000 AXPZ20 KNHC 192144 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC FRI SEP 19 2008 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2015 UTC. ...SPECIAL FEATURES... TROPICAL WAVE ALONG 103W FROM 6N-15N IS MOVING W 10-15 KT. THIS WAVE IS ON THE WESTERN PORTION OF LARGE AND DISORGANIZED AREA OF ACTIVE SCATTERED MODERATE TO STRONG CONVECTION UNDER DIFFLUENT FLOW THAT EXTENDS FROM 9N-15N BETWEEN 93W-107W. VISIBLE SATELLITE IMAGERY CONTINUES TO SHOW BROAD CYCLONIC TURNING OF THE LOW CLOUD FIELD WITH THE ITCZ AXIS SERVING AS THE FOCAL POINT OF THIS AREA. CONVECTION WITHIN THIS AREA IS PRESENTLY UNDER THE INFLUENCE OF STRONG UPPER EASTERLY SHEAR SO THE AREA WILL REMAIN RATHER BROAD WITH ONLY SLOW DEVELOPMENT EXPECTED OVER THE NEXT COUPLE OF DAYS AS IT SLOWLY MOVES WNW UNDER A SLIGHTLY IMPROVED UPPER LEVEL ENVIRONMENT. ...TROPICAL WAVES... TROPICAL WAVE ALONG 93W N OF 7N TO ACROSS SE MEXICO IS MOVING W 5-10 KT. SCATTERED MODERATE CONVECTION IN SMALL CLUSTERS IS WITHIN 30 NM OF THE WAVE FROM 11N-15N. AS THIS WAVE MOVES W IT WILL BECOME ABSORBED INTO THE AREA OF DISTURBED WEATHER DESCRIBED ABOVE UNDER SPECIAL FEATURES. TROPICAL WAVE ALONG 121W FROM 6N TO 15N IS MOVING W 10 KT. A WEAK LOW-LEVEL SWIRL IS ON THE WAVE AXIS NEAR 10N121W...BUT WILL PROBABLY NOT BE NOTICEABLE WITHIN THE NEXT 12 HOURS. ONLY ISOLATED RELATIVELY WEAK TSTM ACTIVITY IS NOTED WITHIN 90 NM OF THE LOW. ISOLATED SHOWERS ARE WITHIN 30-60 NM OF THE WAVE AXIS. THE WAVE IS ENHANCING ITCZ CONVECTION BETWEEN 119W-122W. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 10N86W TO 12N91W TO 10N98W TO 10N105W TO 10N120W TO 8N130W TO 9N140W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 240 NM S OF THE AXIS E OF 91W...AND 180 NM S OF THE AXIS BETWEEN 105W-110W. SCATTERED MODERATE CONVECTION IS WITHIN 180 NM S OF THE AXIS BETWEEN 118W-123W... AND FROM 5N-09N BETWEEN 127W-130W. ...DISCUSSION... E OF 130W... AN ELONGATED E TO W MID/UPPER LEVEL ANTICYCLONE MOVING ESE 15 KT IS IDENTIFIED NEAR 18N118W. A RIDGE EXTENDS SW FROM THE ANTICYCLONE TO BEYOND 18N130W...WITH ANOTHER RIDGE NNW TO 27N121W TO 32N124W. A PRONOUNCED ANTICYCLONIC CIRCULATION IS E OF THE AREA OVER MEXICO NEAR 20N98W WITH A RIDGE WNW TO 23N117W. WATER VAPOR IMAGERY SHOWS WEAK MID/UPPER LEVEL TROUGH IN BETWEEN BOTH ANTICYCLONES WITH A COL REGION CENTERED NEAR 21N107W. A DEEP LAYERED TROUGH N OF THE AREA MOVING INTO NORTHERN AND CENTRAL CALIFORNIA HAS ITS WEAK AXIS EXTENDING SSE TO 32N120W. ANTICYCLONIC FLOW AND MOSTLY STRONG SUBSIDENCE ASSOCIATED WITH THE ANTICYCLONE NEAR 22N112W IS NOTED FROM 24N-30N WHERE IT MERGES WITH CYCLONIC FLOW RELATED WITH THE TROUGH N OF THE AREA RESULTING IN A CONFLUENT FLOW PATTERN ALLOWING FOR A DRY STABLE