[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 021200
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SUN OCT 02 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...SPECIAL FEATURES...

TROPICAL STORM STAN CENTERED NEAR 19.7N 87.7W ON THE EAST COAST
OF THE YUCATAN PENINSULA ABOUT 30 NM/60 KM SOUTH-SOUTHWEST
OF TULUM MEXICO AT 02/1200 UTC MOVING WEST-NORTHWEST 5 KT.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 1003 MB. MAXIMUM SUSTAINED
WIND SPEED IS 40 KT WITH GUSTS TO 50 KT. SEE LATEST NHC
FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT5/WTNT25 KNHC
AND THE PUBLIC ADVISORY UNDER HEADERS MIATCPAT5/WTNT35 KNHC FOR
MORE DETAILS.  RECON FLEW INTO T.D. TWENTY EARLIER AND FOUND THE
WINDS HAD INCREASED ENOUGH TO GIVE THE SYSTEM A NAME.  TSTMS
REMAIN FAIRLY CONCENTRATED AROUND THE CENTER WITH SCATTERED
MODERATE CONVECTION FROM 17N22N BETWEEN 85.5W-89W WITH OTHER
CURVED BANDS PRODUCING STRONG GUSTY WINDS WITHIN 60 NM OF LINE
17.5N84.5W 20.5N84.5W 21.5N85.5W.  HEAVY RAIN IS EXPECTED TO BE
THE MAIN THREAT WITH STAN DUE TO ITS SLOW MOVEMENT OVER YUCATAN
WITH OTHER HEAVY RAINS POSSIBLE IN BELIZE AND NRN GUATEMALA.

TROPICAL DEPRESSION NINETEEN CENTERED NEAR 16.0N 34.8W...OR 715
MILES W OF THE CAPE VERDE ISLANDS...AT 02/0900 UTC MOVING NNW 7
KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1008 MB. MAXIMUM
SUSTAINED WIND SPEED IS 30 KT WITH GUSTS TO 40 KT. SEE LATEST
NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24
KNHC FOR MORE DETAILS.  WLY SHEAR HAS NOT ALLOWED THE SYSTEM TO
INTENSIFY.  TWO AREAS OF CONVECTION ARE NOTED.. ONE E OF THE
CENTER WITH SCATTERED MODERATE FROM 13N-17.5N BETWEEN 30W-34W
AND A SMALLER AREA OF SIMILAR CONVECTION WITHIN 60 NM OF
19N35.5W.  MODERATE TO STRONG WLY SHEAR IS FORECAST TO PERSIST
AND WILL LIKELY INHIBIT MUCH STRENGTHENING.

...TROPICAL WAVES...

E ATLC TROPICAL WAVE LOCATED NEAR THE WRN CAPE VERDE ISLANDS
ALONG 25W/26W S OF 19N MOVING W 10-15 KT.  ISOLATED
SHOWERS/TSTMS REMAIN WITHIN 90 NM OF THE WAVE AXIS INCLUDING
SOME OF THE CAPE VERDES. MOISTURE SHOULD DEPART THE CAPE VERDES
BY TONIGHT WITH TYPICAL NE TRADES RESUMING.  SCATTERED TSTMS ARE
ALSO WITHIN 120 NM OF 6N23W.

CENTRAL CARIBBEAN/W ATLC TROPICAL WAVE NEAR JAMAICA ALONG
77W/78W S OF 25N MOVING W 15 KT.  NLY SHEAR IS COMBINING WITH
DEEP-LAYERED MOISTURE TO CREATE A LOT OF RAIN NEAR THE WAVE
AXIS.  SCATTERED MODERATE CONVECTION IS IN THE BAHAMAS AND
ADJACENT WATERS S OF 25N BETWEEN 73.5W-78W.  OTHER TSTMS ARE
OVER JAMAICA WITH SCATTERED MODERATE ACTIVITY NW OF COLOMBIA S
OF 14N BETWEEN 72W-78W.  ADDITIONAL RAINFALL AMOUNTS COULD CAUSE
AREAS OF FLOODING ESPECIALLY IN THE MORE RUGGED AREAS OF CUBA
AND JAMAICA.  IT LOOKS LIKE A WET COUPLE OF DAYS FOR THE W
CARIBBEAN WITH THIS WAVE MOVING THROUGH.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 11N16W 8N23W 11N40W 13N55W.  EARLIER
SQUALL LINE HAS WEAKENED WITH AN AREA OF WIDELY SCATTERED
MODERATE CONVECTION FROM 5N-10N BETWEEN 13W-20W IN ADDITION TO
ISOLATED TSTMS WITHIN 60 NM OF 21W BETWEEN 10N-14N.  SCATTERED
MODERATE FROM 9N-12.5N BETWEEN 37W-42W...POSSIBLY ASSOCIATED
WITH THE WAVE THAT SPAWNED T.D. 19.  ISOLATED MODERATE WITHIN 60
NM OF AXIS BETWEEN 47W-55W.

...DISCUSSION...

