[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 251824
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU AUG 25 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 1200 UTC SURFACE ANALYSIS AND
SATELLITE IMAGERY THROUGH 1745 UTC.

...SPECIAL FEATURES...
THE CENTER OF TROPICAL STORM AT 25/1700 UTC WAS NEAR 26.2N 79.5W
OR ABOUT 40 MILES EAST-NORTHEAST OF FORT LAUDERDALE FLORIDA AND
ABOUT 40 MILES EAST-SOUTHEAST OF BOCA RATON FLORIDA. THIS
INFORMATION COMES FROM NOAA DOPPLER RADARS AND A NOAA
RECONNAISSANCE AIRCRAFT. KATRINA WAS MOVING WESTWARD 5 KT.
THE ESTIMATED MINIMUM CENTRAL PRESSURE WAS 997 MB. THE MAXIMUM
SUSTAINED WIND SPEEDS WERE 50 KT WITH GUSTS TO 60 KT.
PLEASE READ THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO
HEADERS MIATCMAT2/WTNT22 KNHC AND THE PUBLIC ADVISORY UNDER
HEADERS MIATCPAT1/WTNT32 KNHC FOR MORE DETAILS. NUMEROUS STRONG
SHOWERS AND THUNDERSTORMS ARE OCCURRING IN THE STRAITS OF
FLORIDA AND IN THE BAHAMAS ISLANDS...AND OVER SOUTH FLORIDA FROM
23N TO 29N BETWEEN 76W AND 82W. ANOTHER LITTLE 15 NM WIDE BAND
OF SHOWERS RUNS FROM 24N80W TO 24N83W TO 26N86W. THE FORECAST
CALLS FOR KATRINA TO MAKE LANDFALL IN SOUTHEAST FLORIDA LATE
TONIGHT OR EARLY TOMORROW MORNING. A MIDDLE TO UPPER LEVEL
TROUGH IS TO THE NORTH OF KATRINA...ASSOCIATED WITH THE SURFACE
COLD FRONT WHICH PASSES THROUGH 33N70W TO 31N77W TO 31N82W AT
THE SOUTHEASTERN GEORGIA COAST. A SUBTROPICAL RIDGE TO THE NORTH
OF KATRINA IS STEERING ITS MOVEMENT.

AN ATLANTIC OCEAN 1009 MB LOW PRESSURE CENTER...WHICH IS NOW AND
WHICH HAS BEEN TOO WEAK TO CLASSIFY ACCORDING TO THE DVORAK
CLASSIFICATION TECHNIQUE FOR THE LAST 24 HOURS...WAS NEAR 17N44W
MOVING WEST ABOUT 10 KT. WIDELY SCATTERED MODERATE SHOWERS TO
ISOLATED STRONG THUNDERSTORMS ARE TO THE SOUTHWEST OF THE LOW
CENTER FROM 8N TO 16N BETWEEN 42W AND 51W. NUMEROUS STRONG
SHOWERS AND THUNDERSTORMS ARE FOUND FROM 17.5N TO 19N BETWEEN
40W AND 42W. OVERCAST MULTILAYERED CLOUDS AND POSSIBLE
PRECIPITATION ARE ELSEWHERE FROM 17N TO 22N BETWEEN 37W AND 42W.

...TROPICAL WAVES...
AN ATLANTIC OCEAN TROPICAL WAVE WAS ALONG 31W/32W SOUTH OF 16N
MOVING WEST 10 TO 15 KT. IT IS POSSIBLE THAT THERE MAY BE SOME
ISOLATED SHOWERS IN SOME LOW CLOUDS FROM 10N TO 15N BETWEEN 30W
AND 33W. THESE LOW CLOUDS APPEAR TO BE TURNING CYCLONICALLY
IN SATELLITE IMAGERY.

