[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 171119
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1045 UTC.

...SPECIAL FEATURES...

A 1005 MB LOW IS CENTERED IN THE FAR SW CARIBBEAN ALONG THE
COAST OF NICARAGUA NEAR 12N83W. THIS BROAD LOW IS SLOWLY
DRIFTING WESTWARD WHICH WILL TAKE IT INLAND OVER CENTRAL AMERICA
BEFORE IT CAN DEVELOP INTO A TROPICAL CYCLONE. HOWEVER...EVEN
WITHOUT FURTHER DEVELOPMENT OF THIS SYSTEM...HEAVY RAINS TO
PORTIONS OF CENTRAL AMERICA 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
16N-19N BETWEEN 80W-83W. SCATTERED MODERATE/STRONG CONVECTION
COVERS THE REMAINDER OF THE AREA FROM 13.5N-20N BETWEEN 79W-85W.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 10N12W 6N24W 6N34W 12N48W 9N61W.
SCATTERED MODERATE/STRONG CONVECTION IS WITHIN 90/120 NM OF THE
AXIS FROM 20W-25W AND WITHIN 75 NM OF LINE 13N40W 15N45W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 150 NM
OF THE AXIS FROM 25W-30W...31W-39W...AND WITHIN 90/120 NM S OF
THE AXIS FROM 53W-59W. WIDELY SCATTERED THUNDERSTORMS DOT THE
AREA FROM 4N-13N E OF 45W.

...DISCUSSION...

GULF OF MEXICO...
A STRONG COLD FRONT EXTENDS ACROSS THE N FLORIDA PENINSULA INTO
THE GULF NEAR 30N81W SW ALONG 22N92W INTO S MEXICO NEAR VERACRUZ
THE ISTHMUS OF TEHUANTEPEC WITH A STATIONARY FRONT ALONG THE
BASE OF THE SIERRA MADRE MOUNTAINS. GALE CONDITIONS ARE W OF THE
FRONT S OF 23N. 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 TODAY 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 SE GULF THIS WEEKEND FROM THE CARIBBEAN IN ASSOCIATION
WITH THE SURFACE LOW IN THE SPECIAL FEATURES ABOVE.

CARIBBEAN SEA...
SEE SPECIAL FEATURES FOR THE 1005 MB LOW IN THE SW CARIBBEAN. AN
UPPER HIGH IS IN THE N/CENTRAL CARIBBEAN NEAR 17N75W WITH A
RIDGE EXTENDING NW THROUGH THE YUCATAN CHANNEL/W CUBA 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 SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS S OF 14N TO INLAND OVER SOUTH AMERICA E OF 77W TO
OVER THE WINDWARD ISLANDS. AN UPPER TROUGH EXTENDS INTO THE NE
CARIBBEAN FROM THE W/CENTRAL ATLC GIVING THE AREA N OF 14N FROM
THE S LEEWARD/N WINDWARD ISLANDS TO HISPANIOLA DRY AIR/STRONG
SUBSIDENCE AND CLEAR CONDITIONS. MOISTURE LEVELS WILL REMAIN
HIGH FOR THE S AND W CARIBBEAN THROUGH THE WEEKEND.

ATLANTIC OCEAN...
UPPER HIGH FROM THE CARIBBEAN COVERS THE FAR W ATLC W OF 67W
GIVING THE BAHAMAS DRY AIR/STRONG SUBSIDENCE WITH A FEW HIGH
CLOUDS MOVING IN. REMAINDER OF THE W ATLC INTO THE CENTRAL ATLC
ALSO HAS EXTENSIVE DRY AIR IN THE MID/UPPER LEVELS TO 57W. 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 25N54W WITH A TROUGH AXIS
EXTENDING SW INTO THE NE CARIBBEAN OVER THE VIRGIN/LEEWARD
ISLANDS. DRY UPPER AIR AND STRONG SUBSIDENCE ARE BEING DRAWN
INTO THE CIRCULATION FROM 20N-24N BETWEEN 50W-57W. SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 75 NM OF LINE FROM
28N50W TO 31N55W. A SURFACE TROUGH IS ALONG THE EDGE OF THE
UPPER TROUGH FROM 16N49W 24N48W TO 33N50W. BROAD RIDGE IS TO THE
E OF THE SURFACE TROUGH S OF 32N BETWEEN 27W-44W PROVIDING UPPER
DIFFLUENCE TO GENERATE A BROAD AREA OF SCATTERED SHOWERS/
THUNDERSTORMS WITHIN 200/250 NM OF LINE 15N35W TO 29N49W. A
SECOND CUT-OFF UPPER LOW IS IN THE NE ATLC OVER THE CANARY
ISLANDS NEAR 28N15W AND COVERS THE AREA N OF 20N E OF 25W. DRY
AIR AND MODERATE/STRONG SUBSIDENCE IS ROUNDING THE BASE OF THE
UPPER LOW WITHIN 150/175 NM OF LINE 30N22W 24N20W TO INLAND OVER
WESTERN SAHARA NEAR 23N16W. AT THE SURFACE...HIGH PRESSURE
COVERS THE ENTIRE ATLC WITH A WEAKNESS ALONG THE SURFACE TROUGH.

$$
WALLACE


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