[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 132340
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST MON MAR 13 2006

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN
SECTIONS OF SOUTH AMERICA...AND THE 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.

...THE ITCZ...
ITCZ IS CENTERED ALONG 5N10W 3N23W 4N35W INTO S AMERICA NEAR
2N51W. SCATTERED SHOWERS AND ISOLATED TSTMS S OF THE ITCZ W OF
35W.

...DISCUSSION...

GULF OF MEXICO...
STRONG MIDDLE TO UPPER LEVEL RIDGE REMAINS OVER THE GLFMEX WITH
MEAN AXIS EXTENDING FROM A ANTICYCLONE OVER THE YUCATAN
PENINSULA NEWD OVER THE W ATLC BETWEEN BERMUDA AND THE SE U.S.
FURTHER N...BROAD MIDDLE TO UPPER LEVEL TROUGH LIES OVER THE
CENTRAL U.S. FROM THE GREAT LAKES SW THROUGH TEXAS.
HOWEVER...THE CORE OF THE STRONGEST WESTERLIES AND ASSOCIATED
DYNAMICS/LIFT ARE CONFINED WELL N OF THE AREA.  AT THE
SURFACE...ATTENDANT COLD FRONT IS NOW ENTERING THE NW GULF FROM
CENTRAL LOUISIANA INTO NE MEXICO.  LACKING APPRECIABLE
DYNAMICS...ONLY A NARROW BAND OF SCATTERED SHOWERS ACCOMPANIES
THE FRONT.  WITH THE UPPER FLOW EXPECTED TO BECOME INCREASINGLY
ZONAL OVER THE NEXT FEW DAYS...THE FRONT WILL BECOME INCREASING
WEAK AS IT PUSHES SWD OVER THE REMAINDER OF THE GULF CLEARING
THE FLORIDA PENINSULA TUE NIGHT INTO EARLY WED.  LOW LEVEL
MOISTURE POOLING ALONG THE BOUNDARY MAY PRODUCE SCATTERED
SHOWERS AND ISOLATED TSTMS PRIMARILY OVER THE NE GULF AND N
FLORIDA TONIGHT THROUGH TUE. ELSEWHERE OVER THE GULF AND
FLORIDA...A PROLONGED PERIOD OF E TO SE FLOW HAS CREATED
SUMMER-LIKE CONDITIONS WITH DEWPOINTS IN THE UPPER 60S AND 70S.
HOWEVER...THE APPROACHING COLD FRONT WILL PRODUCE A
COOLING/DRYING TREND ESPECIALLY OVER THE NE GULF AND N FLORIDA.

CARIBBEAN SEA...
AFOREMENTIONED ANTICYCLONE OVER THE YUCATAN PENINSULA NOSES SEWD
ACROSS THE S CARIBBEAN INTO COLOMBIA. OVER THE E CARIBBEAN...THE
SW EXTENT OF A CENTRAL ATLC TROUGH HAS FRACTURED FORMING A LARGE
UPPER CUTOFF LOW N OF PUERTO RICO NEAR 22N66W. CONFLUENT FLOW ON
THE BACK/WEST SIDE OF THE UPPER LOW IS ENHANCING AN ALREADY
DRY/STABLE ENVIRONMENT ALOFT WITH STRONG SUBSIDENCE COVERING THE
ENTIRE CARIBBEAN...CENTRAL AMERICA...AND N PORTIONS OF S
AMERICA.   AT THE LOWER LEVELS...THE SCREAMING EAGLE OVER THE E
CARIBBEAN YESTERDAY HAS WEAKENED DURING THE LAST 24 HOURS NOW
OVER THE CENTRAL CARIBBEAN S OF HISPANIOLA.  THE FEATURE IS
STILL PRODUCING SCATTERED SHOWERS AND ISOLATED TSTMS OVER THE
OPEN WATERS OF THE CENTRAL CARIBBEAN FROM 14N-17N BETWEEN
68W-74W. THIS ACTIVITY WILL SPREAD WESTWARD OVER THE NEXT COUPLE
OF DAYS BUT WILL LIKELY WEAKEN SIGNIFICANTLY BEFORE REACHING
CENTRAL AMERICA LATE WED/EARLY THU.  A SECOND AREA OF SCATTERED
SHOWERS/TSTMS IS OBSERVED MOVING WESTWARD OVER THE WINDWARD
ISLANDS GENERALLY S OF 13N.  ELSEWHERE...THE BRISK TRADES WHICH
HAVE PERSISTED ACROSS MUCH OF THE CARIBBEAN SEA OVER THE LAST
SEVERAL DAYS ARE GRADUALLY WEAKENING AS THE ATLANTIC SUBTROPICAL
RIDGE SHIFTS EWD FROM THE W ATLC INTO THE CENTRAL ATLC.

ATLANTIC OCEAN...
THE UPPER LEVEL PATTERN HAS BECOME HIGHER AMPLITUDE DURING THE
LAST 24 HOURS AS A STRONG SHORTWAVE DISTURBANCE DIGS SEWD OVER
THE CENTRAL ATLC CARVING OUT THE PRE-EXISTING LONG-WAVE TROUGH
PATTERN.  ADDITIONALLY...MIDDLE TO UPPER LEVEL RIDGING IS
OBSERVED OVER THE W ATLC AHEAD OF A STRONG TROUGH OVER THE
CENTRAL U.S.  THE EVOLUTION HAS RESULTED IN THE S EXTENT OF THE
CENTRAL ATLC LONG-WAVE TROUGH FRACTURING FORMING A LARGE
UPPER-LEVEL CUTOFF LOW N OF PUERTO RICO NEAR 22N66W.
FINALLY...THE SUBTROPICAL JET TO 120 KT LIES BETWEEN 15N-25N
FROM THE E CARIBBEAN EWD INTO AFRICA OVER MAURITANIA.  DEEP
CONVECTION REMAINS ABSENT OVER ALL BUT THE ITCZ OWING TO THE
NEAR DOMINANCE OF MODERATE TO STRONG SUBSIDENCE AND DRY/STABLE
CONDITIONS ALOFT ACROSS THE ENTIRE ATLANTIC.  WHAT LITTLE SHOWER
ACTIVITY EXISTS REMAINS SHALLOW BASED AND FOCUSED PRIMARILY
ALONG LOWER LEVEL FEATURES.  THE MOST NOTABLE OF THESE FEATURES
IS A WEAKENING COLD FRONT OVER THE CENTRAL TO E ATLC ALONG
32N28W 27N32W 25N40W DISSIPATING STATIONARY TO 26N58W.
SCATTERED/BROKEN TO LOCALLY OVERCAST LOW/MID CLOUDS AND
SCATTERED SHOWERS LIE WITHIN 360 NM AHEAD OF FRONT. SOUTH AND
EAST OF THE FRONT...SATELLITE IMAGERY CONTINUES TO SHOW A STRONG
SAHARAN AIR LAYER AND DUST OUTBREAK WITH THE HIGHEST
CONCENTRATION OF DUST S OF 16N E OF 25W INCLUDING THE CAPE VERDE
ISLANDS. VISIBILITY MAY BE OCCASIONALLY REDUCED BELOW 5 SM
WITHIN THIS AREA.  ELSEWHERE AT THE SURFACE...THE SUBTROPICAL
RIDGE EXTENDS FROM A 1026 MB HIGH SE OF BERMUDA NEAR 29N63W ESE
TO 28N47W.

$$
RHOME


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