[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 211753
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT WED MAY 21 2014

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
1715 UTC.

...TROPICAL WAVE...
VISIBLE SATELLITE IMAGERY SHOWS A TROPICAL WAVE MOVING OUT OF
AFRICA THIS MORNING. THE UPPER-AIR TIME SECTION FROM DAKAR AND
THE TPW ANIMATION BOTH INDICATE A BULGE OF MOISTURE ALONG THE
COAST OF AFRICA THAT COINCIDES WITH THE WAVE AXIS. BASED ON THIS
DATA...A TROPICAL WAVE IS ADDED TO THE 1200 UTC ANALYSIS/SURFACE
MAP EXTENDING FROM 15N17W TO 10N18W. THIS SYSTEM WILL MOVE
WESTWARD AT 10-15 KT.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH IS ANALYZED ACROSS AFRICA INTO THE TROPICAL
ATLC NEAR 6N10W ALONG 4N12W TO 3N15W WHERE THE ITCZ BEGINS AND
CONTINUES S OF THE EQUATOR NEAR 22W. CLUSTERS OF SCATTERED
MODERATE TO ISOLATED STRONG CONVECTION ARE N OF THE EQUATOR TO
INLAND OVER W AFRICA BETWEEN THE PRIME MERIDIAN AND 10W...AND
FROM 1N TO 6N BETWEEN 10W AND 20W. ISOLATED MODERATE CONVECTION
IS N OF THE EQUATOR TO 2.5N W OF 40W.

...DISCUSSION...

GULF OF MEXICO...
A 1024 MB HIGH PRES LOCATED OVER THE NE GULF NEAR 29N84W EXTENDS
A RIDGE WESTWARD TOWARD TEXAS DOMINATING THE ENTIRE GULF WATERS
WITH MOSTLY FAIR WEATHER. SOUTH OF RIDGE...AN EARLIER ASCAT PASS
INDICATED A BROAD AREA OF 20 TO 25 KT WINDS OVER THE STRAITS OF
FLORIDA OFF THE NW COAST OF CUBA. W OF THE RIDGE...SOUTHERLY
RETURN FLOW HAS ESTABLISHED OVER THE WESTERN GULF. THE HIGH IS
FORECAST TO MOVE TOWARD THE MOUTH OF THE MISSISSIPPI RIVER
THROUGH THU WITH LITTLE CHANGE IN THE WEATHER PATTERN ACROSS THE
REGION OVER THE NEXT 24 HOURS. A WEAK SURFACE TROUGH IS ANALYZED
FROM 28N86W TO 25N86.5W AND WILL DISSIPATE LATER TODAY OR
TONIGHT. ALOFT...AN UPPER RIDGE EXTENDS FROM THE E PACIFIC
REGION ACROSS THE BAY OF CAMPECHE AND THE CENTRAL GULF TO BEYOND
LOUISIANA GIVING MOST OF THE GULF NW FLOW IN THE UPPER-LEVELS.
MODERATE TO STRONG MID/UPPER LEVEL SUBSIDENCE AND IMPLIED DRY
AIR MASS IS NOTED ON WATER VAPOR IMAGERY ACROSS MOST OF THE GULF
REGION.

