[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 132351
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT TUE MAY 13 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...
WEAK TROPICAL WAVE IS ALONG 57W/58W S OF 10N MOVING W 10-15 KT.
THE WAVE IS STILL ENHANCING SOME SHOWER/TSTM ACTIVITY OVER THE
GUYANAS REGION AND ADJACENT COASTAL WATERS. THE WAVE IS EXPECTED
TO ENTER THE FAR SOUTHERN WATERS OF THE EASTERN CARIBBEAN SEA
DURING THE NEXT 24 TO 48 HOURS BRINGING SOME INCREASE IN MOISTURE
OVER THE SRN WINDWARD ISLANDS.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 7N10W 4N24W 1N35W EQ52W. 1N40W AND
INTO NE BRAZIL NEAR 2N51W. CLUSTERS OF MODERATE TO STRONG
CONVECTION ARE OVER SW AFRICA. SCATTERED MODERATE/ISOLATED
STRONG CONVECTION ARE FROM 1N-5N BETWEEN 17W-23W. SIMILAR
CONVECTION IS FROM THE EQUATOR TO 6N BETWEEN 30W-36W...AND
WITHIN 50 NM EITHER SIDE OF AXIS WEST OF 40W.

...DISCUSSION...

GULF OF MEXICO...
SFC HIGH PRES DOMINATES THE SE CONUS...INCLUDING THE STATE OF
FLORIDA AND THE EASTERN HALF OF THE GULF KEEPING THE ATMOSPHERE
DRY AND STABLE. AS OF 2100 UTC...A 1018 MB HIGH IS ANALYZED OVER
THE FAR NE CORNER OF THE GULF NEAR 29N84W. SOUTHERLY RETURN FLOW
HAS DEVELOPED OVER THE WESTERN HALF OF THE GULF AROUND A WEAK
RIDGE ANCHORED ON THE ABOVE MENTIONED SFC HIGH. AN EARLIER ASCAT
PASS SHOWED WIND SPEEDS OF 15 TO 20 KT. A NARROW BAND OF
LOW-LEVEL CLOUDS WITH POSSIBLE ISOLATED SHOWERS...REMNANTS OF A
FRONTAL BOUNDARY...REMAINS ACROSS THE CENTRAL AND SE GULF.
ALOFT...A RIDGE CENTERED OVER BELIZE AND NORTHERN GUATEMALA
ENVELOPS THE ENTIRE GULF. SWLY AND THEN WLY FLOW AROUND THE
WESTERN PERIPHERY OF THIS UPPER FEATURE IS TRANSPORTING
UPPER-LEVEL MOISTURE FROM THE EPAC THROUGH CENTRAL MEXICO INTO
THE GULF. THESE WINDS ARE ALSO HELPING TO INDUCE SCATTERED
SHOWERS AND TSTMS OVER PARTS OF CENTRAL MEXICO. HIGH PRES OVER
THE SE CONUS WILL MOVE INTO THE W ATLC TONIGHT THROUGH WED. THE
NEXT COLD FRONT IS FORECAST TO MOVE OFF THE TEXAS COAST LATE
THU.

CARIBBEAN SEA...
A SFC HIGH PRESSURE CENTERED IN THE E ATLC EXTENDS A RIDGE SW TO
OVER THE EASTERN CARIBBEAN PROVIDING FAIR WEATHER AND PATCHY
CLOUDS ACROSS THE REGION. LIGHT TO MODERATE TRADE WINDS CONTINUE
TO DOMINATE THE BASIN WITH THE STRONGEST WINDS...AS USUAL JUST
OFFSHORE THE COLOMBIAN COAST. A COLD FRONT FROM THE WESTERN ATLC
CROSSES THE CENTRAL BAHAMAS AND THE N COAST OF WEST AND CENTRAL
CUBA WHERE IT IS DISSIPATING. CONVECTION HAS DEVELOPED OVER
CAMAGUEY AHEAD OF THE FRONT WITH LIGHTNING DATA SHOWING
SCATTERED TSTMS. WIND SPEED CONVERGENCE IN THE SW CARIBBEAN IS
GENERATING A LINE OF SHOWERS FROM THE COAST OF NICARAGUA NEAR
12N84W TO THE PANAMA CANAL. THIS CONVECTION IS BEING ENHANCED BY
A DIFFLUENT PATTERN ALOFT BETWEEN THE BASE OF AN UPPER TROUGH
AND THE SOUTHERN PERIPHERY OF THE UPPER HIGH SITUATED OVER
BELIZE AND N GUATEMALA. MODERATE TO STRONG SUBSIDENCE ALOFT
CONTINUES TO INHIBIT THE DEVELOPMENT OF ANY SIGNIFICANT
CONVECTION. AS A RESULT...ONLY SMALL PATCHES OF SHALLOW MOISTURE
ARE SEEN ACROSS THE BASIN. EXPECT SOME INCREASE IN MOISTURE OVER
THE SRN WINDWARD ISLANDS OVER THE NEXT 24 TO 48 HOURS AS THE
TROPICAL NOW ALONG 57W/58W CONTINUES TO MOVE WWD.

ATLANTIC OCEAN...
A STRONG DEEP-LAYERED LOW PRESSURE SYSTEM IS CENTERED OFFSHORE
THE MID-ATLANTIC STATES NEAR 37N64W. THE ASSOCIATED COLD FRONT
ENTERS THE FORECAST AREA NEAR 31N60W THEN CONTINUES SW ACROSS
THE CENTRAL BAHAMAS AND THE N COAST OF WEST-CENTRAL CUBA. A
120-140 NM WIDE BAND OF SHOWERS WITH EMBEDDED TSTMS IS JUST
AHEAD OF THE FRONTAL SYSTEM N OF 23N. COLD AIR STRATOCUMULUS
CLOUDS AND NW WINDS OF 20 TO 25 KT ARE FOUND BEHIND THE COLD
FRONT WHILE  SWLY WINDS WITH SIMILAR SPEED ARE ALSO SEEN AHEAD
OF THE FRONT AFFECTING THE AREA N OF 26N BETWEEN 50W AND 60W. A
BROAD SFC RIDGE COVERS THE CENTRAL AND EAST ATLC ANCHORED BY A
1024 MB SFC HIGH PRESSURE NEAR 29N36W. FRAGMENTS OF MAINLY LOW
LEVEL CLOUDS AND MODERATE TRADE WINDS ARE OBSERVED OVER THE
TROPICAL ATLC UNDER THE INFLUENCE OF THIS FEATURE. AN ELONGATED
UPPER-LEVEL RIDGE IS S OF 18N BETWEEN AFRICA AND THE LESSER
ANTILLES ENHANCING CONVECTION ALONG THE ITCZ.

$$
GR




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