[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 181712
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SAT APR 18 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
1645 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 08N13W SW
TO 04N17W WHERE THE ITCZ BEGINS AND CONTINUES TO 01S35W TO THE
NORTHERN COAST OF BRAZIL NEAR 01S46W. SCATTERED MODERATE
CONVECTION IS FROM 04S TO 04N BETWEEN 18W AND 37W.

...DISCUSSION...

GULF OF MEXICO...

A 1013 MB LOW CONTINUES TO SPIN IN THE ATLC WATERS OFFSHORE THE
CAROLINAS WHICH SUPPORTS A FRONTAL SYSTEM THAT EXTENDS ACROSS FL
AS A STATIONARY FRONT AND ALONG THE NORTHERN GULF COAST FROM THE
BIG BEND OF FL TO THE MOUTH OF THE MISSISSIPPI AND THEN ALONG
THE TX COAST...FINALLY MOVING INLAND OVER S TEXAS NEAR 27N98W.
A PRE-FRONTAL SURFACE TROUGH EXTENDS OVER THE NW GULF FROM
29N91W TO 26N95W. CLUSTERS OF MODERATE CONVECTION WITH
THUNDERSTORMS ARE ALONG AND NW OF A LINE FROM 24N97W TO 29N86W. E
TO SE WINDS OF 15 TO 20 KT ARE BETWEEN THE TROUGH AND FRONT OVER
THE NW GULF. ANTICYCLONIC FLOW AROUND ATLC HIGH PRESSURE IS
PRODUCING MAINLY SOUTHERLY FLOW OF 10 TO 15 KT OVER THE SOUTHERN
HALF OF THE BASIN. OVER THE NEXT 24 HOURS THE STATIONARY FRONT
WILL GRADUALLY DISSIPATE. HOWEVER...UPPER LEVEL DISTURBANCES
PASSING ACROSS THE NORTHERN GULF AND SOUTHERN US WILL CONTINUE
TO BRING ROUNDS OF CONVECTION ACROSS THE NORTHERN AND CENTRAL
GULF THROUGH MONDAY.

CARIBBEAN SEA...

SURFACE RIDGING OVER THE ATLC EXTENDS SW ACROSS THE CARIBBEAN
WHILE LOWER PRESSURE RESIDES OVER COLOMBIA. TRADE WINDS BETWEEN
THESE TWO FEATURES OF 15 TO 20 KT DOMINATE MUCH OF THE
BASIN...EXCEPT FOR AN AREA OF WINDS UP TO 25 KT WITHIN 130 NM OF
THE COAST OF N COLOMBIA...AND LIGHTER WINDS BETWEEN JAMAICA AND
CUBA. LOW LEVEL MOISTURE IN THE TRADE WIND FLOW SUPPORTS
ISOLATED SHOWERS ACROSS THE BASIN. HOWEVER...STABLE CONDITIONS
AND DRY AIR ALOFT ARE INHIBITING THE DEVELOPMENT OF DEEP
CONVECTION ACROSS THE CARIBBEAN TODAY. THESE CONDITIONS ARE
FORECAST TO PERSIST THROUGH MONDAY.

...HISPANIOLA...

LOW LEVEL MOISTURE IN THE TRADE WIND FLOW SUPPORTS ONGOING
ISOLATED SHOWERS ACROSS THE ISLAND. OTHERWISE...MOSTLY FAIR
WEATHER PREVAILS. THIS PATTERN IS EXPECTED TO PERSIST THROUGH
MONDAY.

ATLANTIC OCEAN...

A SHORTWAVE TROUGH EXTENDING FROM THE MID ATLC TO THE BAHAMAS
SUPPORTS A LOW OFF THE CAROLINA COASTS WITH A COLD FRONT
EXTENDING FROM THE LOW TO 31N75W TO 29N78W WHERE IT TRANSITIONS
TO A STATIONARY FRONT TO CENTRAL FL NEAR 28N81W. SCATTERED
MODERATE CONVECTION IS FROM 27N TO 31N BETWEEN 69W AND 80W.
FARTHER EAST...A BROAD UPPER TROUGH OVER THE CENTRAL ATLC
SUPPORTS A COLD FRONT THAT ENTERS THE AREA OF DISCUSSION NEAR
32N28W TO 25N40W TO 25N48W WHERE IT TRANSITIONS TO A STATIONARY
FRONT TO 27N54W WHERE IT TRANSITIONS TO A WARM FRONT TO 31N65W.
SCATTERED SHOWERS ARE POSSIBLE WITHIN 100 NM OF THE FRONTAL
SYSTEM. OVER THE NEXT 24 HOURS THE FRONTAL SYSTEM OFFSHORE OF FL
WILL MOVE EAST WITH CONVECTION.

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

$$
LATTO


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