[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 160005
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT FRI JUN 15 2007

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...

A TROPICAL WAVE IS ALONG 32W/33W S OF 13N MOVING W NEAR 15 KT.
AN INVERTED V SIGNATURE WITH SUBTLE LOW TO MID LEVEL CYCLONIC
TURNING IS NOTED. ISOLATED SHOWERS AND TSTMS ARE WITHIN 150NM
EITHER SIDE OF THE AXIS.

A WEAK TROPICAL WAVE IS IN THE ERN CARIBBEAN ALONG 67W S OF 16N
MOVING W NEAR 15 KT. THIS WAVE IS NO LONGER DISCERNIBLE IN
SATELLITE PICTURES OR SFC OBSERVATIONS AND LIES IN A REGION OF
VERY STABLE AIR UNDER PRONOUNCED UPPER CONFLUENCE.

A LOW AMPLITUDE TROPICAL WAVE IS MOVING ACROSS THE SRN CARIBBEAN
ALONG 76W MOVING W 10-15 KT. THIS WAVE ALSO REMAINS DIFFICULT TO
LOCATE ALTHOUGH MAY HAVE ASSISTED IN TRIGGERING THE SCATTERED
TSTMS NEAR THE COLOMBIAN COAST FROM 10N-13N BETWEEN 74W-80W.

...THE ITCZ...

ITCZ AXIS IS CENTERED ALONG 9N13W 6N24W 7N30W 5N45W 5N52W.
BESIDES FOR CONVECTION ASSOCIATED WITH THE TROPICAL WAVE...A
CLUSTER OF MODERATE TO STRONG CONVECTION IS MOVING OFF THE COAST
OF AFRICA FROM 9N-13N BETWEEN 13W-18W. ISOLATED MODERATE IS
WITHIN 150 NM EITHER SIDE OF THE AXIS BETWEEN 21W-30W AND
37W-42W. SIMILAR ACTIVITY IS WITHIN 90 NM N OF THE AXIS W OF 42W.

...DISCUSSION...

THE GULF OF MEXICO...
OVERALL A WEAK SFC PRES PATTERN CONTINUES IN THE GULF ASSOCIATED
WITH A TROUGH OF LOW PRES EXTENDING NEWD FROM THE NW CARIB AND
WEAK RIDGING OVER THE FAR NRN GULF. THE NET EFFECT IS 5-15 KT
WINDS AND SEAS MOSTLY LESS THAN 4'. SLIGHTLY HIGHER S TO SE
WINDS POSSIBLE IN THE STRAITS OF FLORIDA. THE MOST SIGNIFICANT
AREA OF MOISTURE ALSO LOCATED IN THE FAR SE PORTION ASSOCIATED
WITH THE SFC TROUGHING FROM THE NW CARIBBEAN.
RADAR...SATELLITE...AND LIGHTNING DATA DEPICT SCATTERED
SHOWERS/TSTMS AFFECTING CUBA AND THE STRAITS OF FLORIDA. MORE ON
THIS FEATURE IN THE CARIBBEAN SECTION. SCATTERED SHOWERS AND
TSTMS HAVE ALSO REMAINED OVER THE COASTAL WATERS OF E TEXAS AND
LOUISIANA. THIS ACTIVITY IS LIKELY CAUSED BY INSTABILITY
ASSOCIATED WITH AN UPPER LOW OVER OKLAHOMA AND TEXAS AIDED BY
LOW-LEVEL INFLOW AND DAYTIME HEATING. ELSEWHERE AN UPPER RIDGE
ALONG 94W IS PROVIDING A STABLE AIRMASS ALLOWING FAIR CONDITIONS
TO PREVAIL.

