000 AXPZ20 KNHC 211005 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC WED NOV 21 2012 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0900 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... MONSOON TROUGH EXTENDS FROM 08N74W TO 10N84W TO 05.5N95W...WHERE IT TRANSITIONS TO ITCZ..CONTINUING ON 09N120W TO BEYOND 07N140W. SCATTERED TO NUMEROUS MODERATE TO STRONG CONVECTION NOTED N OF 05N E OF 86W. ISOLATED TO SCATTERED MODERATE ISOLATED STRONG CONVECTION NOTED WITHIN 90 NM EITHER SIDE OF THE ITCZ W OF 119W. ...DISCUSSION... A PAIR OF MID/UPPER LEVEL SHORT WAVE TROUGHS ARE THE MAIN WEATHER INFLUENCES N OF 20N AND W OF 105W. A VIGOROUS AND WELL DEFINED MID/UPPER LEVEL CYCLONE CENTERED NEAR 27N112W CONTINUES TO LIFT NE OVER UPPER RIDGING TO THE E. LIGHTNING DATA NETWORK OVERNIGHT SHOWED NUMEROUS LIGHTNING STRIKES ACROSS THE SE QUADRANT AS THIS LOW APPROACHED AND THEN MOVED ACROSS S CENTRAL BAJA CALIFORNIA. HOWEVER...LACK OF LOW LEVEL MOISTURE SUGGESTS THAT THIS WAS ELEVATED CONVECTION YIELDING LIGHT TO MODERATE RAINFALL. LIGHTNING THERE HAS SINCE DECREASED CONSIDERABLY AND BECOME VERY ISOLATED. A 45-60 KT SWLY JET LOCATED SE OF THE ASSOCIATED TROUGH AXIS WAS PROVIDING LIFT AND EVACUATION TO ENHANCE SCATTERED MODERATE CONVECTION ALONG A NARROW AND SEMI-PERMANENT CONVERGENCE LINE EXTENDING FROM THE MEXICAN COAST JUST W OF ACAPULCO SW TO 12N112W. A SECOND SHORT WAVE TROUGH WAS UPSTREAM OF ALL THIS...EXTENDING FROM 30N122W TO 21N134W. THE FIRST CYCLONE WILL MOVE NE AND INLAND ACROSS MEXICO THIS MORNING AND THEN INTO THE SW U.S. THIS EVENING...ALLOWING THE SECOND SHORT WAVE TO SHIFT E AND DIG S TO 19N...THEN SHIFT E ACROSS THE BAJA PENINSULA THU. THIS WILL ACT TO PRODUCE A MUCH MORE ZONAL UPPER LEVEL FLOW ACROSS THE AREA N OF 10N BY THU AFTERNOON AND EVENING. AT THE SURFACE...THE PRES GRADIENT BETWEEN LOWER PRESSURE ALONG THE SIERRA MADRE OCCIDENTALES AND A 1024 MB SURFACE HIGH PRES CENTERED NEAR 29N126W IS ALLOWING FRESH NW WINDS TO FLOW DOWN THE LENGTH OF MUCH OF THE GULF OF CALIFORNIA...AS EVIDENCED BY RECENT SHIP OBSERVATIONS AND A 0402 UTC ASCAT PASS. SEAS TO 8 FT ARE OCCURRING ACROSS S PORTIONS OF THE GULF S OF 24N. SHIP DATA ALSO INDICATED MODERATE TO FRESH NW WINDS ON THE PACIFIC COAST OF THE BAJA PENINSULA...ON THE WESTERN EDGE OF THE SURFACE HIGH PRES. SEAS THERE ARE RUNNING 6-7 FT IN NW SWELL. THE SURFACE HIGH IS EXPECTED TO WEAKEN AND SHIFT NW DURING THE NEXT 24 HOURS TO REDUCE THE PRES GRADIENT ON BOTH SIDES OF BAJA CALIFORNIA...WITH WINDS FALLING BELOW 20 KT. DEEP LAYER RIDGING FOLLOWING THE WESTERN MOST SHORT WAVE TROUGH WILL BUILD N OF 30N...AHEAD OF A ANOTHER MORE VIGOROUS LONG WAVE TROUGH OVER THE N CENTRAL PACIFIC MOVING INTO THE NE PACIFIC. THE REINFORCED SURFACE HIGH PRES WILL ALLOW FRESH TO OCCASIONALLY STRONG TRADES IN A BROAD AREA FROM ROUGHLY 12N TO 19N W OF 120W. COMBINED SEAS TO AROUND 10 FT IN A MIX OF FRESH NW AND LONGER PERIOD NW SWELL PERSIST IN THE AREA OF FRESH TO STRONG TRADES. ANOTHER PULSE OF NW SWELL IS STARTING TO MOVE INTO THE AREA FROM THE N CENTRAL PACIFIC...AND WILL MIX WITH THE SUBSIDING SEAS IN THE AREA OF TRADES OVER THE NEXT 48 HOURS. N WINDS 25 TO 35 KT CONTINUE TO EXIT THE CHIVELAS PASS AND THROUGH THE GULF OF TEHUANTEPEC THIS MORNING...AND A GALE WARNING REMAINS IN EFFECT THERE. A 0358 UTC ASCAT PASS SHOWED 30-35 KT WINDS THERE N OF 15N. PERSISTENT N TO NE WIND FLOW ACROSS THE SW GULF OF MEXICO...AND A SUFFICIENT PRES GRADIENT BETWEEN THE NORTHERN AND SOUTHERN ENDS OF THE ISTHMUS SHOULD CONTINUE TO SUPPORT GALE CONDITIONS A LITTLE LONGER...ESPECIALLY DURING THE LATE NIGHT AND EARLY MORNING HOURS WHEN DRAINAGE IMPACTS CONTRIBUTE TO THE AGGREGATE GAP FLOW. WINDS ACROSS THE SW GULF ARE FORECAST TO BEGIN TO VEER MORE NE TO E THU NIGHT INTO FRI...AND GALE CONDITIONS WILL LIKELY END FRI MORNING...AFTER PERSISTING FOR SEVERAL DAYS. GALES ARE LIKELY AGAIN THIS WEEKEND HOWEVER...AFTER A NEW COLD FRONT MOVES INTO THE SW GULF OF MEXICO. PULSING OF NOCTURNAL WINDS ARE ALSO EXPECTED TO CONTINUE ACROSS THE GULF OF PAPAGAYO...WITH WINDS TO 25 KT AND SEAS OF 8-9 FT FOR THE NEXT FEW DAYS. A LARGE POOL OF LOW LEVEL MOISTURE HAS CONVERGED ACROSS THE FAR W CARIBBEAN...ADJACENT CENTRAL AMERICA...AND THE FAR EPAC E OF 90W. UPPER LEVEL CONDITIONS HAVE BECOME MORE FAVORABLE TO SUPPORT DEEP CONVECTION ACROSS THIS AREA IN THE PAST 24 HOURS...AND THE SW MONSOONAL FLOW ACROSS THE EPAC HAS INCREASED TO 20 TO 25 KT N OF 06N E OF 83W AND INTO THE GULF OF PANAMA. THESE CONDITIONS ARE EXPECTED TO CONTINUE THROUGH TONIGHT BEFORE WINDS BEGIN TO DIMINISH THERE EARLY THU. $$ STRIPLING