[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 301157
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT FRI MAY 30 2008

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF
SOUTH AMERICA...AND 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...SPECIAL FEATURE...

TROPICAL STORM ALMA WAS DOWNGRADED AT 30/0900 UTC TO A TROPICAL
DEPRESSION. TROPICAL DEPRESSION ALMA IS INLAND OVER HONDURAS
CENTERED NEAR 14.6N 87.6W AT 30/0900 UTC WHICH IS ABOUT 40 NM NW
OF TEGUCIGALPA HONDURAS MOVING NNW AT 10 KT. MAXIMUM SUSTAINED
WIND SPEED IS 25 KT WITH GUSTS TO 30 KT. ESTIMATED MINIMUM
CENTRAL PRESSURE IS 1005 MB. ALMA IS EXPECTED TO CONTINUE MOVE
MORE NW THEN WESTWARD OVER THE NEXT COUPLE OF DAYS DUE TO THE
BUILDING HIGH SURFACE PRESSURE OVER THE S US AND N GULF OF
MEXICO CLIPPING THE GULF OF HONDURAS. ALMA SHOULD BECOME A
REMNANT LOW IN ABOUT 12 HOURS THEN DISSIPATE BY 48 HOURS.
ALTHOUGH THE WINDS WILL CONTINUE TO WEAKEN HEAVY RAINFALL WILL
CONTINUE FROM COSTA RICA...THROUGH PORTIONS OF NICARAGUA...
HONDURAS...EL SALVADOR...GUATEMALA...AND BELIZE DURING THE NEXT
COUPLE OF DAYS AS A STEADY STREAM OF TROPICAL MOISTURE LIFTS N
FROM THE PACIFIC AND POSSIBLE RE-FORMATION OF ALMA OVER THE GULF
OF HONDURAS OR A SECOND LOW FORMING IN THE WAKE OF ALMA. TOTAL
RAINFALL ACCUMULATIONS OF 10-15 IN ARE POSSIBLE WITH ISOLATED
AMOUNTS UP TO 20 IN...ESPECIALLY OVER THE HIGHER TERRAIN AND
COULD PRODUCE FLASH FLOODS AND MUD SLIDES. SEE LATEST NHC
INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS
MIATCPEP1/WTPZ31 KNHC AND THE FULL FORECAST/ADVISORY UNDER
AWIPS/WMO HEADERS MIATCMEP1/WTPZ21 KNHC FOR MORE DETAILS.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 33W/34W S OF 16N MOVING W 15 KT.
MIMIC-TPW SHOWS A WELL-DEFINED DEEP-LAYERED MOISTURE SURGE
EXTENDING FROM THE TROPICS NWD TO ABOUT 16N EVEN WITH A WEAK
SIGNATURE ON SATELLITE IMAGERY. ANY CONVECTION IS CONCENTRATED
ALONG THE ITCZ AXIS AND FURTHER SOUTH.

TROPICAL WAVE IS ALONG 49W S OF 8N MOVING W 10-15 KT. THIS
POSITION IS BASED PRIMARILY ON MIMIC-TPW. THE WAVE IS AT A VERY
LOW AMPLITUDE AND SO EMBEDDED WITHIN THE ITCZ...SATELLITE
SIGNATURE IS INDISCERNIBLE. ANY CONVECTION IS CONCENTRATED ALONG
THE ITCZ AXIS.

TROPICAL WAVE IS IN THE CENTRAL CARIBBEAN ALONG 75W S OF 20N
MOVING W 10-15 KT. WAVE REMAINS EMBEDDED WITHIN AN EXTREMELY
MOIST ENVIRONMENT ASSOCIATED WITH THE TROPICAL DEPRESSION ALMA.
THE AXIS REMAINS DIFFICULT TO LOCATED. SCATTERED MODERATE/
ISOLATED STRONG CONVECTION IS INLAND OVER N COLOMBIA.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 7N10W 3N26W 6N34W 4N41W 5N48W 4N52W.
SCATTERED MODERATE/STRONG CONVECTION IS FROM 1N-10N BETWEEN
13W-17W...N OF 2N TO INLAND OVER SW AFRICA BETWEEN 10W-23W AND
WITHIN 90 NM ALONG THE COAST OF SW AFRICA BETWEEN 1W-3W.
CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION ARE WITHIN 150
NM OF THE ITCZ AXIS FROM 34W-45W AND FROM 4N TO THE EQUATOR
BETWEEN 29W-37W. SMALL CLUSTERS OF SCATTERED MODERATE/ISOLATED
STRONG CONVECTION ARE WITHIN 50 NM OF THE ITCZ AXIS W OF 45W TO
THE COAST OF SOUTH AMERICA.

