000 AXPZ20 KNHC 181531 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC SUN NOV 18 2007 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 1500 UTC. ...TROPICAL WAVES... TROPICAL WAVE LOCATED OVER COSTA RICA AND EASTERN NICARAGUA ALONG 84W N OF 5N MOVING W 15 KT. A FAIRLY WELL-DEFINED AXIS...FOR MID-NOVEMBER...IS VISIBLE MOVING ACROSS CENTRAL AMERICA AT THE MOMENT WITH SCATTERED SHOWERS/TSTMS TO THE N OVER THE GULF OF HONDURAS. SOUTHWESTERLY SHEAR IS KEEPING THE DEEPEST CONVECTION E OF THE WAVE AXIS WHERE SCATTERED MODERATE CONVECTION IS LOCATED OVER THE SW CARIBBEAN. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 7N77W 6N90W 9N110W 10N140W. SCATTERED MODERATE CONVECTION FROM 4N-7N BETWEEN 78W-81W. SCATTERED MODERATE/ISOLATED STRONG WITHIN 120 NM OF AXIS BETWEEN 109W-136W. ...DISCUSSION... THE GENERAL LONGWAVE PATTERN FEATURES TWO RIDGES AND TWO TROUGHS WITHIN AND FLANKING THE DISCUSSION AREA. FIRST...AN UPPER RIDGE AXIS IS LOCATED E OF THE AREA OVER THE CENTRAL CARIBBEAN ALONG 75W WITH DOMINATING MID-LEVEL HIGH CENTERED NEAR THE WINDWARD PASSAGE. WIDESPREAD MODERATE/STRONG SUBSIDENCE LIES E OF 95W BENEATH THE RIDGE ALTHOUGH SOME AREAS OF CONVECTION ARE LOCATED ALONG AND E OF THE TROPICAL WAVE ALONG 84W. ABUNDANT LOW-LEVEL DRY AIR COVERS THE PACIFIC WATERS N OF THE ITCZ E OF 115W ALTHOUGH DEEP MOISTURE WILL GRADUALLY INCREASE FROM EAST TO WEST OVER THE NEXT FEW DAYS WITH THE PASSAGE OF THE WAVE. AN UPPER TROUGH AXIS...PARTIALLY CUT-OFF FROM THE PREVAILING MID-LATITUDE WESTERLIES OVER THE EASTERN UNITED STATES...EXTENDS FROM CENTRAL TEXAS SW ACROSS NORTHERN MEXICO TO 15N110W. ALTHOUGH THE SHARPEST PART OF THE TROUGH LIES N OF THE TROPICS...BROAD CYCLONIC CURVATURE IS NOTED IN THE UPPER LEVEL WINDS FARTHER S AS WELL. MODERATE/STRONG SUBSIDENCE COVERS WESTERN MEXICO N OF 17N BETWEEN 102W-115W BENEATH THE TROUGH AXIS WHILE SCATTERED MID/HIGH CLOUDINESS IS MOVING NE ACROSS CENTRAL MEXICO ALONG THE ASSOCIATED JET. A WEAK OMEGA BLOCK IS LOCATED JUST W OF BAJA CALIFORNIA WITH A NEARLY STATIONARY RIDGE AXIS ALONG 119W BORDERED BY THE TROUGH OVER MEXICO AND A SHARPER TROUGH NE OF HAWAII. THE RIDGE IS DEEP-LAYERED AND IS REFLECTED AS A 1021 MB HIGH NEAR 30N129W...ALL OF WHICH IS PRODUCING AN OVERCAST/BROKEN BUT RELATIVELY SHALLOW MARINE LAYER N OF 20N. FARTHER W...THE SHARP UPPER TROUGH IS PASSING BY HAWAII TO THE NE WHILE A CUT-OFF UPPER LOW IS LOCATED SE OF THE ISLANDS NEAR 15N149W. THE LOW IS EXPECTED TO BECOME ABSORBED BY THE LARGER TROUGH...BUT IN THE MEANTIME UPPER DIVERGENCE E OF THE LOW IS PRODUCING BROKEN MID/HIGH LEVEL CLOUDS FROM 15N-27N W OF 130W. THE UPPER LEVEL FLOW IS PRIMARILY WESTERLY S OF 15N ALTHOUGH THERE IS ENOUGH DIFFLUENCE WHERE SOME OF THE WINDS TURN TO THE SE TO ENHANCE DEEP CONVECTION ALONG THE ITCZ BETWEEN 105W-135W. $$ BERG