[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 072358
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST MON 07 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 8N1W 2N20W 1N50W.  SMALL AREA OF
WIDELY SCATTERED MODERATE CONVECTION S OF 2N BETWEEN 37W-42W.

...DISCUSSION...

GULF OF MEXICO...
A S STREAM CUT-OFF LOW OVER THE BAJA PENINSULA COUPLED WITH AN
AMPLIFYING TROUGH OVER THE CENTRAL UNITED STATES CONTINUES TO
CARVE OUT A LONGWAVE TROUGH PATTERN EXTENDING FROM THE GREAT
LAKES REGION ACROSS NRN MEXICO.  STRENGTHENING SUBTROPICAL JET
REMAINS ACROSS THE AREA FROM THE S TIP OF THE BAJA PENINSULA
NEWD ACROSS CENTRAL MEXICO INTO THE SE UNITED STATES. BROAD
SCALE DIFFLUENT FLOW WITH THE JET IS SUPPORTING WIDESPREAD
CLOUDINESS AND WIDELY SCATTERED SHOWERS OVER THE E HALF OF THE
GULF N OF 24N. MEANWHILE...STRONG DYNAMICS ASSOCIATED WITH THE
DIGGING CENTRAL U.S. SHORTWAVE IS PRODUCING NUMEROUS
SHOWERS/THUNDERSTORMS ALONG THE N GULF COAST BETWEEN MOBILE
BAY TO THE TEXAS/LOUISIANA BORDER. AT THE SURFACE...A MODERATE
COLD FRONT CURRENTLY PUSHING SWD OVER TEXAS WILL EMERGE INTO THE
NW GULF LATER THIS EVENING THEN SWEEP QUICKLY ACROSS THE E GULF
WATERS CLEARING FLORIDA TUE AFTERNOON/EVENING. THE EVOLVING
UPPER LEVEL PATTERN IS EXPECTED TO GENERATE GOOD DYNAMICS/LIFT
ALONG THE FRONT PRODUCING A BAND OF SCATTERED TO NUMEROUS
SHOWERS/TSTMS ALONG THE FRONT BEGINNING LATER TONIGHT.
SHOWERS/THUNDERSTORMS LOOK TO BE MOST NUMEROUS/STRONGEST AFTER
MIDNIGHT TONIGHT OVER THE E GULF INTO FLORIDA.  MEANWHILE THE
COLD FRONT PULLS UP STATIONARY OVER THE W GULF NEAR THE BAY OF
CAMPECHE LATE TUE.  THIS SHOULD PRODUCE WIDELY SCATTERED TO
SCATTERED SHOWERS/THUNDERSTORMS S OF 25N WITH POST-FRONTAL NLY
FLOW PRODUCING WIDESPREAD CLOUDINESS AND SHOWERS ALONG THE
WINDWARD FACING SLOPES OF THE SIERRA MADRE ORIENTAL MOUNTAINS OF
MEXICO.

CARIBBEAN...
BROAD MIDDLE TO UPPER LEVEL RIDGE CONTINUES TO PREVAIL OVER THE
CARIBBEAN WITH MEAN AXIS EXTENDING E/W ACROSS NRN PORTIONS ALONG
10N. UPSTREAM MOISTURE IS RIDING UP AND OVER THE RIDGE PRODUCING
MODERATE SUBSIDENCE AND DRY/STABLE AIR IN THE UPPER LEVELS. AT
THE SURFACE...A PAIR OF DISSIPATING COLD FRONTS ARE SAGGING SWD
OVER THE E CARIBBEAN...ONE CURRENTLY PASSING OVER PUERTO RICO
AND THE VIRGIN ISLANDS AND THE SECOND FURTHER S FROM GUADELOUPE
TO 15N70W. A NARROW BAND OF WIDELY SCATTERED SHOWERS ACCOMPANIES
BOTH BOUNDARIES.  RESIDUAL CLOUDINESS AND A FEW SHOWERS CONTINUE
OVER HISPANIOLA. ELSEWHERE...MAINLY DRY AIR IN THE LOWER LEVELS
IS LIMITING SHOWER ACTIVITY ESPECIALLY OVER THE NW CARIBBEAN.
THIS DRY AIR SHOULD REMAIN IN PLACE UNTIL LATE TUE WHEN A COLD
FRONT OVER THE GULF OF MEXICO APPROACHES THE AREA.

ATLANTIC...
AMPLIFYING MIDDLE TO UPPER LEVEL TROUGH OVER THE CENTRAL UNITED
STATES IS RESULTING IN A BUILDING RIDGE OVER THE W ATLC WATERS.
FOR NOW...THE BUILDING RIDGE IS MAINTAIN DRY/TRANQUIL CONDITIONS
ACROSS THE AREA W OF 60W.  HOWEVER...EXPECT RAPIDLY INCREASING
MIDDLE TO HIGH CLOUDINESS TONIGHT AS AN UPSTREAM SYSTEM
APPROACHES.  SCATTERED TO NUMEROUS SHOWERS/THUNDERSTORMS
ASSOCIATED WITH A COLD FRONT APPROACH THE AREA AFTER MIDNIGHT
THEN MOVE INTO THE W ATLC WATERS EARLY TUE. COLD FRONT THEN
RACES ACROSS THE W ATLC TUE REACHING BERMUDA TUE NIGHT AROUND
MIDNIGHT AND TRAILING SWD TO THE CENTRAL BAHAMAS.  AT THE SAME
TIME...UPPER TROUGH LIFTS NEWD WITH ASSOCIATED DYNAMICS/LIFT
CONFINED N OF 26N BY TUE NIGHT.  SHIFTING EWD...COMPLEX PATTERN
EXISTS OVER THE CENTRAL ATLC AS TWO FRONTS MERGE ALONG 31N38W
20N50W THEN DISSIPATING INTO THE NE CARIBBEAN SEA. IN THE UPPER
LEVELS...VIGOROUS DEEP LAYERED LOW IS SUPPORTING SCATTERED
MODERATE CONVECTION AHEAD OF THE MERGING FRONTS N OF 27N BETWEEN
25W-35W.  THIS ACTIVITY IS EXPECTED TO LIFT N OF THE AREA
OVERNIGHT WITH WIDELY SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS REMAINING ALONG THE TRAILING COLD FRONT WHICH WILL
EXTEND FROM 32N24W TO 20N43W BY TUE MORNING. ELSEWHERE OVER THE
E ATLC  AND TROPICS...MIDDLE TO UPPER RIDGE IS MAINTAINING VERY
DRY CONDITIONS.  DRY AIR ALOFT HAS PENETRATED WELL INTO THE
TROPICAL WATERS SUPPRESSING ITCZ ACTIVITY TO MAINLY S OF THE
EQUATOR. ADDITIONALLY...LOW-LEVEL DRY AIR IS ALSO MOVING WWD OFF
AFRICA FROM 6N-22N E OF 24W.

$$
RHOME





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