...DISCUSSION...
GULF OF MEXICO...
AN UPPER HIGH REMAINS CENTERED ALONG THE PACIFIC COAST OF MEXICO
NEAR MAZATLAN WITH THE RIDGE AXIS EXTENDING NW ACROSS E TEXAS TO
CENTRAL MISSISSIPPI. A NARROW UPPER TROUGH AXIS EXTENDS FROM THE
NE GULF SW TO 25N92W BECOMING A SHEAR AXIS TO NEAR TUXPAN
MEXICO. BROAD UPPER RIDGE ASSOCIATED WITH TROPICAL DEPRESSION
ALMA COVERS THE S GULF S OF THE ABOVE UPPER TROUGH/SHEAR AXIS.
MODERATE/STRONG SUBSIDENCE LIES NW OF THE UPPER RIDGE WHILE DEEP
MOISTURE IS REMAINS FROM THE S OVER THE CARIBBEAN. SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS ARE EMBEDDED IN THE DEEP
LAYER MOISTURE ACROSS THE BAY OF CAMPECHE ACROSS THE YUCATAN
THROUGH THE YUCATAN CHANNEL TO OVER W CUBA. OTHERWISE THE
REMAINDER OF THE GULF IS EXPERIENCING FAIR WEATHER. THE SURFACE
RIDGE THAT EXTENDS FROM THE W ATLC COVERS THE N GULF/E US AND
WILL CONTINUE TO BUILD OVER THE NEXT COUPLE OF DAYS.

CARIBBEAN...
TROPICAL DEPRESSION ALMA IS INLAND OVER CENTRAL AMERICA AND IS
ADVECTING DEEP TROPICAL MOISTURE FROM OVER THE FAR E PACIFIC
ACROSS MUCH OF THE CARIBBEAN W OF 70W. UPPER LEVEL OUTFLOW IS
SPREADING AWAY FROM ALMA WITH THE ASSOCIATED UPPER HIGH COVERING
THE ENTIRE CARIBBEAN. A SURFACE TROUGH OVER THE NW CARIBBEAN
EXTENDS FROM INLAND OVER HONDURAS NEAR 15N86W ALONG 18N85W TO
20N83W. SCATTERED MODERATE/STRONG WITH EMBEDDED NUMEROUS STRONG
CONVECTION IS WITHIN 90 NM OF LINE FROM 15N80W 18N82W TO THE
TROUGH AXIS NEAR 19N85W. CLUSTERS OF SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS COVER THE AREA N OF 15N TO OVER THE GREATER
ANTILLES FROM OVER HISPANIOLA THROUGH THE YUCATAN CHANNEL TO
OVER THE YUCATAN PENINSULA AND THE AREA S OF 15N W OF 80W TO
INLAND OVER CENTRAL AMERICA. MOSTLY CLEAR SKIES COVER THE E
CARIBBEAN WITH SOME HIGH CIRRUS CLOUDS OVER PUERTO RICO THROUGH
THE LEEWARD ISLANDS.

ATLANTIC...
DEEP LAYERED TROUGH IS DIPPING S OVER THE W ATLC N OF 27N W OF
67W INTO THE E COAST OF FLORIDA WITH THE ASSOCIATED STATIONARY
FRONT DISSIPATING ALONG THE N PERIPHERY OF THE REGION. A SURFACE
TROUGH IS S OF THE UPPER TROUGH EXTENDING FROM 27N75W ACROSS THE
N BAHAMA ISLANDS TO THE N COAST OF CUBA NEAR 23N80W GENERATING
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 90 NM OF THE
TROUGH AXIS MOVING ONSHORE OVER S FLORIDA. AN UPPER RIDGE
EXTENDS FROM NEAR 25N65W NE TO BEYOND 32N55W. A SECOND SURFACE
TROUGH EXTENDS FROM 25N68W TO N OF HISPANIOLA NEAR 20N72W
GENERATING SCATTERED SHOWERS/THUNDERSTORMS WITHIN 150 NM SE OF
THE TROUGH AXIS N OF 22N. A BROAD UPPER TROUGH EXTENDS FROM THE
NE ATLC THROUGH 32N20W ALONG 26N35W TO 20N54W. AN UPPER HIGH IS
IN THE E TROPICAL ATLC BETWEEN THE COAST OF W AFRICA AND THE
CAPE VERDE ISLANDS WITH THE UPPER RIDGE AXIS EXTENDING W ACROSS
THE TROPICAL ATLC. BROAD SUBTROPICAL RIDGE COVERS THE ENTIRE
ATLC AND INTO THE E US/N GULF OF MEXICO WITH A WEAKNESS IN THE
AREA AROUND BERMUDA WHERE THE DISSIPATING FRONT EXTENDS ALONG
THE N PERIPHERY OF THE REGION WITH A 1026 MB HIGH CENTERED NEAR
32N39W.

$$
WALLACE




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