000 AXNT20 KNHC 021142 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT WED AUG 02 2006 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN SECTIONS OF SOUTH AMERICA...AND THE ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR... AND METEOROLOGICAL ANALYSIS. BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1115 UTC. ...SPECIAL FEATURE... TROPICAL STORM CHRIS CONTINUES TO STRENGTHEN THIS MORNING AS IT SKIRTS THE NORTHERNMOST LEEWARD ISLANDS. THE CENTER OF T.S. CHRIS IS LOCATED NEAR 19.0 NORTH 63.0 WEST OR ABOUT 65 NM...NORTH OF ST. MAARTEN AT 02/1200 UTC. CHRIS IS MOVING TOWARD THE WEST-NORTHWEST NEAR 9 KT. ON THIS TRACK...THE CENTER OF CHRIS WILL REMAIN NORTH OF THE VIRGIN ISLANDS AND PUERTO RICO THIS AFTERNOON AND EVENING. HOWEVER...SOME OF THE STRONG RAIN BANDS ON THE SOUTH SIDE OF CHRIS MAY AFFECT PUERTO RICO AND THE VIRGIN ISLANDS LATER TONIGHT AND EARLY THURSDAY MORNING. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1001 MB. THE MAXIMUM SUSTAINED WINDS HAS INCREASED TO 55 KT WITH HIGHER GUSTS. CHRIS IS EXPECTED TO PRODUCE TOTAL RAINFALL ACCUMULATIONS OF 3 TO 5 INCHES OVER THE NORTHERN LEEWARD ISLANDS...THE U.S. VIRGIN ISLANDS...AND PORTIONS OF PUERTO RICO...WITH ISOLATED MAXIMUM AMOUNTS OF 8 INCHES POSSIBLE OVER HIGHER TERRAIN THROUGH THURSDAY. PLEASE REFER TO THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT3/ WTNT23 KNHC AND THE PUBLIC ADVISORY MIATCPAT3/WTNT33 KNHC FOR MORE DETAILS. CONVECTION IS MORE CONSOLIDATED THIS MORNING WITH A CENTRAL DENSE OVERCAST. THUNDERSTORM ACTIVITY IS CURRENTLY CONFINED WITHIN A RADIUS OF ABOUT 100 NMI FROM THE CENTER. NORTHWESTERLY VERTICAL WIND SHEAR HAS WEAKENED TO ABOUT 10 KT ACCORDING TO THE CIMSS ANALYSES AND OUTFLOW IS NOW OBSERVED IN ALL QUADRANTS. DRY MID TO LOW LEVEL AIR...ASSOCIATED WITH A SAHARAN AIR LAYER...IS TO THE NORTH AND WEST OF TROPICAL STORM CHRIS...THOUGH THIS MAY BE TOO FAR FROM THE STORM'S CENTER TO INHIBIT INTENSIFICATION. ...TROPICAL WAVES... A TROPICAL WAVE IN THE EASTERN ATLANTIC ALONG 35W MOVING WEST 15-20 KT. THIS WAVE IS SUPERIMPOSED UPON A STRONG WEST AFRICAN MONSOONAL FLOW ON THE SOUTH SIDE OF THE ITCZ...WITH SURFACE SOUTHWESTERLIES EXTENDING ALL THE WAY TO 42W. ONLY ISOLATED SHOWERS AND TSTMS EXIST FROM 11-15N BETWEEN 30W-40S. MORE EXTENSIVE SHOWERS AND TSTMS ARE EMBEDDED IN THE MONSOONAL FLOW EQUATORWARD OF 10N...WHICH IS DISCUSSED IN THE ITCZ SECTION. A TROPICAL WAVE IS INLAND OVER THE YUCATAN PENINSULA ALONG 93W S OF 20N MOVING W NEAR 10-15 KT. THIS WEAK WAVE WILL LIKELY MOVE W THROUGH THE BAY OF CAMPECHE ON WEDNESDAY. WHILE THE WAVE HAS ONLY A WEAK 700 MB VORTICITY SIGNATURE...THE COMBINATION OF THE WAVE AND A DIVERGENT FLOW ALOFT HAS INITIATED NUMEROUS SHOWERS AND TSTMS OVER THE YUCATAN OF MEXICO...SOUTHEAST MEXICO...AND GUATEMALA. