[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 141801
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SUN AUG 14 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
1715 UTC.

...SPECIAL FEATURES...

TROPICAL STORM IRENE IS NEAR 33.6N 69.9W AT 14/1500 UTC OR ABOUT
300 NM ESE OF CAPE HATTERAS N CAROLINA MOVING NNE 10 KT. THE
ESTIMATED MINIMUM CENTRAL PRESSURE IS 999 MB AND THE MAXIMUM
SUSTAINED WIND SPEEDS ARE 55 KT WITH GUSTS TO 65 KT. PLEASE READ
THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT4/WTNT24 KNHC OR MIATCPAT4/WTNT34 KNHC FOR MORE DETAILS.
IRENE LOOKS A LITTLE BETTER ORGANIZED THAN OVERNIGHT ON
SATELLITE WITH A LARGE WELL-DEFINED CURVED BAND AROUND A CENTER
WHICH LOOKS LIKE AN EYE.  A RECENT REPORT FROM AIRCRAFT SAYS THE
PRESSURE IS NOW DOWN TO 994...THE LOWEST MEASURED IN ITS
LIFETIME.  OUTFLOW IS EXPANDING GREATLY TO THE S FOR THE FIRST
TIME IN THE STORM'S LIFE BUT IS A BIT RESTRICTED TO THE N.
IRENE IS GOING IN BETWEEN A LARGE HIGH JUST NE OF BERMUDA AND
ANOTHER HIGH NEAR CAPE HATTERAS WITH A WEAK TROUGH OFFSHORE OF
NEW JERSEY.  THE CYCLONE HAS A CHANCE TO BECOME A HURRICANE
OVERNIGHT AS SSTS PROGRESSIVELY WARM AND SHEAR REMAINS LOW.
SCATTERED MODERATE FROM 32N-34N BETWEEN 69W-71.5W.

TROPICAL DEPRESSION TEN IS NEAR 13.8N 46.5W AT 14/1500 UTC OR
ABOUT 8800 NM E OF THE LESSER ANTILLES MOVING NW 7 KT. THE
ESTIMATED MINIMUM CENTRAL PRESSURE IS 1009 MB AND THE MAXIMUM
SUSTAINED WIND SPEEDS ARE 25 KT WITH GUSTS TO 35 KT. PLEASE READ
THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT5/WTNT25 KNHC OR MIATCPAT5/WTNT35 KNHC FOR MORE
DETAILS.  SW SHEAR HAS TOTALLY EXPOSED THE LOW-LEVEL CIRCULATION
WHICH IS OVER 90 NM FROM ANY CONVECTION.  THERE IS SOME
POTENTIAL FOR REGENERATION AS THE SYSTEM MOVES SLOWLY NW WITH
LIGHTER SHEAR FORECAST IN A COUPLE OF DAYS.  HOWEVER THE SYSTEM
IS RATHER BARE BONES FOR THE MOMENT AND COULD SLOWLY SPIN DOWN
BEFORE HAVING A CHANCE TO REFORM.  ISOLATED MODERATE CONVECTION
WITHIN 60 NM OF 14.5N44W.

...TROPICAL WAVES...

E ATLC WAVE IS ORIENTED FROM NNW TO SSE ALONG 20N31W TO 9N27W
MOVING W 10-15 KT WITH A 1012 MB LOW ALONG THE WAVE NEAR
11N29W.  THE WAVE IS WELL-DEFINED IN SATELLITE WITH A LARGE
CYCLONIC ENVELOPE OF LOW CLOUDS WITH WIDELY SCATTERED SHOWERS
AND A FEW POSSIBLE TSTMS WITHIN 180 NM OF 14N30W.  THE GFS
DISSIPATES THE LOW WITHIN 24 HOURS AND TRIES TO FORM A NEW LOW
NEAR THE WEAK CONVECTION... TRACKING WSW.  A NEW OUTBREAK OF
DUST/DRY AIR FROM AFRICA IS BEHIND THE WAVE E OF A LINE FROM
24N30W 20N30W TO THE CAPE VERDES ISLAND THEN TO NEAR DAKAR.

CENTRAL CARIBBEAN WAVE IS ALONG 73W S OF 18N MOVING W 20 KT.
BUOY 42058 SUGGEST THE WAVE COULD HAVE RECENTLY PASSED WITH
WINDS SHIFTING FROM ELY TO SELY...THOUGH NEARBY SHOWERS COULD
HAVE CONTAMINATED THE DATA.  SATELLITE SHOWS CYCLONIC CURVATURE
IN THE LOW CLOUDS WITH WLY SHEAR ENHANCING THE WAVE'S SCATTERED
MODERATE CONVECTION FROM 14N-16.5N BETWEEN 72W-77W.  AN
INCREASED CHANCE OF RAIN IS LIKELY IN THE W CARIBBEAN W OF 80W
DUE TO THIS WAVE MOVING THROUGH UNTIL TUE.

W CARIBBEAN WAVE IS ALONG 82W S OF 17N MOVING W 15-20 KT. WAVE
IS CAUSING A LARGE AREA OF ISOLATED MODERATE CONVECTION S OF 18N
BETWEEN 80W-85W AND SHOULD BRING A FAIRLY WET DAY TO CENTRAL
AMERICA.

