[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 131739
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT FRI JUN 13 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...TROPICAL WAVES...

A TROPICAL IS APPROACHING THE CAPE VERDE ISLANDS WHERE NE WINDS
ARE BLOWING AT THIS TIME. IT AXIS IS ALONG 23W S OF 17N MOVING W
10-15 KT. A FEW CELLS ARE NOTED WHERE THE TROPICAL WAVE MEETS
THE ITCZ WITH A BAND OF LOW/MID CLOUDS JUST BEHIND THE WAVE
AXIS. SFC DATA...SATELLITE IMAGERY AND THE SSMI-DERIVED TPW
SUPPORT THE POSITION OF THE WAVE AXIS.

A TROPICAL WAVE IS OVER THE FAR EASTERN CARIBBEAN ALONG 62W S OF
18N MOVING W 15-20 KT. THE WAVE IS WELL DEPICTED IN THE MOISTURE
PRODUCTS AND E CARIBBEAN ISLANDS SURFACE OBSERVATIONS. BARBADOS
REPORTED THIS MORNING 2.93 INCHES OF RAIN IN 24 HOURS...AND
MARTINIQUE ALSO REPORTED HEAVY RAIN AT TIMES AND GUSTY WINDS OF
33 KT WITH THE PASSAGE OF THE WAVE. SCATTERED SHOWERS AND
ISOLATED TSTMS ARE NOTED OVER THE LESSER ANTILLES PARTICULARLY
BETWEEN GUADELOUPE AND ST. LUCIA. THIS TROPICAL WAVE IS FORECAST
BY THE COMPUTER MODELS TO MOVE OVER THE UK/US VIRGIN ISLANDS AND
PUERTO RICO TONIGHT INCREASING THE LIKELIHOOD OF SHOWERS AND
TSTMS. ALSO...IT IS EXPECTED TO REACH DOMINICAN REPUBLIC
SATURDAY MORNING.

A WEAK TROPICAL WAVE EXTENDS FROM THE EASTERN TIP OF DOMINICAN
REPUBLIC TO CURACAO ALONG 69W. THE WAVE STILL SHOWS UP ON VIS
SATELLITE PICTURES WHERE AN INVERTED-V PATTERN IS OBSERVED.
YESTERDAY...THE SAN JUAN VERTICAL SOUNDING SHOWED CLEARLY THE
PASSAGE OF THE WAVE AXIS WITH DEEP TROPICAL MOISTURE UP TO 700
MB AND SE WINDS AT LOW LEVELS. THIS FEATURE WILL ENHANCE SOME
SHOWER/TSTM ACTIVITY OVER HISPANIOLA THIS AFTERNOON AND TONIGHT
AND IS EXPECTED TO WEAKEN FURTHER OVER THE WESTERN CARIBBEAN ON
SAT. SCATTRED SHOWERS AND ISOLATED TSTMS ARE NEAR THE N END OF
THE WAVE AXIS AND CLOSE TO 16N70W.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 8N13W 10N22W 7N27W 3N40W 2N52W.
MODERATE/ISOLATED STRONG CONVECTION IS NOTED WITHIN 100 NM N OF
AXIS BETWEEN 30W-40W...AND WITHIN 125 NM N OF AXIS BETWEEN
46W-51W. SIMILAR CONVECTION IS FROM 4N-6N EAST 14W TO THE
AFRICAN COAST.

...DISCUSSION...

GULF OF MEXICO...
A MID/UPPER LEVEL CYCLONE IS CENTERED NEAR 22N94W. AS OF 1500
UTC...A SFC TROUGH...REFLECTION OF THIS CLOSED LOW IS ANALYZED
OVER THE SW GULF AND RUNS FROM 22N96W TO 18N94W. EAST OF THE
UPPER LOW...AN UPPER-LEVEL RIDGE ANCHORED ON HIGH OVER THE GULF
OF HONDURAS EXTENDS N ACROSS THE EASTERN GULF OF MEXICO. UNDER
THIS WEATHER PATTERN...A FAIR AMOUNT OF CLOUDINESS WITH EMBEDDED
SHOWERS AND TSTMS IS MAINLY OVER THE WESTERN HALF OF THE GULF
WHILE ANOTHER AREA OF SCATTERED SHOWERS AND TSTMS IS VERY CLOSE
TO THE FLORIDA PANHANDLE. A 1023 MB SFC HIGH OVER THE SE CONUS
ENVELOPS THE EASTERN GULF AND THE STATE OF FLORIDA. PRES
GRADIENT BETWEEN THE SFC HIGH AND THE TROUGH OVER THE SW GULF IS
PRODUCING MODERATE TO OCCASIONALLY FRESH SE WINDS OVER PARTS OF
THE CENTRAL AND WESTERN GULF. THESE WINDS ARE EXPECTED TO
DIMINISH LATE TODAY INTO THIS EVENING.

