000 AXNT20 KNHC 130552 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT THU SEP 13 2007 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN 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...METEOROLOGICAL ANALYSIS... WEATHER OBSERVATIONS...AND RADAR. BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...SPECIAL FEATURES... HUMBERTO HAS BEEN UPGRADED TO A HURRICANE. AT 13/0515 UTC...THE CENTER OF HURRICANE HUMBERTO WAS LOCATED NEAR 29.4N 94.4W OR ABOUT 17 NM EAST OF GALVESTON TEXAS...AND ABOUT 13 NM SOUTH OF HIGH ISLAND TEXAS MOVING NNE AT 7 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 992 MB. MAXIMUM SUSTAINED WIND SPEED IS 70 KT WITH GUSTS TO 85 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS. DOPPLER RADAR DATA HAS DISPLAYED AN IMPROVED STRUCTURE WITH AN EYE-LIKE FEATURE AND WELL DEFINED BANDING N OF THE CENTER EVIDENT. BASED ON THIS DATA...SOME OF THE HEAVIEST RAINS AND STRONGEST WINDS WILL BEGIN TO IMPACT THE COASTLINE SHORTLY. TOTAL RAINFALL AMOUNTS OF 5 TO 10 INCHES ARE EXPECTED ALONG THE TRACK OF HUMBERTO THROUGH EASTERN TEXAS AS WELL AS WESTERN AND CENTRAL LOUISIANA...WITH ISOLATED MAXIMUM ACCUMULATIONS OF 15 INCHES POSSIBLE. TROPICAL DEPRESSION EIGHT IS CENTERED NEAR 13.4N 46.4W AT 13/0300 UTC OR ABOUT 875 NM EAST OF THE LESSER ANTILLES MOVING WEST NEAR 10 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1006 MB. MAXIMUM SUSTAINED WIND SPEED IS 30 KT WITH GUSTS TO 40 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT3/WTNT23 KNHC FOR MORE DETAILS. THIS DEPRESSION HAS GENERALLY CHANGED LITTLE THROUGHOUT THE EVENING HOURS WITH THE LOW-LEVEL CENTER LOCATED TO THE E OF A PERSISTENT AREA OF MODERATE CONVECTION WHICH EXTENDS ROUGHLY 120 NM W OF THE CENTER. SOME STRENGTHENING IS EXPECTED IN THE SHORT TERM AS THE NELY SHEAR IS EXPECTED TO RELAX SLIGHTLY. ...TROPICAL WAVES... A HIGH AMPLITUDE TROPICAL WAVE IS IN THE E ATLC ALONG 37W S OF 24N MOVING W 15 KT. IN GENERAL...THIS WAVE HAS CHANGED LITTLE OVER THE PAST COUPLE OF DAYS. THE STRUCTURE REMAINS WELL DEFINED WITH A LARGE SHIELD OF CYCLONIC TURNING NOTED IN THE LOW TO MID LEVEL CLOUD FIELD. IN ADDITION...THE UW-CIMSS TPW ANIMATION REVEALS A LARGE WWD PROPAGATING SURGE OF MOISTENED AIR. DESPITE THE FAIR STRUCTURE...DEEP MOISTURE IS SPARSE WITH WIDELY SCATTERED MODERATE CONVECTION WITHIN 180 NM OF THE AXIS. MORE ORGANIZED ACTIVITY IS SITUATED AT THE BASE OF THE WAVE WITHIN THE ITCZ. TROPICAL WAVE IS IN THE CENTRAL CARIBBEAN ALONG 77W S OF 23N MOVING W 15-20 KT. A SURGE OF MOISTURE ASSOCIATED WITH THIS FEATURE IS STILL WELL DEFINED ON THE TPW ANIMATION FROM CIMSS...WHICH WAS THE PRIMARY TOOL USED TO TRACK THIS WAVE AS LITTLE SIGNATURE IS APPARENT IN CONVENTIONAL SATELLITE IMAGERY. THE INTERACTION WITH AN UPPER LOW CENTERED JUST S OF CENTRAL CUBA IS SUPPORTING SCATTERED SHOWERS AND TSTMS OVER CUBA AND A PORTION OF THE NW CARIB N OF 19N W OF 78W. