[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 121147
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST THU FEB 12 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1130 UTC.

...SPECIAL FEATURES...

A GALE WARNING IS IN EFFECT FOR A PORTION OF THE W ATLC COVERING
THE AREA N OF 28N BETWEEN 51W AND 55W AND N OF 29N BETWEEN 60W
AND 64W...ASSOCIATED WITH A PAIR OF COLD FRONTS. ONE EXTENDING
FROM 31N54W TO 19N65W AND ANOTHER FROM 31N60W TO 25N65W TO
20N70W. GALE FORCE WINDS ASSOCIATED WITH THE EASTERNMOST FRONTAL
BOUNDARY ARE FORECAST THROUGH FRIDAY MORNING. PLEASE SEE LATEST
NWS 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 07N12W TO 04N20W WHERE THE ITCZ BEGINS AND CONTINUES ALONG
01N30W 01N40W TO THE NORTHERN COAST OF BRAZIL NEAR 02S51W.
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE N
OF 01N BETWEEN 01W AND 14W. SCATTERED MODERATE CONVECTION IS
FROM 03S TO 05N BETWEEN 17W AND 37W.

...DISCUSSION...

GULF OF MEXICO...

SURFACE RIDGING CONTINUES TO DOMINATE ACROSS THE GULF AND
PROVIDES VARIABLE WINDS IN THE RANGE OF 5 TO 10 KT...EXCEPT
ALONG THE WESTERN COAST OF THE YUCATAN PENINSULA WHERE NE WINDS
OF 15 KT ARE NOTED IN THE LAST SCATTEROMETER PASS.
ALOFT...SOUTHWESTERLY FLOW CONTINUES TO ADVECTS MOISTURE TO THE
WESTERN AND CENTRAL GULF FROM A MIDDLE TO UPPER LEVEL LOW ON THE
EPAC WATERS. ADVECTION FOG IS BEING REPORTED ON THE NW GULF N OF
28N WEST OF 90W...COINCIDING WITH GOES-13 IFR AND LIFR MEDIUM TO
HIGH FOG PROBABILITIES. DEEP LAYER DRY AIR IS ELSEWHERE ACROSS
THE BASIN SUPPORTING FAIR WEATHER. A COLD FRONT ENTERED THE
NORTHERN GULF THIS MORNING BEING SUPPORTED BY A WEAK MIDDLE-
LEVEL TROUGH ACROSS THE BASIN. THE COLD FRONT EXTENDS FROM THE
FLORIDA PANHANDLE SW-W TO COASTAL WATERS OF LOUISIANA NEAR
29N91W SW TO SOUTHERN TEXAS NEAR 27N97W. THE FRONT WILL MOVE
ACROSS THE BASIN AND THE REMAINDER FLORIDA PENINSULA THROUGH
EARLY FRIDAY MORNING.

CARIBBEAN SEA...

A MIDDLE-LEVEL LOW OVER THE NW ATLC WATERS EXTENDS A TROUGH S TO
A BASE OVER NORTHERN COASTAL WATERS OF PUERTO RICO AND DOMINICAN
REPUBLIC. THIS UPPER TROUGH SUPPORT A BROAD LOW PRESSURE SYSTEM
N OF THE AREA OF DISCUSSION FROM WHICH TWO COLD FRONTS EXTENDS.
THE TAIL OF THE EASTERNMOST COLD FRONT REACHES NORTHERN PUERTO
RICO NEAR 18N66W THEN MOVES ACROSS THE MONA PASSAGE TO SOUTHERN
WATERS OF DOMINICAN REPUBLIC NEAR 18N70W. TROUGHING ALOFT ALSO
SUPPORTS A PRE-FRONTAL TROUGH WITH TAIL REACHING THE NE
CARIBBEAN FROM 19N62W TO 17N65W. SHALLOW MOISTURE ASSOCIATED
WITH THESE BOUNDARIES SUPPORT PASSING SHOWERS OVER EASTERN
DOMINICAN REPUBLIC...PUERTO RICO...THE U.S. VIRGIN ISLANDS AND
THE LEEWARD ISLANDS AS WELL AS ADJACENT WATERS.
ALOFT...SOUTHWESTERLY FLOW AND DRY AIR DOMINATES. VARIABLE WINDS
OF 5 TO 10 KT ARE ACROSS THE BASIN...EXCEPT FOR THE SW CARIBBEAN
S OF 15N WHERE NE FLOW OF 15 KT IS OBSERVED. THE COLD FRONT WILL
MOVE ACROSS PUERTO RICO TODAY AND DISSIPATES FRI MORNING OVER
CENTRAL ATLC WATERS.

...HISPANIOLA...

THE TAIL OF A COLD FRONT MOVES ACROSS THE MONA PASSAGE TO
SOUTHERN DOMINICAN REPUBLIC COASTAL WATERS. LOW-LEVEL MOISTURE
ASSOCIATED WITH THE FRONT SUPPORTS PASSING SHOWERS ACROSS THE
EASTERN ISLAND AS WELL AS ADJACENT WATERS AND FOG OVER THE
NORTHERN SIDE OF THE MOUNTAINOUS TERRAIN. LIMITED SHOWER
ACTIVITY IS EXPECTED THROUGH FRIDAY MORNING.

ATLANTIC OCEAN...

A MIDDLE-LEVEL LOW OVER THE NW ATLC WATERS EXTENDS A TROUGH S TO
A BASE OVER NORTHERN COASTAL WATERS OF PUERTO RICO AND DOMINICAN
REPUBLIC. THIS UPPER TROUGH SUPPORT A BROAD LOW PRESSURE SYSTEM
N OF THE AREA OF DISCUSSION FROM WHICH TWO COLD FRONTS EXTENDS.
THE FIRST FRONT IS A DISSIPATING COLD FRONT THAT EXTENDS FROM
30N59W SW TO 22N66W. THE SECOND COLD FRONT EXTENDS FROM 30N53W
SW TO 22N59W...ACROSS THE MONA PASSAGE TO DOMINICAN REPUBLIC
SOUTHERN COASTAL WATERS. A PRE-FRONTAL SURFACE TROUGH EXTENDS
FROM 23N55W TO THE NE CARIBBEAN NEAR 17N65W. ISOLATED SHOWERS
AND TSTMS ARE WITHIN 50 NM E OF THE SURFACE TROUGH AND WITHIN
200 NM E OF THE FRONT N OF 24N. SURFACE RIDGING DOMINATES THE
REMAINDER CENTRAL AND EASTERN BASIN...EXCEPT FROM 21N TO 28N
BETWEEN 31W AND 36W WHERE AN UPPER-LEVEL LOW SUPPORTS A 1015 MB
LOW CENTERED NEAR 26N34W FROM WHICH A TROUGH EXTENDS SW TO
21N35W. SCATTERED SHOWERS AND TSTMS ARE FROM 22N TO 28N BETWEEN
24W AND 31W. SCATTERED SHOWERS AND TSTMS ARE ALSO NOTED OVER THE
CAPE VERDE ISLANDS. THE LEADING W ATLC FRONT WILL DISSIPATE FRI
MORNING OVER THE CENTRAL ATLC. GALE FORCE WINDS ARE ASSOCIATED
WITH THE FRONTS. SEE SPECIAL FEATURES. A NEW COLD FRONT WILL BE
ENTERING THE SW N ATLC WATERS THIS EVENING.

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

$$
NR


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