[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 191748
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...ITCZ...
ITCZ AXIS ALONG 10N1W 1N30W 2N40W 5N60W.  WIDELY SCATTERED
STRONG CONVECTION WITHIN 100 NM EITHER SIDE OF AXIS FROM
10W-40W.

...DISCUSSION...
GULF OF MEXICO...
BROAD MIDDLE TO UPPER LEVEL RIDGING REMAINS OVER THE GLFMEX
WHILE A PERSISTENT UPSTREAM TROUGH LIES ALONG THE W COAST OF THE
UNITED STATES INTO NW MEXICO.  SUBTROPICAL JET AND ASSOCIATED
UPPER LEVEL MOISTURE PLUME CUTS ACROSS CENTRAL MEXICO BETWEEN
PUERTO VALLARTA AND THE S TIP OF THE BAJA PENINSULA THEN UP AND
OVER THE RIDGE INTO TEXAS AND THE CENTRAL UNITED STATES. S OF
THE THIS MOISTURE...STRONG SUBSIDENCE COVERS THE ENTIRE GULF OF
MEXICO CREATING DRY/STABLE CONDITIONS ALOFT. AT THE
SURFACE...RAPIDLY WEAKENING COLD FRONT LIES OVER THE EXTREME SE
PORTION OF THE AREA FROM THE W TIP OF CUBA TO JUST N OF THE
YUCATAN PENINSULA. LATEST VISIBLE SAT IMAGERY INDICATES THE
FRONT HAS WASHED OUT WITH HIGH PRES OVER THE SE UNITED STATES
NOW CONTROLLING THE AREA. RESULTING LOW LEVEL FLOW IS NOW
VEERING WITH RETURN FLOW DEVELOPING OVER THE W GULF.  THE ONLY
CLOUDS OF NOTE IS A SMALL AREA OF  BROKEN LOW CLOUDS AND WIDELY
SCATTERED SHOWERS OVER THE CENTRAL GULF FROM 23N-26N BETWEEN
87W-91W. ADDITIONALLY...LOW CLOUDS AND ISOLATED SHOWERS REMAIN
ALONG E SLOPES OF THE SIERRA MADRE ORIENTAL MOUNTAINS IN
MEXICO.  THE PATTERN IS EXPECTED TO REMAIN DRY WITH LIMITED
SHOWER ACTIVITY THROUGH THE WEEKEND PRIOR TO A COLD FRONT
APPROACHING THE AREA MONDAY.

CARIBBEAN...
MID/UPPER LEVEL RIDGE REMAINS ANCHORED OVER THE CARIBBEAN
EXTENDING FROM THE N COAST OF VENEZUELA TO W CUBA.  STRONG
SUBSIDENCE ASSOCIATED WITH THIS PATTERN COVERS THE ENTIRE
CARIBBEAN BASIN WITH LITTLE VERTICAL DEVELOPMENT OF CLOUDS AND
SHOWER ACTIVITY. IN FACT...THE ONLY ACTIVITY OF NOTE IS
BROKEN/OVERCAST CLOUDINESS AND WIDELY SCATTERED SHOWERS ALONG
THE WINDWARD FACING SLOPES OF W PANAMA AND COSTA RICA.  ELY
TRADES HAVE INCREASED DURING THE LAST 24 HOURS AS A HIGH PRES
BUILDS SWD OVER THE E GULF AND W ATLC.  LOW LEVEL MOISTURE AND
SHOWER ACTIVITY IS EXPECTED TO REMAIN SPARSE THROUGH THE WEEKEND
PRIOR TO THE ARRIVAL OF A DIFFUSE FRONTAL BOUNDARY OVER THE NE
CARIBBEAN SUN NIGHT INTO MONDAY.  LOW LEVEL MOISTURE POOLING
ALONG THE BOUNDARY SHOULD PRODUCE A LINE OF SCATTERED SHOWERS AS
THE WEAKENING BOUNDARY SAGS SWD REACHING THE ABC ISLANDS LATE
TUE.

ATLANTIC...
PERSISTENT MIDDLE TO UPPER LEVEL TROUGH REMAINS OVER THE W ATLC
N OF 30N AND WEST OF 50W RESULTING IN PREDOMINATELY ZONAL FLOW
AND SUBSIDENCE OVER THE SW N ATLC. ATTENDANT WEAK COLD FRONT
ENTERS THE CENTRAL ATLC NEAR 32N51W SWD ALONG 24N65W THROUGH THE
CENTRAL BAHAMAS TO W CUBA.  THE FRONT LACKS UPPER SUPPORT WITH
ONLY A NARROW CLOUD LINE WITH ISOLATED SHOWERS ALONG THE LEADING
EDGE. A DEVELOPING SURFACE LOW WELL N OF THE AREA NEAR 39N56W IS
DRAGGING DOWN A REINFORCING SURGE OF COOL AIR WITH THE LEADING
EDGE EXTENDING FROM 32N55W TO THE N BAHAMAS. OVER CENTRAL TO E
ATLC...MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH ALONG 30W IS
PRODUCING SOME HIGH CLOUDINESS FROM THE CAPE VERDE ISLANDS NWD
TO 26N.  ELSEWHERE...STRONG SURFACE HIGH PRESSURE N OF THE
AZORES EXTENDS SWD INTO THE NE PORTION OF THE AREA PRODUCING
MODERATE TO STRONG NE FLOW.  THE PERSISTENT AREA OF AFRICAN DUST
OVER THE FAR E TROPICAL ATLC HAS BECOME PARTIALLY OBSCURED BY
HIGH CLOUDINESS BUT THE HIGHEST CONCENTRATION IS EXPECTED S AND
E OF THE CAPE VERDE ISLANDS TO THE ITCZ.

$$
RHOME


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