A CARIBBEAN SEA TROPICAL WAVE WAS ALONG 76W/77W SOUTH OF 20N
JUST EAST OF JAMAICA...AND WITH THE SOUTHERN PART OF THE WAVE
MOVING THROUGH THE GULF OF URABA OF COLOMBIA. CONVECTIVE DEBRIS
CLOUDS REMAIN IN THE CARIBBEAN SEA SOUTH OF 13N BETWEEN 75W AND
80W WHICH INCLUDES THE GULF OF URABA AND THE COLOMBIA COAST. THE
ITCZ IS PASSING THROUGH THIS AREA ROUGHLY ALONG 9N/11N BETWEEN
70W AND PANAMA. UPPER LEVEL NORTHEASTERLY WIND FLOW IS MOVING
ACROSS THE WAVE...AS UPPER LEVEL ANTICYCLONIC OUTFLOW MOVES FROM
THE TOP OF TROPICAL STORM KATRINA INTO THE NORTH CENTRAL
CARIBBEAN SEA. A MIDDLE TO UPPER LEVEL CYCLONIC CIRCULATION
CENTER IS NEAR 14N81W. SCATTERED MODERATE TO STRONG SHOWERS AND
THUNDERSTORMS ARE IN A NORTHEAST-TO-SOUTHWEST ORIENTED LINE OR
BAND FROM NORTHEASTERN JAMAICA NEAR 18N76W TO 16N79W TO 14N83W.
ISOLATED TO WIDELY SCATTERED MODERATE SHOWERS ALSO ARE SOUTH OF
14N BETWEEN 80W AND THE EAST COAST OF CENTRAL AMERICA.

INTERIOR MEXICO TROPICAL WAVE ALONG 98W SOUTH OF 21N MOVING
A MIDDLE TO UPPER LEVEL CYCLONIC CIRCULATION CENTER IS ALONG
THE MEXICO COAST NEAR 20N96W IN THE SOUTHWESTERN GULF OF MEXICO.
ISOLATED MODERATE SHOWERS REMAIN FROM 18N TO 23N BETWEEN 95W AND
98W...AFTER THE EARLIER STRONG SHOWERS AND THUNDERSTORMS IN THIS
AREA DISSIPATED.

...THE ITCZ...
ITCZ 12N16W 7N27W 7N33W 14N41W TO THE 17N44W SURFACE LOW
PRESSURE CENTER...TO 12N50W TO 11N60W. WIDELY SCATTERED
MODERATE SHOWERS TO ISOLATED STRONG THUNDERSTORMS FROM
5N TO 12N BETWEEN 16W AND 37W.

...DISCUSSION...
THE GULF OF MEXICO...
THE SURFACE PRESSURE GRADIENT STILL IS WEAK...WITH ONLY THE
1014 MB ISOBAR MEANDERING FROM THE WEST CENTRAL FLORIDA COAST
TO THE CENTRAL GULF WATERS...TOWARD THE SOUTHWEST GULF...AND
NORTHWARD TO THE MIDDLE TO LOWER TEXAS GULF COAST. THE OBVIOUS
BIG FEATURE IS TROPICAL STORM KATRINA...NOW MOVING FROM THE
BAHAMAS ISLANDS TOWARD THE SOUTHEASTERN FLORIDA COAST. A MIDDLE
TO UPPER LEVEL TROUGH IS MOVING OFF THE UNITED STATES EAST
COAST. UPPER LEVEL ANTICYCLONIC WIND FLOW IS OVER THE UNITED
STATES NORTHERN GULF COAST STATES IN THE WAKE OF THE EASTWARD-
MOVING TROUGH. ANTICYCLONIC FLOW COVERS THE GULF WATERS NORTH
OF 28N. A MIDDLE TO UPPER LEVEL CYCLONIC CIRCULATION CENTER IS
MOVING WESTWARD NOW...CENTERED NEAR 24N88W ABOUT 150 NM NORTH OF
THE NORTHERN YUCATAN PENINSULA. ISOLATED MODERATE SHOWERS COVER
THE NORTHERN GULF WATERS FROM 27N TO 30N BETWEEN 86W AND 96W.

