[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 190541
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST SUN 19 DEC 2004

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.

...ITCZ...

ITCZ IS CENTERED ALONG 7N10W 2N50W 5N80W.  WIDELY SCATTERED
MODERATE TO STRONG CONVECTION WITHIN 90 NM EITHER SIDE OF
BOUNDARY E OF 40W. WIDELY SCATTERED MODERATE CONVECTION FROM
7N-13N BETWEEN 22W-32W.

...DISCUSSION...

GULF OF MEXICO...
A BROAD LONGWAVE TROUGH REMAINS ENTRENCHED OVER THE E TWO THIRDS
OF THE UNITED STATES WITH A 130 KT S STREAM JET EXTENDING ACROSS
THE N GLFMEX ALONG 28N.  A SERIES OF SHORTWAVE IMPULSES EMBEDDED
WITHIN THE S STREAM FLOW HAVE SLOWLY CARVED OUT THE LONGWAVE
TROUGH OVER THE LAST FEW DAYS. THIS EVOLUTION HAS SHIFTED THE
MAIN BAND OF MOISTURE AND ASSOCIATED CLOUDS/PRECIP SWD WITH DRY
AIR NOW INFILTRATING THE N GULF. BROKEN CLOUDINESS AND SCATTERED
SHOWERS NOW COVER THE AREA FROM 23N-26N WITH THE MOST NUMEROUS
ACTIVITY CURRENTLY OVER THE FLORIDA STRAITS.  THE SURFACE COLD
FRONT ALONG THE E COAST OF FLORIDA LAST NIGHT HAS SHIFTED WELL E
OF THE AREA RESULTING IN NLY FLOW OVER MOST OF THE GULF.
HOWEVER...ONLY WEAK COLD AIR ADVECTION ACCOMPANIES THIS
PATTERN.  LOOKING UPSTREAM...A VIGOROUS SHORTWAVE IS CURRENTLY
DROPPING SWD OVER THE MISSISSIPPI VALLEY BRINGING WITH IT A
STRONG SURGE OF CANADIAN. THIS SECOND FRONT WILL SWEEP ACROSS
THE GLFMEX SUNDAY. HOWEVER MOISTURE AND SCATTERED SHOWERS/TSTMS
WILL LINGER OVER THE S GULF THROUGH SUN AFTERNOON PRIOR TO THE
FRONT CLEARING OUT THE ENTIRE AREA SUNDAY NIGHT.

CARIBBEAN...
STRONG MIDDLE TO UPPER LEVEL RIDGE DOMINATES THE ENTIRE
CARIBBEAN WITH AXIS EXTENDING E/W FROM NICARAGUA TO THE LEEWARD
ISLANDS.  RESULTING FLOW IS PRIMARILY WESTERLY ACROSS THE
CARIBBEAN BASIN WITH MODERATE SUBSIDENCE PRODUCING DRY/STABLE
CONDITIONS ABOVE 700 MB.  AT THE LOWER LEVELS...MOISTURE IS
LIMITED OVER THE E HALF OF THE CARIBBEAN RESULTING IN MOSTLY
CLEAR SKIES. A REMNANT FRONTAL TROUGH FROM E CUBA TO COSTA RICA
CONTINUES TO PRODUCE A 150 NM WIDE BAND OF CLOUDINESS AND
SCATTERED SHOWERS. ELSEWHERE NW OF THE TROUGH...DRY/TRANQUIL
WEATHER PREVAILS SAVE PORTIONS OF HONDURAS AND GUATEMALA WHERE
NLY FLOW IS PRODUCING CLOUDINESS AND SHOWERS ALONG WINDWARD
FACING SLOPES.  AN AMPLIFYING UPSTREAM TROUGH WILL PRODUCE A
MORE UNSTABLE/WET PATTERN OVER THE NW CARIBBEAN SUN AND MON AS
THE ASSOCIATED FRONT PUSHES INTO THE AREA.  MEANWHILE...MAINLY
DRY CONDITIONS SHOULD PREVAIL OVER THE E CARIBBEAN SAVE THE AREA
S OF 13N/14N WHERE A LOW LEVEL ELY DISTURBANCE WILL PRODUCE
SCATTERED SHOWERS.

ATLANTIC...
HIGHLY AMPLIFIED PATTERN IS UNFOLDING OVER THE W ATLC AS A
MIDDLE TO UPPER LEVEL TROUGH DIGS OVER THE E UNITED STATES.  THE
AMPLIFYING TROUGH WILL IGNITE CYCLOGENESIS OFF THE MID-ATLANTIC
COAST SUNDAY NIGHT AND MONDAY.  CURRENTLY...A WEAK COLD FRONT
TRAILS SWD OVER THE AREA IN BETWEEN BERMUDA AND THE CAROLINA
COAST REACHING THE CENTRAL BAHAMAS NEAR 25N76W THEN SW OVER CUBA
ALONG 22N80W.  SCATTERED SHOWERS/THUNDERSTORMS LIE AHEAD OF THE
FRONT TO 70W FROM THE BAHAMAS NWD TO 30N.  ANOTHER...MUCH
STRONGER...COLD FRONT IS CURRENTLY PUSHING SWD OVER THE CENTRAL
UNITED STATES AND WILL ENTER THE AREA SUNDAY NIGHT WITH STRONG
NW FLOW AND STRONG COLD AIR ADVECTION.  FURTHER E...A NEARLY
STATIONARY MID/UPPER LEVEL TROUGH OVER THE CNTRL ATLC WATERS
ALONG 50W IS PRODUCING AN AREA OF CLOUDINESS AND SCATTERED
SHOWERS/ THUNDERSTORMS N OF 10N BETWEEN 45W-51W.   OVER THE E
ATLC... A CUTOFF LOW HAS FORMED NEAR 26N35W WITH INDUCED RIDGING
AND DIFFLUENT FLOW TO THE EAST.  RESULTING PATTERN CONTINUES TO
SUPPORT ENHANCED ITCZ CONVECTION E OF 40W WITH ASSOCIATED HIGH
CLOUDINESS AND WIDELY SCATTERED SHOWERS EXTENDING NWD OVER THE
CAPE VERDE ISLANDS.

$$
RHOME








This weather bulletin was brought to you by:
www.nashvilleweather.net