[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 132355
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST THU 13 JAN 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 1N1W 3N20W 2N40W 7N55W 6N80W. WIDELY
SCATTERED MODERATE CONVECTION IS FROM EQ-5N BETWEEN 20W-45W.

...DISCUSSION...

GULF OF MEXICO...
A COLD FRONT EXTENDS FROM MISSISSIPPI TO THE BAY OF CAMPECHE AT
2100 UTC ALONG 30N89W 24N93W 18N95W 20N98W.  A SQUALL LINE IS E
OF THE FRONT OVER THE FLORIDA PANHANDLE AND NE GULF OF MEXICO
ALONG 31N85W 26N87W.  THE SYSTEM IS MOVING RAPIDLY E.  SCATTERED
MODERATE CONVECTION IS N OF 26N WITHIN 150 NM W OF THE COLD
FRONT... AND WITHIN 90 NM E OF THE SQUALL LINE.  THIS WHOLE
SYSTEM IS BEING SUPPORTED BY A DEEP UPPER LEVEL LONGWAVE TROUGH
WHICH IS CENTERED OVER THE CNTRL PLAINS EXTENDING SWD TO NE
MEXICO. UPPER DIVERGENCE IS AHEAD OF THE TROUGH SPREADING INTO
THE TENNESSEE/OHIO VALLEYS.

CARIBBEAN...
BROAD MID/UPPER LEVEL RIDGE IS TILTED BACKWARDS FROM NW
VENEZUELA OVER THE W CARIBBEAN TOWARDS CUBA...THEN SLOPES TO
MORE ZONAL FLOW OVER THE E CARIBBEAN AND LESSER ANTILLES. THE
FLOW IS SLIGHTLY DIFFLUENT EMERGING AWAY FROM CNTRL AMERICA
TOWARDS JAMAICA AND THIS IS PRODUCING AN AREA OF SCATTERED
MODERATE CONVECTION NEAR HONDURAS FROM 13N-19N BETWEEN 81W-85W.
THE MIDDLE AND UPPER ATMOSPHERE IS RATHER DRY HOWEVER...SO
ACTIVE WEATHER IS HARD TO COME BY OVER MUCH OF THE AREA.
SCATTERED SHOWERS ARE ADVECTING OVER THE E CARIBBEAN E OF 70W
WITH THE TRADES.

ATLANTIC OCEAN...
STRONG HIGH PRESSURE IS CENTERED N OF THE AREA AND IS PRODUCING
A TIGHT PRESSURE GRADIENT ACROSS THE ATLC OCEAN BETWEEN AFRICA
AND THE BAHAMAS.  THE EASTERLY WINDS HAVE BEEN UP TO 30 KT AS
INDICATED BY QSCAT IMAGERY.  A LARGE AREA OF BROKEN LOW CLOUDS
AND SCATTERED SHOWERS ARE OVER THE TROPICAL AND SUBTROPICAL
ATLANTIC FROM 6N-30N BETWEEN 35W-60W MOVING W.  A SURFACE TROUGH
IS E OF THE WINDWARD ISLANDS ALONG 16N54W 9N53W.  ISOLATED
MODERATE CONVECTION IS FROM 9N-11N BETWEEN 50W-57W.  A WEAKENING
COLD FRONT IS OVER THE CENTRAL ATLANTIC ALONG 32N34W 29N40W
29N49W.  NO SIGNIFICANT CONVECTION IS NOTED.  A PLUME OF AFRICAN
DUST IS SEEN E OF 40W AND S OF 15N MOVING W.  IN THE UPPER
LEVELS...A SMALL-SCALE BUT AMPLIFIED RIDGE EXTENDS FROM THE NRN
BAHAMAS NEWD PAST 32N73W AND IS KEEPING THE MID/UPPER LEVEL
CLOUDS ASSOCIATED WITH THE UPSTREAM GULF SYSTEM WELL TO THE N OF
THE AREA. A SHORTWAVE TROUGH IS DROPPING INTO THE AREA FROM
31N58W 26N70W BUT IS CAUSING NO SIGNIFICANT WEATHER.  THE FLOW
IS MOSTLY ZONAL ELSEWHERE AND IS PRECLUDING FRONTAL ACTIVITY
FROM DROPPING INTO THE REGION.


$$
FORMOSA




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