000 AXNT20 KNHC 172346 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SUN JUN 17 2012 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2100 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 17N41W TO 8N42W MOVG W AT 10-15 KT. THE WAVE LIES ON THE WRN LEADING EDGE OF A SURGE IN DEEP LAYER MOISTURE PRESENT IN TOTAL PRECIPITABLE WATER IMAGERY. NO DEEP CONVECTION IS CURRENTLY ASSOCIATED WITH THE WAVE. THIS MAY BE DUE TO A LARGE AREA OF SAHARAN DUST THAT EXTENDS E OF THE WAVE TO THE AFRICAN COAST. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS W AFRICA TO THE COAST OF SENEGAL AT 13N17W TO 9N25W. THE ITCZ CONTINUES AT 9N25W ALONG 7N32W 9N41W 6N53W. CONVECTION ALONG THE AXIS IS LIMITED DUE TO A LARGE AREA OF SAHARAN DUST EXTENDING FROM THE COAST OF AFRICA TO THE TROPICAL WAVE. ONLY A SMALL AREA OF MODERATE CONVECTION IS NOTED ALONG THE AXIS BETWEEN 30W-37W. ...DISCUSSION... GULF OF MEXICO... A SURFACE TROUGH CONTINUES TO IMPACT THE NRN GULF OF MEXICO ALONG 30N91W TO 26N97W PRODUCING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 24N-31N BETWEEN 86W-91W. THE SURFACE TROUGH IS SUPPORTED BY A SHORTWAVE UPPER TROUGH THAT EXTENDS FROM LOUISIANA TO THE YUCATAN CHANNEL. UPPER LEVEL RIDGING IS TO EITHER SIDE OF THE SHORTWAVE TROUGH ACCOMPANIED BY DRY AIR ALOFT. THIS DRY AIR IS HELPING PROVIDE FAIR CONDITIONS ACROSS THE FLORIDA PENINSULA AND THE NW GULF. WEAK SURFACE RIDGING ALSO EXTENDS INTO THE NE GULF FROM A HIGH CENTER OVER NRN GEORGIA. THE SW GULF IS HIT BY MOISTURE STREAMING AROUND THE E PACIFIC MONSOON TROUGH...WHICH HAS SHIFTED TO THE N OVER THE PAST COUPLE OF DAYS. THIS IS CAUSING WIDESPREAD SHOWERS/THUNDERSTORMS ACROSS CENTRAL AMERICA...SRN MEXICO...AND THE YUCATAN PENINSULA. SOME OF THE ACTIVITY EXTENDS OVER THE SW GULF S OF 20N. EXPECT MOIST CONDITIONS TO REMAIN OVER THE SRN GULF FOR THE NEXT SEVERAL DAYS AS A SURFACE TROUGH CURRENTLY IN THE WRN CARIBBEAN DRIFTS NW THROUGH THE MIDDLE OF THE WEEK. FLOODING AND MUDSLIDES WILL BE POSSIBLE IN AREAS ACROSS CENTRAL AMERICA AND MEXICO THAT HAVE ALREADY RECEIVED LARGE AMOUNTS OF RAIN...ESPECIALLY OVER MOUNTAINOUS TERRAIN. THE SURFACE TROUGH CURRENTLY IN THE N CENTRAL GULF WILL CONTINUE TO MOVE WNW INTO TEXAS WITH SHOWERS LIKELY IN CLOSE PROXIMITY TO THE AXIS. CARIBBEAN SEA... BROAD CYCLONIC SURFACE FLOW ALONG WITH A LARGE AREA OF SHOWERS/THUNDERSTORMS COVER PORTIONS OF THE CENTRAL AND WRN CARIBBEAN. CURRENTLY A LARGE CLUSTER OF STRONG SHOWERS/THUNDERSTORMS IS APPROACHING HISPANIOLA FROM 14N-18N BETWEEN 67W-72W. A CLUSTER OF SIMILAR ACTIVITY IS NOW MOVING N OF PUERTO RICO LEAVING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ACROSS THE ISLAND. