000 AXNT20 KNHC 131759 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT FRI SEP 13 2013 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF SOUTH AMERICA...AND 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...SPECIAL FEATURES... FORMER TROPICAL DEPRESSION TEN IN THE BAY OF CAMPECHE HAS INTENSIFIED THUS BECOMING THE NINTH TROPICAL STORM OF THE SEASON NAMED INGRID. THE CENTER OF TROPICAL STORM INGRID IS NEAR 19.4N 95.3W AT 13/1500 UTC OR ABOUT 50 NM ENE OF VERACRUZ MEXICO MOVING W AT 2 KT. ITS ESTIMATED MINIMUM CENTRAL PRESSURE IS 1000 MB. MAXIMUM SUSTAINED WIND SPEED IS 40 KT WITH GUSTS TO 50 KT. A BIG CLUSTER OF MODERATE/ISOLATED STRONG CONVECTION IS OVER THE BAY OF CAMPECHE FROM 18N-22N BETWEEN 91W-95W. SCATTERED MODERATE CONVECTION AND TSTMS ARE IN THE WESTERN GULF FROM 18N-27N W OF 90W AS WELL AS IN THE SE BASIN S OF 26N E OF 90W. THE STORM IS EXPECTED TO PRODUCE 10 TO 15 INCHES OF RAIN OVER A LARGE PART OF EASTERN MEXICO...WITH ISOLATED AMOUNTS OF 25 INCHES POSSIBLE...ESPECIALLY IN AREAS OF MOUNTAINOUS TERRAIN. THESE RAINS ARE LIKELY TO RESULT IN LIFE-THREATENING FLASH FLOODS AND MUD SLIDES. SEE LATEST NHC INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT5/WTNT35 KNHC AND THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT5/WTNT25 KNHC FOR MORE DETAILS. FORMER HURRICANE HUMBERTO WEAKENED INTO A TROPICAL STORM AT 13/1200 UTC. THE TROPICAL STORM CENTER IS NEAR 24.7N 31.3W AT 13/1500 UTC OR ABOUT 665 NM NW OF THE CAPE VERDE ISLANDS MOVING W-NW AT 9 KT. ITS ESTIMATED MINIMUM CENTRAL PRESSURE IS 991 MB. MAXIMUM SUSTAINED WIND SPEED IS 60 KT WITH GUSTS TO 75 KT. SCATTERED MODERATE CONVECTION IS TO THE NE OF THE LOW CENTER FROM 22N-28N BETWEEN 25W-30W. SEE LATEST NHC INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT4/WTNT34 KNHC AND THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS. TROPICAL DEPRESSION GABRIELLE IS NEAR 39.1N 66.5W AT 13/1500 UTC OR ABOUT 211 NM SE OF NANTUCKET MASSACHUSETTS MOVING NNE AT 20 KT. ITS ESTIMATED MINIMUM CENTRAL PRESSURE IS 1007 MB. MAXIMUM SUSTAINED WIND SPEED IS 30 KT WITH GUSTS TO 40 KT. NUMEROUS MODERATE CONVECTION WITH ISOLATED TSTMS IS N OF 39N BETWEEN 61W- 67W. SCATTERED MODERATE CONVECTION AND TSTMS ARE FROM 35N-39N BETWEEN 63W-66W AS WELL AS FROM 35N-38N BETWEEN 70W-73W. SEE LATEST NHC INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT2/WTNT32 KNHC AND THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... A TROPICAL WAVE HAS COME OFF THE WEST AFRICAN COAST EXTENDING AN AXIS FROM 15N17W TO 07N15W. TOTAL PRECIPITABLE WATER IMAGERY INDICATE THE WAVE IS MOSTLY WITHIN A MODERATE MOIST ENVIRONMENT WHILE THE METEOSAT PSEUDO NATURAL COLOR IMAGERY DEPICT THE WAVE IS EMBEDDED WITHIN A DUST AIRMASS COVERING THE E ATLC E OF 25W. SCATTERED MODERATE CONVECTION IS FROM 06N-13N E OF 20W. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL ATLC NEAR 10N15W AND CONTINUES ALONG 07N25W TO 11N36W. THE ITCZ AXIS EXTENDS ALONG 11N37W TO 10N45W TO 11N50W. BESIDES THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVE ALREADY DISCUSSED...WIDELY SCATTERED MODERATE CONVECTION IS FROM 02N-09N BETWEEN 20W-30W. ISOLATED SHOWERS ARE WITHIN 200 NM S OF THE ITCZ BETWEEN 45W-51W AND WITHIN 140 NM N OF THE AXIS BETWEEN 46W- 49W. ...DISCUSSION... GULF OF MEXICO... A MIDDLE-LEVEL LOW CENTERED IN THE BAY OF CAMPECHE NEAR 