[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 122345
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU JUN 12 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE IS ALONG 19W S OF 15N BASED ON VISIBLE SATELLITE
IMAGERY AND SURFACE DATA. SINCE YESTERDAY WAVE HAS NOW PASSED W
OF DAKAR SENEGAL AND IS MOVING W NEAR 15 KT. IN ADDITION...THE
SSMI-DERIVED TPW ANIMATION SHOWS A NORTHWARD SURGE OF MOISTURE
IN THIS AREA. MOST DEEP CONVECTION ASSOCIATED WITH THIS WAVE HAS
DIMINISHED DURING THE PAST 6 HOURS...WITH ONLY SCATTERED SHOWERS
WITHIN 200 NM ON EITHER SIDE OF THE AXIS FROM 7N-14N REMAINING.

A TROPICAL WAVE IS ALONG 56W/57W S OF 16N MOVING W NEAR 15-20
KT. THE WAVE SHOWS UP VERY WELL ON THE UW-CIMSS TPW PRODUCT WITH
A NORTH-SOUTH MOISTURE MAXIMUM. THE GFS MODEL 850 MB LOW-LEVEL
VORTICITY ALSO SUPPORTS THE POSITION OF THE WAVE. SCATTERED
MODERATE TO STRONG CONVECTION IS W OF THE WAVE AXIS FROM 10N-14N
BETWEEN 57W-61W. MOISTURE FROM THIS WAVE WILL CONTINUE TO AFFECT
THE WINDWARD ISLANDS THROUGH FRI...SPREADING OVER THE UK/US
VIRGIN ISLANDS AND PUERTO RICO SAT.

A WEAK TROPICAL WAVE IS OVER THE UK/US VIRGIN ISLAND EXTENDING
SOUTH TO CENTRAL VENEZUELA. MOISTURE IS MAINLY BEHIND THE WAVE
AXIS AFFECTING THE WINDWARD ISLANDS WITH SCATTERED SHOWERS AND
ISOLATED TSTMS. THIS SYSTEM STILL SHOWS UP WELL ON THE UW-CIMMS
TPW PRODUCT WHERE A HIGH AMPLITUDE BULGE OF MOISTURE IS
OBSERVED. THE WAVE IS EXPECTED TO MOVE ACROSS PUERTO RICO
INCREASING THE CHANCES OF SHOWERS AND THUNDERSTORMS THROUGH
FRIDAY.

A TROPICAL WAVE IS OVER THE SW GULF OF MEXICO AND THE ISTHMUS OF
TEHUANTEPEC ALONG 95W S OF 22N MOVING W NEAR 10 KT. WAVE REMAINS
EMBEDDED WITHIN AN AREA OF DEEP LAYERED MOISTURE AS DEPICTED ON
THE MIMIC-TPW ANIMATION. THE WAVE IS ALSO INTERACTING WITH AN
UPPER-LEVEL LOW OVER THE WESTERN GULF. AS A RESULT SCATTERED
MODERATE CONVECTION IS ACROSS THE YUCATAN PENINSULA...NRN
GUATEMALA AND ACROSS THE BAY OF CAMPECHE FROM 19N-24N BETWEEN
90W-95W.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 5N9W 8N17W 8N21W 2N40W 1S48W.
SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM 7N-9N
BETWEEN 21W-25W. CLUSTERS OF WIDELY SCATTERED MODERATE
CONVECTION ARE WITHIN 150 NM OF A LINE FROM THE EQUATOR NEAR
38W TO 5N46W.

...DISCUSSION...

GULF OF MEXICO...
THE COMBINATION OF A TROPICAL WAVE IN THE SW GULF OF MEXICO AND
AN UPPER-LEVEL LOW CENTERED OVER THE WESTERN GULF IS GENERATING
ABUNDANT CLOUDINESS WITH EMBEDDED SHOWERS AND TSTMS OVER TWO
AREAS ACROSS THE GULF. SCATTERED SHOWERS ARE ACROSS THE ERN BAY
OF CAMPECHE FROM 19N-24N BETWEEN 90W-95W. ANOTHER AREA OF
SCATTERED SHOWERS WITH EMBEDDED TSTMS IS FROM 25N-30N BETWEEN
85W-89W. A SURFACE RIDGE OF HIGH PRESSURE EXTENDS FROM THE SE
CONUS THROUGH W ATLC WATERS TO NEAR W CUBA. THE PRESSURE
GRADIENT BETWEEN THE SURFACE HIGH AND THE TROPICAL WAVE IS
PRODUCING MODERATE TO FRESH SE WINDS OVER PARTS OF THE CENTRAL
AND W GULF. THESE WINDS ARE EXPECTED TO DIMINISH BY LATE FRI.
ACCORDING TO THE GFS MODEL...WEAKENING ENERGY ASSOCIATED WITH
THE TROPICAL WAVE WILL CONTINUE TO DRIFT N-NW OVER THE W GULF
TOWARDS THE N GULF STATES IN ABOUT 24 HOURS UNDER A PREVAILING
SE FLOW.