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 14N18W 11N25W 15N36W 14N45W 9N61W. SCATTERED MODERATE CONVECTION IS LOCATED FROM 12N-15N E OF 22W ASSOCIATED WITH THE NEXT TROPICAL WAVE...WHICH WILL LIKELY BE ADDED TO THE 06Z SYNOPTIC MAP. SIMILAR ACTIVITY IS FROM 6N-8N BETWEEN 33W-37W AND S OF THE DEPRESSION FROM 11N-13N BETWEEN 40W-45W. DISCUSSION... THE GULF OF MEXICO... NEWLY UPGRADED HURRICANE HUMBERTO IS THE HIGHLIGHT IN THE GULF OF MEXICO AS IT APPROACHES LANDFALL ON THE GULF COAST. FOR DETAILS REFER TO THE SPECIAL FEATURE SECTION ABOVE. THE REMAINDER OF THE REGION REMAINS EMBEDDED IN A MOIST ENVIRONMENT AS INDICATED BY WATER VAPOR IMAGERY AND THE CIMSS TPW ANIMATION. THE UPPER FEATURES MAINTAINING THIS WIDESPREAD HIGH LEVEL MOISTURE PLUME CONSIST OF AN ELONGATED UPPER HIGH OVER THE NW GULF AND AN UPPER LOW JUST S OF CUBA. IR IMAGERY...BEFORE THE ECLIPSE...SHOWS ONLY SPOTS OF PRECIP. ONE SOMEWHAT PERSISTENT AREA...ALSO EVIDENT ON MOSAIC RADAR IMAGERY...IS OVER THE SE GULF ROUGHLY S OF 27N BETWEEN 83W-85W. WEAKENING POCKETS OF SCATTERED MODERATE CONVECTION ARE OVER THE W YUCATAN AND ERN BAY OF CAMPECHE WHERE DIFFLUENCE ALOFT IS MORE PRONOUNCED. ISOLATED SHOWERS ARE POSSIBLE JUST ABOUT ANYWHERE ELSE IN THE REGION. THE CARIBBEAN SEA... A BROAD UPPER LOW HAS BEEN DRIFTING WWD OVER THE PAST 24 HOURS CENTERED S OF CENTRAL CUBA NEAR 21N79W. DIFFLUENCE ALOFT TO THE S OF THE UPPER LOW COUPLED WITH THE ITCZ IS ENHANCING CLUSTERS OF SCATTERED MODERATE CONVECTION OVER THE SW CARIBBEAN AND PORTIONS OF COSTA RICA...PANAMA AND NICARAGUA ROUGHLY S OF 13N W OF 80W. THE INTERACTION BETWEEN A WEAK TROPICAL WAVE AND THE UPPER LOW IS PRODUCING SOME SHOWER ACTIVITY ACROSS THE NW CARIB...FOR DETAILS SEE ABOVE. THE ERN CARIB IS EXPERIENCING MOSTLY FAIR WEATHER AS DRIER AIR FROM THE TROPICAL ATLC HAS BEEN ADVECTED INTO THE AREA AROUND AN UPPER HIGH. MODERATE TO STRONG TRADE WINDS ARE BLOWING ACROSS THE REGION...STRONGEST BETWEEN COLOMBIA AND HISPANIOLA WHERE QSCAT DEPICTED A SOLID AREA OF 20-25 KT WINDS. THE ATLANTIC OCEAN... TROPICAL DEPRESSION EIGHT IS THE MAIN FEATURE OF INTEREST ACROSS THE TROPICAL AND SUBTROPICAL ATLC DISCUSSION ZONE. FOR DETAILS AND REFERENCES REFER TO THE SPECIAL FEATURE SECTION ABOVE. OTHERWISE...THE ATLC BASIN IS FAIRLY QUIET THIS MORNING. THE SFC PATTERN HAS GENERALLY CHANGED LITTLE OVER THE PAST COUPLE OF DAYS. A PAIR OF 1022 MB HIGHS ARE ANALYZED JUST N OF THE REGION IN THE CENTRAL AND W ATLC NEAR 33N62W AND 37N48W. ANOTHER 1022 MB HIGH IS CENTERED IN THE E ATLC NEAR 33N25W. A SLIGHT WEAKNESS IN THE SUBTROPICAL RIDGING LIES BETWEEN 35W-45W ASSOCIATED WITH A TROUGH OF LOW PRES IN THE N CENTRAL ATLC. THIS WEAKNESS HAS ALLOWED WINDS TO BE FAIRLY LIGHTER IN THAT VICINITY...WITH MODERATE TRADES OBSERVED ELSEWHERE. ALOFT...A COMPLEX PATTERN IS IN PLACE ACROSS THE SW ATLC. THE CONTRIBUTING LARGE SCALE FEATURES CONSIST OF A WESTWARD MOVING UPPER LOW CENTERED JUST S OF CENTRAL CUBA...THE ERN PERIPHERY OF THE GULF RIDGE AND ANOTHER UPPER LOW CENTERED NEAR 28N63W. THE LATTER UPPER LOW ACTUALLY BECAME CUT OFF FROM THE TAIL END OF THE EXTENSIVE TROUGHING COVERING THE CENTRAL ATLC N OF OF 20N BETWEEN 32W-54W...ASSOCIATED WITH AFOREMENTIONED TROUGH OF LOW PRES IN THE N CENTRAL ATLC. THIS PATTERN IS ONLY GENERATING A SHIELD OF MID TO HIGH LEVEL CLOUDINESS AND ISOLATED SHOWERS W OF 70W AND N OF 25N BETWEEN 37W-47W. MUCH OF THE REMAINDER OF THE AREA IS DOMINATED BY AN E-W RIDGE COVERING THE AREA FROM THE LESSER ANTILLES EWD WITH A MEAN AXIS ALONG 18N WITH SEVERAL EMBEDDED ANTICYCLONES. THIS RIDGE AND A CONFLUENT PATTERN...TO THE S OF A LARGE UPPER LOW NEAR SRN PORTUGAL...IS KEEPING WEATHER CONDITIONS FAIRLY TRANQUIL. $$ CANGIALOSI