000 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