GULF OF MEXICO...
THE SOUTHERN PART OF THE AREA IS SLOWLY MOISTENING DUE TO STAN
WHICH IS FORECAST TO MOVE OVER GULF WATERS IN ABOUT 24 HOURS.
SLY WINDS IN THE UPPER LEVELS CONTINUES TO TRANSPORT CIRRUS
CLOUDS NORTHWARD AND SLOWLY MODIFY THE DRY AIR ALOFT IN THE NRN
GULF.  A TROUGH HANGS FROM SW LOUISIANA TO E MEXICO NEAR
22N98W... SLOWLY MOVING EASTWARD.   UPPER RIDGING IS EXPANDING
IN THE E GULF FROM W CUBA TO JUST W OF TAMPA.  PASSING SHOWERS
ARE STILL PRESENT OVER S FLORIDA AND THE COASTAL WATERS OF
LOUISIANA.  THE NW GULF SHOWERS SHOULD CONTINUE TO FILTER
WESTWARD AND IMPACT COASTAL TEXAS LATER TODAY WHILE A SLUG OF
MOISTURE IN THE SE BAHAMAS WILL LIKELY KEEP S FLORIDA VERY
UNSTABLE AND FAIRLY WET.  THE GFS FORECASTS ANOTHER CHUNK OF
MOISTURE TO ENTER THE STATE ON TUE... WITH SOME SLIGHT
POSSIBILITY OF TROPICAL GENESIS HINTED TO IN THE MODEL FIELDS.
MODEL CONSENSUS IS FOR A LARGE LOW TO FORM IN THE E GULF BY
MID-WEEK AHEAD OF A COLD FRONT AND REGARDLESS OF DEVELOPMENT..
KEEP THE E GULF VERY WET.

CARIBBEAN...
AN UPPER LEVEL ANTICYCLONE IS GETTING BETTER-DEFINED IN THE NW
CARIBBEAN NEAR 21N82W WITH FAIRLY LIGHT SHEAR IN THE VICINITY OF
STAN.  NLY OR NE WINDS ALOFT CONTROL THE REGION W OF 68W WITH
ISOLATED TSTMS OUTSIDE OF THE TROPICAL WAVE NEAR 77W.  SCATTERED
TO BROKEN CIRRUS CLOUDS ARE EVERYWHERE W OF 70W. AN UPPER TROUGH
REMAINS SITUATED FROM THE NRN LEEWARD ISLANDS SW TO THE OFFSHORE
VENEZUELAN ISLANDS AND DEMARCATES THE MOIST ATMOSPHERE TO THE W
FROM DRIER WEATHER TO THE E. EXCEPT FOR SCATTERED SHOWERS/TSTMS
OCCURRING OVER THE NRN LEEWARD ISLANDS IN ASSOCIATION WITH THE
UPPER LOW TO THE N...MOST OF THE E CARIBBEAN IS UNDER GENERALLY
FAIR SKIES.  THE GFS SUGGESTS THE DRY WEATHER WILL CONTINUE IN
THE SE CARIBBEAN FOR AT LEAST THE NEXT FEW DAYS WHILE A BAND OF
ENHANCED MOISTURE WILL STAY OVER THE NE CARIBBEAN NW OF
GUADELOUPE.

ATLANTIC...
STATIONARY UPPER LEVEL LOW IS LOCATED ABOUT 420 NM E OF
JACKSONVILLE FLORIDA NEAR 30N73W AND HAS BEEN ENHANCING WIDELY
SCATTERED SHOWERS/TSTMS PRIMARILY NE OF THE BAHAMAS FROM 25N-31N
BETWEEN 66W-76W.  HIGH PRESSURE OVER THE MID-LATITUDE W ATLC IS
KEEPING LOW-LEVEL ELY FLOW AROUND 20 KT AND UNSTABLE ESPECIALLY
NEAR LARGE-SCALE LIFTING MECHANISMS LIKE UPPER LOWS.  UNSETTLED
WEATHER CONTINUES FARTHER E WITH ANOTHER UPPER LOW NE OF THE
LEEWARD ISLANDS NEAR 21N62W...WITH SCATTERED MODERATE CONVECTION
FROM 18N-26N BETWEEN 59W-67W.  THIS UPPER LOW IS STUCK BENEATH A
SLOW-MOVING HIGH NEAR 31N63W ESE OF BERMUDA.  A SURFACE TROUGH
IS ALIGNED FROM PUERTO RICO TO 27N72W WITH WIDELY SCATTERED
SHOWERS/TSTMS WITHIN 5 DEGREES E OF THE TROUGH AXIS.  THIS
FEATURE HAS PLENTY OF SUPPORT NEAR UPPER TROUGH AXES.  OVER THE
CENTRAL ATLC...AN UPPER LEVEL HIGH IS IN THE TROPICS NEAR 12N46W
AND CONTINUES TO PROVIDE A DIFFLUENT ENVIRONMENT FOR CONVECTION
ALONG THE ITCZ BETWEEN 35W-50W. ANOTHER UPPER LOW IS OVER THE NE
ATLC NEAR 27N32W BUT IS ELONGATING INTO AN E-W ORIENTING
TROUGH.  ISOLATED TSTMS ARE N OF THE UPPER TROUGH FROM 27N-31N
BETWEEN 26W-41W.  UPPER LEVEL WESTERLY FLOW EXTENDS S OF THE
UPPER LOW/TROUGH TO ABOUT 13.5N...WHICH IS PLACING A RELATIVELY
HOSTILE ENVIRONMENT OVER T.D. 19. UPPER RIDGING MAY ACTUALLY
BUILD IN THE E ATLC IF THE GFS IS TO BE BELIEVED AS THE UPPER
LOW OVER THE NE ATLC WEAKENS.  WEAK UPPER TROUGH IS ALSO ALONG
36W FROM 12N-19N... BETWEEN TWO HIGHS IN THE TROPICAL ATLC.
LOW-LEVEL WLY FLOW IS QUITE IMPRESSIVE IN THE DEEP TROPICS FOR
EARLY OCT WITH A LOT LESS SHEAR THAN AVERAGE AS WELL.

$$
BLAKE

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