[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 012358 RRA
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI
FL 805 PM EDT MON APR 01 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2330 UTC.

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

THE MONSOON TROUGH EXTENDS THROUGH THE COAST OF GUINEA NEAR
9N13W INTO THE EASTERN TROPICAL ATLC ALONG 5N16W 2N22W 2N30W.
THE ITCZ BEGINS NEAR 2N31W AND CONTINUES ALONG 3N40W 1N49W.
CLUSTERS OF MODERATE CONVECTION ARE WITHIN 90 NM EITHER SIDE OF
THE MONSOON TROUGH AXIS BETWEEN 15W AND 28W. SCATTERED MODERATE
CONVECTION IS S OF THE MONSOON TROUGH FROM 3S TO 3N BETWEEN 6W
AND 23W.

...DISCUSSION...

GULF OF MEXICO...
A MIDDLE TO UPPER LEVEL TROUGH IS MOVING OVER THE EASTERN CONUS
SUPPORTING A WEAK SURFACE TROUGH THAT EXTENDS ACROSS NORTHERN
FLORIDA AND THEN OVER THE NE GULF ALONG 29N83W 27N85W 25N88W. A
FEW CLUSTERS OF SHOWERS/THUNDERSTORMS ARE NEAR THE AXIS OVER
FLORIDA...OTHERWISE NO CONVECTIVE PRECIPITATION IS OBSERVED
ALONG THE PORTION OF THE TROUGH OVER THE GULF. EXCEPT FOR THE NW
GULF WHERE THE OBSERVED WINDS ARE UP TO 15 KT...SURFACE WINDS
OVER THE GULF ARE RELATIVELY LIGHT RANGING FROM 5-10 KT. WEST OF
THE TROUGH WIND IS FROM THE NW WHILE E OF IT WESTERLY FLOW
DOMINATE...OVER THE WESTERN GULF W OF 90W EASTERLY WINDS
DOMINATE. OVER THE COURSE OF 24 HOURS...THE SURFACE TROUGH IS
EXPECTED TO DRIFT EASTWARD MERGING WITH A COLD FRONT TO THE
NORTH WHICH WILL CONTINUE INTO THE WEST ATLC OVER THE NEXT
COUPLE OF DAYS. SE RETURN FLOW WILL SPREAD ACROSS THE GULF
BEFORE THE NEXT FRONTAL BOUNDARY MOVES OFF THE TEXAS COAST EARLY
THURSDAY.

CARIBBEAN SEA...
MOSTLY CLEAR SKIES SPREAD ACROSS THE BASIN DUE TO MOSTLY DRY AIR
ALOFT EMBEDDED IN A SHORT-WAVE TROUGH OVER THE CENTRAL
CARIBBEAN. SOME MODERATE MOISTURE FLOWS AROUND THE EAST SIDE OF
THE SHORT-WAVE TROUGH PRODUCING SOME UPPER LEVEL CLOUDS AND
ISOLATED SHOWERS ACROSS LA HISPANIOLA...PUERTO RICO AS WELL AS
OVER THE CENTRAL AND EASTERN CARIBBEAN WATERS E OF 73W. MOISTURE
BEING ADVECTED FROM THE E PACIFIC BY MIDDLE-UPPER LEVEL WESTERLY
FLOW IS SUPPORTING RAINSHOWERS AND THUNDERSTORMS OVER CUBA WHICH
EXTEND WITHIN 60 NM OFF THE SOUTHERN COASTLINE OF THE ISLAND.
THIS MOISTURE FROM THE E PACIFIC IS ALSO SUPPORTING
PRECIPITATION ACTIVITY OVER THE ISLAND OF JAMAICA WHICH COULD
EXTEND UP TO 83 NM OFF THE EASTERN COAST OF THIS ISLAND. A
STRONG PRESSURE GRADIENT OVER THE CENTRAL...SOUTHERN AND EASTERN
CARIBBEAN CONTINUES TO SUPPORT TRADEWIND FLOW OF 20-25 KT. A
WEAKER PRESSURE GRADIENT OVER THE WESTERN CARIBBEAN ALLOWS FOR
LIGHTER WINDS OF 5-15 KT. OVER THE COURSE OF 24 HOURS...LITTLE
CHANGE IS EXPECTED.

ATLANTIC OCEAN...
A MIDDLE-UPPER LEVEL TROUGH EXTENDING OVER THE EASTERN CONUS IS
SUPPORTING A WEAK SURFACE TROUGH ACROSS NORTHERN FLORIDA
EXTENDING INTO THE GULF AS WELL AS ANOTHER SURFACE TROUGH ALONG
THE E COAST OF FLORIDA FROM TITUSVILLE TO THE FLORIDA STRAITS.
ABUNDANT MOISTURE IN THE MIDDLE-UPPER LEVELS ARE SUPPORTING
SCATTERED MODERATE CONVECTION OVER THE WESTERN ATLC W OF 70W AND
N OF 20N. OVER THE CENTRAL ATLC...AN UPPER LEVEL TROUGH N OF 32N
SUPPORTS A COLD FRONT THAT ENTERS THE DISCUSSION AREA NEAR
30N34W 26N43W 24N52W 24N57W. ISOLATED SHOWERS ARE POSSIBLE ALONG
AND WITHIN 20 NM OF THE FRONTAL BOUNDARY. SURFACE RIDGING
CONTINUES SOUTH OF THE FRONT AND INTO THE EASTERN ATLC WHERE IT
IS SUPPORTED BY A BROAD UPPER RIDGE CENTERED NEAR 18N19W. A
DISSIPATING COLD FRONT IS OVER THE FAR N EASTERN ATLC EXTENDING
ALONG 30N8W 28N13W 27N18W WITH NO CONVECTIVE PRECIPITATION
ASSOCIATED TO IT.

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

$$
NR


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