[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 092351
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT FRI MAY 09 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 37/38W S OF 8N MOVING W AT 15 KT. LATESTS
VIS SAT IMAGERY FOR THE DAY REVEALED WEAK CYCLONIC TURNING ALONG
THE WAVE AXIS NEAR 6N WHERE THERE ARE SOME SHOWER/TSTM ACTIVITY.
THE MIMIC-TPW PRODUCT FROM CIMSS ALSO SHOWS THE PRESENCE OF THIS
WAVE WITH A PRONOUNCED BULGE OF MOISTURE ON EITHER SIDE OF THE
WAVE AXIS. ACCORDING TO THE COMPUTER MODELS...THIS TROPICAL WAVE
WILL ENTER THE CARIBBEAN SEA ON TUE.

...ITCZ...
ITCZ AXIS IS ALONG 5N9W 2N20W 4N35W THEN ALONG 2N39W CROSSING
THE EQUATOR NEAR 45W INTO NE BRAZIL NEAR 2S50W. SCATTERED
MODERATE TO STRONG CONVECTION IS FROM 2N-5N BETWEEN 9W-15W.
SIMILAR CONVECTION IS OVER NE BRAZIL NEAR THE ITCZ AXIS. WIDELY
SCATTERED MODERATE CONVECTION IS WITHIN 120-140 NM N OF AXIS
BETWEEN 27W-32W.

...DISCUSSION...

GULF OF MEXICO...
BROAD UPPER LEVEL RIDGE ANCHORED ON A HIGH ACROSS THE CENTRAL
MEXICAN PLATEAU REMAINS IN CONTROL OF THE ENTIRE GULF PRODUCING
MODERATE TO STRONG SUBSIDENCE OVER THE BAY OF CAMPECHE AND
SOUTHERN MEXICO...INCLUDING ALSO THE YUCATAN PENINSULA. ABUNDANT
UPPER LEVEL MOISTURE IS BEING TRANSPORTED FROM THE EPAC ACROSS N
MEXICO AND THE NORTHERN GULF WATERS BY SWLY AND THEN WLY
UPPER-LEVEL WINDS  AROUND THE PERIPHERY OF THE RIDGE. AT THE
SURFACE...A RIDGE ALSO DOMINATES THE REGION GIVING THE AREA
SOUTHERLY 10-15 KT SURFACE WINDS AND MOSTLY FAIR WEATHER. THE
RIDGE WILL BEGIN TO SHIFT E SAT NIGHT IN ADVANCE OF A COLD FRONT
MOVING INTO NW WATERS EARLY SUN MORNING.

CARIBBEAN SEA...
UPPER LEVEL ANTICYCLONIC FLOW OVER THE GULF OF MEXICO EXTENDS
ACROSS WEST-CENTRAL CUBA AND THE NW CARIBBEAN. AN ELONGATED
UPPER LEVEL TROUGH REMAINS OVER THE BASIN EXTENDING FROM THE S
BAHAMAS THROUGH THE WINDWARD PASSAGE TO NEAR CABO GRACIAS A DIOS
NICARAGUA. THE REMAINDER OF THE CARIBBEAN SEA IS UNDER THE
INFLUENCE OF A BOARD UPPER LEVEL RIDGE ANCHORED IN THE TROPICAL
ATLC OFF THE COAST OF NE BRAZIL. UPPER LEVEL MOISTURE IS BEING
DRAWN ACROSS THE S AND E CARIBBEAN SEA BY STRONG SWLY WINDS
BETWEEN THE AFOREMENTIONED UPPER LEVEL TROUGH AND THE RIDGE OFF
THE COAST OF BRAZIL. A BAND OF TRANSVERSE HIGH CLOUDS EXTENDS
FROM NEAR 14N80W ALL THE WAY NE TO BEYOND THE LEEWARD ISLANDS.
FAIRLY STRONG TRADEWINDS COVER MOST OF THE REGION WITH THE
STRONGEST WINDS JUST OFFSHORE THE COAST OF COLOMBIA. AN EARLIER
QUIKSCAT PASS SHOWED ELY WINDS OF 20 TO 30 KT. MODERATE TO
STRONG CONVECTION IS OVER WEST PANAMA AND COSTA RICA DUE TO THE
CLOSE PROXIMITY OF THE ITCZ AND A DIFFLUENT PATTERN ALOFT.
CONVECTION HAS ALSO FIRED UP OVER CENTRAL AND EASTERN CUBA WITH
LIGHTNING DATA SHOWING NUMEROUS TSTMS. THIS ACTIVITY HAS
DEVELOPED ALONG THE SEA BREEZE FRONT AIDED BY UPPER DIFFLUENCE.
MODERATE SUBSIDENCE/DRY AIR DOMINATES THE NW CARIBBEAN BRINGING
FAIR WEATHER TO THAT AREA.

ATLANTIC OCEAN...
A 1023 MB SURFACE HIGH IS CENTERED NEAR 28N58W. THIS HIGH
ENVELOPS THE BAHAMAS...FLORIDA AND THE EASTERN GULF OF MEXICO.
ANOTHER 1023 MB HIGH PRESSURE CENTER NEAR 34N24W EXTENDS A RIDGE
OVER THE E ATLC. PATCHES OF LOW CLOUDS AND NELY WINDS ARE FOUND
UNDER THIS RIDGE. THE STRONGEST WINDS...UP TO 25 KT ARE NEAR THE
WEST COAST OF AFRICA DUE THE TIGHT PRES GRADIENT BETWEEN THE
SFC HIGH AND LOWER PRES OVER AFRICA. ALOFT...BROAD UPPER TROUGH
REMAINS OVER THE W-CENTRAL ATLC DIPPING S INTO THE CARIBBEAN SEA
THROUGH THE WINDWARD PASSAGE. THE ASSOCIATED COLD FRONT ENTERS
THE AREA NEAR 31N37W THEN CONTINUES SW TO 25N51W. AT THIS
POINT...THE FRONT BECOMES STATIONARY TO 25N60W. BROKEN MAINLY
LOW CLOUDS ARE ASSOCIATED WITH THE FRONTAL BOUNDARY WITH
ISOLATED TSTMS NEAR THE TAIL END OF THE FRONT. MOSTLY ZONAL FLOW
COVERS THE REMAINDER OF THE FORECAST REGION WITH ANOTHER UPPER
LEVEL TROUGH CLIPPING THE E ATLC BETWEEN 25W AND 35W. AN UPPER
RIDGE EXTENDS NWD ALONG 22/23W FROM AN UPPER HIGH LOCATED SE OF
THE CAPE VERDE ISLANDS NEAR 9N18W.

$$
GR





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