CARIBBEAN...
A PAIR OF TROPICAL WAVES ARE MOVING WWD ACROSS THE EASTERN
CARIBBEAN. SEE TROPICAL WAVE SECTION FOR MORE DETAILS. EXPECT AN
INCREASE IN WINDS AND SEAS TO ACCOMPANY THE PASSAGE OF BOTH
WAVES. AN EARLIER QSCAT PASS SHOWED SOME WIND BARS OF 25 TO 30
KT OVER PARTS OF THE EASTERN AND CENTRAL CARIBBEAN BUT MAINLY
NEAR THE COLOMBIAN COAST. HIGH PRES BUILDING INTO THE EASTERN
CARIBBEAN LATE THIS WEEKEND SHOULD BRING FRESH TO STRONG TRADES
BY EARLY NEXT WEEK. THE NWW3 ENSEMBLE SUGGESTS A LARGE AREA OF
ELY WINDS OF 25 KT OVER THE E AND CENTRAL CARIBBEAN ON MON.
ALOFT...A RIDGE/TROUGH/RIDGE PATTERN DOMINATES THE BASIN. A
BROAD UPPER TROUGH EXTENDING FROM AN UPPER-LEVEL LOW LOCATED
JUST E OF THE BAHAMAS DIPS S OVER THE N CENTRAL CARIBBEAN. UPPER
DIFFLUENCE BETWEEN THIS TROUGH AND AN UPPER HIGH SITUATED EAST
OF THE LESSER IS HELPING TO INDUCE THE CONVECTIVE ACTIVITY
ASSOCIATED WITH THE ABOVE MENTIONED TROPICAL WAVES. SCATTRED
MODERATE CONVECTION IS OVER PARTS OF PANAMA AND COSTA
RICA...LIKELY ASSOCIATED WITH THE CLOSE PROXIMITY OF THE EPAC
ITCZ AND A DIFFLUENT PATTERN ALOFT.

ATLANTIC...
THE MID/UPPER LEVEL LOW THAT WAS GENERATING STRONG TSTMS OVER
THE STATE OF FLORIDA DURING THE LAST FEW DAYS HAS MOVED SE
ACROSS THE W ATLC AND IS NOW LOCATED JUST EAST OF THE NW BAHAMAS
NEAR 27N76W. THIS LOW HAS A TROUGH EXTENDING S ACROSS THE SE
BAHAMAS INTO THE CENTRAL CARIBBEAN. A FEW HEAVY SHOWERS AND
TSTMS ARE STILL FLARING OVER FLORIDA AND THE BAHAMAS AROUND THE
CYCLONIC FLOW ASSOCIATED WITH THIS FEATURE. THE SUBTROPICAL
CENTRAL ATLC IS DOMINATED BY THE SOUTHERN END OF A LONG WAVE
TROUGH WHICH IS SUPPORTING A STATIONARY FRONT EXTENDING ALONG
30N34W 28N55W 25N72W. A BROKEN BAND OF LOW/MID CLOUDS WITH
EMBEDDED SHOWERS AND ISOLATED TSTMS IS RELATED TO THIS FRONTAL
SYSTEM. A SECOND COLD FRONT IS APPROACHING THE AREA AND IS
CURRENTLY PASSING THROUGH BERMUDA WITH A WELL DEFINED BAND OF
CLOUDS. THE UPPER LEVELS OF THE SUBTROPICAL EASTERN ATLC IS
DOMINATED BY A RIDGE. IN THE TROPICS...AN UPPER LEVEL HIGH IS
CENTERED NEAR 14N55W WITH THE ANTICYCLONIC FLOW REACHING THE SE
CARIBBEAN TO THE WEST AND THE CAPE VERDE ISLANDS TO THE EAST.
UPPER DIFFLUENCE ASSOCIATED WITH THIS SYSTEM IS ENHANCING
CONVECTION ALONG THE ITCZ.

$$
GR







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