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITH SOME CLUSTERS OF STRONG SHOWERS COVER THE AREA FROM 13N-20N BETWEEN 72W-89W INCLUDING MUCH OF CENTRAL AMERICA. CLUSTERS OF SHOWERS/THUNDERSTORMS ARE ALSO ACROSS CUBA. SOME OF THIS ACTIVITY IS ATTRIBUTED TO A BROAD SURFACE TROUGH ALONG 19N80W TO A 1008 MB LOW NEAR 14N82W...AS OF 2100 UTC. TROUGHING ALSO EXTENDS TOWARDS THE NE INTO THE W ATLC. ACTIVITY ACROSS CENTRAL AMERICA IS ALSO ENHANCED BY A PORTION OF THE E PACIFIC MONSOON TROUGH THAT EXTENDS FROM SRN MEXICO THROUGH MOST OF CENTRAL AMERICA. THE FAR ERN CARIBBEAN IS THE ONLY PORTION OF THE BASIN THAT IS UNDER MOSTLY FAIR CONDITIONS WITH REPORTS OF DUST. ALOFT...MAINLY ZONAL WLY FLOW COVERS THE BASIN WRAPPING AROUND A HORIZONTALLY ALIGNED UPPER RIDGE THAT EXTENDS FROM CENTRAL MEXICO ACROSS NRN CENTRAL AMERICA TO THE NE CARIBBEAN WHERE IT CONTINUES INTO THE ATLC. EXPECT THE BROAD AREA OF SURFACE TROUGHING TO MOVE SLOWLY TOWARDS THE NW. THIS MEANS THAT MOIST CONDITIONS WILL REMAIN ACROSS MUCH OF THE CENTRAL AND WRN CARIBBEAN. FLOODING AND MUDSLIDES ARE POSSIBLE IN AREAS THAT HAVE ALREADY RECEIVED LARGE AMOUNTS OF RAIN...ESPECIALLY ACROSS MOUNTAINOUS TERRAIN. ATLANTIC OCEAN... A LARGE UPPER LEVEL LOW CENTERED NEAR 33N68W IS IMPACTING THE WRN ATLC. THE UPPER LOW SUPPORTS A 1005 MB SURFACE LOW NEAR 32N64W. A SURFACE TROUGH EXTENDS FROM THE LOW CENTER TO THE WINDWARD PASSAGE IN THE CARIBBEAN. SHOWERS/THUNDERSTORMS EXTEND UP TO 525 NM E OF THE AXIS WITH ONLY A SMALL AREA OF SHOWERS/THUNDERSTORMS W OF THE AXIS FROM 25N-28N. A SURFACE RIDGE IS BUILDING IN BEHIND THE TROUGH PROVIDING FAIR CONDITIONS W OF THE TROUGH AXIS. ACROSS THE CENTRAL ATLC...A SHORTWAVE UPPER RIDGE...TROUGH...RIDGE PATTERN IS PRESENT WITH AN UPPER RIDGE AXIS ALONG 56W AND 46W WITH AN UPPER TROUGH BETWEEN THE TWO. ACROSS THE ERN ATLC...AN UPPER LEVEL RIDGE IS CENTERED NEAR 30N376W SUPPORTING A 1026 MB SURFACE HIGH NEAR 31N29W...WHICH IS PROVIDING FAIR CONDITIONS ACROSS THE REMAINDER OF THE BASIN. AN UPPER LEVEL LOW IS S OF THE UPPER RIDGE CENTERED NEAR 18N38W...BUT IS NOT CAUSING ANY SIGNIFICANT WEATHER. AN UPPER LEVEL RIDGE COVERS THE FAR ERN ATLC CENTERED OVER W AFRICA NEAR 20N15W. THE LAST VISIBLE SATELLITE IMAGERY OF THE DAY ALONG WITH GOES-R IMAGERY ENHANCEMENTS INDICATE THAT A LARGE AREA OF SAHARAN DUST EXTENDS FROM THE COAST OF AFRICA TO NEAR 45W...CLEARING SOMEWHAT AROUND THE TROPICAL WAVE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON