[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 171715
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST THU 17 MAR 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1700 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 5N10W 2N15W 1N33W 1N42W 1S47W.
WIDELY SCATTERED MODERATE CONVECTION WITHIN 60 NM OF AXIS
BETWEEN 17W-20W AND WITHIN 75 NM OF 5N10W.  SCATTERED MODERATE
CONVECTION IS FROM 1N-3N BETWEEN 33W-38W WITH MORE WIDELY
SCATTERED ACTIVITY S OF 4N BETWEEN 40W-45W.

...DISCUSSION...

GULF OF MEXICO...
MID/UPPER LOW SWINGING THRU THE W GULF WILL BE THE PUSH THE COLD
FRONT OVER THE SE GULF NEEDS TO GO THRU THE AREA.  FRONT RUNS
FROM ROUGHLY TAMPA FLORIDA INTO THE YUCATAN PENINSULA NEAR
MERIDA WITH SCATTERED TSTMS AHEAD OF THE FRONT ALONG AN OLD
CONVECTIVE BOUNDARY BETWEEN MIAMI AND TAMPA.  A STATIONARY FRONT
EXTENDS NW AGAINST THE E SLOPES OF THE SIERRA MADRE MOUNTAINS.
WEAK LOWS ARE ALONG THE FRONT OVER N FLORIDA UNDER UPPER
DIFFLUENCE FROM THE TROUGH.  SLIGHT CHANCE OF SEVERE WEATHER
CONTINUES IN S FLORIDA DUE TO THE UPPER TROUGH ENHANCING WINDS
ALOFT AND DAYTIME INSTABILITY.  HIGH PRESSURE OVER N MEXICO IS
CAUSING WINDS OF GALE FORCE IN THE FAR SW GULF.  COLD FRONT
SHOULD CLEAR THE GULF OVERNIGHT WITH MUCH NICER WEATHER FRI FOR
THE SUNSHINE STATE.  THE NEXT COLD FRONT SHOULD ENTER THE AREA
LATE MON WITH TSTMS ALONG THE NORTHERN GULF COAST E OF TEXAS.

CARIBBEAN...
IMPRESSIVE MID/UPPER HIGH OVER THE CENTRAL CARIBBEAN NEAR 13N72W
IS KEEPING QUIET WEATHER IN THE AREA.  STRONG SUBSIDENCE HAS A
LID ON ANY SIGNIFICANT CONVECTION WITH THE HIGH SHUNTING ANY
SIGNIFICANT MID/UPPER LEVEL MOISTURE SOUTH AND WESTWARD TOWARD
THE EPAC.  MOISTURE IS EVEN LIMITED IN THE LOW LEVELS WITH
DEWPOINTS BELOW 70 AS FAR SOUTH AS MARTINIQUE.  A FEW SHOWERS
ARE IN THE SE CARIBBEAN S OF 13.5N E OF 70W OTHERWISE MOSTLY
FAIR SKIES RULE.  SOME CHANGES ARE IN STORE FOR THE NW CARIBBEAN
AS A COLD FRONT SHOULD ENTER THE REGION OVERNIGHT...BRINGING
SCATTERED SHOWERS AND A FEW TSTMS NW OF JAMAICA.  UPPER RIDGING
SHOULD REMAIN STRONG THROUGHOUT THE FORECAST PERIOD.

ATLANTIC...
LARGE AMPLITUDE RIDGE-TROUGH-RIDGE PATTERN IS LOCKED IN PLACE
OVER THE SUBTROPICAL ATLANTIC WITH A BROAD MID/UPPER LEVEL RIDGE
W OF 45W...DEEP LAYERED TROUGH OVER THE CENTRAL ATLC BETWEEN
20W-45W...AND RIDGE OVER THE E ATLC E OF 24W INTO NW AFRICA.
OVERCAST CLOUDS ARE NW OF A LINE FROM WEST PALM BEACH FLORIDA TO
BERMUDA ASSOCIATED WITH A STATIONARY FRONT FROM N FLORIDA TO
31N77W IN THE NW ATLC.  ASSOCIATED COLD FRONT SHOULD MOVE INTO
THE REGION OVERNIGHT WITH TSTMS LIKELY.  FARTHER E...ACTIVE
WEATHER IS FOCUSED ALONG AND AHEAD OF A COLD FRONT OVER THE
CENTRAL ATLC WHICH ENTERS THE AREA NEAR 31N31W SW TO 22N42W
DISSIPATING TO 20N50W.   THERE IS PLENTY OF ENERGY WITH THIS
FEATURE AS GALES HAVE DIPPED INTO THE REGION ALONG ABOUT 45W.
PREFRONTAL TROUGH IS 60-90 NM AHEAD OF THE FRONT WHERE WIDELY
SCATTERED MODERATE CONVECTION IS N OF 28N WITHIN 60 NM OF THE
TROUGH.  W OF THE FRONT...HIGH PRESSURE AND POST-FRONTAL NW FLOW
PREVAILS WITH THE TYPICAL COLD AIR STRATOCUMULUS CLOUDS
PREVAILING TO 60W. THE E ATLC REMAINS RELATIVELY DRY/TRANQUIL
WITH LATEST VISIBLE SATELLITE IMAGERY SHOWING NEARLY CLOUD FREE
CONDITIONS FROM 8N-20N E OF 38W AS SAHARAN AIR SQUELCHES ANY
DEVELOPMENT.  UPPER DIFFLUENCE IS PLENTIFUL ALONG THE ITCZ WITH
ENHANCED TSTM ACTIVITY.

$$
BLAKE

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