[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 252308
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT MON 25 APR 2005

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN
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
2245 UTC.

...THE ITCZ...

ITCZ AXIS IS CENTERED ALONG 8N12W 3N27W 3N43W 2N50W.  ISOLATED
MODERATE CONVECTION WITHIN 60 NM OF AXIS BETWEEN 35W-45W.
SIMILAR CONVECTION IS E OF 15W S OF 7N...MOST CONCENTRATED ALONG
2.5N.

...DISCUSSION...

GULF OF MEXICO...
HIGH PRESSURE HAS MOVED OFFSHORE OF FLORIDA... LEAVING THE GULF
WITH MOSTLY SLY FLOW AT AROUND 15-20 KT.  RETURN LOW LEVEL FLOW
IS PRODUCING BROKEN TO OVERCAST LOW CLOUDS N OF 27N W OF
85W...WITH WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS WITHIN 60
NM OF THE TEXAS AND LOUISIANA COASTS IN ASSOCIATION WITH A
DISSIPATING SFC TROUGH. THE MOST SIGNIFICANT ACTIVITY IS OVER
THE HOUSTON-GALVESTON AREA WITH OTHER ISOLATED TSTMS N OF 28N
BETWEEN THE MOUTH OF THE MISSISSIPPI RIVER AND 85W.  IN THE
UPPER LEVELS...A BROAD FLAT RIDGE WITH ZONAL FLOW COVERS THE
AREA WEAK SHORTWAVES EMBEDDED WITHIN THE FLOW...THE MOST
SIGNIFICANT OF THESE OVER ARKANSAS IS FORECAST TO SPREAD
SHOWERS/TSTMS ALL ALONG THE NORTHERN GULF COAST INTO THE E GULF
FOR TOMORROW WITH A COLD FRONT MOVING OFFSHORE OF TEXAS.  THIS
FRONT SHOULD BE SIGNIFICANTLY WEAKER THAN THE PAST ONE BUT IS
FORECAST TO CLEAR MIAMI BY LATE WED.

CARIBBEAN SEA...
RATHER LIGHT SURFACE WINDS CONTINUE IN MOST OF THE CARIBBEAN AS
THE PRESSURE GRADIENT IS QUITE WEAK DUE TO THE STRONG WINTER
STORM EXITING THE EASTERN US DIMINISHING THE SUBTROPICAL HIGH.
WIDELY SCATTERED SHOWERS ARE NOTED OVER THE CARIBBEAN S OF 15N
BETWEEN 67W AND 75W EXTENDING SOUTHWARD TO THE COASTS OF
COLOMBIA AND VENEZUELA.  A SIMILAR COVERAGE OF SHOWERS EXTEND
NORTHEASTWARD N OF 15N E OF PUERTO RICO THRU THE FAR NORTHERN
LEEWARD ISLANDS.  IN THE UPPER LEVELS...A SHEARING TROUGH OVER
THE W ATLANTIC EXTENDS INTO THE NORTHEAST CARIBBEAN WITH STRONG
SUBSIDENCE COVERING HISPANIOLA...THE NORTHERN CARIBBEAN AND
PUERTO RICO. HIGH PRESSURE ALOFT IS BUILDING IN OVER THE SE
CARIBBEAN DUE TO A HIGH OVER NE VENEZUELA WITH BROAD
ANTICYCLONIC SWLY FLOW. THESE WINDS ARE ADVECTING MID TO UPPER
LEVEL MOISTURE NEWD FROM VENEZUELA TO THE CENTRAL WINDWARD AND
LEEWARD ISLANDS FROM DISSIPATING INLAND TSTMS.

ATLANTIC OCEAN...
COLD FRONT EXTENDS FROM 32N63W SW AND WEAKENING TO THE CENTRAL
BAHAMAS NEAR 24N75W. THE FRONT SEEMS TO BE DISSIPATING QUICKLY
WITH CLOUDINESS ASSOCIATED WITH THE FRONT DIMINISHING WITH CLEAR
SKIES BEHIND THE FRONT.  1025 MB HIGH S OF THE AZORES NEAR
33N31W DOMINATES THE E ATLC WITH NEAR CLIMATOLOGICAL TRADES E OF
50W.  IN THE UPPER LEVELS...A TROUGH-RIDGE-TROUGH PATTERN
PREVAILS OVER THE ATLC WATERS WITH A BROAD...BUT LIFTING TROUGH
OVER THE E UNITED STATES AND ATLANTIC W OF 60W. THIS TROUGH IS
ROTATING NEWD N OF THE AREA AND A RIDGE IS FORECAST TO BUILD IN
THE WAKE OF THE TROUGH WITHIN THE NEXT 24 HOURS. THE TROUGH ALSO
HAS FRACTURED WITH A SHEARED PORTION OF THE TROUGH EXTENDING
THROUGH 31N51W TO THE NE LEEWARD ISLANDS. SHARP RIDGE RESIDES
OVER THE CENTRAL ATLANTIC EXTENDING FROM 32N40W TO A HIGH CENTER
NEAR NE VENEZUELA.  STRONG SUBSIDENCE WITH THE RIDGE IS LIMITING
TSTMS TO BE ONLY NEAR THE ITCZ AXIS S OF 5N.  DEEP TROUGH IS
OVER THE E ATLC E OF 35W WITH A DEVELOPING LOW NEAR 24N23W.
BROAD SWLY FLOW EXISTS IN THE E TROPICAL ATLANTIC AND IS
ADVECTING MID AND UPPER LEVEL MOISTURE FROM THE ITCZ OVER THE
WEST COAST OF AFRICA.

$$
BLAKE

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