000 AXNT20 KNHC 200004 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT THU MAR 19 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 06N10W TO THE EQUATOR AT 24W. SCATTERED STRONG CONVECTION IS WITHIN 60 NM OF THE TROUGH BETWEEN 14W-16W. ...DISCUSSION... GULF OF MEXICO... ALOFT...BROAD RIDGING PREVAILS OVER THE GULF WHILE A MID-LEVEL SHORTWAVE TROUGH EXITS THE SE GEORGIA AND NE FLORIDA COASTS. A MEAN RIDGE AXIS EXTENDS FROM A MID/UPPER LEVEL ANTICYCLONE OVER NORTHERN HONDURAS NW TO 22N91W...AND N TO INLAND LOUISIANA. THE RIDGE IS PROVIDING AMPLE SUBSIDENCE IN THE UPPER LEVELS. THIS IS MAINTAINING A RATHER DRY AND STABLE AIRMASS THROUGHOUT. SATELLITE IMAGERY SHOWS SCATTERED TO BROKEN HIGH CLOUDS STREAMING NNE ACROSS THE BAY OF CAMPECHE AND THE SOUTHERN PORTION OF THE CENTRAL GULF ATTRIBUTED TO A SW JET STREAM BRANCH THAT REACHES INTO THE SW GULF FROM THE EASTERN PACIFIC. THE RIDGE IS FORECAST TO BEGIN TO WEAKEN ON FRI AS A STRONG UPPER TROUGH GRADUALLY APPROACHES FROM THE W. THE ATMOSPHERE THEN DESTABILIZES FURTHER ON SAT MAINLY OVER THE WESTERN PORTION AS THE TROUGH APPROACHES PROVIDING LIFT TO LOW-LEVEL MOISTURE ALREADY IN PLACE THERE. SURFACE... LATEST SURFACE OBSERVATIONS AND GOES-R PROVING GROUND LOW STRATUS/FOG IFR ANIMATION SHOWS PATCHES OF STRATUS AND POSSIBLE FOG OVER PORTIONS OF THE NW AND N AND NE GULF AREAS. WITH RELATIVELY LIGHT WINDS IN PLACE...AND MOIST AIR AT THE LOW LEVELS THE FOG IS EXPECTED TO BECOME DENSE TONIGHT WITH REDUCED VISIBILITIES...LASTING INTO FRI MORNING. THE SURFACE ANALYSIS DEPICTS GENERALLY WEAK HIGH PRES ACROSS THE BASIN. THIS IS ALLOWING FOR SLIGHT TO GENTLE BREEZE CONDITIONS THROUGHOUT. THE WEAK HIGH PRES IS FORECAST TO REMAIN IN PLACE ACROSS THE E GULF AND EASTERN PART OF THE CENTRAL GULF THROUGH THE NEXT COUPLE OF DAYS. A WEAK COLD FRONT IS FORECAST TO ENTER THE NW GULF EARLY ON SUN. CARIBBEAN SEA... THE E PORTION OF THE MID/UPPER RIDGE DESCRIBED UNDER GULF OF MEXICO IS COVERS THE WESTERN CARIBBEAN TO THE W OF 80W. ASSOCIATED NW FLOW ALOFT IS PRESENT OVER THIS AREA. WATER VAPOR IMAGERY ALSO INDICATES RELATIVELY DRY AIR AND STABLE CONDITIONS ALOFT RESULTING IN MOSTLY FAIR SKIES AND CONDITIONS AT THE SURFACE FOR MUCH OF THE BASIN. WITH WEAK HIGH PRESSURE TO THE N ACROSS THE SW NORTH ATLC REGION...THE OVERALL PRESSURE GRADIENT ACROSS THE CARIBBEAN REMAINS WEAK WITH MOSTLY GENTLE TO MODERATE TRADES OCCURRING OUTSIDE OF THE AREA WITHIN CLOSE PROXIMITY TO THE COAST OF COLOMBIA. LITTLE CHANGE IS EXPECTED WITH THE PRESENT CONDITIONS THROUGH THE NEXT 48 HOURS. ...HISPANIOLA... GENERALLY CLEAR SKIES AND FAIR CONDITIONS UNDER VERY DRY CONDITIONS ALOFT CONTINUE TO DOMINATE