20N94W SUPPORTS THE CLUSTER OF MODERATE/ISOLATED STRONG CONVECTION ASSOCIATED WITH TROPICAL STORM INGRID WHICH FORMED AT 13/1500 UTC. IN THE UPPER-LEVEL...AN ELONGATED LOW IS NOW CENTERED OVER NE MEXICO NEAR 24N99W WHILE A RIDGE DOMINATES THE REMAINDER BASIN S OF 28N E OF 96W. THIS UPPER-LEVEL PATTERN IS GENERATING DIFFLUENT FLOW ALOFT TO SUPPORT THE REMAINDER CONVECTION IN THE GULF ASSOCIATED WITH TROPICAL STORM INGRID. FOR MORE INFORMATION ABOUT THE NINTH TROPICAL STORM OF THE SEASON/INGRID SEE THE SECTION OF SPECIAL FEATURES ABOVE. LOWER TO MIDDLE LEVEL DRY AIR IN THE NE GULF SUPPORTS FAIR WEATHER THIS AFTERNOON. INGRID WILL BE MOVING VERY CLOSE TO THE COAST OF MEXICO DURING THE NEXT COUPLE OF DAYS. CARIBBEAN SEA... THE BROAD UPPER-LEVEL RIDGE ASSOCIATED WITH TROPICAL STORM INGRID IN THE SW GULF OF MEXICO COVERS ALSO THE NW CARIBBEAN W OF 80W. THIS UPPER-LEVEL RIDGE ALONG WITH FLOW AROUND A MIDDLE- LEVEL ELONGATED LOW THAT EXTENDS FROM THE YUCATAN PENINSULA TO THE E PACIFIC HAS BEEN ADVECTING VERY MOIST AIR INTO THE NW CARIBBEAN SEA WHERE MIDDLE TO UPPER LEVEL DIFFLUENCE ENHANCES SCATTERED MODERATE CONVECTION N OF 16N W OF 81W. AN UPPER-LEVEL LOW CONTINUES CENTERED IN THE CENTRAL CARIBBEAN NEAR 14N74W BUT ITS CIRCULATION EXTENDS TO 66W IN THE EASTERN CARIBBEAN. THIS UPPER LOW IS ENHANCING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 17N BETWEEN 69W-75W. UPPER-LEVEL DIFFLUENCE GENERATED BY A WEAK RIDGE THAT COVERS THE REMAINDER E CARIBBEAN IS GENERATING SIMILAR CONVECTION S OF 13N E OF 66W...INCLUDING THE WINDWARD ISLANDS. A WEAK 1007 MB LOW PRESSURE CENTER IS TO THE EAST OF THE LEEWARD ISLANDS THIS AFTERNOON. THIS LOW IS EXPECTED TO DISSIPATE WITHIN THE NEXT 24 HOURS AS IT DRIFTS SW TOWARDS THE EASTERN CARIBBEAN. RAINSHOWERS SHOULD BE EXPECTED FOR THE LESSER ANTILLES WITHIN THAT PERIOD. GENTLE WINDS AND SUBSIDING SEAS WILL PREVAIL ACROSS MOST OF THE CARIBBEAN EXCEPT THE GULF OF HONDURAS THROUGH SAT NIGHT. WINDS WILL INCREASE IN THE CENTRAL CARIBBEAN SUN AND MON AS HIGH PRESSURE BUILDS ACROSS THE W ATLC. HISPANIOLA... ISOLATED SHOWERS/TSTMS ARE ACROSS HISPANIOLA THIS AFTERNOON ASSOCIATED WITH THE UPPER-LEVEL LOW DISCUSSED ABOVE WHICH IS CENTERED SOUTH OF THE ISLAND. THE UPPER LOW OVER THE CENTRAL CARIBBEAN WILL CONTINUE TO SHIFT W BRINGING MORE SOUTHERLY SURFACE FLOW ACROSS THE ISLAND. THIS UPPER FLOW WILL REMAIN IN PLACE THROUGH THE FIRST OF NEXT WEEK. AFTERNOON HEATING WILL BRING THE POTENTIAL SCATTERED THUNDERSTORMS ACROSS THE ISLAND THROUGH THE WEEKEND. ATLANTIC OCEAN... THE PRIMARY CONCERN FOR THE ATLC BASIN S OF 30N IS TROPICAL STORM HUMBERTO. FOR MORE INFORMATION ABOUT IT SEE SPECIAL FEATURES ABOVE. AN UPPER-LEVEL LOW IS IN THE W/CENTRAL ATLC NEAR 26N58W SUPPORTING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 25N-30N BETWEEN 56W-59W. A WEAK 1007 MB LOW PRESSURE CENTER IS TO THE EAST OF THE LEEWARD ISLANDS NEAR 17N56W. THIS LOW IS EXPECTED TO DISSIPATE WITHIN THE NEXT 24 HOURS AS IT DRIFTS SW TOWARDS THE EASTERN CARIBBEAN. ISOLATED SHOWERS ARE IN THE VICINITY OF THIS LOW FROM 13N-20N BETWEEN 50W-57W. A NEW TROPICAL WAVE HAS EMERGED FROM THE W COAST OF AFRICA AND IS DISCUSSED IN THE TROPICAL WAVES SECTION ABOVE. WEAK PRESSURE PATTERN AND LIGHT WINDS COVER THE W ATLC AND WILL CONTINUE THROUGH MON. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ RAMOS