000 AXPZ20 KNHC 161004 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC TUE JUN 16 2009 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0930 UTC. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 7N78W 8N84W 7N92W 10N100W 9N110W 7N120W 9N130W 7N140W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 45 NM EITHER SIDE OF THE AXIS BETWEEN 99W-114W. SCATTERED MODERATE CONVECTION IS WITHIN 60 NM OF THE AXIS E OF 81W. ...DISCUSSION... A DEEP LAYER TROUGH PUSHING SEWD EXTENDS FROM SOUTHERN CALIFORNIA SW INTO THE AREA THROUGH 32N121W...AND CONTINUES SW TO 22N125W WHERE IT BECOMES A SHEAR AXIS TO A DEVELOPING LOW NEAR 18N134W. A TROUGH THEN EXTENDS FROM THE LOW S TO 10N134W TO 5N134W AND SW TO NEAR 1N136W. MODERATE SUBSIDENCE INDICATED AS A DRY SLOT WITHIN ABOUT 200 NM WIDE IS ADVECTING SWD INTO THE AREA WITHIN 360 NM W OF THE TROUGH N OF 28N. AN EXTENSIVE AREA OF UPPER LEVEL MOSITURE N OF THE AREA IS SPILLING SWD INTO THE NORTHERN BOUNDARY OF THE AREA AS IT WORKS AROUND A LARGE RIDGE CREST NW OF THE REGION. A WEAK SURFACE TROUGH ASSOCIATED WITH THE DEEP LAYER TROUGH EXTENDS FROM 32N119W SW TO 26N126W. BROKEN TO OVERCAST LOW AND MID LEVEL CLOUDS WITH POSSIBLE ISOLATED SHOWERS ARE ALONG AND TO THE NW OF THE TROUGH. TO THE SE OF THE DEEP LAYER TROUGH...A RATHER ELONGATED UPPER LEVEL ANTICYCLONE IS CENTERED OVER WESTERN MEXICO NEAR 23N105W. A RIDGE EXTENDS FROM THE ANTICYCLONE SW TO 18N111W TO NEAR 15N115W. UPPER LEVEL DIFFLUENCE ON ITS SE PERIPHERY IS AGAIN ENHANCING ITCZ CONVECTION BETWEEN 99W-114W. AN UPPER LEVEL LOW SW OF THE GULF OF TEHUANTEPEC NEAR 14N99W HAS PROGRESSIVELY MOVED SW OFF THE COAST OF MEXICO DURING THE PAST FEW DAYS. A DRY AIR SLOT IS SEEN BETWEEN THE LOW AND THE RIDGE TO ITS NW. THE DRY AIR IS SPREADING OFF THE MEXICAN COAST AND EXPANDING WSW TOWARDS ITCZ CONVECTION OCCURRING BETWEEN 103W-110W. THE RIDGE IS EXPECTED TO SHIFT N AND WEAKEN SLIGHTLY OVER THE NEXT FEW DAYS AS THE UPPER LOW BEGINS TO MOVE NW. THE DEEP LAYER TROUGH IS FORECAST TO SHARPEN AS IT MOVES INLAND THE NORTHERN BAJA CALIFORNIA ON WED...WITH A POSSIBLE CUT-OFF LOW DEVELOPING OFF NORTHERN BAJA CALIFORNIA LATE BY LATE WED. AT THE SURFACE A WEAK 1010 MB LOW IS ANALYZED NEAR 14N104W WITH A TROUGH EXTENDING SW TO 10N113W. A PARTIAL QUIKSCAT PASS FROM EARLY THIS MORNING PICKED UP ON THE CYCLONIC CIRCULATION WITH THE LOW WHILE INDICATING 20 KT WIND VECTORS WITHIN 150 NM W OF THE LOW. A HIGH RESOLUTION ASCAT PASS FROM 0444 UTC THIS MORNING REVEALED 20-25 KT WINDS WITHIN 90 NM IN THE E QUADRANT. INTERMITTENT CONVECTION THAT EARLIER WAS OBSERVED WITH THE LOW HAD DISSIPATED...BUT JUST RECENTLY HAS FLARED UP AGAIN AS SCATTERED STRONG OVER AND EXTENDING WITHIN 90 NM S OF THE CENTER. THIS LOW IS IN THE VICINITY OF THE AREA OF BROAD LOW PRES THAT GLOBAL MODELS WERE SUGGESTING IT COULD FORM. STRONG NE UPPER LEVEL WINDS BETWEEN THE UPPER LEVEL ANTICYCLONE AND LOW MENTIONED ABOVE ARE CURRENTLY IMPINGING ON THE LOW...BUT THESE WINDS ARE FORECAST TO DECREASE LATER TODAY INTO WED AS THE UPPER LEVEL PULLS AWAY FROM THIS AREA. OVER THE FAR WESTERN PORTION OF THE AREA...AN UPPER LEVEL ANTICYCLONE NW OF THE REGION NEAR 32N144W EXTENDS A RIDGE SEWD TO 26N136W TO 24N128W. THE SURFACE RIDGE ENTERS THE DISCUSSION AREA AT 29N140W...AND STRETCHES SE TO 24N127W...AND E TO NEAR 25N116W. THE PRES GRADIENT AT THE SOUTHERN PERIPHERY OF THIS RIDGE IS ALLOWING FOR NE TRADE WINDS TO 20 KT TO BE CONFINED FROM 10N-18N W OF 130W AS CONFIRMED BY A QUIKSCAT PASS FROM 0330 UTC THIS MORNING. THIS AREA OF WINDS IS FORECAST TO CHANGE LITTLE OVER THE NEXT 24 HOURS...THEN REFORM FROM 17N-27N W OF 134W IN 48 HOURS. THE PRES GRADIENT BETWEEN THE AFOREMENTIONED HIGH AND LOWER PRES OVER MEXICO...AS WELL AS TERRAIN VARIATIONS OVER THE BAJA PENINSULA IS CONTINUING TO PRODUCE NW WINDS OF 20 KT ALONG A PORTION OF THE BAJA CALIFORNIA COAST...WITHIN THE AREA FROM 23N TO 27N EXPANDING W TO 115W. THESE WINDS ARE EXPECTED TO LAST FOR THE NEXT 24 HOURS...THEN DIMINISH IN 48 HOURS. LIKE YESTERDAY...SCATTEROMETER DATA FROM EARLIER THIS MORNING DEPICTED THESE WINDS PRETTY WELL. IN REFERENCE TO MARINE ISSUES...LONG PERIOD S TO SW SWELLS OF 13-15 SECONDS HAVE OVERSPREAD MUCH OF THE EASTERN PORTION OF THE AREA WITH SIGNIFICANT WAVE HEIGHTS TO NEAR 7 FT...EXCEPT UP TO 8 FT S OF THE ITCZ TO 4N BETWEEN 98W-1118W. LATEST MODEL GUIDANCE OF WAVE PERIODS AND SIGNIFICANT WAVE GUIDANCES SUGGEST THAT A NEW SWELL TRAIN OF INCREASED PERIODS (IN THE RANGE OF 14-15 SECONDS) WILL EMERGE FROM THE SOUTHERN HEMISPHERE TO ACROSS THE EQUATOR...AND REACH THE COASTS OF CENTRAL AMERICA AND SE MEXICO TODAY BEFORE GRADUALLY LETTING UP LATER TODAY INTO WED. $$ AGUIRRE