THE ISLAND'S WEATHER EARLY THIS EVENING. LATEST SATELLITE IMAGERY ALONG WITH RECENT SURFACE OBSERVATIONS REVEAL SCATTERED TO OCCASIONALLY BROKEN LOW CLOUDS OVER THE INTERIOR PORTION...AND JUST INLAND THE THE COASTAL SECTIONS. ISOLATED SHOWERS TO WEAK ISOLATED TSTMS ARE POSSIBLE WITH SOME OF THESE CLOUDS. ISOLATED WEAKENING SHOWERS ARE POSSIBLE WITHIN ABOUT 75 NM OFFSHORE THE SW PART OF HAITI WITH MOTION TO THE W. THE FAIR WEATHER IS EXPECTED TO PERSIST DURING THE NEXT COUPLE OF DAYS AS NW FLOW ALOFT ON THE E SIDE OF MID/UPPER LEVEL RIDGING CONTINUES TO PROVIDE RELATIVELY DRY AND STABLE CONDITIONS ALOFT INHIBITING DEEP CONVECTIVE ACTIVITY FROM FORMING. ATLANTIC OCEAN... BROAD TROUGHING IS NOTED N OF 28N OVER THE SW NORTH ATLC REGION STEMMING FROM A DEEP LAYERED LOW CENTERED OFF THE COAST OF NEWFOUNDLAND CANADA SUPPORTING A COLD FRONT THAT ENTERS THE REGION THROUGH 32N52W...AND CONTINUES SW TO 28N60W AND TO 27N68W WHERE IT BECOMES STATIONARY TO 27N74W AND TO 27.5N78W. FROM THERE IT CONTINUES NW AS A WARM FRONT TO 28.5N80W AND TO INLAND FLORIDA VICINITY OF DAYTONA BEACH. LATEST NWS COMPOSITE RADAR DISPLAYS SHOWS ISOLATED SHOWERS ENE OF THE WARM FRONT TO 79W. ISOLATED SHOWERS ARE ALSO POSSIBLE ELSEWHERE WITHIN 60-75 NM OF THE WARN FRONT. SCATTERED SHOWERS AND ISOLATED TSTMS ARE POSSIBLE WITHIN 90 NM OF THE COLD AND STATIONARY FRONTS. OVER THE FAR NW PART...A MID-LEVEL SHORTWAVE TROUGH IS SEEN EXITING THE SE GEORGIA AND NE FLORIDA COASTS. THIS FEATURE IS HELPING TO GENERATE ISOLATED SHOWERS N OF 30N W OF 74W. OTHERWISE...THE REMAINDER OF THE SW NORTH ATLC S OF THE COLD FRONT REMAINS UNDER THE INFLUENCE OF WEAK RIDGING ANCHORED BY A 1019 MB HIGH CENTERED NEAR 25N66W. THIS HIGH IS FORECAST TO DISSIPATE OVER THE NEXT 24 HOURS AS THE FRONT PRESSES S. FINALLY...THE REMAINDER OF THE EASTERN ATLC IS UNDER THE INFLUENCE OF A RIDGE ANCHORED BY A 1030 MB HIGH CENTERED S OF THE AZORES NEAR 37N29W. PATCHES OF BROKEN TO OVERCAST STRATOCUMULUS CLOUDS MOVING WSW IN RESPONSE TO THE ANTICYCLONIC FLOW AROUND THE RIDGE ARE OBSERVED N OF ABOUT 10N AND E OF ABOUT 45W. THESE CLOUDS ARE MOST NOTICEABLE IN THE PROVING GROUND GOES-R GEOCOLOR SATELLITE ENHANCEMENT. A WEAK FRONTAL TROUGH ENTERS THE REGION THROUGH 32N55W...AND EXTENDS TO 24N53W. SCATTERED SHOWERS AND ISOLATED TSTMS ARE NOTED WITHIN 120 NM EITHER SIDE OF THE TROUGH. ANOTHER COLD FRONT IS FORECAST TO MOVE INTO THE NW PORTION TONIGHT...AND REACH FROM NEAR 32N68W TO 29N81W BY EARLY SAT BEFORE IT BECOMES STATIONARY NEAR 26N BY SAT EVENING. THIS FRONT IS EXPECTED TO BE ON THE WEAK SIDE WITH RESPECT TO ITS ASSOCIATED WINDS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ AGUIRRE