AIR MASS TO PRESENT OVER THE NRN SECTION OF THE AREA. STRONG UPPER LEVEL EASTERLY FLOW...WHICH IS RESPONSIBLE FOR CREATING THE EASTERLY OVER THE AREA OF DISORGANIZED CONVECTION MENTION ABOVE WITH THE WAVE ALONG 103W...IS EVIDENT TO THE S AND SW OF THE ANTICYCLONE OVER MEXICO NEAR 20N98W. THIS SAME FLOW IS SPREADING UPPER LEVEL MOISTURE WESTWARD TO 110W...AND ALONG AND NEAR THE ITCZ FROM 4N-14N W OF 110W. MODERATE TO STRONG SUBSIDENCE IS NOTED ELSEWHERE ACROSS THE AREA. AT THE SURFACE...A 1020 MB HIGH IS ANALYZED NEAR 28N129W WITH A WEAK RIDGE SE TO 25N121W. WEAK HIGH PRES COVERS THE AREA N OF 21N W OF 120W. MODEL GUIDANCE SUGGESTS THAT THE N-NE WINDS TO 20 KT IN THE GULF OF TEHUANTEPEC SHOULD DIMINISH IN ABOUT 18 HRS. SCATTERED TO BROKEN STRATOCUMULUS CLOUDS MOVING WSW WITH POSSIBLE ISOLATED SHOWERS ARE LOCATED FROM 18N-28N BETWEEN 123W-130W. A TILTED NW-SE INVERTED MID/UPPER LEVEL TROUGH MOVING W 15 KT IS OVER THE ITCZ REGION FROM 4N-11N BETWEEN 125W-130W. THIS TROUGH IS ENHANCING ITCZ CONVECTION SOME IN THAT AREA. W OF 130W... THE CORRESPONDING SURFACE FEATURE ASSOCIATED WITH THE DEEP LAYERED TROUGH MENTIONED UNDER E OF 130W IS ANALYZED AS A WEAKENING STATIONARY FRONT EXTENDING THROUGH 32N131W SW TO W OF THE AREA AT 28N140W. BROKEN LOW AND MID LEVEL CLOUDS WITH WIDELY SCATTERED SHOWERS ARE WITHIN 60 NM SE OF THE FRONT. THE IS FORECAST TO BECOME A SHEAR AXIS THROUGH THE NEXT 6-12 HOURS BEFORE DISSIPATING. THE WESTERN EXTENSION OF THE MID/UPPER LEVEL ANTICYCLONE E OF THE AREA NEAR 18N118W EXTENDS SW TO A SMALL UPPER LEVEL ANTICYCLONE NEAR 13N133W AND TO 11N140W. A SMALL MID/UPPER LEVEL CYCLONIC CIRCULATION MOVING E 15 KT IS JUST NW OF THE AREA NEAR 33N142W. ITS ASSOCIATED TROUGH EXTENDS SSE TO 26N138W...THEN SW OF THE AREA AT 20N140W. THE SOUTHERN PART OF THIS TROUGH IS CUTTING-OFF FROM THE MID-LATITUDES AS FORECAST BY THE MODELS. THE UPPER LEVEL FLOW PATTERN IS CONFLUENT IN BETWEEN BOTH THE CYCLONIC CIRCULATION AND ANTICYCLONE...WHICH IS ALLOWING FOR MODERATE TO STRONG SUBSIDENCE AND ASSOCIATED DRY STABLE AIR TO PREVAIL THROUGHOUT THIS AREA PROHIBITING THE DEVELOPMENT OF ANY DEEP CONVECTIVE ACTIVITY. PATCHES OF BROKEN STRATOCUMULUS CLOUDS WITH POSSIBLE ISOLATED SHOWERS ARE NOTED ELSEWHERE S OF THE WEAKENING FRONT. A VERY NARROW LINE...ABOUT 20 NM IN WIDTH...OF INCREASING SCATTERED SHOWERS AND TSTMS EXTENDS FROM 10N137W TO 13N137W. THIS ACTIVITY IS BEING FORCED BY A WEAK SURFACE TROUGH THAT EXTENDS FROM 9N137W ACROSS THE ITCZ TO 12N137W TO 14N137W. A 45 NM WIDE CYCLONIC SWIRL IS JUST TO THE SE OF SOUTHERN TIP OF THE TROUGH NEAR 10N136W. A QUIKSCAT PASS FROM NEAR 1500 UTC THIS MORNING REVEALED N-E 20 KT WINDS WITHIN 180 NM E OF THE TROUGH FROM 11N-14N. $$ AGUIRRE 