000 AXPZ20 KNHC 010331 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC FRI FEB 1 2008 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0300 UTC. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 3N78W 5N95W 5N125W 10N140W. NO SIGNIFICANT CONVECTION. ...DISCUSSION... A DEEP LONGWAVE TROUGH OVER THE CENTRAL UNITED STATES REACHES S OVER NORTHERN MEXICO. CONFLUENCE INTO THE BASE OF THE TROUGH IS PRODUCING SUBSIDENCE AND CLEAR SKIES. A CUT-OFF UPPER TROUGH EXTENDING S FROM TEHUANTEPEC TO 9N98W IS COLLOCATED WITH A MID-LEVEL RIDGE ALONG 17N. AS A RESULT...LARGE SCALE SUBSIDENCE IS STRONGEST E OF THE TROUGH AXIS. QUIKSCAT SHOWS SURFACE WINDS ARE GENERALLY LIGHT... ALTHOUGH WINDS CONTINUE TO PULSE TO 20 KT IN THE GULF OF PAPAGAYO. A GALE WARNING IS IN EFFECT FOR THE GULF OF TEHUANTEPEC FOR WINDS INCREASING TO 30-40 KT FRI AFTERNOON. A COLD FRONT MOVING OFF THE TEXAS COAST WILL REACH SOUTHERN MEXICO FRI AND WILL PROVIDE A QUICK SURGE OF N WINDS OVER TEHUANTEPEC. GALE CONDITIONS ARE EXPECTED TO LAST FOR ONLY 18 HRS OR SO. CONFIDENCE IS HIGH THAT THE EVENT WILL OCCUR BUT TIMING/STRENGTH IS A LITTLE UNCERTAIN. OUR FORECAST TAKES A BLEND OF THE MIXED-LAYER WINDS FROM THE GFS AND NAM MODELS. UPPER LEVEL SPLIT FLOW IS ENTRENCHED OVER THE WESTERN PART OF THE AREA...WITH RIDGING N OF 17N ALONG 130W...AND A WEAK UPPER TROUGH S OF 17N. BROAD UPPER DIFFLUENCE IN THE REGION W OF THE RIDGE AXIS IS PRODUCING WIDESPREAD CIRRUS N OF 10N. SOME EMBEDDED MODERATE SHOWERS ARE POSSIBLE NEAR THE ITCZ...BUT DEEP CONVECTION IS NOT OBSERVED. A SURFACE TROUGH ALONG 140W S OF 18N IS GENERATING SCATTERED SHOWERS. $$ MUNDELL