[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 191116
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST SAT 19 FEB 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
1115 UTC.

...ITCZ...
ITCZ AXIS ALONG 6N9W 1N27W 2N50W.  SCATTERED MODERATE TO
ISOLATED STRONG CONVECTION FROM 1N-3N BETWEEN 17W-27W AND FROM
EQ-2N BETWEEN 20N-44W.

...DISCUSSION...
GULF OF MEXICO...
UPPER LEVELS...VERY BROAD RIDGING...ALMOST ZONAL FLOW...
DOMINATES FORECAST AREA FROM MEXICO ACROSS GULF. ABUNDANT
TROPICAL MOISTURE PLUME ADVECTED BY STRONG JETSTREAM OF OVER 100
KT ACROSS NW MEXICO INTO W TEXAS AND THEN EWD INTO N GULF STATES
N OF 28N.  STRONG SUBSIDENCE COVERS GULF OF MEXICO S OF 29N
EXCEPT SWATH FROM 23N TO 26N WHERE RAPIDLY DISSIPATING COLD
FRONT LIES.

AT THE SURFACE...1028 MB HIGH PRES OVER ALABAMA/MISSISSIPPI AT
32N88W.  WEAK COLD FRONT ACROSS CENTRAL GULF OF MEXICO FROM
STRAITS OF FLORIDA TO BAY OF CAMPECHE DRIFTING SE WHILE
DISSIPATING.  GRADIENT N OF FRONT FINALLY DECREASING AS HIGH
PRES WEAKENS FOR LACK OF UPPER SUPPORT AND QUASI-ZONAL FLOW
OVER RIDGE.  BROKEN LOW CLOUDS AND WIDELY SCATTERED SHOWERS
ALONG FRONT DECREASING AS SUBSIDENCE ALOFT MAKES ITS WAY TO
SURFACE. AREA OF LOW LEVEL CLOUDS AND SCATTERED SHOWERS OVER SW
BAY OF CAMPECHE RESULT FROM DAMMING OF LOW LEVEL MOISTURE ALONG
FRONT. CLOUDS ALONG E EDGE OF SIERRA MADRE FROM 18N-23N W OF 95W
SHOULD DECREASE NEXT 24 HOURS AS FRONTAL BOUNDARY DISSIPATES AND
SUBSIDENCE TAKES OVER.

CARIBBEAN...
WELL ANCHORED MID/UPPER LEVEL RIDGE REMAINS IN PLACE ALONG N
COAST OF S AMERICA TO YUCATAN PENINSULA.  STRONG SUBSIDENCE
UNDER RIDGE COVER ENTIRE CARIBBEAN BASIN WITH LITTLE VERTICAL
DEVELOPMENT OF CLOUDS MAINLY OVER SW CORNER WHERE STRONG SURFACE
WINDS CONVERGE ON MOUNTAINS OVER COSTA RICA.  HIGH PRES RIDGE
BUILDING SWD FROM GULF OF MEXICO TIGHTENED GRADIENT OVER
CARIBBEAN WITH INCREASING E TRADES.  LOW LEVEL MOISTURE AND
SHOWERS TO REMAIN SPARSE THROUGH WEEKEND PRIOR TO ARRIVAL SUN
NIGHT OF DIFFUSE FRONTAL BOUNDARY NOW OVER NE CARIBBEAN.

ATLANTIC...
AT THE UPPER LEVELS...PREDOMINATELY ZONAL FLOW OVER SW N ATLC
N OF 20N AND W OF 50W.  COLD FRONT ENTERS W ATLANTIC E OF OF
BERMUDA ALONG 32N55W AND EXTENDS SW TO 25N71W THEN TO STRAITS
OF FLORIDA AT 23N80W.  LACK OF UPPER SUPPORT DUE TO ZONAL FLOW
ALOFT WEAKENS FRONT WITHIN NEXT 36 HRS.  NARROW CLOUD LINE WITH
ISOLATED SHOWERS ALONG LEADING EDGE OF FRONT.  OVER CENTRAL
ATLC...MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH 33N53W PRODUCING
CLOUDINESS AND SCATTERED SHOWERS/THUNDERSTORMS N OF 18N FROM
20W-40W.  ACTIVITY SHOULD DECREASE NEXT 24 HOURS AS SHORTWAVE IS
FORCED NE OUT OF AREA BY LARGER STRONGER LONGWAVE TROUGH.  OVER
E ATLANTIC AND W AFRICA...MID/UPPER LEVEL TROUGH N OF 20N E OF
25W.  ON THE SURFACE...1011 MB LOW PRES 26N48W DISSIPATING NEXT
24 HRS AS IT DRIFTS NE.

$$
WALLY BARNES

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