000 AXPZ20 KNHC 192144 RRA TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC FRI SEP 19 2008 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2115 UTC. ...SPECIAL FEATURES... TROPICAL WAVE ALONG 103W FROM 6N-15N IS MOVING W 10-15 KT. THIS WAVE IS ON THE WESTERN PORTION OF LARGE AND DISORGANIZED AREA OF ACTIVE SCATTERED MODERATE TO STRONG CONVECTION UNDER DIFFLUENT FLOW THAT EXTENDS FROM 9N-15N BETWEEN 93W-107W. VISIBLE SATELLITE IMAGERY CONTINUES TO SHOW BROAD CYCLONIC TURNING OF THE LOW CLOUD FIELD WITH THE ITCZ AXIS SERVING AS THE FOCAL POINT OF THIS AREA. CONVECTION WITHIN THIS AREA IS PRESENTLY UNDER THE INFLUENCE OF STRONG UPPER EASTERLY SHEAR SO THE AREA WILL REMAIN RATHER BROAD WITH ONLY SLOW DEVELOPMENT EXPECTED OVER THE NEXT COUPLE OF DAYS AS IT SLOWLY MOVES WNW UNDER A SLIGHTLY IMPROVED UPPER LEVEL ENVIRONMENT. ...TROPICAL WAVES... TROPICAL WAVE ALONG 93W N OF 7N TO ACROSS SE MEXICO IS MOVING W 5-10 KT. SCATTERED MODERATE CONVECTION IN SMALL CLUSTERS IS WITHIN 30 NM OF THE WAVE FROM 11N-15N. AS THIS WAVE MOVES W IT WILL BECOME ABSORBED INTO THE AREA OF DISTURBED WEATHER DESCRIBED ABOVE UNDER SPECIAL FEATURES. TROPICAL WAVE ALONG 121W FROM 6N TO 15N IS MOVING W 10 KT. A WEAK LOW-LEVEL SWIRL IS ON THE WAVE AXIS NEAR 10N121W...BUT WILL PROBABLY NOT BE NOTICEABLE WITHIN THE NEXT 12 HOURS. ONLY ISOLATED RELATIVELY WEAK TSTM ACTIVITY IS NOTED WITHIN 90 NM OF THE LOW. ISOLATED SHOWERS ARE WITHIN 30-60 NM OF THE WAVE AXIS. THE WAVE IS ENHANCING ITCZ CONVECTION BETWEEN 119W-122W. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 10N86W TO 12N91W TO 10N98W TO 10N105W TO 10N120W TO 8N130W TO 9N140W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 240 NM S OF THE AXIS E OF 91W...AND 180 NM S OF THE AXIS BETWEEN 105W-110W. SCATTERED MODERATE CONVECTION IS WITHIN 180 NM S OF THE AXIS BETWEEN 118W-123W... AND FROM 5N-09N BETWEEN 127W-130W. ...DISCUSSION... E OF 130W... AN ELONGATED E TO W MID/UPPER LEVEL ANTICYCLONE MOVING ESE 15 KT IS IDENTIFIED NEAR 18N118W. A RIDGE EXTENDS SW FROM THE ANTICYCLONE TO BEYOND 18N130W...WITH ANOTHER RIDGE NNW TO 27N121W TO 32N124W. A PRONOUNCED ANTICYCLONIC CIRCULATION IS E OF THE AREA OVER MEXICO NEAR 20N98W WITH A RIDGE WNW TO 23N117W. WATER VAPOR IMAGERY SHOWS WEAK MID/UPPER LEVEL TROUGH IN BETWEEN BOTH ANTICYCLONES WITH A COL REGION CENTERED NEAR 21N107W. A DEEP LAYERED TROUGH N OF THE AREA MOVING INTO NORTHERN AND CENTRAL CALIFORNIA HAS ITS WEAK AXIS EXTENDING SSE TO 32N120W. ANTICYCLONIC FLOW AND MOSTLY STRONG SUBSIDENCE ASSOCIATED WITH THE ANTICYCLONE NEAR 22N112W IS NOTED FROM 24N-30N WHERE IT MERGES WITH CYCLONIC FLOW RELATED WITH THE TROUGH N OF THE AREA RESULTING IN A CONFLUENT FLOW PATTERN ALLOWING FOR A DRY