[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 211803
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST SAT FEB 21 2015

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
1745 UTC.

...SPECIAL FEATURES...

...GALE WARNING FOR THE SW CARIBBEAN...
A GALE WARNING IS IN EFFECT OFF THE NW COAST OF COLOMBIA FROM
10N TO 13N BETWEEN 74W AND 76W WITH ASSOCIATED SEAS RANGING FROM
10 TO 13 FT. GALE FORCE WINDS WILL DIMINISH SUNDAY MORNING.
PLEASE SEE THE LATEST HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS
MIAHSFAT2/FZNT02 KNHC FOR MORE DETAILS.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE TROPICAL ATLC
NEAR 06N11W TO 01N18W ALONG THE EQUATOR TO 24W. THE ITCZ BEGINS
CONTINUES FROM THERE TO 01N30W TO 02S37W TO THE NORTHERN COAST
OF BRAZIL NEAR 02S42W. SCATTERED MODERATE CONVECTION AND TSTMS
ARE FROM 01N TO 07N E OF 15W. SCATTERED MODERATE CONVECTION IS
FROM 04S TO 05N W OF 35W.

...DISCUSSION...

GULF OF MEXICO...

A 1036 MB HIGH PRESSURE CENTER OVER THE NW ATLC WATERS NEAR
39N69W ANCHORS A BROAD SURFACE RIDGE THAT EXTENDS SW ACROSS THE
EASTERN CONUS...THE SW N ATLC AND THE EASTERN GULF OF MEXICO.
THIS RIDGE CONTINUES TO ADVECT COLD AIR ACROSS THE FLORIDA
PENINSULA AS WELL AS THE EASTERN GULF. RIDGING IS ALSO PROVIDING
SOUTHEASTERLY TO SOUTHERLY WIND FLOW IN THE RANGE OF 20 TO 25 KT
BASIN-WIDE. LOW-LEVEL MOISTURE CONVERGENCE ALONG THE NW GULF
COAST SUPPORTS BROKEN TO OVERCAST SKIES N OF 27N...HAZE AND
POSSIBLE ISOLATED SHOWERS. FAIR WEATHER PREVAILS ELSEWHERE.
ALOFT...WESTERLY FLOW ADVECTS MOISTURE FROM THE EPAC WATERS TO
THE GULF N OF 25N. SURFACE RIDGING WILL CONTINUE TO DOMINATE
ACROSS THE BASIN THROUGH SUNDAY NIGHT. A NEW COLD FRONT WILL
ENTER THE GULF AND FLORIDA PENINSULA EARLY MONDAY MORNING.

CARIBBEAN SEA...

A MIDDLE TO UPPER LEVEL TROUGH IS OVER THE WESTERN ATLC WITH
BASE EXTENDING N OF THE MONA PASSAGE. THIS TROUGH ALOFT SUPPORTS
A STATIONARY FRONT EXTENDING ACROSS THE SW N ATLC TO NORTHERN
HAITI TO THE WINDWARD PASSAGE WHERE IT TRANSITIONS TO A SHEAR
LINE NEAR 18N74W SW ACROSS JAMAICA TO 17N81W. LOW-LEVEL MOISTURE
ASSOCIATED WITH THE FRONT AND A MIDDLE-LEVEL DIFFLUENT
ENVIRONMENT SUPPORT SCATTERED TO ISOLATED SHOWERS OVER
HISPANIOLA AND ADJACENT WATERS. ISOLATED SHOWERS ARE WITHIN 75
NM EITHER SIDE OF THE SHEAR LINE. SHOWERS AND TSTMS ARE FORECAST
ACROSS PUERTO RICO THIS AFTERNOON ASSOCIATED WITH A WEAK SURFACE
TROUGH WITH NORTHERN AXIS MOVING THROUGH THE ISLAND. THE RIDGE
ACROSS THE GULF OF MEXICO AND W ATLC HAS INCREASED THE SURFACE
PRESSURE GRADIENT ACROSS THE BASIN...RESULTING IN TRADES OF 15
TO 20 KT ACROSS THE BASIN AND GALE FORCE WINDS ALONG THE COAST
OF COLOMBIA. SEE SPECIAL FEATURES SECTION. THE SURFACE TROUGH IS
FORECAST TO DISSIPATE SUNDAY MORNING OVER THE EASTERN DOMINICAN
REPUBLIC.

...HISPANIOLA...

A MIDDLE TO UPPER LEVEL TROUGH OVER THE WESTERN ATLC WITH BASE
EXTENDING EXTENDING N OF THE MONA PASSAGE SUPPORTS A STATIONARY
FRONT EXTENDING ACROSS THE SW N ATLC...NORTHERN HAITI TO THE
WINDWARD PASSAGE WHERE IT TRANSITIONS TO A SHEAR LINE NEAR
18N74W SW ACROSS JAMAICA TO 17N81W. LOW-LEVEL MOISTURE
ASSOCIATED WITH THE FRONT AND A MIDDLE-LEVEL DIFFLUENT
ENVIRONMENT SUPPORT SCATTERED TO ISOLATED SHOWERS OVER
HISPANIOLA AND ADJACENT WATERS. SHOWERS ARE FORECAST TO CONTINUE
THROUGH SUNDAY MORNING AS A DISSIPATING SURFACE TROUGH
APPROACHES THE EASTERN ISLAND.

ATLANTIC OCEAN...

A MIDDLE TO UPPER LEVEL TROUGH IS OVER THE WESTERN ATLC WITH
BASE EXTENDING N OF THE MONA PASSAGE. A STATIONARY FRONT IS
BEING SUPPORTED BY THE TROUGH ALOFT ENTERING THE SW N ATLC ALONG
30N57W SW TO NORTHERN HAITI TO THE WINDWARD PASSAGE WHERE IT
TRANSITIONS TO A SHEAR LINE NEAR 18N74W SW ACROSS JAMAICA TO
17N81W. SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS ARE N
OF 25N BETWEEN 55W AND 63W. A 1041 MB HIGH NEAR 36N35W ANCHORS A
BROAD SURFACE RIDGE THAT COVERS THE REMAINDER CENTRAL AND
EASTERN ATLC N OF 16N. THE FRONT WILL DISSIPATE SUNDAY MORNING
AND RIDGING WILL DOMINATE. A NEW COLD FRONT ENTERS THE SW N ATLC
EARLY MONDAY MORNING.

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

$$
NR


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