THE CARIBBEAN SEA...
SCATTERED SHOWERS AND TSTMS ARE AFFECTING A LARGE PORTION OF THE
NW CARIB N OF 18N BETWEEN 75W-87W...WHICH INCLUDES THE ISLAND OF
CUBA. THIS ACTIVITY IS ASSOCIATED WITH DEEP LAYER TROUGHING
ACROSS THE REGION. AS OF 15/2100 UTC THE SFC BOUNDARY IS
ANALYZED FROM HONDURAS TO THE SE GULF...AND THROUGH SOUTH
FLORIDA ALONG 15N87W 22N86W 27N79W. ALL OF THE DEEP CLOUDINESS/
CONVECTION IS LOCATED TO THE E OF THE SFC TROUGH...MORE IN LINE
WITH THE UPPER DIFFLUENT ZONE. THERE ARE NO SIGNS OF
ORGANIZATION AT THIS TIME...AND ANY DEVELOPMENT SHOULD BE SLOW
TO OCCUR.  EVEN IF NO DEVELOPMENT OCCURS...LOCALLY HEAVY RAINS
ARE POSSIBLE ACROSS PORTIONS OF CUBA...THE BAHAMAS...AND
SOUTHERN FLORIDA DURING THE NEXT DAY OR TWO AS THE SYSTEM MOVES
SLOWLY NORTHWARD.

WIDESPREAD FAIR WEATHER...BESIDES FOR THE TYPICAL ISOLATED TRADE
WIND SHOWERS...DOMINATE THE CENTRAL AND ERN CARIB. THESE
TRANQUIL CONDITIONS ARE BEING PRODUCED BY UPPER CONFLUENCE
BETWEEN A RIDGE OVER CENTRAL AMERICA AND A LARGE UPPER LOW JUST
E OF THE LESSER ANTILLES. TRADES WINDS REMAIN STRONG 20-30 KT IN
THIS REGION DUE TO A TIGHT PRES GRADIENT BETWEEN LOWER PRES OVER
COLOMBIA AND BROAD RIDGING NE OF THE AREA. FRESH TO STRONG
TRADES CONTINUE THROUGH THE WEEKEND.

THE ATLANTIC OCEAN...
EXTENSIVE W TO SWLY UPPER FLOW TO THE S OF A LARGE AND ELONGATED
UPPER TROUGH COVERS THE ATLC WATERS N OF 24N W OF 60W. THE FLOW
BENDS MORE NW S OF 24N AROUND RIDGING FROM THE CARIBBEAN. THIS
UPPER DIFFLUENCE SUPPORTS THE SCATTERED TSTMS FROM 24N-26N
BETWEEN 64W-71W AND ALSO OVER MUCH OF THE SE BAHAMAS. A PLUME OF
TROPICAL MOISTURE/HIGH CLOUDS ARE STRETCHING NE FROM THIS
CONVECTION AND THE ACTIVITY IN THE NW CARIBBEAN WELL INTO THE
CENTRAL ATLC....GENERALLY WITHIN 200 NM EITHER SIDE OF A LINE
FROM CENTRAL CUBA TO 32N58W. OVERALL THE SYNOPTIC PRES GRADIENT
OVER THE WRN ATLC IS WEAK...LEAVING WINDS MOSTLY 15 KT OR BELOW.
HIGHER WINDS POSSIBLE UNDER THE AFOREMENTIONED CONVECTION
THOUGH. THERE IS A SMALL TO MODERATE MEDIUM PERIOD (9-12S) NE
SWELL AFFECTING THE REGION TONIGHT FROM RECENT NE FLOW OFF THE
MID ATLANTIC COAST. ANOTHER VERY INTERESTING BUT NOT SIGNIFICANT
FEATURE IS THE 16-17 SECOND ENERGY REGISTERING AT SOME OF THE
OUTER BUOYS ALONG THE EASTERN SEABOARD...SUSPECT THIS IS MINOR
ENERGY SNEAKING IN FROM THE SOUTHERN HEMISPHERE.

THE REMAINDER OF THE ATLC...E OF 60W...LIES IN A REGION OF
FAIRLY DRY STABLE AIR. THE DRIEST AIR IS IN CONFLUENT ZONES
BETWEEN AN UPPER LOW E OF THE LESSER ANTILLES NEAR 13N60W...AN
UPPER HIGH NEAR 27N48W AND ANOTHER UPPER HIGH NEAR 17N28W. THE
SFC PATTERN IS JUST ABOUT AS TRANQUIL WITH A BROAD RIDGE
EXTENDING NEARLY E-W ALONG 27N. THESE PATTERNS ARE MAINTAINING
WIDESPREAD FAIR WEATHER AND MODERATE TRADES ACROSS THIS REGION.

$$
WILLIS




This weather bulletin was brought to you by:
www.nashvilleweather.net