[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 271734
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU MAR 27 2008

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
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...METEOROLOGICAL ANALYSIS...
WEATHER OBSERVATIONS...AND RADAR.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 7N5W 9N20W 3N30W 1S45W 2S50W.
SCATTERED SHOWERS/ISOLATED TSTMS FROM THE EQUATOR TO 5N BETWEEN
17W-23W. SCATTERED MODERATE CONVECTION WITHIN 180 NM N OF AXIS
BETWEEN 28W-33W. NUMEROUS MODERATE/STRONG ALONG THE EQUATOR FROM
2S-2N BETWEEN 35W-52W INCLUDING ALONG THE BRAZILIAN COAST NEAR
THE AMAZON DELTA.

...DISCUSSION...

GULF OF MEXICO...
A FAST-MOVING PROGRESSIVE UPPER LEVEL PATTERN DOMINATES NORTH
AMERICA WITH A FEW SHORTWAVE TROUGHS/RIDGES MOVING ACROSS THE
GULF WATERS. A BROAD SHORTWAVE TROUGH HAS MOVED E OF FLORIDA
WITH THE TAIL END OF ITS AXIS STRETCHING TO THE YUCATAN
PENINSULA...AND CONFLUENCE INTO THE TROUGH IS PRODUCING A LARGE
AREA OF MODERATE/STRONG SUBSIDENCE WHICH COVERS MUCH OF THE
REGION. A SURFACE RIDGE LIES ROUGHLY ALONG THE N GULF COAST AND
IS PRODUCING E/SE LOW-LEVEL FLOW WITH SOME ENHANCEMENT TO NEAR
20 KT OFF THE TEXAS COAST DUE TO A DEVELOPING STORM SYSTEM OVER
OKLAHOMA. THE AIR MASS IS CONSIDERABLY DRY AT THE MOMENT WITH
PRECIPITABLE WATER VALUES AT 1.0" OR LESS BUT THE ATMOSPHERE IS
EXPECTED TO MOISTEN UP A BIT BY SAT AS MOISTURE OVER THE NW
CARIBBEAN IS ADVECTED NWD. OTHERWISE...A FRONTAL SYSTEM IS
EXPECTED TO PUSH S ACROSS TEXAS AND THE LOWER MISSISSIPPI VALLEY
ON FRI BUT WILL NOT REACH THE GULF COAST AND INSTEAD RETREAT
BACK TO THE N ON SAT AS THE SURFACE RIDGE MAINTAINS ITS HOLD.

CARIBBEAN...
WITH A BROAD UPPER TROUGH COVERING THE W ATLC...FAIRLY STRONG
WESTERLY FLOW ALOFT COVERS THE CARIBBEAN BASIN SWD TO NEAR 12N
WITH ONLY A MINOR AMOUNT OF UPPER LEVEL MOISTURE BEING PULLED
NEWD FROM COLOMBIA AND THE FAR E PACIFIC. A DECAYING FRONTAL
BOUNDARY EXTENDS FROM THE WINDWARD PASSAGE TO NE HONDURAS BUT
THE ASSOCIATED LOW-LEVEL WIND SHEAR HAS BECOME LESS DEFINED AND
IS MAINLY MARKED BY STRONGER WINDS NW OF THE BOUNDARY. SCATTERED
SHOWERS ASSOCIATED WITH THE OLD FRONT LIE ACROSS PARTS OF
HISPANIOLA...JAMAICA...AND SE CUBA AS WELL AS FARTHER W ACROSS
THE GULF OF HONDURAS AND THE ADJACENT LAND AREAS. THIS BELT OF
MOISTURE IS EXPECTED TO MOVE LITTLE OVER THE NEXT FEW DAYS AND
WILL CONTINUE THE CHANCE FOR SHOWERS ACROSS THE NW/N-CENTRAL
CARIBBEAN INTO THE WEEKEND. ELSEWHERE...A WEAK LOW-LEVEL
DISTURBANCE IS LOCATED S OF PUERTO RICO ALONG 68W AND IS
PRODUCING SCATTERED SHOWERS FROM 12N-16N BETWEEN 65W-70W...AND A
SECOND DISTURBANCE IS PRODUCING SCATTERED SHOWERS ACROSS THE
LESSER ANTILLES MAINLY FROM GRENADA NWD TO THE VIRGIN ISLANDS.

WEST/CENTRAL ATLANTIC...
A FRONTAL BOUNDARY HAS BECOME MAINLY STATIONARY FROM 31N45W TO
25N67W THEN CONTINUES AS A WEAKENING WARM FRONT TO THE WINDWARD
PASSAGE. A SURFACE RIDGE LIES N OF THE FRONT FROM BERMUDA TO N
FLORIDA. A SHORTWAVE TROUGH IS MOVING ACROSS THE W ATLC FROM
30N68W TO CENTRAL CUBA AND IS INTERACTING WITH THE FRONT...WITH
THE UPPER DIFFLUENCE E OF THE TROUGH PRODUCING SCATTERED
SHOWERS/ISOLATED TSTMS WITHIN 240 NM NW OF THE BOUNDARY BETWEEN
58W-73W. MODERATE/STRONG SUBSIDENCE LIES W OF THE UPPER LEVEL
SHORTWAVE AND IS PRODUCING MAINLY FAIR SKIES W OF 74W. FARTHER
E...A BROAD UPPER RIDGE LIES ACROSS THE CENTRAL ATLC FROM GUYANA
NEWD TO 30N40W AND PRODUCING A SUBSIDENT INVERSION THAT IS
KEEPING THE TRADE WIND CUMULUS CLUSTERS SHOWERY WITH NO DEEP
CONVECTION.

EAST ATLANTIC...
A LARGE CUT-OFF MID/UPPER LOW DOMINATES THE E ATLC
WATERS...CENTERED NEAR 27N27W WITH AN ASSOCIATED TROUGH AXIS
CONTINUING SW TO 3N45W. THE UPPER LOW IS BOUNDED BY A 130 KT JET
WHICH EXTENDS FROM THE CAPE VERDE ISLANDS TO THE CANARY ISLANDS
AND COAST OF MOROCCO...THEN TURNS E ACROSS ALGERIA. UPPER LEVEL
MOISTURE IS BEING DRAWN FROM THE TROPICS NEWD ACROSS THE CAPE
VERDES IN THE FORM OF A CIRRUS/CIRROCUMULUS SHIELD NEAR THE
COASTS OF MAURITANIA AND WRN SAHARA. A 1032 MB HIGH S OF THE
AZORES NEAR 35N29W IS MAINTAINING NE/E 15-20 KT TRADES ACROSS
MUCH OF THE REGION.

$$
BERG




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