STABLE AIR MASS TO PRESENT OVER THE NRN SECTION OF THE AREA. STRONG UPPER LEVEL EASTERLY FLOW...WHICH IS RESPONSIBLE FOR CREATING THE EASTERLY OVER THE AREA OF DISORGANIZED CONVECTION MENTION ABOVE WITH THE WAVE ALONG 103W...IS EVIDENT TO THE S AND SW OF THE ANTICYCLONE OVER MEXICO NEAR 20N98W. THIS SAME FLOW IS SPREADING UPPER LEVEL MOISTURE WESTWARD TO 110W...AND ALONG AND NEAR THE ITCZ FROM 4N-14N W OF 110W. MODERATE TO STRONG SUBSIDENCE IS NOTED ELSEWHERE ACROSS THE AREA. AT THE SURFACE...A 1020 MB HIGH IS ANALYZED NEAR 28N129W WITH A WEAK RIDGE SE TO 25N121W. WEAK HIGH PRES COVERS THE AREA N OF 21N W OF 120W. MODEL GUIDANCE SUGGESTS THAT THE N-NE WINDS TO 20 KT IN THE GULF OF TEHUANTEPEC SHOULD DIMINISH IN ABOUT 18 HRS. SCATTERED TO BROKEN STRATOCUMULUS CLOUDS MOVING WSW WITH POSSIBLE ISOLATED SHOWERS ARE LOCATED FROM 18N-28N BETWEEN 123W-130W. A TILTED NW-SE INVERTED MID/UPPER LEVEL TROUGH MOVING W 15 KT IS OVER THE ITCZ REGION FROM 4N-11N BETWEEN 125W-130W. THIS TROUGH IS ENHANCING ITCZ CONVECTION SOME IN THAT AREA. W OF 130W... THE CORRESPONDING SURFACE FEATURE ASSOCIATED WITH THE DEEP LAYERED TROUGH MENTIONED UNDER E OF 130W IS ANALYZED AS A WEAKENING STATIONARY FRONT EXTENDING THROUGH 32N131W SW TO W OF THE AREA AT 28N140W. BROKEN LOW AND MID LEVEL CLOUDS WITH WIDELY SCATTERED SHOWERS ARE WITHIN 60 NM SE OF THE FRONT. THE IS FORECAST TO BECOME A SHEAR AXIS THROUGH THE NEXT 6-12 HOURS BEFORE DISSIPATING. THE WESTERN EXTENSION OF THE MID/UPPER LEVEL ANTICYCLONE E OF THE AREA NEAR 18N118W EXTENDS SW TO A SMALL UPPER LEVEL ANTICYCLONE NEAR 13N133W AND TO 11N140W. A SMALL MID/UPPER LEVEL CYCLONIC CIRCULATION MOVING E 15 KT IS JUST NW OF THE AREA NEAR 33N142W. ITS ASSOCIATED TROUGH EXTENDS SSE TO 26N138W...THEN SW OF THE AREA AT 20N140W. THE SOUTHERN PART OF THIS TROUGH IS CUTTING-OFF FROM THE MID-LATITUDES AS FORECAST BY THE MODELS. THE UPPER LEVEL FLOW PATTERN IS CONFLUENT IN BETWEEN BOTH THE CYCLONIC CIRCULATION AND ANTICYCLONE...WHICH IS ALLOWING FOR MODERATE TO STRONG SUBSIDENCE AND ASSOCIATED DRY STABLE AIR TO PREVAIL THROUGHOUT THIS AREA PROHIBITING THE DEVELOPMENT OF ANY DEEP CONVECTIVE ACTIVITY. PATCHES OF BROKEN STRATOCUMULUS CLOUDS WITH POSSIBLE ISOLATED SHOWERS ARE NOTED ELSEWHERE S OF THE WEAKENING FRONT. A VERY NARROW LINE...ABOUT 20 NM IN WIDTH...OF INCREASING SCATTERED SHOWERS AND TSTMS EXTENDS FROM 10N137W TO 13N137W. THIS ACTIVITY IS BEING FORCED BY A WEAK SURFACE TROUGH THAT EXTENDS FROM 9N137W ACROSS THE ITCZ TO 12N137W TO 14N137W. A 45 NM WIDE CYCLONIC SWIRL IS JUST TO THE SE OF SOUTHERN TIP OF THE TROUGH NEAR 10N136W. A QUIKSCAT PASS FROM NEAR 1500 UTC THIS MORNING REVEALED N-E 20 KT WINDS WITHIN 180 NM E OF THE TROUGH FROM 11N-14N. $$ AGUIRRE