[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 232345
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT WED JUL 23 2008

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...METEOROLOGICAL ANALYSIS...WEATHER
OBSERVATIONS...AND RADAR.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...SPECIAL FEATURES...

HURRICANE DOLLY IS LOCATED INLAND OVER EXTREME SOUTH TEXAS
CENTERED NEAR 26.6N 98.0W AT 24/0000 UTC OR ABOUT 60 MILES...
95 KM...NORTHWEST OF BROWNSVILLE TEXAS MOVING NORTHWEST AT 7 KT.
ESTIMATED MINIMUM PRESSURE IS 976 MB. MAXIMUM SUSTAINED WIND
SPEED IS 65 KT WITH GUSTS TO 80 KT. PLEASE SEE THE LATEST NHC
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC
AND THE PUBLIC ADVISORY UNDER MIATCPAT4/WTNT34 KNHC FOR MORE
DETAILS. THE EYE OF DOLLY MADE LANDFALL EARLIER THIS AFTERNOON
AND CONTINUES TO TRACK OVER FAR SOUTH TEXAS THIS EVENING. WITH
LANDFALL HAVING ALREADY OCCURRED...A CONTINUED WEAKENING IS
FORECAST BUT DOLLY REMAINS A LARGE AND SLOW MOVING SYSTEM AND
WILL CONTINUE TO PRODUCE VERY HEAVY RAINFALL DURING THE NEXT DAY
OR TWO. THESE RAINS WILL LIKELY CAUSE WIDESPREAD FLOODING ACROSS
PORTIONS OF SOUTH TEXAS AND NORTHEASTERN MEXICO. MOST OF DOLLY'S
CONVECTIVE CORE HAS MOVED INLAND BUT CONVECTIVE BANDS STILL
REMAIN IN THE WRN GULF WATERS WITH SCATTERED MODERATE TO STRONG
CONVECTION FROM 24N-29N W OF 95W. ANOTHER AREA OF SCATTERED
MODERATE CONVECTION IS FROM 25N TO THE LOUISIANA AND TEXAS
COASTLINE BETWEEN 89W-95W.

...TROPICAL WAVES...

A TROPICAL WAVE IS ALONG 29W/30W S OF 23N MOVING W NEAR 15 KT.
SATELLITE IMAGERY INDICATES A BROAD CIRCULATION WHICH REMAINS
ELONGATED IN THE MID/LOW LEVELS. THE WAVE SHOWS UP VERY WELL ON
THE MIMIC-TPW PRODUCT FROM CIMSS WHERE A LARGE AMPLITUDE
MOISTURE SURGE IS OBSERVED. SCATTERED SHOWERS ARE W OF THE WAVE
AXIS WITHIN 350 NM WITH ONLY A VERY SMALL AREA OF SCATTERED
MODERATE CONVECTION WITHIN 60 NM OF THE POINT 16N32W.

A TROPICAL WAVE IS ALONG 58W S OF 15N MOVING W 10-15 KT. WEAK
INVERTED-V CURVATURE IS OBSERVED ON SATELLITE IMAGERY. THE WAVE
IS BENEATH STRONG TO MODERATE SUBSIDENCE/DRY AIR ALOFT WITH ONLY
SCATTERED SHOWER ACTIVITY ACROSS GUYANA.

A TROPICAL WAVE IN THE WESTERN CARIBBEAN EXTENDS FROM NEAR THE
CAYMAN ISLANDS TO WESTERN PANAMA ALONG 82W AND IS MOVING W NEAR
10-15 KT. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM
8N-15N BETWEEN 79W-86W...WHICH INCLUDES HONDURAS...NICARAGUA AND
COSTA RICA. A DIFFLUENT PATTERN ALOFT OVER THE SW CARIBBEAN SEA
IS ALSO ENHANCING THIS CONVECTIVE ACTIVITY.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 13N16W 13N20W 10N27W 7N32W 6N56W.
SCATTERED MODERATE AND ISOLATED STRONG CONVECTION ARE FROM 6N-9N
BETWEEN 16W-22W. SIMILAR CONVECTION REMAINS ALONG THE W AFRICAN
COAST WITHIN 90 NM OF A LINE FROM 5N7W TO 12N16W. ISOLATED
MODERATE CONVECTION IS FROM 4N-9N BETWEEN 45W-51W.

...DISCUSSION...