CARIBBEAN...
A TROPICAL WAVE IS OVER THE E CARIBBEAN AND A SECOND MORE
IMPRESSIVE ONE IS APPROACHING THE WINDWARD ISLANDS. SEE TROPICAL
WAVE SECTION. MODEL GUIDANCE SUGGESTS THAT WESTERN WAVE WILL
WEAKEN SLIGHTLY WITH SOME ENERGY MOVING NW ACROSS PUERTO RICO
AND DIMINISHING WITHIN BROAD MID-UPPER TROUGHING ACROSS THE W
ATLC AND THE EASTERN WAVE ABSORBING THE REMAINING ENERGY KEEPING
A FAIR AMOUNT OF MOISTURE IN PLACE OVER THE ERN AND CENTRAL
CARIBBEAN. ALSO...EXPECT AN INCREASE IN WINDS AND SEAS TO
ACCOMPANY THE PASSAGE OF BOTH WAVES. IN THE MEANTIME...MODERATE
TO FRESH TRADEWINDS ARE NOTED THROUGHOUT THE BASIN WITH THE
STRONGEST WINDS OFF THE COLOMBIAN COAST BETWEEN 72W-78W.
SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS OVER THE SW
CARIBBEAN ALONG THE COASTS OF PANAMA AND COSTA RICA DUE LARGELY
IN PART TO THE PROXIMITY OF THE EPAC ITCZ AND A DIFFLUENT
PATTERN ALOFT. IN THE UPPER LEVELS...MOSTLY WLY ZONAL FLOW IS
NOTED ACROSS THE CARIBBEAN SEA WITH A FAIR AMOUNT OF UPPER LEVEL
MOISTURE PARTICULARLY W OF 75W AND OVER THE FAR SE CARIBBEAN.

ATLANTIC...
TWO UPPER-LEVEL LOWS EMBEDDED WITHIN BROAD UPPER TROUGHING
PERSIST OVER THE W ATLC. ONE IS N OF THE NW BAHAMAS NEAR 29N76W
AND CONTINUES TO ENHANCE SHOWERS AND ISOLATED TSTMS OVER THE
STATE OF FLORIDA AND THE NW BAHAMAS. THE SECOND UPPER-LEVEL LOW
IS NE OF PUERTO RICO NEAR 25N62W WHERE A SURFACE TROUGH EXTENDS
FROM 28N59W TO 22N63W. A RIDGE OF HIGH PRESSURE EXTENDS FROM THE
SE CONUS ACROSS THE W ATLC TO NEAR 26N72W WHERE FAIR WEATHER
REMAINS IN PLACE E OF THE BAHAMAS AND W OF 65W. A COLD FRONT
ENTERS THE AREA NEAR 32N33W AND EXTENDS W-SW TO NEAR 29N53W. A
BROKEN BAND OF LOW/MID CLOUDS WITH EMBEDDED SHOWERS IS
ASSOCIATED WITH THE FRONT. BROAD UPPER-LEVEL TROUGH OVER THE
CENTRAL ATLC SUPPORTS THIS FRONT. A NARROW SURFACE RIDGE IS
MAINLY SOUTH OF THE FRONTAL BOUNDARY COVERING THE FORECAST AREA
EAST OF 55W WITH AXIS ALONG 32N22W 24N35W 23N50W. NEARLY ZONAL
UPPER FLOW IS OVER THE E ATLC N OF 20N AND E OF 30W. IN THE
TROPICS...AN UPPER LEVEL HIGH IS CENTERED NEAR 13N44W WITH THE
ANTICYCLONIC FLOW REACHING THE SE CARIBBEAN TO THE WEST AND THE
CAPE VERDE ISLANDS TO THE EAST. THIS FEATURE IS AIDING IN
PROVIDING UPPER DIFFLUENCE TO THE DEVELOPMENT OF SHOWERS AND
TSTMS RELATED TO THE ABOVE MENTIONED TROPICAL WAVES.

$$
HUFFMAN




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