[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 042335
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST WED JAN 04 2006

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...SPECIAL FEATURE...

TROPICAL STORM ZETA AT 04/2100 UTC IS NEAR 21.7N 45.0W...OR
ABOUT 1200 MILES ENE OF THE NORTHERN LEEWARD ISLANDS... MOVING W
7 KT. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1000 MB. THE
MAXIMUM SUSTAINED WINDS ARE 45 KT WITH GUSTS TO 55 KT. PLEASE
REFER TO THE LATEST FORECAST/ADVISORY LISTED UNDER THE AWIPS/WMO
HEADERS MIATCMAT5/ WTNT25 KNHC FOR MORE DETAILS.  WLY SHEAR HAS
CAUSED THE CENTER TO BECOME EXPOSED WITH ANY REMAINING
CONVECTION IN THE ERN SEMICIRCLE.  ZETA SEEMS TO BE HAVE A SHORT
LIFE-EXPECTANCY WITH STRONG WLY SHEAR... RELATIVELY DRY AIR
ALOFT NEARBY... AND LIMITED CONVECTION.  ISOLATED WEAK
CONVECTION WITHIN 75 NM OF THE CENTER IN THE ERN SEMICIRCLE.

...ITCZ...
ITCZ AXIS IS ALONG 7N12W 3N28W 3N45W 1N50W.  SCATTERED MODERATE
CONVECTION S OF 3N BETWEEN 30W-37W.  WIDELY SCATTERED MODERATE
FROM 4N-10N BETWEEN 30W-36W.  ISOLATED TSTM CLUSTERS ARE NEAR
5.5N19W AND 5N25W.

...DISCUSSION...

GULF OF MEXICO...
RELATIVELY QUIET DAY DUE TO THE FRONT THAT PASSED THRU THE AREA
YESTERDAY.  MOSTLY CLEAR SKIES SAVE A FEW HIGH CLOUDS N OF 27N
DOMINATE WITH A WEAKENING 1018 MB HIGH IN THE CENTER OF THE
GULF.  A COLD FRONT IS RIGHT AT THE NW CORNER OF THE REGION AND
SHOULD MOVE INTO THE GULF IN THE NEXT FEW HOURS.  ALTHOUGH THE
FRONT DOESN'T APPEAR THAT STRONG YET... A VERY DEEP TROUGH IS
FORECAST TO DROP OVER THE ERN US AND FLORIDA OVER THE NEXT FEW
DAYS.. BRINGING THE COLDEST WEATHER OF THE SEASON FOR THE DEEP
SOUTH THU THRU SAT.  WIND CHILL VALUES COULD EVEN GET NEAR
FREEZING FOR S FLORIDA EARLY SAT.  FOR NOW SW FLOW ALOFT
CONTROLS THE REGION WITH MOISTURE INCREASING FROM SE TO NW.

CARIBBEAN SEA...
DISSIPATING COLD FRONT IS ACROSS W CUBA BUT IS FORECAST TO DIE
BEFORE MAKING MUCH OF AN IMPACT ON CARIBBEAN WATER.  SCATTERED
HIGH CLOUDS COVER THE REGION TO THE N OF A STRONGER-THAN-AVERAGE
UPPER RIDGE FROM NW VENEZUELA TO NICARAGUA.  TRADES ARE ALSO
LIGHT IN THE CARIBBEAN WITH NO HIGH PRESSURE AREA TO THE N DUE
TO A FRONTAL BOUNDARY.  WIDELY SCATTERED SHOWERS ARE S OF 15N W
OF 78W IN THE SW CARIBBEAN IN ADDITION TO OTHER ISOLATED SHOWERS
S OF 15N E OF 78W... INCLUDING THE ABC ISLANDS.  A STRONG COLD
FRONT WILL ENTER THE NW PART OF THE AREA ON FRI AND SHOULD PUSH
THRU THE GREATER ANTILLES NEAR HAITI BY LATE SAT...LIKELY
BRINGING A CLOUDY WET LATE WEEKEND TO A GOOD PORTION OF
HISPANIOLA.

ATLANTIC OCEAN...
COLD FRONT EXTENDS FROM 32N62 IN THE W ATLC TO 25N70W INTO THE
S-CENTRAL BAHAMAS TO CENTRAL CUBA NEAR 22.5N78W.  WIDELY
SCATTERED TSTMS ARE N OF 23N BETWEEN 63W-58W.  STRONG ASSOCIATED
UPPER TROUGH IS RESPONSIBLE FOR THE TSTMS AS WELL AS LOTS OF
DRYING ALOFT W OF 63W N OF THE ANTILLES.  UPPER RIDGING
CONTINUES N OF 25N BETWEEN 25W-60W WITH UPPER TROUGHING S OF THE
RIDGE NEAR ZETA WITH ANOTHER LOW NEAR 20N35W.  THE UPPER TROUGH
IN THE W ATLC IS QUICKLY SWEEPING EASTWARD WHICH SHOULD ACT TO
FURTHER WEAKEN ZETA IN THE NEXT FEW DAYS.  STRONG WLY FLOW IS
OVER THE TROPICAL ATLC WITH THE GFS INDICATING WINDS UP TO 125
KT W OF THE CAPE VERDES.  DRY AIR ALOFT DOMINATES W OF 35W S OF
20N WITH RELATIVELY LIGHT TRADES DUE TO ZETA AND NO STRONG
SUBTROPICAL HIGH.  MORE TYPICAL CONDITIONS ARE PRESENT IN THE NE
ATLC WITH TRADES TO 25N N OF THE CAPE VERDES AND RIDGING FROM A
1026 MB HIGH JUST SE OF THE AZORES.

$$
BLAKE


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