THE CARIBBEAN SEA...
A CARIBBEAN SEA TROPICAL WAVE WAS ALONG 76W/77W SOUTH OF 20N
JUST EAST OF JAMAICA...AND WITH THE SOUTHERN PART OF THE WAVE
MOVING THROUGH THE GULF OF URABA OF COLOMBIA. CONVECTIVE DEBRIS
CLOUDS REMAIN IN THE CARIBBEAN SEA SOUTH OF 13N BETWEEN 75W AND
80W WHICH INCLUDES THE GULF OF URABA AND THE COLOMBIA COAST. THE
ITCZ IS PASSING THROUGH THIS AREA ROUGHLY ALONG 9N/11N BETWEEN
70W AND PANAMA. UPPER LEVEL NORTHEASTERLY WIND FLOW IS MOVING
ACROSS THE WAVE...AS UPPER LEVEL ANTICYCLONIC OUTFLOW MOVES FROM
THE TOP OF TROPICAL STORM KATRINA INTO THE NORTH CENTRAL
CARIBBEAN SEA. A MIDDLE TO UPPER LEVEL CYCLONIC CIRCULATION
CENTER IS NEAR 14N81W. SCATTERED MODERATE TO STRONG SHOWERS AND
THUNDERSTORMS ARE IN A NORTHEAST-TO-SOUTHWEST ORIENTED LINE OR
BAND FROM NORTHEASTERN JAMAICA NEAR 18N76W TO 16N79W TO 14N83W.
ISOLATED TO WIDELY SCATTERED MODERATE SHOWERS ALSO ARE SOUTH OF
14N BETWEEN 80W AND THE EAST COAST OF CENTRAL AMERICA. A MIDDLE
TO UPPER LEVEL CYCLONIC CIRCULATION CENTER IS IN THE ATLANTIC
OCEAN NEAR 28N66W. CYCLONIC FLOW AROUND IT GOES FROM 25N TO 32N
BETWEEN 60W AND 70W. AN UPPER LEVEL RIDGE IS JUST TO THE SOUTH
OF IT ALONG 24N63W 21N67W TO 19N69W NEAR THE EASTERN DOMINICAN
REPUBLIC. UPPER LEVEL ANTICYCLONIC FLOW SPILLS OFF THIS RIDGE AS
NORTHERLY FLOW OVER THE EASTERN CARIBBEAN SEA. MIDDLE TO UPPER
LEVEL OVERCAST CLOUDS ARE NORTH OF 14N76W 15N70W 16N64W. STRONG
SHOWERS AND THUNDERSTORMS IN A FEW CLUSTERS ARE IN THE AREAS
FROM THE SOUTHWESTERN DOMINICAN REPUBLIC GOING EASTWARD...AND IN
SOUTHWESTERN PUERTO RICO. HIGH CLOUDS ARE MOVING ACROSS PUERTO
RICO AND SOME OF THE NORTHEASTERN CARIBBEAN SEA ISLANDS.
SCATTERED TO NUMEROUS STRONG SHOWERS AND THUNDERSTORMS WHICH ARE
FOUND NOW FROM 14N TO 19N BETWEEN 60W AND 63W IN THE EASTERN
CARIBBEAN ISLANDS ARE RELATED TO A SURGE
IN THE SURFACE WIND FIELD.

THE ATLANTIC OCEAN...
TROPICAL STORM KATRINA IS APPROACHING SOUTHEASTERN FLORIDA AT
THIS TIME. SHOWERS AND THUNDERSTORMS ARE BEING SPREAD FROM THE
STRAITS OF FLORIDA TO THE BAHAMAS ISLANDS AND FLORIDA NORTH AS
28N...AND INTO THE FLORIDA COASTAL WATERS TO 29N77W.  A MIDDLE
TO UPPER LEVEL TROUGH IS MOVING OFF THE UNITED STATES EAST
COAST. UPPER LEVEL ANTICYCLONIC WIND FLOW IS OVER THE UNITED
STATES NORTHERN GULF COAST STATES IN THE WAKE OF THE
EASTWARD-MOVING TROUGH. A MIDDLE TO UPPER LEVEL CYCLONIC
CIRCULATION CENTER IS IN THE ATLANTIC OCEAN NEAR 28N66W.
CYCLONIC FLOW AROUND IT GOES FROM 25N TO 32N BETWEEN 60W AND
70W. AN UPPER LEVEL RIDGE IS JUST TO THE SOUTH OF IT ALONG
24N63W 21N67W TO 19N69W NEAR THE EASTERN DOMINICAN REPUBLIC.
UPPER LEVEL ANTICYCLONIC FLOW SPILLS OFF THIS RIDGE AS NORTHERLY
FLOW OVER THE EASTERN CARIBBEAN SEA. A MIDDLE TO UPPER LEVEL
CYCLONIC CIRCULATION CENTER IS NEAR 36N49W...WITH A TROUGH TO
32N48W. ANTICYCLONIC FLOW IS WEST OF THIS TROUGH TO 60W NORTH
OF 30N. A TROUGH CONNECTS AN EASTERN ATLANTIC OCEAN CYCLONIC
CENTER NEAR 33N24W TO 30N33W AND 30N40W TO 25N45W AND TO A
COMPARATIVELY WEAKER MIDDLE TO UPPER LEVEL CYCLONIC CENTER NEAR
22N51W. MIDDLE TO UPPER LEVEL DRY AIR SURROUNDS THIS TROUGH.
BROAD UPPER LEVEL ANTICYCLONIC FLOW IS SOUTHEAST OF THIS
TROUGH...NORTH OF 10N.

$$
MT


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