[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 051744
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST SAT 05 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 IS CENTERED ALONG 6N10W 2.5N30W INLAND OVER S AMERICA
NEAR FRENCH GUIANA. WIDELY SCATTERED MODERATE CONVECTION WITHIN
90 NM EITHER SIDE OF ITCZ FROM COAST OF AFRICA TO S AMERICA.

...DISCUSSION...

GULF OF MEXICO...
HIGHLY AMPLIFIED PATTERN ALOFT EXISTS OVER THE GULF COURTESY A
POTENT SHORTWAVE TROUGH WHICH HAS CARVED OUT AN UNUSUALLY DEEP
TROUGH OVER THE E PACIFIC AND BAJA PENINSULA. INDUCED DOWNSTREAM
RIDGE CONTINUES TO BUILD NWD OVER THE E HALF OF THE UNITED
STATES.  AN ACTIVE SUBTROPICAL JET TO 130 KT IS
ADVECTING SIGNIFICANT PACIFIC MOISTURE UP AND OVER THE RIDGE
RESULTING WIDESPREAD CLOUDINESS AND SHOWERS/THUNDERSTORMS OVER A
GOOD PORTION OF THE COUNTRY FROM MEXICO CITY NWD. STREAKS OF
HIGH CLOUDS ALSO COVER THE NW GULF POLEWARD OF A LINE FROM
VERACRUZ TO THE FLORIDA PANHANDLE.  AT THE LOWER LEVELS
...POST-FRONTAL NLY FLOW AND COLD AIR ADVECTION CONTINUE TO
PRODUCE A LARGE FIELD OF OPEN-CELLULAR STRATOCUMULUS CLOUDS OVER
ALL BUT THE NE GULF WHERE A SHADOW EFFECT EXISTS OFF THE FLORIDA
WEST COAST.  FLORIDA REMAINS PRIMARY CLOUD FREE EXCEPT FOR SOME
ATLANTIC CLOUDINESS AND ISOLATED SHOWERS ALONG THE IMMEDIATE E
COAST.  THE POTENT SHORTWAVE TROUGH CURRENTLY OVER THE BAJA
PENINSULA WILL MOVE NEWD THROUGH THE SW AND CENTRAL UNITED
STATES OVER THE NEXT 48 HOURS WITH ATTENDANT COLD FRONT
APPROACHING THE NW GULF LATE SUN NIGHT INTO MONDAY.  EXPECT
INCREASING CLOUDINESS AND SHOWERS/THUNDERSTORMS AHEAD OF FRONT
BEGINNING LATE SUNDAY. LOW LEVEL FLOW WILL VEER THROUGH THE
WEEKEND WITH MODERATE RETURN FLOW DEVELOPING OVER THE W GULF BY
SUN AND NE TO ELY FLOW OVER THE E GULF AND FLORIDA.

CARIBBEAN SEA...
MIDDLE TO UPPER LEVEL RIDGE DOMINATES THE S HALF OF THE
CARIBBEAN WITH AXIS EXTENDING FROM S AMERICA NW ALONG CENTRAL
AMERICA WHILE W ATLC TROUGH DOMINATES THE N HALF OF THE
CARIBBEAN. RESULTING FLOW IS PRIMARILY NW TO W WITH MODERATE TO
STRONG SUBSIDENCE PRODUCING VERY DRY/STABLE CONDITIONS ALOFT.
SIGNIFICANT WEATHER IS CONFINED TO SHALLOW BASED SHOWERS
PRIMARILY FOCUSED WITHIN 60 NM EITHER SIDE OF A COLD FRONT
ENTERING THE AREA OVER THE E TIP OF CUBA WHERE IT BECOMES
DISSIPATING TO BELIZE AND N GUATEMALA.  A SECOND AREA OF SHOWERS
EXIST ALONG A LOW LEVEL TROUGH EXTENDING FROM THE VIRGIN
ISLANDS WSW TO JUST S OF HISPANIOLA NEAR 16N72W THEN SW TO E
PANAMA. ELSEWHERE...MAINLY DRY CONDITIONS PREVAIL ESPECIALLY
OVER THE E CARIBBEAN.  HOWEVER...SOME INCREASE IN LOW LEVEL
MOISTURE AND SHOWER ACTIVITY IS EXPECTED OVER THE E CARIBBEAN
DURING THE NEXT 24 HOURS AS THE UPSTREAM FRONTAL BOUNDARY
APPROACHES.

ATLANTIC OCEAN...
HIGH AMPLITUDE TROUGH-RIDGE-TROUGH PATTERN PREVAILS OVER THE
ATLANTIC WATERS WITH TROUGH W OF 50W TO THE E COAST OF THE
UNITED STATES...RIDGE BETWEEN 30W-50W...AND TROUGH E OF 30W INTO
NW AFRICA.  PERSISTENT W ATLC TROUGH HAS AMPLIFIED SWD AS A
DISTINCT UPPER LOW JUST SW OF BERMUDA ROTATES CYCLONICALLY
AROUND A STRONG UPPER LOW FURTHER N NEAR 39N57W.  THIS EVOLUTION
HAS RESULTED IN SOME INCREASE IN UPPER LEVEL DIVERGENCE AND
ASSOCIATED SHOWER ACTIVITY ALONG THE ATTENDANT COLD FRONT
STRETCHING FROM BERMUDA SEWD ALONG 27N62W 22N66W TO THE E TIP OF
CUBA.  STRONGEST SHOWER/THUNDERSTORM ACTIVITY LIES WITHIN 60 NM
AHEAD OF FRONT FROM 24N-30N.  WIDELY SCATTERED ACTIVITY
ACCOMPANIES THE COLD CORE LOW ITSELF N OF 27N BETWEEN 60W-70W.
ELSEWHERE W OF FRONT...POST-FRONTAL NLY FLOW...COLD AIR
ADVECTION...AND TYPICAL COLD AIR STRATOCUMULUS CLOUDS PREVAIL TO
THE FLORIDA E COAST. FURTHER E...LARGE SCALE DIFFLUENCE WELL
AHEAD OF THE W ATLC TROUGH IS SUPPORTING WIDESPREAD CLOUDINESS
AND WIDELY SCATTERED SHOWERS/THUNDERSTORMS OVER THE CENTRAL ATLC
N OF 21N BETWEEN 36W-46W. EXPECT UPPER W ATLC TROUGH TO SHARPEN
THROUGH LATE SUNDAY WHEN AFOREMENTIONED LOW SW OF BERMUDA BEGINS
TO LIFT NEWD.  OVER THE E ATLC...CONFLUENT FLOW AND MIDDLE TO
UPPER LEVEL SUBSIDENCE IS PRODUCING DRY/STABLE CONDITIONS ALOFT
WITH AFRICAN DUST PREVAILING IN THE LOW LEVELS E OF THE CAPE
VERDE ISLANDS.

$$
RHOME


WWWW
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