GULF OF MEXICO...
HURRICANE DOLLY REMAINS THE FOCUS ACROSS THE WRN GULF OF MEXICO
THIS EVENING...SEE SPECIAL FEATURES ABOVE FOR DETAILS. BROAD
UPPER LEVEL ANTICYCLONE ASSOCIATED WITH DOLLY EXTENDS UPPER
RIDGING ACROSS THE ENTIRE GULF AND FLORIDA PENINSULA. THIS IS
AIDING IN GENERATING SCATTERED SHOWER ACTIVITY WITH EMBEDDED
TSTMS ACROSS THE NE GULF WATERS NEAR THE FLORIDA BIG BEND
REGION. ANOTHER AREA OF SCATTERED SHOWERS/TSTMS IS ACROSS
CENTRAL FLORIDA FROM CAPE CANAVERAL TO SAINT PETERSBURG AND FORT
MYERS DUE LARGELY IN PART TO THE UPPER DIFFLUENCE OVER THE
REGION. AT THE SURFACE THE ATLANTIC RIDGE EXTENDS WESTWARD AND
ENVELOPS THE ERN GULF GIVING THE AREA LIGHT TO MODERATE SE WINDS.

CARIBBEAN SEA...
UPPER-LEVEL NORTHERLY OUTFLOW FROM HURRICANE DOLLY COVERS THE NW
CARIBBEAN W OF 81W. BROAD COMPLEX UPPER TROUGHING IN THE W ATLC
EXTENDS A VERY NARROW TROUGH S OVER THE CENTRAL CARIBBEAN
THROUGH CENTRAL CUBA AND JAMAICA PRODUCING MODERATE SUBSIDENCE
AND DRY AIR. THE REMAINDER OF THE BASIN IN UNDER THE INFLUENCE
OF AN UPPER RIDGE ANCHORED ON AN UPPER LEVEL HIGH LOCATED E OF
THE LEEWARD ISLANDS NEAR 17N59W. S-SW FLOW BETWEEN THE ABOVE
MENTIONED UPPER LEVEL FEATURES IS DRAWING SUFFICIENT UPPER LEVEL
MOISTURE FROM NRN SOUTH AMERICA INTO THE CARIBBEAN SEA ACROSS
HISPANIOLA. A TROPICAL WAVE IS MOVING WESTWARD ACROSS THE WRN
CARIBBEAN ALONG 82W AND MOISTURE FROM THIS SYSTEM IS FORECAST TO
SPREAD OVER CENTRAL AMERICA THROUGH THU. MODERATE TO STRONG
TRADE WINDS ARE ACROSS THE AREA WITH THE STRONGEST WINDS JUST
OFF THE COLOMBIAN COAST.

ATLANTIC OCEAN...
A PAIR OF 1029 MB SURFACE HIGH PRESSURE CENTERS ARE LOCATED NEAR
36N50W AND 35N45W EXTENDING A RIDGE FROM THE CENTRAL ATLANTIC TO
THE FLORIDA PENINSULA AND THE ERN GULF. THIS SYSTEM WILL
GRADUALLY STRENGTHEN OVER THE NEXT 24-36 HOURS PRODUCING
MODERATE TO STRONG TRADE WINDS ACROSS THE TROPICS. BROAD AREA OF
UPPER TROUGHING COVERS THE WRN ATLC AND EXTENDS S INTO THE
CENTRAL CARIBBEAN. AN AREA OF WIDELY SCATTERED SHOWERS IS FROM
26N-31N BETWEEN 67W-72W AND LIKELY THE RESULT OF LOW LEVEL WIND
SPEED CONVERGENCE. A SURFACE TROUGH IS ANALYZED OVER THE CENTRAL
ATLC FROM 31N52W TO 24N56W. SATELLITE IMAGERY AND UPPER LEVEL
WINDS INDICATE CYCLONIC TURNING AND POSSIBLE ISOLATED SHOWERS
FROM 26N-30N BETWEEN 54W-56W. OTHERWISE THE REMAINDER OF THE
ATLC IS
DOMINATED BY BENIGN UPPER LEVEL FEATURES WHERE STRONG SUBSIDENCE
AND A DRY STABLE ATMOSPHERE ARE IN PLACE E OF 60W. A LARGE AREA
OF STRATOCUMULUS CLOUDS IS WRAPPING AROUND THE MID-LEVEL
CIRCULATION ASSOCIATED WITH THE TROPICAL WAVE OVER THE FAR ERN
ATLC.

$$
HUFFMAN




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