...ITCZ...

ITCZ AXIS IS ALONG 9N13W 13N23W 11N28W 9N34W 13N42W 13N46W
10N55W 10N61W.  ISOLATED MODERATE CONVECTION WITHIN 60 NM OF
7N35W. WIDELY SCATTERED MODERATE WITHIN 60 NM OF AXIS W OF 52W.

...DISCUSSION...

GULF OF MEXICO...
MOST OF THE AREA IS UNDER A LARGE AREA OF CYCLONIC FLOW ALOFT
WITH A TROUGH RUNNING FROM SE LOUISIANA THRU THE YUCATAN
CHANNEL.  WITHIN THIS BROAD TROUGH... A CLOSED LOW IS OVER THE
FLORIDA KEYS... ASSISTING TSTMS IN THE E GULF WITHIN 120 NM OF
THE LOW MOSTLY JUST W OF TAMPA.  THE UNSTABLE AIR ALOFT COMBINED
WITH THE WARM GULF WATERS MOSTLY OVER 30C ARE PRODUCING ISOLATED
TSTMS OVER ALL OF THE AREA.  1018 MB HIGH OFFSHORE OF THE E
COAST OF FLORIDA IS CAUSING MOSTLY SE TO S WINDS OF AROUND 10 KT
THRU E GULF WATERS WITH SLIGHTLY HIGHER WINDS AROUND 15 KT IN
THE W GULF.  LITTLE CHANGE IS LIKELY IN THE SHORT-TERM WITH MORE
SIGNIFICANT AREAS OF TSTMS POSSIBLE OVER YUCATAN INTO THE SW
GULF FROM DIURNAL CONVECTION.

CARIBBEAN SEA...
UPPER TROUGH EXTENDS FROM W-CENTRAL CUBA BETWEEN THE CAYMANS AND
JAMAICA SOUTHWARD TO 13N79W.  SW SHEAR IS CAUSING INCREASING
CONVECTION WITH A TROPICAL WAVE S OF JAMAICA WITH WEAK UPPER
RIDGING S OF SAN ANDRES.   MODERATE/ STRONG SUBSIDENCE IS
KEEPING THE NW CARIBBEAN WITHOUT SIGNIFICANT CONVECTION N OF
JAMAICA W OF 78W.  IN THE E CENTRAL CARIBBEAN... UPPER RIDGE
LIES FROM HISPANIOLA TO THE ABC ISLANDS WITH A DRIER DAY IN THE
E CARIBBEAN AS MODERATE SUBSIDENCE ON THE W SIDE OF A DEEP UPPER
TROUGH E OF THE CARIBBEAN IMPACTS THE LESSER ANTILLES.  THE ONLY
EXCEPTION TO THIS IS NEAR THE ITCZ CLOSE TO TRINIDAD WHERE A FEW
TSTMS EXIST.  THIS MOISTURE SHOULD SLOW OVERSPREAD THE REST OF
WINDWARD ISLANDS BY TUE.

ATLANTIC OCEAN...
THE W ATLC HAS A LARGE HIGH IN THE MID-LATITUDE RIDGING
SOUTHWARD TO COVER THE AREA W OF 60W N OF 22N.  GENERALLY QUIET
WEATHER IS BENEATH THE RIDGE EXCEPT NEAR THE SOUTHERN FRINGE OF
IRENE WHERE A FEW SHOWERS ARE LINGERING.   DEEP MID-OCEANIC
TROUGH EXTENDS FROM 32N40W TO 10N59W JUST E OF TRINIDAD.  THIS
TROUGH IS BRINGING DOWN A WEAK TROUGH INTO THE AREA FROM 30N55W
TO 32N49W WITH WIDELY SCATTERED SHOWERS N OF 28N BETWEEN
46W-55W.  THIS IS THE TROUGH THAT LIKELY CAUSED THE DEMISE OF
T.D. TEN.  A SMALL AREA OF UPPER DIVERGENCE IS JUST NW OF PUERTO
RICO NEAR 21N68W... CAUSING WIDELY SCATTERED TSTMS WITHIN 90 N M
OF THAT POINT.  FARTHER E...HIGH-AMPLITUDE RIDGE IS NEAR 22N18W
IN THE FAR E ATLC RIDGING WSW TO 11N52W.  DEEP ELYS CONTROLS THE
DEEP TROPICS EXCEPT FOR AN INVERTED TROUGH ALONG 36W S OF 20N.
SURFACE PRESSURE IS SLIGHTLY BELOW AVERAGE IN THE DEEP TROPICS
THOUGH THE SUBTROPICAL RIDGE IS BUILDING BACK IN.. NOW 1024 MB
NEAR 32N27W.  TRADES ARE STILL A BIT BELOW AVERAGE BUT SHOULD BE
INCREASING WITH THE HIGH FORECAST TO STRENGTHEN DURING THE NEXT
FEW DAYS.   STRONG WLY LOW-LEVEL FLOW CONTINUES IN THE E ATLC...
CAUSING SCATTERED MODERATE CONVECTION OFFSHORE OF W AFRICA
WITHIN 90 NM OF 8N14W.

$$
BLAKE




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