000 AXNT20 KNHC 131744 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT WED MAY 13 2015 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... A TIGHT PRESSURE GRADIENT BETWEEN HIGH PRESSURE ACROSS THE CENTRAL ATLC AND LOWER PRESSURE ACROSS NORTHWESTERN SOUTH AMERICA IS GENERATING NEAR GALE TO GALE FORCE WINDS WITHIN CLOSE PROXIMITY TO THE COAST OF COLOMBIA. THESE CONDITIONS ARE FORECAST TO CONTINUE THROUGH THURSDAY MORNING. SEE LATEST NWS HIGH SEAS FORECAST UNDER WMO/AWIPS HEADERS MIAHSFAT2/FZNT02 KNHC FOR MORE DETAILS. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 09N13W TO 05N22W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 05N22W TO 06N30W TO 04N42W TO THE EQUATOR NEAR 51W. SCATTERED MODERATE CONVECTION IS FROM THE EQUATOR TO 02N BETWEEN 03W- 12W...AND FROM 03N-08N BETWEEN 13W-34W. ...DISCUSSION... GULF OF MEXICO... A MID-LEVEL SHORTWAVE TROUGH IS NOTED ON WATER VAPOR IMAGERY OVER SOUTHERN TEXAS WITH THE PARENT UPPER LEVEL TROUGH TO THE NW OVER NEW MEXICO AND WEST TEXAS. THE TROUGHING SUPPORTS A STATIONARY FRONT EXTENDING FROM ACROSS THE NEW ORLEANS LOUISIANA AREA WESTWARD ALONG THE GULF COAST TO GALVESTON BAY THEN INLAND ACROSS SE TEXAS TO THE RIO GRANDE RIVER NEAR 29N101W. GIVEN AN OVERALL DIFFLUENT ENVIRONMENT ALOFT OVER THE WESTERN GULF AND SOUTHERN U.S. PLAINS...AND MOIST CONVERGENT SOUTHEASTERLY SURFACE FLOW TO THE SOUTH OF THE FRONTAL BOUNDARY...SCATTERED SHOWERS AND TSTMS ARE OCCURRING WEST OF A LINE FROM 30N92W TO 21N97W...INCLUDING INLAND PORTIONS OF TEXAS AND WESTERN LOUISIANA. TO THE SOUTH ACROSS THE SW GULF...A SURFACE TROUGH IS ANALYZED FROM THE MEXICO COAST NEAR 18N94W TO 23N95W AND IS PROVIDING FOCUS FOR SCATTERED SHOWERS AND TSTMS S OF 21N BETWEEN 94W-96W. OTHERWISE...AN UPPER LEVEL RIDGE AXIS EXTENDING FROM 20N94W TO 29N91W INFLUENCES THE REMAINDER OF THE GULF. NORTHERLY FLOW ALOFT ON THE EASTERN PERIPHERY OF THE UPPER LEVEL RIDGE IS PROVIDING OVERALL STABLE CONDITIONS AT THE SURFACE. HOWEVER... THE SOUTHERN EXTENT OF A SW NORTH ATLC COLD FRONT EXTENDS ACROSS THE FLORIDA PANHANDLE TO NEAR 29N90W WITH POSSIBLE ISOLATED SHOWERS OCCURRING WITHIN 90 NM EITHER SIDE OF THE BOUNDARY. GENTLE TO MODERATE E-SE WINDS ARE EXPECTED TO PREVAIL ACROSS THE GULF INTO THURSDAY AS THE FRONTAL BOUNDARY GRADUALLY SHIFTS NORTH OF THE GULF COAST OVERNIGHT. A SURFACE RIDGE IS THEN EXPECTED RE-ESTABLISH FOR THE UPCOMING WEEKEND. CARIBBEAN SEA... ASIDE FROM NEAR GALE TO GALE FORCE CONDITIONS OCCURRING ACROSS PORTIONS OF THE SW CARIBBEAN OFF THE COAST OF COLOMBIA...BROAD UPPER LEVEL TROUGHING IS NOTED ON WATER VAPOR IMAGERY OVER THE SW NORTH ATLC THAT STRETCHES W-SW OVER NW CARIBBEAN WITH WEST- SOUTHWESTERLY FLOW PREVAILING TO THE EAST OF 80W OVER THE CENTRAL AND EASTERN CARIBBEAN. OTHERWISE...THE STRONG TRADE WINDS ARE THE MAIN IMPACT GENERATED BY A STRENGTHENED PRESSURE GRADIENT BETWEEN A 1028 MB SUBTROPICAL HIGH CENTERED NEAR 30N50W AND LOWER PRESSURE ACROSS NORTHWESTERN SOUTH AMERICA ANCHORED BY A 1006 MB LOW CENTERED NEAR 10N76W. THE PRESSURE GRADIENT IS FORECAST TO RELAX SOMEWHAT BY FRIDAY AS FRONTAL TROUGHING MOVES ACROSS THE SW NORTH ATLC REGION TO THE N-NE OF THE BASIN. ...HISPANIOLA... CURRENTLY...RELATIVELY CLEAR SKIES PREVAIL ACROSS THE ISLAND THIS AFTERNOON...HOWEVER A BROAD UPPER LEVEL TROUGH IS NOTED ON WATER VAPOR IMAGERY OVER THE SW NORTH ATLC AND NW CARIBBEAN WITH AXIS FROM 28N65W TO 20N81W PROVIDING FOR MARGINALLY DIFFLUENT CONDITIONS ALOFT. ISOLATED SHOWERS ARE POSSIBLE DURING THE AFTERNOON AND EVENING HOURS GIVEN PEAK DAYTIME HEATING AND INSTABILITY. ATLANTIC OCEAN... UPPER LEVEL TROUGHING EXTENDS FROM OVER THE NE CONUS TO THE SE CONUS SUPPORTING A COLD FRONT EXTENDING FROM OFFSHORE OF THE CAROLINAS NEAR 35N76W SW TO THE SOUTH CAROLINA/GEORGIA BORDER NEAR 32N81W. THE FRONT WILL CONTINUE TO MOVE INTO THE SW NORTH ATLC DISCUSSION AREA THROUGH THURSDAY SKIRTING ALONG 30N WHILE MOVING EASTWARD AND GRADUALLY WEAKENING. ISOLATED SHOWERS AND TSTMS ARE OCCURRING WITHIN 90 NM EITHER SIDE OF THE BOUNDARY. FARTHER EAST...AN UPPER LOW IS CENTERED NEAR 31N60W THAT ANCHORS BROAD UPPER LEVEL TROUGHING WITH AXIS EXTENDING FROM THE LOW CENTER SW TO A BASE OVER THE NW CARIBBEAN SEA NEAR 20N80W. THE TROUGHING SUPPORTS ISOLATED SHOWERS AND TSTMS OCCURRING FROM 22N- 27N BETWEEN 63W-68W. OTHERWISE...THE REMAINDER OF THE CENTRAL AND EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1028 MB HIGH CENTERED NEAR 30N51W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN