[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 291738
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT FRI MAR 29 2013

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
1700 UTC.

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH PASSES THROUGH COASTAL LIBERIA NEAR 5N10W TO
4N15W EQ20W. THE ITCZ CONTINUES FROM EQ21W TO EQ30W EQ40W EQ47W.
A CLUSTER OF MODERATE TO ISOLATED STRONG CONVECTION IS FROM 2N
TO 6N BETWEEN 12W AND 17W. SMALLER CLUSTERS OF SIMILAR
CONVECTION ARE WITHIN 220 NM N OF THE ITCZ AXIS BETWEEN 27W AND
40W...ALSO WITHIN 100 NM S OF THE ITCZ W OF 40W.

...DISCUSSION...

THE GULF OF MEXICO...
SURFACE RIDGING CONTINUES OVER THE GULF ANCHORED BY A 1028 MB
HIGH PRESSURE LOCATED OVER NW SOUTH CAROLINA NEAR 34N81W. THE
HIGH PRESSURE IS PROVIDING EASTERLY WINDS OF 10-15 KT E OF 90W
AND SOUTHEASTERLY WINDS OF THE SAME MAGNITUDE W OF 90W. THE
SURFACE WIND FLOW OVER THE WESTERN GULF IS BANKING LOW LEVEL
CLOUDS ALONG THE E COAST OF MEXICO FROM S OF MATAMOROS TO THE
CITY OF VERACRUZ. METAR OBSERVATIONS IN THIS REGION HAVE
REPORTED HAZE AND FOG WHICH MIGHT AFFECT THE VISIBILITY
OFFSHORE. SATELLITE COMPOSITE TOTAL PRECIPITABLE WATER
IMAGERY INDICATE THE POSSIBILITY OF ISOLATED SHOWERS WITHIN 70
NM OF THE E COAST OF MEXICO. NEARLY WESTERLY FLOW SPREAD OVER
THE BASIN IN THE MIDDLE TO UPPER LEVELS. CLEAR SKIES AND FAIR
WEATHER DOMINATE THE REMAINDER OF THE BASIN ASSISTED BY A TONGUE
OF DRY AIR ALOFT EMBEDDED IN MIDDLE TO UPPER FLOW. OVER THE
COURSE OF 24 HOURS...RETURN FLOW WILL SPREAD ACROSS THE BASIN AS
A NEW HIGH PRESSURE BUILDS OVER THE SOUTHEASTERN CONUS AND THEN
DISPLACES OVER THE W ATLC. NO VARIATIONS IN WIND MAGNITUDE ARE
EXPECTED.

THE CARIBBEAN SEA...
AS OF 1500 UTC...THE TAIL OF A COLD FRONT LOCATED OVER THE
CENTRAL ATLC IS MOVING ACROSS PUERTO RICO AND THEN ACROSS THE
MONA PASSAGE WHERE IT TRANSITIONS TO A SHEARLINE ALONG 17N68W
17N71W 16N74W 15N77W 13N80W. RAINSHOWERS ARE OCCURRING OVER THE
ISLAND OF PUERTO RICO AS INDICATED BY RADAR IMAGERY AS WELL AS
WITHIN 100 NM OF THE ISLAND S COAST. SATELLITE COMPOSITE TOTAL
PRECIPITABLE WATER IMAGERY INDICATE THE POSSIBILITY OF
RAINSHOWERS OVER THE MONA PASSAGE AS WELL AS WITHIN 50 NM EITHER
SIDE OF THE SHEARLINE. RAINSHOWERS MAY ALSO BE WITHIN 150 NM OF
THE COASTS OF VENEZUELA AND COLOMBIA ASSISTED BY MIDDLE TO UPPER
LEVEL MOISTURE ADVECTION FROM BRAZIL AS WELL AS AN AREA OF
SURFACE LOW PRESSURE OVER COLOMBIA. WESTERLY WINDS SPREAD ACROSS
THE CARIBBEAN IN THE MIDDLE TO UPPER LEVELS AND DRY AIR EMBEDDED
IN THIS FLOW IS PROVIDING FAIR WEATHER TO THE REMAINDER
CARIBBEAN WATERS. IN TERMS OF WINDS...20 KT NORTHEASTERLY WIND
DOMINATE THE REGION W OF 68W WHILE EASTERLY TRADEWINDS IN THE
RANGE OF 10-15 KT SPREAD E OF 68W. OVER THE COURSE OF 24
HOURS...WINDS OVER THE CENTRAL CARIBBEAN ARE EXPECTED TO AUGMENT
TO NEAR GALE FORCE AS A TIGHTER PRESSURE GRADIENT BUILDS OVER
THE BASIN DUE TO THE DEVELOPMENT OF A HIGH PRESSURE CENTER OVER
THE W ATLC.

THE ATLANTIC OCEAN...
A COLD FRONT EXTENDS ACROSS THE CENTRAL ATLC TO THE NE CARIBBEAN
ALONG 30N36W 25N47W 20N56W 18N65W THEN ACROSS PUERTO RICO TO THE
MONA PASSAGE. THIS FRONT IS BEING SUPPORTED BY A BROAD MIDDLE TO
UPPER LEVELS TROUGH COVERING THE WESTERN AND CENTRAL ATLC.
RAINSHOWERS ARE POSSIBLE WITHIN 80 NM OF THE COLD FRONT N OF 25N
AS WELL AS WITHIN 140 NM E OF THE FRONT S OF 22N. THE HEAVIEST
RAINSHOWERS ARE OCCURRING WITHIN 100 NM OFF THE COAST OF NORTHERN
PUERTO RICO. A BROAD SURFACE RIDGE SPREADS E OF THE COLD FRONT
IN THE EASTERN ATLC N OF 19N ANCHORED BY A 1023 MB HIGH PRESSURE
NEAR 28N19W. OVER THE COURSE OF 24 HOURS...THE COLD FRONT WILL
CONTINUE TO MOVE ACROSS THE CENTRAL ATLC WATERS WHILE A NEW HIGH
PRESSURE BUILDS BEHIND IT OVER THE SOUTHEASTERN CONUS...THEN
DRIFTING TO THE WEST ATLC.

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

$$
NR

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