[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 081821
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT MON AUG 08 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 HARVEY AT 08/1500 UTC WAS NEAR
40.3N 47.1W MOVING NORTHEAST 19 KT. THE ESTIMATED MINIMUM
CENTRAL PRESSURE WAS 1001 MB. THE MAXIMUM SUSTAINED WIND SPEED
WAS 45 KT WITH GUSTS TO 55 KT. SEE THE LATEST NHC FORECAST/
ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT3/WTNT23 KNHC OR
MIATCPAT3/WTNT33 KNHC FOR MORE DETAILS. HARVEY IS LOSING
TROPICAL CHARACTERISTICS MORE AND MORE. THE LOW LEVEL CENTER
IS EXPOSED AND THE WEAKENING SHOWERS AND THUNDERSTORMS ARE
CONFINED TO THE NORTH OF THE CENTER...AND ALONG A NARROW BAND
STRETCHING TO THE SOUTHEAST. DVORAK INTENSITY ESTIMATES STILL
SUPPORT 45 KT...WHICH IS THE ADVISORY INTENSITY. LITTLE CHANGE
IN STRENGTH IS EXPECTED AS HARVEY GOES THROUGH EXTRATROPICAL
TRANSITION IN 12 HOURS...OR LESS.

TROPICAL STORM IRENE WAS DOWNGRADED TO TROPICAL DEPRESSION IRENE
AT 08/1500 UTC. THE CENTER OF TROPICAL DEPRESSION IRENE AT
08/1500 UTC WAS NEAR 22.4N 50.7W MOVING WEST-NORTHWEST 14 KT.
THE ESTIMATED MINIMUM CENTRAL PRESSURE WAS 1009 MB. THE MAXIMUM
SUSTAINED WIND SPEED WAS 30 KT WITH GUSTS TO 40 KT. SEE THE
LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT4/WTNT24 KNHC OR MIATCPAT4/WTNT34 KNHC FOR MORE DETAILS.
THE EXPOSED LOW LEVEL CIRCULATION HAS BECOME INCREASINGLY
SEPARATED FROM WHAT WAS LEFT OF THE SHOWERS/THUNDERSTORMS TO
ITS EAST THAT OCCURRED OVERNIGHT. SCATTERED MODERATE TO STRONG
SHOWERS AND THUNDERSTORMS FROM 22N TO 23N BETWEEN 49W AND 50W.

...TROPICAL WAVES...
EASTERN ATLANTIC TROPICAL WAVE ALONG 30W SOUTH OF 18N MOVING
WEST 10 TO 15 KT. THE CURRENT VISIBLE SATELLITE IMAGERY SHOWS
A CERTAIN AMOUNT OF CYCLONIC FLOW TO THE LOW CLOUDS BETWEEN
35W AND 40W SOUTH OF 15N. THE ITCZ APPEARS TO BE GETTING PULLED
NORTHWARD IN RESPONSE TO THIS BROAD CYCLONIC FLOW. IT MAY BE
NECESSARY TO MOVE THE WAVE POSITION FOR THE 08/1800 UTC SURFACE
MAP ANALYSIS IN ORDER TO AGREE MORE WITH THE SATELLITE
REPRESENTATION.

AN EASTERN CARIBBEAN SEA TROPICAL WAVE WAS ALONG 61W/62W SOUTH
OF 19N MOVING WEST 10 TO 15 KT. SCATTERED MODERATE TO ISOLATED
STRONG SHOWERS AND THUNDERSTORMS FROM 13N TO 15N BETWEEN 58W AND
60W. SCATTERED MODERATE TO ISOLATED STRONG SHOWERS AND
THUNDERSTORMS IN A SURGE OF MOISTURE WEST OF THE WAVE...
FROM 14N TO 17.5N BETWEEN 63W AND 67W.

...THE ITCZ...
ITCZ 15N16W 12N24W 10N32W 9N50W 12N60W. WIDELY SCATTERED
MODERATE TO ISOLATED STRONG SHOWERS AND THUNDERSTORMS WITHIN
60 TO 120 NM ON EITHER SIDE OF 10N55W 9N26W 8N35W 5N40W...AND
FROM 4N TO 12N BETWEEN 40W AND 53W. ISOLATED MODERATE SHOWERS
DISSIPATING WITH TIME FROM GUYANA TO 10N BETWEEN 56W AND 60W.

...DISCUSSION...

