[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 220553
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST WED 22 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 AXIS IS CENTERED ALONG 7N11W 4N25W 4N43W 5N53W.  ISOLATED
MODERATE FROM 2N-6N BETWEEN 22W-28W.  SIMILAR CONVECTION WITHIN
90 NM OF 8N40W.

...DISCUSSION...

GULF OF MEXICO...
WIDELY SCATTERED SHOWERS/TSTMS HAVE FORMED OFFSHORE OF
LOUISIANA/SE TEXAS DUE TO A WEAK SURFACE TROUGH AND DIVERGENCE
AHEAD OF UPPER ENERGY PULLING OUT OF THE SOUTHWEST USA.  THE
RAIN IS N OF 27.5N BETWEEN 89W AND 95.5W AND IS LIKELY TO PUSH
OFFSHORE IN THE NEXT FEW HOURS.  OTHERWISE MOIST RETURN FLOW
COVERS THE GULF WITH SLY WINDS APPROACHING 25 KT IN THE NW
GULF.  SEVERE STORMS APPEAR TO BE POSSIBLE LATER TODAY ALONG THE
GULF COAST AS A STRONG COLD FRONT ENTERS THE REGION COMBINED
WITH THE UPPER DISTURBANCE PROVIDING LIFT AND SOME
INSTABILITY.   FORECAST WIND PROFILES ALSO SUGGEST THE THREAT
FOR A FEW TORNADOES GIVEN THE STRONG TURNING IN THE LOWER
TROPOSPHERE.  MUCH COLDER CONDITIONS ARE LIKELY FOR THU W OF
FLORIDA AS THE ARCTIC FRONT PUSHES THRU THE GULF.  A WAVE SHOULD
FORM ON THE FRONT IN THE N-CENTRAL GULF LATE THU AS ANOTHER
PIECE OF ENERGY EXITS THE SW USA AND THE TRACK OF THIS LOW
PRESSURE WAVE IS CRITICAL IN DETERMINING WHETHER PLACES IN THE
DEEP SOUTH HAVE ANY CHANCE OF WINTRY PRECIPITATION XMAS EVE INTO
XMAS DAY.  THE LATEST GFS SUGGESTS A BETTER CHANCE OF WINTRY
WEATHER THAN THE ETA WHICH KEEPS MOST SIGNIFICANT PRECIP
OFFSHORE.  IN ANY EVENT A COLD CHRISTMAS LOOKS ON TAP FOR A GOOD
CHUNK OF THE SOUTHERN US EXCEPT FOR THE FLORIDA PENINSULA.

WEST ATLANTIC...
MAIN COLD FRONTS IS NOW STATIONARY ALONG 31N53W TO NW DOMINICAN
REPUBLIC WITH ISOLATED TSTMS WITHIN 90 NM OF THE FRONT S OF 27N.
1029 MB HIGH LIES JUST W OF BERMUDA WITH RIDGING WSW THRU THE
FLORIDA STRAITS INTO THE W GULF.  THERE REMAINS PLENTY OF
LOW/MID CLOUDINESS WITH COLD AIR ONLY SLOWLY MODIFYING OVER THE
WARM W ATLC WATERS W OF THE FRONT... BECOMING MORE SCATTERED
OVER THE BAHAMAS.  FAST-MOVING SHORTWAVE NEAR BERMUDA IS ZIPPING
E IN MOSTLY ZONAL FLOW AND IS PRODUCING AN AREA OF HIGH LEVEL
CLOUDINESS N OF 25N BETWEEN 55W-75W.    COLD FRONT SCHEDULED TO
ENTER THE GULF WED SHOULD HIT THE W ATLC BY LATE THU BUT IS NOT
EXPECTED TO HAVE NEARLY THE PUNCH OF THE LAST SYSTEM AS A WAVE
FORMS ON THE TAIL END OF THE FRONT IN THE GULF.

CARIBBEAN...
DISSIPATING STATIONARY FRONT EXTENDS FROM JAMAICA TO NICARAGUA
WITH ONLY A FEW SHOWERS ALONG THE BOUNDARY.  ELSEWHERE IN THE
LOW-LEVELS WEAK TROUGHING PERSISTS IN THE SW CARIBBEAN BUT IS
PRODUCING LESS TSTM ACTIVITY THAN YESTERDAY WITH ONLY WIDELY
SCATTERED SHOWERS S OF 15N W OF 72W.  UPPER LEVEL HIGH IS
LINGERING IN NW VENEZUELA...CONTINUING BROAD SW/W FLOW ACROSS
THE CARIBBEAN SEA.  DRY AIR IN THE MID/UPPER LEVELS LIMITS MOST
CONVECTION WITH ONLY SHALLOW SHOWERS OCCURRING EXCEPT WITHIN 60
NM OF 14.5N75W.    MOSTLY DRY WEATHER APPEARS LIKELY FOR THE
AREA FOR THE NEXT COUPLE DAYS WITH ONLY ISOLATED TRADEWIND
SHOWERS.

CENTRAL AND EASTERN ATLANTIC...
MID/UPPER LEVEL LOW IS NEAR 19N41W WITH TROUGHING S TO 5N43W AND
A SURFACE TROUGH REFLECTION ALONG 40W FROM 12N-25N.  VERY DRY
AIR ALOFT LIES BEHIND THE UPPER TROUGH AXIS DUE TO CONVERGENCE
ON THE BACKSIDE OF THE TROUGH.  HOWEVER ON THE E SIDE BROAD
DIFFLUENCE CONTINUES TO ENHANCE WIDELY SCATTERED MODERATE
CONVECTION FROM 13N-23N BETWEEN THE CAPE VERDE ISLANDS AND 38W
WITH ONLY ISOLATED SHOWERS NEAR THE COLD CORE OF THE LOW FROM
15N-23N BETWEEN 38W-44W.  A WEAK LOW MAY FORM BY TOMORROW NIGHT
NEAR 22N35W AND WILL HAVE TO BE MONITORED AS SEVERAL MODELS
SUGGEST IT COULD BE OF A "HYBRID" TYPE WITH SOME POSSIBLE
SUBTROPICAL CHARACTERISTICS.  HOWEVER THIS SITUATION IS
UNCERTAIN AS THE LOW WILL LIKELY BE OVER VERY COOL WATER TEMPS
NEAR 23C.. MAKING ANY SUBTROPICAL SYSTEM LESS LIKELY.
ELSEWHERE.. SCATTERED/BROKEN LOW CLOUDS REMAIN OVER THE
SUBTROPICAL ATLC OUTSIDE OF THE CONVECTION ASSOCIATED WITH THE
CENTRAL ATLC TROUGH.  UPPER LEVEL RIDGING COVERS THE E ATLC...
BRINGING AREAS OF HIGH CLOUDINESS OVER THE E ATLC INTO W AFRICA.

$$
BLAKE

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