CARIBBEAN SEA...
A MID/UPPER LEVEL TROUGH EXTENDS ACROSS CENTRAL CUBA AND THE NW
CARIBBEAN. A WESTERLY UPPER JET REMAINS SE OF THE TROUGH AND IS
HELPING TO INDUCE CONVECTION ACROSS THE CARIBBEAN SEA AND PARTS
OF THE GREATER ANTILLES...PARTICULARLY ACROSS EASTERN CUBA...
JAMAICA AND HISPANIOLA. VISIBLE SATELLITE IMAGERY REVEALS A BAND
OF MULTILAYERED CLOUDS EXTENDING FROM NE HONDURAS ALL THE WAY NE
ACROSS JAMAICA AND THE WINDWARD PASSAGE INTO THE ATLC WATERS.
COMPUTER MODELS SHOW A GRADUAL AMPLIFICATION OF THE MID/UPPER
LEVEL TROUGH ACROSS THE CENTRAL CARIBBEAN. AS A RESULT...IT WILL
CONTINUE TO SUPPORT THE DEVELOPMENT OF SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS ACROSS E CUBA...JAMAICA...HISPANIOLA AND
PUERTO RICO MAINLY DURING THE AFTERNOON AND EARLY EVENING HOURS.
A CLUSTER OF MODERATE TO ISOLATED STRONG CONVECTION IS NOTED
OVER THE SW CARIBBEAN MAINLY S OF 11N E OF 80W LIKELY ASSOCIATED
WITH THE MONSOON TROUGH. PATCHES OF LOW LEVEL CLOUDS EMBEDDED IN
THE TRADE WIND FLOW ARE CROSSING THE LEEWARD ISLANDS PRODUCING
ISOLATED TO SCATTERED PASSING SHOWERS. HIGH PRESSURE NORTH OF
THE AREA WILL MAINTAIN FRESH TO STRONG TRADEWINDS IN THE CENTRAL
CARIBBEAN OFF NE COLOMBIA AND NW VENEZUELA WITH MODERATE TO
FRESH TRADES ELSEWHERE THROUGH SUNDAY.

...HISPANIOLA...
THE ABOVE MENTIONED MID/UPPER LEVEL TROUGH WILL COMBINE WITH
DAYTIME HEATING...A MOIST SOUTHEASTERLY FLOW AND LOCAL EFFECTS
TO INDUCE THE DEVELOPMENT OF SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS ACROSS PARTS OF THE ISLAND MAINLY DURING THE
AFTERNOON AND EARLY EVENING HOURS THROUGH AT LEAST FRI.

ATLANTIC OCEAN...
A 1024 MB HIGH PRES LOCATED NEAR 32N74W EXTENDS A RIDGE ACROSS
THE W ATLC. LIGHT TO MODERATE NE-E FLOW ON THE S PERIPHERY OF
THE RIDGE IS TRANSPORTING SOME CLOUDINESS ACROSS THE BAHAMAS
INTO CUBA. THE RIDGE IS BUILDING BEHIND A STATIONARY FRONT THAT
ENTERS THE FORECAST REGION NEAR 31N56W THEN CONTINUES SW TO NEAR
27N64W WHERE IT BEGINS TO DISSIPATE. A NARROW LINE OF CLOUDINESS
IS RELATED TO THE FRONT. THE HIGH IS FORECAST TO MOVE TO A
POSITION NEAR 30N61W IN ABOUT 24 HOURS. A SECOND SURFACE RIDGE
COVERS THE REMAINDER OF THE ATLC ANCHORED BY A HIGH LOCATED WELL
N OF THE REGION. A SURFACE TROUGH...REFLECTION OF THE PREVIOUSLY
MENTIONED MID/UPPER LEVEL TROUGH EXTENDS FROM 23N70W TO HAITI
NEAR 18.5N72W. SURFACE DATA ALONG WITH A RECENT ASCAT PASS SHOW
THE WIND SHIFT ASSOCIATED WITH THE TROUGH AXIS. A WEAK TROUGH
RUNS FROM 08N27W TO 2N29W. A FEW SHOWERS ARE ASSOCIATED WITH THE
TROUGH FORECAST TO DISSIPATE LATER TODAY OR TONIGHT. ALOFT...
BROAD UPPER TROUGH EXTENDS FROM NEAR BERMUDA TO CENTRAL CUBA. A
WESTERLY UPPER JET IS SE OF THE TROUGH AXIS PRODUCING A BAND OF
MULTILAYERED CLOUDS THAT EXTEND FROM THE WINDWARD PASSAGE ALL
THE WAY NE TO BEYOND 31N50W. TRANSVERSE HIGH CLOUDS ARE ALSO
NOTED IN ASSOCIATION WITH THE STRONG UPPER-LEVEL WINDS. ANOTHER
UPPER LEVEL TROUGH IS OVER THE E ATLC EXTENDING FROM 31N28W TO
NEAR 10N42W.

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

$$
GR


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