THE GULF OF MEXICO...
AN UPPER LEVEL RIDGE RUNS FROM THE EAST CENTRAL GULF WATERS
THROUGH SOUTHEASTERN GEORGIA...UPPER LEVEL ANTICYCLONIC FLOW
COVERS THE GULF EAST OF 90W. A MIDDLE TO UPPER LEVEL CYCLONIC
CIRCULATION CENTER IN THE YUCATAN CHANNEL/NORTHWESTERN CARIBBEAN
SEA KEEPS MIDDLE TO UPPER LEVEL CYCLONIC FLOW SOUTH OF 23N EAST
OF 93W. A TROUGH CONNECTS THE ATLANTIC 29N72W CYCLONIC CENTER...
THROUGH THE STRAITS OF FLORIDA AND ACROSS WESTERN CUBA...TO THE
CYCLONIC CENTER NEAR COZUMEL JUST OFF THE YUCATAN PENINSULA.
THE TROUGH CONTINUES TO MEXICO SOUTHWEST OF THE PENINSULA NEAR
17N93W. A MIDDLE TO UPPER LEVEL CYCLONIC CENTER IN THE GULF OF
CALIFORNIA IS NEAR 23N108W. A SURFACE 1014 MB LOW PRESSURE
CENTER IS RIGHT AT THE COAST OF THE FLORIDA PANHANDLE NEAR
30N86W. A TROUGH RUNS FROM SOUTH CENTRAL ALABAMA TO THE LOW
CENTER...INTO THE GULF NEAR 28N87W AND 24N/25N ALONG 90W.
ISOLATED TO WIDELY SCATTERED MODERATE SHOWERS AND LOCALLY STRONG
THUNDERSTORMS ARE NORTH OF 26N BETWEEN THE FLORIDA WEST COAST
AND 86W. ISOLATED MODERATE SHOWERS AND FEW THUNDERSTORMS ARE
FOUND ALSO FROM 25N TO 28N BETWEEN 94W AND 97W ALONG THE TEXAS
COAST...AND FROM 28.5N TO THE COAST BETWEEN SOUTHEASTERN
LOUISIANA AND THE UPPER TEXAS COAST.

THE CARIBBEAN SEA...
A MIDDLE TO UPPER LEVEL TROUGH RUNS FROM THE 29N72W ATLANTIC
OCEAN CYCLONIC CENTER...THROUGH THE FLORIDA STRAITS AND WESTERN
CUBA TO THE MIDDLE TO UPPER LEVEL CYCLONIC CIRCULATION CENTER IS
NEAR COZUMEL MEXICO IN THE NORTHWESTERN CORNER OF THE AREA.
ISOLATED MODERATE SHOWERS ARE OCCURRING IN THE GULF OF HONDURAS
ON THE SOUTHERN SIDE OF THIS TROUGH. ISOLATED MODERATE SHOWERS
HAVE DEVELOPED WITHIN 15 TO 30 NM ON EITHER SIDE OF THE LINE
FROM 16N79W TO EASTERN JAMAICA TO THE WINDWARD PASSAGE. AN UPPER
LEVEL RIDGE RUNS FROM THE ATLANTIC WATERS NEAR 25N64W TOWARD THE
COAST OF VENEZUELA NEAR 10N65W. A SURGE OF MOISTURE TO THE WEST
OF THE 61W/62W TROPICAL WAVE IS HELPING THE SHOWERS AND
THUNDERSTORMS FROM 14N TO 17.5N BETWEEN 63W AND 67W. SHOWERS
AND THUNDERSTORMS IN THE SOUTHWESTERN CORNER OF THE AREA...FROM
NICARAGUA TO THE PANAMA COASTAL WATERS ARE OCCURRING IN AN AREA
OF BROAD SURFACE LOW PRESSURE...EASTERLY SURFACE WINDS...AND
THE ITCZ...UNDER AN UPPER LEVEL RIDGE.

ATLANTIC OCEAN...
A MIDDLE TO UPPER LEVEL CYCLONIC CIRCULATION CENTER...WHICH USED
TO BE IN THE NORTHEASTERN AND EASTERN CARIBBEAN SEA AND WHICH
EVENTUALLY MOVED NORTHWARD...NOW IS NEAR 29N72W. MIDDLE TO UPPER
LEVEL CYCLONIC FLOW AROUND THIS FEATURE COVERS THE SOUTHWESTERN
NORTH ATLANTIC OCEAN NORTH OF 20N WEST OF 67W. THE FLOW TO THE
SOUTHWEST OF THIS CYCLONIC CENTER LEADS RIGHT INTO THE EASTERN
GULF OF MEXICO UPPER LEVEL RIDGE. THE CENTRAL MIDDLE TO UPPER
LEVEL CYCLONIC CIRCULATION IS NEAR 32N41W...HOLDING ITS POSITION
FIRMLY...HAVING ABOUT 4 DEGREES OF LATITUDE TO THE SOUTH ON
FRIDAY OF LAST WEEK. A TROUGH STRETCHES FROM THIS CENTER TO
20N55W. A BIG UPPER LEVEL RIDGE IS SOUTHEAST OF THIS TROUGH.
MIDDLE TO UPPER LEVEL CYCLONIC FLOW BREAKS UP THIS RIDGE...IN
THE AREA OF CYCLONIC FLOW NEAR 36W/37W...POSSIBLY THE POSITION
FOR 08/1800 UTC OF THE TROPICAL WAVE.

$$
MT


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