[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 170530
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST THU NOV 17 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
0445 UTC.

...SPECIAL FEATURES...

A 1004 MB LOW IS CENTERED IN THE FAR SW CARIBBEAN ALONG THE
COAST OF NICARAGUA NEAR 12N83W. THIS BROAD LOW IS DRIFTING
WESTWARD WHICH WILL TAKE IT INLAND OVER CENTRAL AMERICA BEFORE
IT CAN DEVELOP INTO A TROPICAL CYCLONE. HOWEVER...EVEN WITHOUT
FURTHER DEVELOPMENT THIS SYSTEM IS BRINGING HEAVY RAINS TO
PORTIONS OF CENTRAL AMERICA WHICH COULD PRODUCE FLASH FLOODS AND
MUD SLIDES ESPECIALLY TO NICARAGUA AND HONDURAS. THERE IS IS
STILL A POSSIBILITY OF FURTHER DEVELOPMENT IF THE LOW LEVEL
CENTER REMAINS OFFSHORE. SCATTERED/NUMEROUS STRONG CONVECTION IS
FROM 15N-17.5N BETWEEN 78.5W-83.5W. SCATTERED MODERATE/ISOLATED
STRONG CONVECTION COVERS THE REMAINDER OF THE AREA FROM 12N-18N
BETWEEN 80W-89W.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 11N15W 8N22W 12N45W 11N61W.
SCATTERED MODERATE/STRONG CONVECTION IS WITHIN 90 NM OF LINE
16N38W 15N44W...WITHIN 120 NM S OF THE AXIS FROM 17W-30W...AND
WITHIN 150 NM S OF THE AXIS FROM 31W-35W. SCATTERED MODERATE/
ISOLATED STRONG CONVECTION IS WITHIN 60 NM OF OF LINE 4N32W
6N38W. CLUSTERS OF SIMILAR CONVECTION ARE WITHIN 150 NM OF THE
AXIS FROM 38W-51W.

...DISCUSSION...

GULF OF MEXICO...
A STRONG COLD FRONT EXTENDS ACROSS NE FLORIDA INTO THE GULF NEAR
30N83W SW ALONG 23N92W INTO S MEXICO NEAR VERACRUZ THEN NW AS A
STATIONARY FRONT ALONG THE BASE OF THE SIERRA MADRE MOUNTAINS.
GALE CONDITIONS ARE W OF THE FRONT WITH AN AREA OF STORM
CONDITIONS S OF 23N W OF THE FRONT. BROKEN/OVERCAST MULTILAYERED
CLOUDS ARE BEHIND THE FRONT WITH POSSIBLE ISOLATED SHOWERS
WITHIN 45 NM OF THE FRONT. IN THE UPPER LEVELS...BROAD DEEP
LAYERED TROUGH COVERS THE E TWO-THIRDS OF THE U.S. COUPLED WITH
THE UPPER HIGH IN THE CARIBBEAN IS PRODUCING STRONG SW FLOW
ACROSS THE ENTIRE GULF ADVECTING TROPICAL MOISTURE N ACROSS THE
AREA. THE COLD FRONT WILL CLEAR THE GULF IN THE NEXT 24 HOURS
AND BEGIN TO WEAKEN WITH MODERATE/STRONG N TO NE SURFACE WINDS
REMAINING OVER THE GULF THROUGH THE FIRST PART OF THE WEEKEND.
SHOWERS/THUNDERSTORMS WILL MOVE NE INTO THE GULF FROM THE
CARIBBEAN IN ASSOCIATION WITH THE SURFACE LOW IN THE SPECIAL
FEATURES ABOVE.

CARIBBEAN SEA...
SEE SPECIAL FEATURES FOR THE 1004 MB LOW IN THE SW CARIBBEAN. AN
UPPER HIGH IS IN THE N/CENTRAL CARIBBEAN NEAR 16N75W WITH A
RIDGE EXTENDING NW THROUGH THE YUCATAN CHANNEL TO OVER THE GULF
OF MEXICO PRODUCING GENEROUS OUTFLOW TO THE SURFACE LOW MAINLY
TO THE N AND W. ABUNDANT TROPICAL MOISTURE REMAINS OVER THE S
CARIBBEAN PRODUCING NOT ONLY THE CONVECTION ASSOCIATED WITH THE
SURFACE LOW...BUT CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG
CONVECTION S OF 14N TO INLAND OVER SOUTH AMERICA BETWEEN
64W-77W. AN UPPER TROUGH EXTENDS INTO THE NE CARIBBEAN FROM THE
W/CENTRAL ATLC GIVING THE AREA N OF 15N FROM THE LEEWARD
ISLANDS TO HISPANIOLA DRY AIR/STRONG SUBSIDENCE AND CLEAR
CONDITIONS. MOISTURE LEVELS WILL REMAIN FOR THE S AND W
CARIBBEAN THROUGH THE WEEKEND.

ATLANTIC OCEAN...
UPPER HIGH FROM THE CARIBBEAN COVERS THE FAR W ATLC W OF 70W
GIVING THE BAHAMAS DRY AIR/STRONG SUBSIDENCE...BUT WITH HIGH
CLOUDS MOVING IN. REMAINDER OF THE W ATLC INTO THE CENTRAL ATLC
ALSO HAS EXTENSIVE DRY AIR IN THE MID/UPPER LEVELS TO 55W. THIS
COUPLED WITH THE SHALLOW INVERSION IS PRODUCING A BROKEN
STRATOCUMULUS FIELD OVER THE SAME AREA. IN THE CENTRAL ATLC IS A
CUT-OFF UPPER LOW CENTERED NEAR 26N53W WITH A TROUGH AXIS
EXTENDING SW INTO THE NE CARIBBEAN OVER PUERTO RICO AND THE
VIRGIN ISLANDS. DRY UPPER AIR AND STRONG SUBSIDENCE IS BEING
DRAWN INTO THE CIRCULATION FROM 20N-26N BETWEEN 48W-55W.
SCATTERED SHOWERS/THUNDERSTORMS ARE WITHIN 75 NM OF LINE FROM
26N54W 31N51W TO 29N48W. A SURFACE TROUGH IS ALONG THE EDGE OF
THE UPPER TROUGH ALONG 48W FROM 16N-33N. BROAD RIDGE IS TO THE E
OF THE SURFACE TROUGH S OF 33N BETWEEN 27W-43W PROVIDING UPPER
DIFFLUENCE TO GENERATE A BROAD AREA OF SCATTERED SHOWERS/
ISOLATED THUNDERSTORMS FROM 17N-31N BETWEEN 39W AND THE SURFACE
TROUGH. A SECOND CUT-OFF UPPER LOW IS IN THE NE ATLC OVER THE
CANARY ISLANDS NEAR 28N16W AND COVERS THE AREA N OF 20N E OF
27W. DRY AIR AND STRONG SUBSIDENCE IS AT THE BASE OF THE UPPER
LOW FROM 20N-25N E OF 25W TO INLAND OVER WESTERN SAHARA. AT THE
SURFACE...HIGH PRESSURE COVERS THE ENTIRE ATLC WITH A WEAKNESS
ALONG THE SURFACE TROUGH.

$$
WALLACE


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