[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 120002
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SAT APR 11 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 08N13W TO
01N23W WHERE IT TRANSITIONS TO THE ITCZ. THE ITCZ THEN
CONTINUES ACROSS THE EQUATOR NEAR 28N AND TO THE COAST OF S
AMERICA NEAR 03S39W. ISOLATED MODERATE CONVECTION IS FROM 02S TO
02N BETWEEN 09W AND 42W.

...DISCUSSION...

GULF OF MEXICO...
WESTERLY FLOW ALOFT CONTINUES TO PREVAIL OVER MUCH OF THE GULF
BASIN THIS EVENING. TWO UPPER LEVEL DISTURBANCES ARE AFFECTING
THE GULF...WITH THE WESTERNMOST LOCATED OVER THE EXTREME NW GULF
NEAR 28N96W AND THE EASTERNMOST OVER N FLORIDA NEAR 28N83W. A
TROUGH OVER THE OHIO VALLEY/NEW ENGLAND SUPPORTS A FRONTAL
SYSTEM THAT ENTERS OUR AREA OF DISCUSSION AS A STATIONARY FRONT
NEAR 31N83W AND OVER THE GULF WATERS NEAR APALACHICOLA AT 30N85W
AND EXTENDS TO 28N90W TO THE S TEXAS COAST NEAR 27N97W. THE
UPPER LEVEL DISTURBANCES ARE INTERACTING WITH THIS FRONT TO
PRODUCE CLUSTERS OF MODERATE CONVECTION FROM 26N TO 31N BETWEEN
88W AND 96W...AND ALSO OVER THE CENTRAL AND NORTHERN FL
PENINSULA. WEAKENING MODERATE CONVECTION IS ALSO LOCATED OVER
THE NE GULF FROM 28N TO 30N BETWEEN 83W AND 86W ASSOCIATED WITH
A PRE-FRONTAL TROUGH THAT AS OF 1800 UTC EXTENDED FROM 30N86W TO
28N88W. ELSEWHERE...A SURFACE TROUGH VOID OF CONVECTION EXTENDS
OVER THE SW BASIN FROM 23N94W TO 18N95W. SOUTHEASTERLY SURFACE
WINDS OF 10 TO 15 KT DOMINATE THE SOUTHERN GULF AROUND ATLC HIGH
PRESSURE. WINDS BECOME VARIABLE NEAR THE STATIONARY
FRONT...GUSTY IN THE VICINITY OF THUNDERSTORMS. THE STATIONARY
FRONT IS FORECAST TO REMAIN IN TACT AS AT MEANDERS NORTHWARD
OVER THE NORTHERN PORTION OF THE BASIN TONIGHT...DISSIPATING BY
SUNDAY NIGHT. CONVECTION WILL CONTINUE TONIGHT AND INTO THE DAY
SUNDAY ACROSS THE N GULF. ALTHOUGH THE FRONT WILL DISSIPATE
LATER ON SUNDAY...DEEP MOISTURE IN THE PRESENCE OF ADDITIONAL
UPPER LEVEL DISTURBANCES WILL CONTINUE TO SUPPORT CONVECTION
MAINLY OVER THE NORTHERN HALF OF THE BASIN THROUGH MONDAY.

CARIBBEAN SEA...
TRADE WIND FLOW OF 15 TO 20 KT DOMINATES MUCH OF THE CARIBBEAN
THIS EVENING WITH WINDS OF 25 KT WITHIN 150 NM N OF THE COAST OF
COLOMBIA AND WESTERN VENEZUELA. SOUTHWESTERLY FLOW ALOFT COVERS
THE BASIN...WITH DRY AIR IN THE UPPER LEVELS OVER THE WESTERN
CARIBBEAN...AND INCREASING MIDDLE TO UPPER LEVEL MOISTURE OVER
THE CENTRAL AND EASTERN CARIBBEAN. MOSTLY DAYTIME DRIVEN
LANDMASS THUNDERSTORMS ARE OVER CUBA..JAMAICA...AND THE YUCATAN.
CONVECTION OVER COLOMBIA AND PANAMA MAY ENTER THE EXTREME
SOUTHERN PORTIONS OF THE CARIBBEAN TONIGHT. GENERALLY FAIR
WEATHER WITH THE EXCEPTION OF TRADE WIND SHOWERS ARE EXPECTED ON
SUNDAY.

...HISPANIOLA...
ISOLATED THUNDERSTORM ACTIVITY FROM THIS AFTERNOON IS
DISSIPATING OVER THE CENTRAL PORTION OF THE ISLAND THIS EVENING.
MAINLY FAIR CONDITIONS ARE EXPECTED OVERNIGHT. ADDITIONAL
ISOLATED THUNDERSTORMS ARE POSSIBLE DURING THE AFTERNOON AND
EVENING HOURS ON SUNDAY.

ATLANTIC OCEAN...
AN UPPER LEVEL TROUGH OVER THE OHIO VALLEY AND NEW ENGLAND
SUPPORTS A COLD FRONT OFFSHORE OF SOUTH CAROLINA TO THE GEORGIA
COAST. THE COMBINATION OF PRE-FRONTAL CONVERGENCE AND AN UPPER
LEVEL DISTURBANCE MOVING EASTWARD ACROSS N FL IS PRODUCING
SCATTERED MODERATE CONVECTION WITH THUNDERSTORMS FROM 28N TO 31N
BETWEEN 76W AND INLAND OVER THE FLORIDA PENINSULA. FARTHER
EAST...A PAIR OF SURFACE TROUGHS ARE MOVING WESTWARD AROUND THE
PERIPHERY OF ATLC HIGH PRESSURE. THE WESTERNMOST TROUGH IS
LOCATED FROM 26N63W TO 21N64W. THIS TROUGH IS INTERACTING WITH
AN UPPER LOW NEAR 28N59W TO PRODUCE SHOWERS AND ISOLATED
MODERATE CONVECTION MAINLY WITHIN 150 NM EAST OF THE TROUGH
AXIS. THE EASTERNMOST TROUGH EXTENDS FROM 25N54W TO 21N55W AND
HAS SHOWERS WITHIN 75 NM OF EITHER SIDE OF THE TROUGH AXIS. THE
REMAINDER OF THE CENTRAL AND EASTERN SUBTROPICAL ATLC IS
DOMINATED BY RIDGING WITH A 1026 MB HIGH CENTER NEAR 29N48W.
OVER THE NEXT COUPLE OF DAYS A STATIONARY FRONT WILL EXPAND FROM
THE FL COAST AND INTO THE WESTERN ATLC TO NEAR 60W BY MONDAY
MORNING. THIS BOUNDARY WILL BE THE FOCUS FOR CONVECTION AS IT
PROPAGATES EASTWARD OVER THE BASIN ON SUNDAY.

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

$$
LATTO

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