[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 150549
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SUN 15 MAY 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS ADDED ALONG 29W S OF 10N MOVING W 15-20 KT.
THIS WAVE PASSED DAKAR ABOUT 3 DAYS AGO AND WAS MOVING VERY
SLOWLY AT THE TIME.  HOWEVER COMPUTER MODELS SUGGEST IT IS
EMBEDDED WITHIN THE AFRICAN ELY JET AND SHOULD ACCELERATE
WESTWARD.  ISOLATED MODERATE CONVECTION FROM 3N-8N BETWEEN
29W-32W.

TROPICAL WAVE NEAR BARBADOS ALONG 59W S OF 14N MOVING W 15-20
KT.  WLY SHEAR IS PROVIDING FAVORABLE UPPER-LEVEL DYNAMICS WITH
WIDELY SCATTERED SHOWERS/TSTMS BETWEEN 8N-14N FROM 56W-61W.
THE WAVE SHOULD PRODUCE A WET DAY OVER THE WINDWARD ISLANDS S OF
MARTINIQUE TODAY.

TROPICAL WAVE S OF HAITI ALONG 74W S OF 18N MOVING W 10-15 KT.
POSITION IS BASED ON EXTRAPOLATION WITH THE WAVE BEING VERY
DIFFICULT TO FIND IN LARGE-SCALE TROUGHING IN THE CENTRAL/W
CARIBBEAN.  WAVE IS PROBABLY ENHANCING WIDELY SCATTERED
MODERATE/ STRONG CONVECTION FROM 13N-15N BETWEEN 72W-75W AND
WITHIN 60 NM OF 77W FROM 11.5N TO 16N.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 11N15W 7N20W 7N30W 3N35W 5N52W.
WIDELY SCATTERED WEAK/MODERATE CONVECTION IS WITHIN 60 NM OF
LINE 6N11W 4N17W 4.5N23W 7N26W.

...DISCUSSION...

MEXICO...
HEAVY RAINS ARE FALLING TONIGHT OVER NORTHERN MEXICO WITH
FAVORABLE ELY UPSLOPE FLOW AND RELATIVELY STEEP MID-LEVEL LAPSE
RATES AIDING EARLIER CONVECTION DEVELOPMENT.  THIS ACTIVITY
SHOULD FADE OVERNIGHT AS THE ATMOSPHERE BECOMES LESS UNSTABLE IN
THE LOW-LEVELS BUT LINGERING OUTFLOW BOUNDARIES COULD STILL
FORCE ISOLATED TSTMS.

GULF OF MEXICO...
SURFACE WINDS HAVE GENERALLY WEAKENED SINCE 24 HOURS AGO DUE TO
HIGH PRESSURE MOVING EASTWARD FROM THE MID-ATLANTIC STATES INTO
THE W ATLC... SLACKENING THE LARGE-SCALE PRESSURE GRADIENT.  A
COLD FRONT LIES JUST NW OF THE GULF WITH ISOLATED TSTMS OVER S
MISSISSIPPI AND SE LOUISIANA DUE TO THE FRONT.  THE FRONT SHOULD
PUSH INTO THE GULF IN THE NEXT FEW HOURS WITH THE BEST CHANCE OF
OVERNIGHT RAIN FROM NEW ORLEANS EASTWARD TO MOBILE ALABAMA.
OTHERWISE HIGH CONVECTIVE DEBRIS CLOUDS ARE OVER THE W GULF PLUS
A WEAK MID/UPPER TROF IS ACROSS THE NE GULF WATERS FROM E GA TO
THRU FLORIDA BUT IS NOT CAUSING ANY NOTICEABLE WEATHER.  COLD
FRONT SHOULD PROVIDE THE FOCUS FOR TSTMS DURING THE DAY SUN N OF
28N BETWEEN TALLAHASSEE AND BILOXI THOUGH THE MAIN IMPACT OF THE
FRONT WILL BE TO LOWER DEWPOINTS RATHER THAN TEMPERATURES.

