| HOME | ARCHIVES | FORECASTS | IMAGERY | ABOUT NHC | RECONNAISSANCE |

---

Atlantic Tropical Weather Discussion (Text)

000
AXNT20 KNHC 181745
TWDAT 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL 
205 PM EDT FRI APR 18 2014

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 FEATURE...                                           
A GALE WARNING REMAINS IN EFFECT FOR THE NE GULF IN ASSOCIATION 
WITH A DEEPENING AREA OF LOW PRES LOCATED NEAR 28.5N87W AT 1200 
UTC. THE LOW WILL SHIFT SLOWLY NE...MOVING INLAND ACROSS THE 
CENTRAL FLORIDA PANHANDLE LATE THIS AFTERNOON...THEN WILL 
CONTINUE NE OVERNIGHT AND EXIT THE GEORGIA COAST SAT MORNING. 
MINIMAL GALE FORCE WINDS ARE EXPECTED BRIEFLY ACROSS N AND NW 
PORTIONS OF LOW THIS AFTERNOON...WITH FREQUENT GUSTS TO GALE 
FORCE OVER THE NE GULF AHEAD OF THE LOW AND THE ASSOCIATED COLD 
FRONT. IN FACT...THE 1524 UTC ASCAT PASS CONFIRMED THE PRESENCE 
OF MINIMAL GALE FORCE WINDS WITHIN AROUND 70 NM ON THE NW 
QUADRANT OF THE LOW CENTER. PLEASE SEE THE HIGH SEAS FORECAST 
UNDER AWIPS/WMO HEADERS MIAHSFAT2/ FZNT02 KNHC.

...ITCZ/MONSOON TROUGH...                                     
THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE TROPICAL ATLC 
NEAR 14N17W AND CONTINUES TO NEAR 4N24W WHERE THE ITCZ BEGINS 
AND CONTINUES ALONG 1N30W THEN S OF THE EQUATOR TO NEAR 2S44W. 
SCATTERED MODERATE CONVECTION IS NOTED WITHIN 90 NM EITHER SIDE 
OF THE ITCZ AXIS BETWEEN 24W AND 30W. SIMILAR CONVECTION CAN BE 
FOUND S OF 2N TO THE COAST OF SOUTH AMERICA BETWEEN 44W AND 47W. 
A CLUSTER OF MODERATE TO ISOLATED STRONG CONVECTION IS WITHIN 30 
NM OF 6N13W. 

...DISCUSSION...                                                
AN AREA OF LOW PRES HAS DEVELOPED ACROSS THE GULF OF MEXICO AND 
IS CENTERED NEAR 28.5N87W AT 1200 UTC. A COLD FRONT EXTENDS FROM 
THE LOW CENTER TO NEAR TAMPICO MEXICO. THE MOSAIC DOPPLER RADAR 
FROM THE SE U.S. SHOWS NUMEROUS SHOWERS WITH EMBEDDED TSTMS 
COVERING MAINLY THE FLORIDA PANHANDLE AND THE NE GULF. A FLASH 
FLOOD WATCH REMAINS IN EFFECT FOR PARTS OF SOUTH-CENTRAL 
ALABAMA...THE FLORIDA PANHANDLE...NORTHERN FLORIDA AND SOUTHERN 
GEORGIA. THE LOW PRES IS FORECAST TO IMPACT THE REGION THROUGH 
TONIGHT SPREADING AREA OF HEAVY RAINFALL. LATEST SURFACE OBS 
INDICATE WINDS OF 20-25 KT E OF THIS DEEPENING LOW PRES OVER THE 
NE GULF. WINDS HAVE INCREASED TO MINIMAL GALE FORCE ON THE NW 
QUADRANT OF THE LOW CENTER PER THE MOST RECENT ASCAT PASS.  THE 
LOW PRES WILL MOVE SLOWLY NE TOWARD NORTHERN FLORIDA EMERGING 
INTO THE SW N ATLC ON SAT MORNING. THE ASSOCIATED COLD FRONT 
WILL MOVE ACROSS THE FLORIDA PENINSULA TONIGHT INTO SAT MORNING. 
IN ITS WAKE...A RIDGE WILL THEN EXTEND ACROSS THE GULF THE 
REMAINDER OF THE UPCOMING WEEKEND. PLEASE SEE SPECIAL FEATURE.  
ALOFT...A DEEPENING UPPER LEVEL TROUGH SUPPORTS THE LOW PRES 
SYSTEM. THE TROUGH EXTENDS FROM LOUISIANA TO OVER THE W GULF 
AMPLIFYING AN UPPER RIDGE ACROSS THE EASTERN GULF AND FLORIDA. 
UPPER DIFFLUENCE RELATED TO THIS UPPER-LEVEL RIDGE IS HELPING TO 
INDUCE THE CONVECTIVE ACTIVITY ASSOCIATED WITH THE ABOVE 
MENTIONED AREA OF LOW PRES. A WIDE-BAND OF SHOWERS WITH TSTMS 
HAS DEVELOPED AHEAD OF THE FRONT AND COULD PRODUCE STRONG TO 
SEVERE THUNDERSTORMS OVER PARTS OF FLORIDA TONIGHT INTO SAT 
MORNING. 

