND 1009 MB LOWS MENTIONED ABOVE UNDER ITCZ/MONSOON TROUGH ARE FORECAST TO MOVE IN A GENERAL SE DIRECTION OVER THE NEXT 24 HOURS. IN ADDITION TO THOSE LOWS...A VERY ILL-DEFINED 1010 MB LOW...REMNANTS OF IVO...IS IDENTIFIED TO BE NEAR 26N116W. NO DEEP CONVECTION IS PRESENT WITH THIS LOW AS IT IS EXPECTED TO DISSIPATE WITHIN THE NEXT 24 HOURS. A WEAK 1017 MB HIGH NEAR 28N130W IS FORECAST TO REMAIN ABOUT STATIONARY OVER THE NEXT 24 HOURS. S OF THE MONSOON TROUGH AND TO THE S OF MUCH OF THE BROAD AREA OF LOW PRES...AN AREA OF 20-25 KT S-SW INFLOW WINDS INTO THE ACTIVE CONVECTION DESCRIBED ABOVE WITH THE MONSOON TROUGH HAS HAD ENOUGH DURATION AND FETCH TO BUILD SEAS TO A MAX OF 9 FT. THESE CONDITIONS EXIST WITHIN 300 NM E OF A LINE FROM 13N102W TO 05N111W. THESE CONDITIONS ARE FORECAST TO EXPAND N AND NW TO COVER THE AREA FROM 6N-12N BETWEEN 105W AND 130W IN 24 HOURS WITH SEAS TO 10 FT...AND FROM 08N TO 13N BETWEEN 112W AND 118W IN 48 HOURS AS THE BROAD AREA OF LOW PRES OR CONSOLIDATED LOW TO ITS NE LIFTS IN A GENERAL NWD DIRECTION. $$ AGUIRRE