Tropical Weather Discussion
Issued by NWS

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000
AXNT20 KNHC 130604
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT MON APR 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0545 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 09N13W TO
04N16W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
04N16W TO 01N22W...ALONG THE EQUATOR TO THE NORTHERN COAST OF
BRAZIL NEAR 03S42W. NUMEROUS MODERATE TO STRONG CONVECTION IS
FROM 02N TO 08N BETWEEN 10W AND 18W AND FROM 01N TO 06N BETWEEN
18W AND 24W. SCATTERED MODERATE CONVECTION IS FROM 07S TO 02N W
OF 31W.

...DISCUSSION...

GULF OF MEXICO...

BROAD SURFACE HIGH PRESSURE OVER THE ATLC OCEAN EXTENDS A RIDGE
AXIS SW ACROSS THE FLORIDA PENINSULA AND THE EASTERN GULF...THUS
PROVIDING RETURN WIND FLOW OF 10 TO 15 KT ACROSS THE BASIN. A
WEAKNESS IN THE RIDGE IS BEING ANALYZED AS A SURFACE TROUGH FROM
SOUTHERN MISSISSIPPI NEAR 31N89W TO 28N88W TO 25N89W.
SOUTHEASTERLY WIND FLOW ACROSS THE BASIN CONTINUES TO ADVECT
ABUNDANT MOISTURE FROM THE CARIBBEAN TO THE NORTHERN
GULF...WHICH ALONG A ZONE OF DIFFLUENT FLOW ALOFT SUPPORT HEAVY
SHOWERS AND TSTMS WITHIN 75 NM EITHER SIDE OF THE TROUGH AXIS. A
SIMILAR ENVIRONMENT ALOFT SUPPORT HEAVY SHOWERS AND TSTMS
ASSOCIATED WITH A SQUALL LINE EXTENDING FROM SOUTHERN TEXAS TO
NORTHEASTERN MEXICO. CONVECTION ASSOCIATED WITH THE SQUALL LINE
EXTENDS INTO THE NW GULF AS SCATTERED MODERATE N OF 25N W OF
92W. OVER THE SW GULF...A 1004 MB LOW OVER SOUTHERN MEXICO
ENHANCES SCATTERED SHOWERS S OF 22N W OF 94W. AREAS OF DIFFLUENT
FLOW WITHIN AN UPPER RIDGE MOVING ACROSS THE GULF AND ABUNDANT
MOISTURE WILL CONTINUE TO SUPPORT SHOWERS AND TSTMS ACROSS THE
NORTHERN BASIN THROUGH WED NIGHT. OTHERWISE...SURFACE RIDGING
WILL CONTINUE TO BE THE DOMINANT FEATURE DURING THE NEXT THREE
DAYS.

CARIBBEAN SEA...

A BROAD SURFACE RIDGE OVER THE ATLC OCEAN EXTENDS TO THE
NORTHERN AND SE CARIBBEAN WHILE LOW PRESSURE DOMINATES ON THE SW
BASIN BEING ANCHORED BY A 1008 MB LOW N OF PANAMA NEAR 10N78W.
THIS IS SUPPORTING A TIGHTER PRESSURE GRADIENT OVER THE CENTRAL
BASIN...THUS RESULTING IN TRADES OF 20 TO 25 KT BETWEEN 64W AND
80W. ELSEWHERE TRADES OF 15 KT DOMINATE. SSMI TPW IMAGERY
CONTINUE TO SHOW ABUNDANT MOISTURE MOVING ACROSS THE CARIBBEAN
SEA...WHICH ALONG A MIDDLE LEVEL TROUGH OVER THE EASTERN BASIN
SUPPORT SCATTERED TO ISOLATED SHOWERS OVER THE WINDWARD
ISLANDS...PUERTO RICO AND HISPANIOLA. SCATTERED MODERATE
CONVECTION IS W OF THE LOW PRESSURE CENTER...WITHIN 150 NM OF
THE COASTS OF SOUTHERN NICARAGUA...COSTA RICA AND NORTHERN
PANAMA. EXCEPT FOR SHOWERS AND TSTMS OVER SW CUBA COASTAL
WATERS...FAIR WEATHER IS ELSEWHERE BEING SUPPORTED BY DRY AIR
SUBSIDENCE FROM ALOFT. NOT SIGNIFICANT CHANGES ARE EXPECTED
DURING THE NEXT TWO DAYS.

...HISPANIOLA...

A MIDDLE LEVEL TROUGH EXTENDS FROM THE ATLC SW ACROSS PUERTO
RICO AND HISPANIOLA TO THE CENTRAL CARIBBEAN. PATCHES OF SHALLOW
MOISTURE MOVING WITH THE TRADES ACROSS THE ISLAND ALONG WITH
LIFTING ASSOCIATED WITH THE TROUGH SUPPORT CLOUDINESS WITH
POSSIBLE SCATTERED TO ISOLATED SHOWERS. SIMILAR CONDITIONS ARE
EXPECTED TO PREVAIL THROUGH MONDAY NIGHT. WINDS OVER COASTAL
WATERS ARE OF 20 TO 25 KT.

ATLANTIC OCEAN...

A BROAD UPPER TROUGH OVER THE NW ATLC CONTINUE TO SUPPORT A COLD
FRONT N OF THE AREA OF DISCUSSION...WHICH TRANSITIONS INTO A
STATIONARY FRONT ALONG 31N63W TO 29N69W TO 29N75W. LOW-LEVEL
MOISTURE ASSOCIATED WITH THE FRONT AND A REGION OF UPPER LEVEL
DIFFLUENCE SUPPORT SCATTERED SHOWERS N OF 26N W OF THE FRONT. A
BROAD SURFACE RIDGE COVERS THE CENTRAL ATLC ANCHORED BY A 1029
MB HIGH NEAR 28N47W. A RECENT SCATTEROMETER PASS SHOW A WEAKNESS
IN THE RIDGE BEING ANALYZED AS A SURFACE TROUGH ALONG 27N65W TO
23N68W. AN UPPER LEVEL LOW OVER THE NE ATLC NEAR 34N21W
CONTINUES TO SUPPORT A COLD FRONT EXTENDING FROM 30N19W SW TO
27N27W TO A WEAK LOW PRESSURE CENTER NEAR 28N35W. NO CONVECTION
IS ASSOCIATED WITH THIS FRONT. THE FRONT OVER THE SW N ATLC IS
EXPECTED TO DISSIPATE TUESDAY AFTERNOON OVER THE CENTRAL BASIN.
SURFACE RIDGING WILL DOMINATE ELSEWHERE DURING THE NEXT TWO DAYS.

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

$$
NR


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