CARIBBEAN SEA...                                                
AN EARLIER SCATTEROMETER PASS PROVIDED OBSERVATIONS OF 25-30 KT 
WINDS NEAR THE COAST OF COLOMBIA. MODERATE TO FRESH TRADE WINDS 
ARE NOTED ACROSS THE EAST AND CENTRAL CARIBBEAN WITH LIGHTER 
WINDS ACROSS THE WESTERN PAR OF THE BASIN. HIGH PRES CENTERED 
OVER THE CENTRAL ATLC EXTENDS A RIDGE SW COVERING THE NE 
CARIBBEAN...INCLUDING PUERTO RICO AND THE US/UK VIRGIN ISLANDS. 
THE SAN JUAN DOPPLER RADAR SHOWS QUICK PASSING SHOWERS EMBEDDED 
IN THE TRADE WIND FLOW MOVING ACROSS THE ISLANDS AND REGIONAL 
COASTAL WATERS. TYPICAL TRADE WIND SHOWERS ARE ALSO SEEN ON 
VISIBLE SATELLITE IMAGERY CROSSING THE LESSER ANTILLES IN TO THE 
EASTERN CARIBBEAN. THE HIGH PRES IS FORECAST TO MOVE SOUTH 
DURING THE NEXT 24 HOURS. THIS PATTERN WILL MAINTAIN FRESH TO 
LOCALLY STRONG TRADES NEAR THE COAST OF COLOMBIA WITH MODERATE 
TO LOCALLY FRESH TRADES ELSEWHERE THROUGH SAT...WITH WINDS THEN 
WEAKENING SUN AS LOW PRES MOVES N OF AREA AND THE HIGH PRES 
WEAKENS. IN THE UPPER-LEVELS...BROAD UPPER RIDGE COVERS THE 
CARIBBEAN WITH THE AXIS EXTENDING FROM NW VENEZUELA ACROSS EAST-
CENTRAL CUBA INTO THE SW ATLC. 

...HISPANIOLA...                                                
CURRENTLY...SE WINDS AROUND THE SOUTHERN PERIPHERY OF THE ATLC 
RIDGE ARE TRANSPORTING PATCHES OF LOW LEVEL CLOUDS WITH EMBEDDED 
SHOWERS ACROSS OF THE ISLAND. LITTLE CHANGE IS EXPECTED IN THE 
WEATHER PATTERN DURING THE WEEKEND. SOME DRIER AIR WILL BEGIN TO 
FILTER IN FROM THE EAST ON SAT RESULTING IN ISOLATED TO 
SCATTERED SHOWERS. EXPECT INCREASING MOISTURE LATE SUN INTO MON 
AS A COLD FRONT APPROACHES FROM THE WEST. 

ATLANTIC OCEAN...                                               
A WEAKENING STATIONARY FRONT EXTENDING FROM 31N74W TO NEAR COCOA 
BEACH FLORIDA HAS BEGUN TO LIFT N AS A WARM FRONT ACROSS FLORIDA 
THIS MORNING...AND WILL LIFT N OF AREA BY LATE THIS AFTERNOON AS 
LOW PRES OVER THE NE GULF OF MEXICO MOVES SLOWLY NE...AND ACROSS 
NORTHERN FLORIDA TONIGHT...EXITING GEORGIA COAST SAT MORNING. 
FREEPORT IN THE NW BAHAMAS REPORTED 2.31 INCHES OF RAIN LIKELY 
WITH THE FRONTAL PASSAGE. THE ASSOCIATED COLD FRONT WILL REACH 
FROM 31N78W TO FLORIDA KEYS SAT AFTERNOON...THEN EXTEND FROM 
BERMUDA TO TURKS AND CAICOS ISLANDS MON EVENING. FRESH TO STRONG 
NORTHERLY WINDS ARE EXPECTED AHEAD AND BEHIND THE FRONT AS PRES 
GRADIENT TIGHTENS BETWEEN THE LOW PRES AND THE ATLC RIDGE. A 
1032 MB HIGH PRES CENTERED NEAR 36N54W EXTENDS A RIDGE ACROSS 
THE REMAINDER OF THE WEST AND CENTRAL ATLC. MODERATE TO FRESH 
TRADES ARE SEEN ACROSS THE TROPICAL ATLC ON THE SOUTHERN 
PERIPHERY OF THE RIDGE. A WEAK 1019 MB HIGH IS SITUATED NEAR 
29N20W AND WILL DISSIPATE IN ABOUT 24 HOURS. ALOFT...THE UPPER 
RIDGE FROM THE CARIBBEAN EXTENDS OVER THE W ATLC WITH THE AXIS 
ALONG 75W. AN UPPER TROUGH EXTENDS FROM THE NE ATLC TO OVER THE 
CENTRAL ATLC SUPPORTING A SURFACE TROUGH THAT LIES OVER THE 
EASTERN ATLC AND STRETCHES FROM A LOW PRES LOCATED WELL N OF 
AREA TO 31N29W TO 26N36W. 

FOR ADDITIONAL INFORMATION PLEASE 
VISIT WWW.HURRICANES.GOV/MARINE

$$ 
GR