[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 091748
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU MAY 09 2013

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...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL
ANALYSIS.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1615 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE COAST OF SENEGAL TO NEAR
6N25W...THEN TRANSITIONS TO ITCZ...CONTINUING ON TO 3N30W TO
THE COAST OF BRAZIL AT 1S48W. SCATTERED MODERATE TO ISOLATED
STRONG CONVECTION IS NOTED N OF THE EQUATOR TO THE COAST OF
AFRICA BETWEEN THE PRIME MERIDIAM AND 12W. SIMILAR CONVECTION IS
FROM 2N TO 6N BETWEEN 12W AND 25W. ISOLATED TO SCATTERED
MODERATE CONVECTION IS SEEN WITHIN 210 NM N OF ITCZ AXIS W OF
30W.

...DISCUSSION...

GULF OF MEXICO...

A 1021 MB HIGH CENTERED OVER THE NE GULF NEAR 28N85W EXTENDS A
RIDGE SW TO THE BAY OF CAMPECHE. THIS SYSTEM ALSO DOMINATES THE
STATE OF FLORIDA WHERE MAINLY FAIR WEATHER PREVAILS. UNDER THE
INFLUENCE OF THIS FEATURE...E-SE WINDS OF 10-15 KT ARE NOTED OVER
THE EASTERN GULF WHILE SE FLOW HAS INCREASED TO 15-20 KT OVER
THE WESTERN GULF. THESE WINDS ARE TRANSPORTING SOME LOW LEVEL
MOISTURE INTO TEXAS. THE HIGH WILL MOVE LITTLE THROUGH TONIGHT
AND DISSIPATE. THEN...THE ATLC RIDGE WILL EXTEND WESTWARD MAINLY
ALONG 28N E OF 90W DURING THE NEXT COUPLE OF DAYS. THE NEXT COLD
FRONT IS FORECAST TO MOVE OFF THE LOUISIANA AND TEXAS COAST
EARLY ON SAT. IN THE UPPER LEVELS...A RIDGE DOMINATES THE
MAJORITY OF THE REGION WITH THE RIDGE AXIS EXTENDING FROM A
BROAD ANTICYCLONE IN THE EPAC THROUGH THE BAY OF CAMPECHE ACROSS
THE WESTERN GULF TO BEYOND LOUISIANA. A TROUGH IS NOTED OVER THE
FAR EAST GULF AND FLORIDA WHERE THE LIKELIHOOD OF SHOWERS AND
TSTMS IS ON INCREASE.

CARIBBEAN SEA...