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 7N11W 11N27W 9N38W TO THE SOUTH AMERICAN COAST NEAR 6N 54W. A LINE OF MODERATE CONVECTION IS ALONG THE COAST OF WEST AFRICA FROM 6-15N...WHICH MAY BE IN ASSOCIATION WITH A DEVELOPING TROPICAL WAVE. ADDITIONAL ISOLATED CLUSTERS OF SHOWERS AND TSTMS ARE FOUND SOUTH OF THE ITCZ WITHIN THE SOUTHWESTERLY MONSOONAL FLOW IN A BOX FROM 4N-11N TO 24-40W. ...DISCUSSION... THE GULF OF MEXICO... THE GULF OF MEXICO IS DOMINATED BY EAST-SOUTHEASTERLY FLOW OF 10-20 KT ALONG THE SOUTH SIDE OF A SURFACE RIDGE LOCATED ALONG 30N. MUCH OF THE CENTRAL AND EASTERN GULF HAS A FAIR AMOUNT OF DRY STABLE AIR ALOFT LIMITING ANY SHOWER ACTIVITY TO ISOLATED. AS THE TROPICAL WAVE ALONG 93W MENTIONED EARLIER IS EXTENDING INTO THE GULF...CONVECTION IS BEGINNING TO DEVELOP IN THE BAY OF CAMPECHE. SEE THE TROPICAL WAVES SECTION FOR MORE DETAILS. THE CARIBBEAN SEA... THE MAIN FEATURE IN THE REGION IS TROPICAL STORM CHRIS WHICH IS AFFECTING THE NRN LEEWARD ISLANDS. GUSTY WINDS AND SCATTERED MODERATE CONVECTION IS N OF 17N BETWEEN 60W-64W. FOR MORE DETAILS...REFER TO THE SPECIAL FEATURE SECTION ABOVE. BESIDES FOR T.S. CHRIS THERE IS ONE OTHER AREA OF UNSETTLED WEATHER IN THE CARIBBEAN. SCATTERED MODERATE CONVECTION LIES N OF 18N BETWEEN 77W-84W COVERING PORTIONS OF JAMAICA...THE CAYMAN ISLANDS AND CUBA...MAINLY ASSOCIATED WITH UPPER DIFFLUENT FLOW BETWEEN AN UPPER HIGH CENTERED NEAR THE CAYMAN ISLANDS AND A WELL-DEFINED UPPER LOW E OF THE BAHAMAS NEAR 25N74W. THE REMAINDER OF THE CARIBBEAN HAS A DRY/STABLE UPPER LEVEL ENVIRONMENT UNDER WEAK UPPER RIDGING WITH THE AXIS ALONG 19N/20N E OF 83W. AT THE SURFACE...10 TO 25 KT E TO SE TRADE WINDS ARE DOMINATING ON THE SW SIDE OF THE ATLANTIC HIGH. THE ATLANTIC OCEAN... A HIGH AMPLITUDE UPPER LEVEL PATTERN EXISTS OVER THE NORTH ATLANTIC WITH RIDGING OVER THE SOUTHEAST U.S. AND A STRONG SSW-NNE TILTING TROUGH NEAR 50W THAT EXTENDS TO 20N. THIS UPPER TROUGH IS ASSOCIATED WITH SCATTERED SHOWERS AND TSTMS WITHIN 50 NM OF A LINE EXTENDING FROM 26N54W TO 32N43W. AN UPPER LOW IS LOCATED JUST NORTH OF THE BAHAMAS. THIS UPPER LOW NO LONGER APPEARS TO HAVE A SURFACE REFLECTION. ONLY ISOLATED SHOWERS ARE WITHIN 300 NM OF THE UPPER LOW. LARGE SCALE UPPER RIDGING CONTINUES TO DOMINATE MUCH OF THE CENTRAL AND EASTERN ATLC WATERS ANCHORED FROM ITS HIGH CENTER NEAR 22N36W. PLENTY OF DRY/STABLE AIR ALOFT COVERS THE E ATLC OUT TO 45W. ACCORDING TO THE 09 Z SAHARAN AIR LAYER ANALYSIS FROM UW-CIMSS THE LEADING EDGE OF DENSE DUST STRETCHES TO 43W MAINLY N OF 15N. AT THE SURFACE...HIGH PRESSURE IS DOMINATING MUCH OF THE TROPICAL ATLANTIC WATERS ON THE SOUTH AND WEST PORTION OF ITS 1031 MB HIGH OVER THE AZORES AND A 1022 MB HIGH IN THE CENTRAL ATLC NEAR 25N53W. THE OTHER SURFACE FEATURES NOTED ARE T.S CHRIS AFFECTING THE NRN LEEWARD ISLANDS AND THE BROAD TROPICAL WAVE ALONG 35W...SEE MORE INFO ON THESE FEATURES ABOVE. $$ LANDSEA