000 AXPZ20 KNHC 280918 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC SAT JUN 28 2008 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0900 UTC. ...SPECIAL FEATURES... TROPICAL STORM BORIS IS CENTERED NEAR 14.0N 112.1W...OR ABOUT 545 NM SSW OF CABO SAN LUCAS MEXICO...AT 28/0900 UTC MOVING WNW AT 6 KT. MAXIMUM SUSTAINED WIND SPEED IS 45 KT WITH GUSTS TO 55 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1000 MB. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP2/WTPZ22 KNHC FOR MORE DETAILS. A 0526 UTC AMSU MICROWAVE PASS INDICATED THAT THE LOW-LEVEL CENTER OF BORIS WAS LOCATED ON THE NORTHERN EDGE OF THE DEEP CONVECTION DUE TO ABOUT 15 KT OF NORTHEASTERLY SHEAR ON THE S SIDE OF AN UPPER LEVEL HIGH NEAR SOCORRO ISLAND. IR SATELLITE IMAGERY IS SOMEWHAT DECEIVING BECAUSE STRONG ROTATION NOTED IN THE CONVECTION IS MORE LIKELY ASSOCIATED WITH THE MID-LEVEL CIRCULATION...WHICH IS SLIGHTLY S OF THE LOW-LEVEL CENTER. NUMEROUS MODERATE/SCATTERED STRONG CONVECTION IS WITHIN 180 NM S AND 60 NM N SEMICIRCLES MAINLY WITHIN A STRONG BAND CURLING AROUND THE SE AND S SIDE OF THE SYSTEM. TROPICAL DEPRESSION THREE-E IS CENTERED NEAR 14.3N 123.7W...OR ABOUT 940 NM WSW OF CABO SAN LUCAS MEXICO...AT 28/0900 UTC MOVING WNW AT 6 KT. MAXIMUM SUSTAINED WIND SPEED IS 30 KT WITH GUSTS TO 40 KT. ESTIMATED MINIMUM PRESSURE IS 1007 MB. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP3/WTPZ23 KNHC FOR MORE DETAILS. THE DEPRESSION IS UNDER THE INFLUENCE OF A SLIGHT AMOUNT OF SOUTHERLY SHEAR WHICH IS CAUSING THE LOW-LEVEL CENTER TO LIE ON THE SOUTHERN SIDE OF THE DEEP CONVECTION. THE CONVECTIVE PATTERN HAS REMAINED NEARLY STEADY STATE WITH NO SIGNIFICANT INTENSIFICATION NOTED. A STABLE AIR MASS...NOTED BY THE BROKEN STRATOCUMULUS DECK NW OF THE DEPRESSION...WILL SOON BEGIN TO AFFECT THE SYSTEM AND PROBABLY SHRINK THE WINDOW FOR POSSIBLE STRENGTHENING. NUMEROUS MODERATE/SCATTERED STRONG CONVECTION IS WITHIN 120 NM N AND 60 NM S SEMICIRCLES. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 93W/94W N OF 03N MOVING W 10-15 KT. A 1008 MB LOW IS LOCATED ALONG THE WAVE NEAR 08N93W WITH BROAD CYCLONIC TURNING OVER A LARGE PORTION OF THE FAR EASTERN PACIFIC. DEEP CONVECTION HAS BEEN INCREASING PRIMARILY S OF THE LOW ALONG THE ITCZ WITH SOME SLIGHT BANDING NOTED ON THE SW PERIPHERY. SCATTERED MODERATE CONVECTION IS ALSO NEAR THE GULF OF TEHUANTEPEC FROM 13N-15N BETWEEN 90W-95W. MODEL GUIDANCE HAS BEEN CONSISTENT IN TRACKING THIS SYSTEM WNW PARALLEL TO THE MEXICAN COAST OVER THE NEXT FEW DAYS WITH THE POSSIBILITY OF SOME SLOW DEVELOPMENT. ...ITCZ... ITCZ AXIS IS CENTERED FROM 08N77W TO 08N93W TO 14N111W TO 14N124W TO 08N133W TO 09N140W. SCATTERED MODERATE/STRONG CONVECTION FROM 03N-09N E OF 79W. SCATTERED MODERATE/ISOLATED STRONG FROM 03N-09N BETWEEN 89W-103W. SCATTERED MODERATE/STRONG FROM 09N-12N BETWEEN 123W-130W. SCATTERED MODERATE WITHIN 30 NM OF AXIS W OF 133W. ...DISCUSSION... SUBTROPICS... THE CUT-OFF LOW W OF SAN DIEGO CALIFORNIA HAS BEGUN TO LIFT NW OF THE AREA AS THE BLOCKING HIGH SQUEEZES E FROM OREGON TO UTAH. THE SUBTROPICAL JET HAS INTENSIFIED SLIGHTLY WITH MAXIMUM UPPER LEVEL WINDS NEAR 50 KT FROM 24N140W TO 30N119W...AND ONE PIECE CONTINUING NE ACROSS NORTHERN MEXICO. CONFLUENCE INTO THE JET IS PRODUCING MODERATE/STRONG SUBSIDENCE W OF THE GULF OF CALIFORNIA AND CONTINUES TO SUPPORT A BROKEN STRATOCUMULUS FIELD ACROSS THE SUBTROPICAL WATERS. AN AREA OF LOW PRES IS LOCATED N OF THE AREA OFF THE CALIFORNIA COAST NEAR 36N126W AND IS DRIVING NORTHERLY FLOW INTO THE AREA...WHICH IS PUSHING SOME OF THE STRATOCUMULUS WELL S INTO THE TROPICAL REGIONS W OF T.D. THREE-E. ELSEWHERE...AN UPPER LEVEL HIGH IS CENTERED NEAR SOCORRO ISLAND WITH A RIDGE AXIS EXTENDING NE INTO CENTRAL TEXAS. THERE IS ENOUGH LOW-LEVEL MOISTURE OVER THE MEXICAN PLATEAU THAT SCATTERED TSTMS HAVE CONTINUED INTO THE NIGHT PRIMARILY OVER THE SIERRA MADRE OCCIDENTALS. THE LARGEST TSTM CLUSTERS ARE CURRENTLY LOCATED JUST E OF LOS MOCHIS AND NEAR GUADALAJARA. TROPICS... HIGH PRECIPITABLE WATER VALUES HAVE CONTINUED TO CREEP WESTWARD ACROSS THE TROPICAL PACIFIC AND NOW EXTEND AS FAR W AS 130W. GENERAL EASTERLY FLOW ALOFT COVERS THE AREA ALTHOUGH THERE ARE A FEW EMBEDDED DISTURBANCES PROPAGATING TO THE W. IN PARTICULAR...A SHARP UPPER TROUGH OVER THE WESTERN GULF OF MEXICO EXTENDS ACROSS THE GULF OF TEHUANTEPEC AND MESHES WITH AN INVERTED TROUGH ALONG 94W. THIS IS CREATING A GENERAL COL AREA AND IS ALLOWING ENHANCED CONVECTION NEAR A DEVELOPING AREA OF LOW PRES ALONG THE TROPICAL WAVE NEAR 93W. SEE THE SPECIAL FEATURES SECTION FOR ADDITIONAL INFORMATION ON T.S. BORIS AND T.D. THREE-E. $$ BERG