A SURFACE TROUGH EXTENDS FROM 25N72W THROUGH THE WINDWARD
PASSAGE TO HAITI NEAR 18N74W. THIS TROUGH PRODUCED LOCALLY HEAVY
RAIN OVER HISPANIOLA DURING THE PAST 24 HOURS. THE DOMINICAN
REPUBLIC WEATHER SERVICE...ONAMET...REPORTED RAINFALL AMOUNTS OF
4 TO 5 INCHES IN SOME LOCALES DURING THE PAST 24 HOURS. THE
GREATEST TOTAL RAINFALL AMOUNT WAS REPORTED IN BONAO WITH NEAR 6
INCHES...142.7 MM. A DIFFLUENT PATTERN ALOFT ASSOCIATED WITH AN
UPPER LEVEL TROUGH THAT CURRENTLY EXTENDS ACROSS FLORIDA AND
WEST-CENTRAL CUBA TO NEAR PANAMA IS HELPING TO INDUCE THE
CONVECTIVE ACTIVITY ASSOCIATED WITH THIS TROUGH. CURRENTLY...
CONVECTION IS FLARE UP AHEAD OF THE TROUGH AXIS BETWEEN CUBA AND
THE NW BAHAMAS. SHOWERS AND TSMTS ARE ALSO DEVELOPING BETWEEN
JAMAICA AND EASTERN CUBA AS WELL AS ACROSS THE WINDWARD PASSAGE
AND NEAR THE NORTHERN END OF THE TROUGH. LOCALIZED FLOODING IS
STILL POSSIBLE OVER HISPANIOLA AS THE TROUGH DRIFTS WESTWARD.
FURTHER E...THE TAIL END OF A SHEARLINE IS OVER THE NORTHERN
LEEWARD AND THE VIRGIN ISLANDS CROSSING JUST N OF PUERTO RICO.
NE WINDS OF 20 KT ARE NOTED N OF THE SHEAR LINE BY SCATTEROMETER
DATA. THIS FEATURE IS PRODUCING SOME SHOWER ACTIVITY ACROSS THE
NE CARIBBEAN AND COINCIDES WITH A WELL DEFINED BAND OF MOISTURE
AS DEPICTED IN THE TPW PRODUCT. IN FACT...SAN JUAN REPORTED 3.42
INCHES OF RAIN OVER THE PAST 24 HOURS ENDING THIS MORNING AT 8
AM. LOW LEVEL MOISTURE AND UPPER LEVEL DYNAMIC ASSOCIATED WITH
THE ABOVE MENTIONED TROUGH WILL COMBINE WITH LOCAL EFFECTS AND
DIURNAL HEATING TO PRODUCE SHOWER AND THUNDERSTORM ACTIVITY
ACROSS PARTS OF PUERTO RICO...HISPANIOLA...MAINLY EASTERN CUBA
AND THE BAHAMAS. ANOTHER SURFACE TROUGH IS OVER THE CARIBBEAN
SEA AND EXTENDS FROM 18N79W TO A 1010 MB LOW PRES NEAR 9N76W.
SCATTERED MODERATE TO STRONG CONVECTION IS ASSOCIATED WITH THIS
SYSTEM OVER THE SW CARIBBEAN. TRADEWIND FLOW OF 15-20 KT IS
PRESENT ACROSS THE EAST AND CENTRAL CARIBBEAN JUST E OF THE
SURFACE TROUGH. IN THE UPPER LEVELS...A RIDGE DOMINATES MUCH OF
CENTRAL AMERICA. THE WESTERN PORTION OF ANTICYCLONE LOCATED NEAR
10N55W IS OVER THE REMAINDER OF THE CARIBBEAN PRODUCING SW UPPER
LEVEL FLOW. UPPER LEVEL SUBSIDENCE IS OVER THE W CARIBBEAN AND
CENTRAL AMERICA W OF 80W. ABUNDANT MID/UPPER LEVEL MOISTURE IS
NOTED AHEAD OF THE AFOREMENTIONED UPPER LEVEL TROUGH.

ATLANTIC OCEAN...

AS PREVIOUSLY MENTIONED...A SURFACE TROUGH IS OVER THE SOUTHERN
BAHAMAS AND THE WINDWARD PASSAGE WITH SCATTERED SHOWERS AND
TSTMS. SEE THE CARIBBEAN SEA SECTION FOR MORE DETAILS. A 1031 MB
HIGH PRES LOCATED N OF AREA NEAR 35N55W EXTENDS A RIDGE OVER THE
WESTERN AND CENTRAL ATLC. A SURFACE TROUGH IS OVER THE E ATLC
FROM 31N22W TO 23N27W. A SHEARLINE CONTINUES FROM THIS POINT TO
18N40W TO 14N55W TO 18N62W TO 19N67W. A WELL DEFINED BAND OF
MAINLY LOW LEVEL CLOUDS IS ASSOCIATED WITH THE SHEARLINE.  A
1017 MB LOW PRES IS NEAR 31N30W WITH A TROUGH EXTENDING SW TO
NEAR 26N37W. ALOFT...A TROUGH/RIDGE/TROUGH PATTERN DOMINATES THE
REGION. EXPECT THE PORTION OF THE SHEARLINE W OF 55W TO REMAIN
ACTIVE WITH SHOWERS.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

AT THE REQUEST OF METEO-FRANCE AND THE METEOROLOGICAL SERVICES OF
HAITI AND THE DOMINICAN REPUBLIC...THE TROPICAL ANALYSIS AND
FORECAST BRANCH (TAFB) WILL BEGIN PROVIDING...ON A TEMPORARY
BASIS...A SEPARATE DETAILED SECTION WITHIN THE ATLANTIC TROPICAL
WEATHER DISCUSSION (TWDAT). IT WILL COVER BOTH HAITI AND THE
DOMINICAN REPUBLIC DUE TO THE SHARED GEOGRAPHY OF BOTH COUNTRIES
ON THE ISLAND OF HISPANIOLA.

THE SECTION BEGINS ON MAY 15 2013 AT 1800 UTC...2 PM EDT. IT
WILL PROVIDE GUIDANCE FOR SIGNIFICANT WEATHER EVENTS THAT ARE
EXPECTED TO IMPACT THE REGION THROUGH 48 HOURS...WITH THE FOCUS
ON ASSESSING THE POTENTIAL FOR HEAVY RAINFALL.

$$
GR

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