000 AXPZ20 KNHC 022153 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC WED JUL 02 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 2130 UTC. ...SPECIAL FEATURES... TROPICAL STORM BORIS IS CENTERED NEAR 16.9N 127.8W...OR 1075 NM WSW OF CABO SAN LUCAS MEXICO...AT 02/2100 UTC MOVING NW AT 7 KT. MAXIMUM SUSTAINED WIND SPEED HAS DIMINISHED TO 50 KT WITH GUSTS TO 60 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 995 MB. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP2/WTPZ22 KNHC FOR MORE DETAILS. BORIS IS STILL SPORTING A 45 NM-WIDE EYE-LIKE FEATURE BUT DEEP CONVECTION HAS DECREASED IN COVERAGE AND INTENSITY THROUGH THE DAY. IT HAS THEREFORE BEEN DOWNGRADED TO TROPICAL STORM STATUS. THE STORM IS OVER OCEAN WATER WITH A TEMPERATURE NEAR 25C AND IS BECOMING INCREASINGLY AFFECTED BY MORE STABLE AIR TO ITS NW. LIGHT SOUTHEASTERLY SHEAR WILL ONLY MILDLY AFFECT BORIS...SO A GRADUAL WEAKENING IS EXPECTED OVER THE NEXT DAY OR TWO. SCATTERED MODERATE CONVECTION IS WITHIN 90 NM OF THE CENTER. TROPICAL STORM DOUGLAS IS CENTERED NEAR 18.1N 108.3W...OR 235 WSW OF MANZANILLO MEXICO AND 300 NM SSE OF CABO SAN LUCAS MEXICO...AT 02/2100 UTC MOVING NW AT 7 KT. MAXIMUM SUSTAINED WIND SPEED IS 35 KT WITH GUSTS TO 45 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1004 MB. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP4/WTPZ24 KNHC FOR MORE DETAILS. DOUGLAS IS BEING AFFECTED BY ABOUT 20 KT OF EAST-NORTHEASTERLY SHEAR DUE TO AN UPPER HIGH OVER THE SOUTHERN GULF OF CALIFORNIA...AND AS A RESULT THE LOW-LEVEL CENTER IS PARTIALLY EXPOSED FROM DEEP CONVECTION OVER THE SW SEMICIRCLE. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 240 NM SW SEMICIRCLE. ISOLATED MODERATE IS WITHIN 300 NM NE SEMICIRCLE. THE SHEAR IS EXPECTED TO WEAKEN OVER THE NEXT FEW DAYS AND WILL ALLOW FOR SOME SLIGHT STRENGTHENING AS DOUGLAS MOVES NW OFF THE SOUTHERN TIP OF BAJA CALIFORNIA. A 1007 MB LOW IS LOCATED NEAR 10N94W...OR ABOUT 385 NM SSE OF PUERTO ANGEL MEXICO...MOVING NW AT 4 KT. THE LOW IS ASSOCIATED WITH A TROPICAL WAVE WHICH HAS BEEN MOVING W ACROSS CENTRAL AMERICA OVER THE PAST COUPLE OF DAYS. THE LOW-LEVEL CENTER APPEARS SOMEWHAT ELONGATED BUT CONVECTIVE BANDING HAS INCREASED OVER THE WESTERN SEMICIRCLE AND OVER THE NE QUADRANT DURING THE DAY. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 08N-16N BETWEEN 87W-98W. TROPICAL CYCLONE DEVELOPMENT IS POSSIBLE WITHIN THE NEXT 48 HRS AS THIS SYSTEM MOVES SLOWLY NW OFF THE SOUTHERN COAST OF MEXICO. ...TROPICAL WAVES... SEE SPECIAL FEATURES FOR TROPICAL WAVE AND ASSOCIATED LOW ALONG 94W. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 08N77W TO 10N94W TO 06N117W THEN FROM 14N123W TO 07N140W. SCATTERED MODERATE N OF 03N BETWEEN 79W AND 86W. SCATTERED MODERATE WITHIN 45 NM OF AXIS BETWEEN 126W AND 134W. ...DISCUSSION... SUBTROPICS... A SHARP UPPER LEVEL TROUGH IS LOCATED OFF THE W COAST OF THE UNITED STATES...WITH THE AXIS EXTENDING FROM AN UPPER LOW NEAR 43N134W TO 30N137W TO 22N140W. 30-40 KT UPPER LEVEL W/SW WINDS CURVE AROUND THE BASE OF THE TROUGH N OF 27N W OF 126W AND SOME UPPER LEVEL CIRRUS IS PLUNGING SE INTO THE AREA ON THE W SIDE OF THE TROUGH. THE TROUGH IS CAUSING TROPICAL STORM BORIS TO MOVE TOWARDS THE NW DUE TO THE DEEP-LAYERED FLOW COMING OUT OF THE SE. FARTHER E...AN UPPER HIGH IS CENTERED W OF BAJA CALIFORNIA NEAR 26N121W WHILE A SMALL UPPER LOW IS EMBEDDED WITHIN ITS CIRCULATION NEAR 20N120W. MODERATE/STRONG SUBSIDENCE LIES N OF 20N BETWEEN 112W-128W WITH BROKEN STRATOCUMULUS COVERING THE AREA. THE RIDGE ASSOCIATED WITH THE HIGH COVERS MUCH OF WESTERN MEXICO BUT THEN THE FLOW OVER THE EASTERN HALF OF THE COUNTRY TURNS OUT OF THE NW INTO A DEEP TROUGH OVER THE GULF OF MEXICO. SCATTERED TSTMS ARE JUST NOW BEGINNING TO POP OVER THE SIERRA MADRES AND THE MEXICAN PLATEAU. TROPICS... WATER VAPOR IMAGERY SHOWS THAT DEEP MOISTURE EXTENDS ACROSS THE ENTIRE TROPICAL REGIME E OF 120W AS WELL AS IN THE VICINITY OF T.S. BORIS NEAR 18N128W. UPPER LEVEL WINDS ARE PRIMARILY EASTERLY S OF 10N BUT ARE MORE VARIABLE FROM 10N-20N DUE TO THE OUTFLOW AROUND T.S. BORIS AND T.S. DOUGLAS. CIMSS WIND ANALYSES INDICATE THAT HIGH SHEAR VALUES ARE MAINLY CONFINED BETWEEN 100W-125W...ESPECIALLY DUE TO AN OUTFLOW JET SW OF DOUGLAS. ELSEWHERE...BROAD UPPER LEVEL DIVERGENCE LIES E OF 100W AND IS LIKELY ENHANCING CONVECTION NEAR THE SURFACE LOW S OF THE GULF OF TEHUANTEPEC. A COL REGION LIES W OF 130W WHERE THE BASE OF THE MID-LATITUDE TROUGH MEETS THE DEEP-LAYERED TROPICAL EASTERLIES. THIS IS PRODUCING STRONG SUBSIDENCE W OF 133W IN ADVANCE OF T.S. BORIS. $$ BERG