000 AXNT20 KNHC 071803 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST SAT MAR 07 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 STRONG PRESSURE GRADIENT BETWEEN LOWER PRESSURE ACROSS COLOMBIA AND A RIDGE EXTENDING ACROSS THE SOUTHWESTERN NORTH ATLC IS GENERATING GALE FORCE CONDITIONS FOR THE COASTAL WATERS OF COLOMBIA FROM 11N-13N BETWEEN 74W-77W. THESE CONDITIONS ARE EXPECTED TO PERSIST THROUGH MONDAY. SEE LATEST NWS HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/FZNT02 KNHC FOR MORE DETAILS. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 06N10W TO 04N14W WHERE THE ITCZ AXIS BEGINS AND EXTENDS TO THE EQUATOR NEAR 22W THEN TO THE COAST OF SOUTH AMERICA NEAR 44W. WIDELY SCATTERED MODERATE CONVECTION IS WITHIN 200 NM OF THE ITCZ AXIS W OF 15W. ...DISCUSSION... GULF OF MEXICO... WATER VAPORY IMAGERY INDICATES AN UPPER LEVEL TROUGH FROM THE NE GULF ACROSS THE EASTERN US AND OVER THE WESTERN ATLC. THE TROUGH SUPPORTS A COLD FRONT THAT EXTENDS ACROSS THE SOUTHWESTERN N ATLC WHERE IT TRANSITIONS TO A STATIONARY FRONT ACROSS S FL AND OVER THE GULF NEAR 25N82W TO 23N90W TO A 1019 MB SURFACE LOW OVER THE SW GULF NEAR 19N93W. A SURFACE TROUGH EXTENDS NW FROM THE SURFACE LOW TO 21N97W. SCATTERED SHOWERS ARE WITHIN 75 NM OF EITHER SIDE OF THE FRONTAL BOUNDARY. A 1033 MB HIGH CENTERED ACROSS AL/MS IS PRODUCING EASTERLY TO NORTHEASTERLY FLOW MAINLY BETWEEN 15 TO 20 KT ACROSS THE BASIN WITH WINDS UP TO 25 KT OVER THE SW BASIN. OVER THE NEXT 24 HOURS THE FRONT WILL DISSIPATE AND THE SURFACE LOW WILL MOVE INLAND OVER MEXICO. THE HIGH TO THE NORTH OF THE BASIN WILL SLIDE EAST AND OFF THE US EASTERN COAST BY SUNDAY NIGHT. THIS WILL ALLOW FOR WINDS OVER THE GULF TO GRADUALLY DECREASE AS THEY BECOME SOUTHEASTERLY. CARIBBEAN SEA... WATER VAPOR IMAGERY REVEALS VERY DRY AND STABLE AIR ALOFT COVERING THE BASIN. THE COMBINATION OF THE DRY AIR AND LACK OF FORCING IS PREVENTING ANY DEEP CONVECTION FROM DEVELOPING ACROSS THE CARIBBEAN. ALTHOUGH DEEP CONVECTION IS BEING LIMITED...LOW LEVEL MOISTURE IN THE TRADE WIND FLOW IS SUPPORTING PATCHES OF SHOWERS OVER MUCH OF THE CENTRAL AND EASTERN CARIBBEAN INCLUDING PUERTO RICO AND THE VIRGIN ISLANDS. ADDITIONAL SHOWERS ARE ALONG THE COASTS OF HONDURAS AND NICARAGUA. A STRONG PRESSURE GRADIENT BETWEEN HIGHER PRESSURE OVER THE SW NORTHERN ATLC AND LOWER PRESSURE OVER S AMERICA IS PRODUCING GALE FORCE WINDS OFF THE N COAST OF COLOMBIA. SEE THE SPECIAL FEATURES FOR MORE DETAILS. ELSEWHERE...TRADE WINDS OF 15 TO 25 KT COVER THE BASIN. LITTLE CHANGE IS FORECAST OVER THE NEXT 48 HOURS. ...HISPANIOLA... LOW LEVEL MOISTURE IN THE TRADE WIND FLOW SUPPORTS SCATTERED SHOWERS OVER THE EASTERN PORTION OF THE DOMINICAN REPUBLIC TODAY WITH GENERALLY FAIR WEATHER OVER THE REMAINDER OF THE ISLAND. EXPECT SIMILAR CONDITIONS TO PERSIST THROUGH SUNDAY. ATLANTIC OCEAN... AN UPPER TROUGH THAT EXTENDS FORM THE US EAST COAST AND INTO THE WESTERN ATLC SUPPORTS A COLD FRONT OVER THE WESTERN ATLC AND INTO OUR AREA OF DISCUSSION NEAR 31N68W TO 28N75W WHERE IT TRANSITIONS TO A STATIONARY FRONT THAT EXTENDS ACROSS THE NORTHERN BAHAMAS TO HOMESTEAD FL NEAR 25N81W. MOSTLY CLOUDY CONDITIONS AND SCATTERED SHOWERS ARE WITHIN 75 NM OF EITHER SIDE OF THE FRONT. FARTHER EAST...A 1030 MB HIGH CENTERED NEAR 31N38W PROVIDES FAIR WEATHER AND ANTICYCLONIC FLOW OVER THE CENTRAL AND EASTERN ATLC N OF 25N. A SURFACE TROUGH EXTENDS FROM 24N47W TO 14N49W AND IS CO-LOCATED UNDER AN UPPER LOW CENTERED NEAR 19N50W. SCATTERED SHOWERS AND THUNDERSTORMS ARE FROM 14N TO 24N BETWEEN 44W AND 53W. ANOTHER SURFACE TROUGH IS LOCATED OVER THE FAR EASTERN ATLC AND EXTENDS FROM 31N16W TO THE COAST OF AFRICA NEAR 21N17W. OVER THE NEXT 24 HOURS THE STATIONARY PORTION OF THE FRONT WILL TRANSITION TO A SHEAR LINE WHILE THE COLD FRONT CONTINUES TO MOVE EAST INTO THE CENTRAL ATLC. HIGH PRESSURE WILL MOVE OFF THE EASTERN US AND INTO THE WESTERN ATLC. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ LATTO