CARIBBEAN...
VERY WET CONDITIONS CONTINUE FROM THE CENTRAL CARIBBEAN EASTWARD
THRU THE NE CARIBBEAN.  UPPER TROF LIES BETWEEN HAITI AND
JAMAICA... FUELING TSTMS THAT FORMED MOSTLY JUST S OF HISPANIOLA
AND OVER THE FAR NE CARIBBEAN YESTERDAY.  THIS PATTERN IS
KEEPING THE DRIEST WEATHER NW OF A LINE FROM NICARAGUA TO E CUBA
IN THE SUBSIDING W SIDE OF THE UPPER TROUGH.  TSTMS ARE FORMING
NEAR A SURFACE TROUGH IN THE SW CARIBBEAN FROM 11N79W TO 18N79W
WITH SCATTERED MODERATE/STRONG CONVECTION WITHIN 90 NM E OF THE
TROUGH.  ANOTHER ROUND OF HEAVY RAIN IS FORMING NEAR PUERTO RICO
WITH WIDELY SCATTERED SHOWERS/TSTMS S OF 20N BETWEEN 64W-70W.
COMPUTER MODELS ARE INSISTENT THAT A SURFACE LOW OF SOME KIND
WILL FORM S OF JAMAICA AND KEEP THE HEAVY RAIN POTENTIAL FOR AT
LEAST THE NEXT COUPLE OF DAYS IN THE NE CARIBBEAN.  THERE IS A
STRONG POSSIBILITY OF CONTINUED FLOODING OVER PARTS OF THE
GREATER ANTILLES E OF CUBA INTO THE NE LEEWARD ISLANDS.

WEST/CENTRAL ATLANTIC...
A SMALL UPPER RIDGE IS ALONG 76W N OF THE BAHAMAS WITH A TROUGH
BENEATH THE RIDGE INTO THE CENTRAL BAHAMAS.  LARGER MID-LATITUDE
TROUGH LIES OVER THE CENTRAL ATLC BRINGING A COLD FRONT ALONG
THE NORTHERN PERIPHERY OF THE AREA.  FRONT ENTERS NEAR 31N49W TO
28N60W BEFORE BECOMING STATIONARY AND DISSIPATING TO 29N71W.
THERE IS LITTLE WEATHER NEAR THE FRONT WITH JUST AN INCREASE IN
LOW CLOUDINESS AND A FEW SHOWERS AS ANY SIGNIFICANT MOISTURE IS
FARTHER S.  PERSISTENT SURFACE TROUGH RUNS FROM 31N40W 27N47W
24N54W 21N60W TO NEAR PUERTO RICO AND IS SERVING AS A MECHANISM
FOR A LARGE AREA OF OVERCAST MULTI-LAYERED CLOUDS AND WIDELY
SCATTERED SHOWERS/TSTMS FROM 19N-24N BETWEEN 57W-68W.  NEARBY
SUBTROPICAL JET STRETCHES FROM THE N COAST OF HISPANIOLA TO
28N52W AND IS BOUNDED ON ITS S BY A DEEP LAYER OF MOISTURE WITH
WIDESPREAD CIRRUS FROM 18N-28N.  A LOW COULD FORM ALONG THE
TROUGH IN THE NEXT FEW DAYS THOUGH COMPUTER MODELS ARE IN
DISAGREEMENT TO THE INTENSITY AND THE TRACK.

EAST ATLANTIC...
GENERALLY WESTERLY UPPER FLOW SPANS ACROSS THE E ATLC WATERS
WITH A WEAK TROF LOCATED FROM 30N29W TO 7N38W WITH AN INCREASE
IN HIGH CLOUDS AHEAD OF THE FEATURE N OF 20N. ANOTHER TROF IS
LOCATED FARTHER S IN THE TROPICS FROM JUST E OF THE CAPE VERDE
ISLANDS TO 4N35W. SURFACE RIDGE OF HIGH PRES EXTENDS INTO THE
AREA ALONG 32N24W 18N48W. THE SUBTROPICAL JET IS ADVECTING HIGH
CLOUDS ACROSS THE AREA FROM 22N-30N...EXTENDING ACROSS THE
CANARY ISLANDS TO NRN MOROCCO. A DUST PLUME WAS NOTED ON
YESTERDAY'S VISIBLE IMAGES FROM W AFRICA TO ABOUT 55W S OF 25N
THOUGH ITS EXACT AERIAL EXTENT WAS UNCERTAIN.

$$
BLAKE

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