000 AXPZ20 KNHC 311603 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC MON JAN 31 2011 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1430 UTC. ...ITCZ... AXIS ANALYZED ALONG 04N77W TO 04N100W TO 06N122W TO 06N140W. SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION WAS NOTED WITHIN 150 NM N OF AXIS W OF 132W. SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION WAS NOTED OFF THE ITCZ...SPREAD ACROSS A BROAD AREA FROM 10N TO 18N BETWEEN 117W AND 135W. ...DISCUSSION... A HIGH AMPLITUDE BLOCKING PATTERN HAS EVOLVED OVER THE EPAC DURING THE PAST FEW DAYS...EFFECTING A REX BLOCK BETWEEN 160W AND 110W. THIS PATTERN GENERALLY SPANS ACROSS W AND NW PORTIONS OF THE DISCUSSION AREA...WITH A VERY HIGH AMPLITUDE UPPER RIDGE EXTENDING FROM 29N132W N-NW TO BEYOND 50N. S OF THIS RIDGE WERE A PAIR OF MID TO UPPER LEVEL LOWS AT 24N139W AND 17N142W RESPECTIVELY...AND CUT OFF FROM THE MEAN FLOW...WITH A BROAD TROUGH THEN EXTENDING S-SW TO THE EQUATOR ALONG 150W. WRAPPING AROUND THE BASE OF THIS TROUGH WAS A TROPICAL JETSTREAM WITH CORE SPEEDS 60-80 KT...WITH SYNOPTIC SCALE FLOW THEN TURNING S TO SW BETWEEN THE BROAD TROUGH AND 120W...WHERE UPPER RIDGING HAS BECOME ESTABLISHED OVER THE BROAD AREA OF CONVECTION MENTION ABOVE OCCURRING BETWEEN 117W AND 135W. TPW ANIMATIONS SHOW WWD PROPAGATING TROPICAL AND SUB TROPICAL MOISTURE PREVAILING BETWEEN THE ITCZ AND 14N...AND CONVERGING ACROSS THIS CONVECTIVELY ACTIVE ZONE DUE TO THE DEEP LAYERED TROUGH THAT HAS DEVELOPED ALONG 140W. THIS LARGE SCALE BLOCKING PATTERN WILL SHIFT SLOWLY E OVER THE NEXT 48 HOURS BEFORE GRADUALLY BREAKING DOWN DURING THE REMAINDER OF THE WEEK. SYNOPTIC SCALE LIFT AND GOOD LOW LEVEL CONVERGENCE TO THE E AND SE OF THIS DEEP LAYERED TROUGHING WILL MAINTAIN ACTIVE CONVECTION S OF 22N BETWEEN 128W AND 140W DURING THE NEXT 24 HOURS AND ACT TO MAINTAIN THE DOWNSTREAM UPPER RIDGING. E OF 110W...AN UPPER ANTICYCLONE WAS CENTERED OFF THE MEXICAN COAST NEAR 14N98W AND WAS ANCHORING A S/W RIDGE ACROSS OLD MEXICO. ABUNDANT MID AND UPPER LEVEL MOISTURE WAS BEING TRANSPORTED NE AND E ACROSS MUCH OF THE DISCUSSION AREA BY THIS COMBINED UPPER RIDGING. A DEEP LAYERED CYCLONE DIVING INTO THE BASE OF A LONG WAVE TROUGH ACROSS THE WRN U.S. WAS MOVING S-SE ACROSS SRN CALIFORNIA...ARIZONA...AND FAR NW MEXICO...WITH JET ENERGY TO THE S IN EXCESS OF 120 KT MOVING E-NE ACROSS THE S HALF OF BAJA CALIFORNIA AND ACROSS NRN MEXICO. THIS WEATHER SYSTEM WILL BE RESPONSIBLE FOR A MAJOR U.S. STORM SYSTEM IN THE NEXT FEW DAYS. AT THE SURFACE...A 1028 MB HIGH WAS CENTERED NEAR 33N130W WITH RIDGE AXIS EXTENDING SE TO THE MEXICAN COAST ALONG 20N106W. MODERATE TO FRESH TRADES OF 15-25 KT WERE OCCURRING TO THE S OF THE ASSOCIATED RIDGE S OF 22N AND W OF 120W...WHICH WAS CONTRIBUTING TO THE LOW LEVEL FORCING PRODUCING THE BROAD CONVECTION MENTIONED ABOVE. THE LOW DIVING INTO THE DESERT SW OF THE U.S. WAS ALSO BRINGING REINFORCING COOL AIR AND FRESH NWLY SURFACE WINDS TO NE PORTIONS OF THE AREA...SPILLING S INTO CENTRAL BAJA AND THE GULF OF CALIFORNIA....WHERE NW TO N WINDS NEAR 20 KT PREVAILED...ACCOMPANIED BY BUILDING NWLY SWELL. BUOY OBS OFF OF SRN CALIFORNIA THIS MORNING REPORTED SEAS AS HIGH AS 14 FT IN THIS NW SWELL. LOOK FOR THE FRESH TRADES S OF THE RIDGE TO SHIFT E AND NE DURING THE NEXT 24 HOURS BEFORE THIS GRADIENT WEAKENS BY 48 HOURS AS THE LOW ACROSS THE DESERT SW MOVES QUICKLY NE AND HIGH PRES OVER THE NE PACIFIC DRIFTS NE. FRESH EASTERLY TRADES ACROSS THE SOUTHERN AND CENTRAL CARIBBEAN WERE SPILLING ACROSS CENTRAL AMERICA TO PRODUCE MODEST GAP WINDS AROUND 20 KT THROUGH THE GULF OF PAPAGAYO TO 89W. OTHERWISE... WEAK MONSOONAL FLOW PREVAILS ACROSS THE WATERS S OF 10N E OF 95W...WITH LITTLE CHANGE EXPECTED THROUGH TUE MORNING. $$ STRIPLING