[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 120604
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0545 UTC.

...SPECIAL FEATURES...

A GALE WARNING IS IN EFFECT FOR A PORTION OF THE W ATLC COVERING
THE AREA N OF 27N WITHIN 180 NM E OF A COLD FRONT EXTENDING
FROM 31N56W TO 24N61W TO 18N68W AND N OF 27N WITHIN 210 NM E OF
A SECOND COLD FRONT EXTENDING FROM 31N63W TO 25N65W TO 20N72W.
THE AREAS OF GALE FORCE WINDS ARE ASSOCIATED WITH A BROAD LOW
PRESSURE SYSTEM N OF THE DISCUSSION AREA. GALE FORCE WINDS WILL
SHIFT E WITH THE FRONTS THROUGH THU NIGHT WHEN ARE FORECAST TO
DIMINISH. 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 09N14W THEN ALONG 07N15W TO 03N19W WHERE THE ITCZ BEGINS
AND CONTINUES ALONG 01N30W 02N40W TO THE NORTHERN COAST OF
BRAZIL NEAR 01S51W. CLUSTERS OF SCATTERED MODERATE/ISOLATED
STRONG CONVECTION ARE N OF 02N BETWEEN 01W AND 12W. SCATTERED
MODERATE CONVECTION IS FROM 01N-05N BETWEEN 17W-37W.

...DISCUSSION...

GULF OF MEXICO...

SURFACE RIDGING CONTINUES TO DOMINATE ACROSS THE GULF BEING
ANCHORED BY A 1020 MB HIGH ON COASTAL WATERS OF SE LOUISIANA
NEAR 29N89W. THE RIDGE IS PROVIDING 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 GULF FROM A MIDDLE TO UPPER
LEVEL LOW ON THE EPAC WATERS. ADVECTION FOG IS BEING REPORTED ON
THE NW GULF N OF 28N BETWEEN 92W AND 95W...ALSO DEPICTED IN THE
GOES-13 IFR AND LIFR PRODUCTS. DEEP LAYER DRY AIR IS ELSEWHERE
ACROSS THE BASIN SUPPORTING FAIR WEATHER. A COLD FRONT IS
FORECAST TO MOVE INTO THE N GULF THU MORNING AND ACROSS THE
BASIN AND THE FLORIDA PENINSULA THROUGH 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 WESTERNMOST COLD FRONT EXTENDS ACROSS HAITI FROM
20N71W SW TO 18N74W. THE SECOND COLD FRONT MOVES ACROSS THE MONA
PASSAGE TO 16N70W WHERE IT STARTS TO DISSIPATE TO 12N78W.
TROUGHING ALOFT ALSO SUPPORTS A PRE-FRONTAL TROUGH EXTENDING
ACROSS EASTERN PUERTO RICO SW TO 15N69W. LOW-LEVEL MOISTURE
ASSOCIATED WITH THESE FRONTAL BOUNDARIES SUPPORT SHOWERS OVER
EASTERN DOMINICAN REPUBLIC...PUERTO RICO...THE U.S. VIRGIN
ISLANDS AND THE LEEWARD ISLANDS. ALOFT...SOUTHWESTERLY FLOW AND
DRY AIR DOMINATES. VARIABLE WINDS OF 5 TO 10 KT ARE ACROSS THE
BASIN...EXCEPT FOR THE SW CARIBBEAN WHERE NE FLOW OF 15 KT IS
OBSERVED. THE W COLD FRONT WILL MOVE N OF THE AREA BY THU
MORNING WHILE THE SECOND COLD FRONT MOVES ACROSS PUERTO RICO AND
DISSIPATES FRI MORNING. A NEW COLD FRONT ENTERS THE NW CARIBBEAN
FRI DISSIPATING OVER CENTRAL CUBA DURING THE MORNING HOURS.

...HISPANIOLA...

THE TAIL OF A COLD FRONT IS MOVING ACROSS HAITI AND WILL
CONTINUE TO MOVE ACROSS THE REMAINDER ISLAND TONIGHT. A SECOND
COLD FRONT IS JUST E OF THE ISLAND OVER THE MONA PASSAGE. LOW-
LEVEL MOISTURE ASSOCIATED WITH THESE BOUNDARIES IS SUPPORTING
SCATTERED TO ISOLATED SHOWERS ACROSS THE ISLAND AND ADJACENT
WATERS AS WELL AS FOG OVER THE NORTHERN SIDE OF THE MOUNTAINOUS
TERRAIN. LIMITED SHOWER ACTIVITY WILL BE OBSERVED THU INTO FRI.

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 COLD FRONT EXTENDS FROM 30N62W SW TO 24N65W TO SW
HAITI NEAR 18N74W. THE SECOND COLD FRONT EXTENDS FROM 30N56W SW
TO 23N60W...ACROSS THE MONA PASSAGE...DISSIPATING OVER THE
CENTRAL AND SW CARIBBEAN. A PRE-FRONTAL SURFACE TROUGH EXTENDS
FROM 24N56W...ACROSS EASTERN PUERTO RICO TO 15N69W. SCATTERED
SHOWERS AND TSTMS ARE WITHIN 100 NM E OF THE SURFACE TROUGH N OF
17N. SURFACE RIDGING DOMINATES THE REMAINDER CENTRAL AND EASTERN
BASIN...EXCEPT FROM 20N TO 28N BETWEEN 28W AND 35W WHERE AN
UPPER-LEVEL LOW SUPPORTS A 1015 MB LOW NEAR 26N34W FROM WHICH A
TROUGH EXTENDS SW TO 20N34W. SCATTERED SHOWERS AND TSTMS ARE
FROM 20N TO 27N BETWEEN 25W AND 31W. SCATTERED SHOWERS AND TSTMS
ARE ALSO NOTED OVER THE CAPE VERDE ISLANDS. THE LEADING W ATLC
FRONT WILL WEAKEN AS IT MOVES INTO THE CENTRAL ATLC AND NE
CARIBBEAN. GALE FORCE WINDS ARE ASSOCIATED WITH THE FRONTS. SEE
SPECIAL FEATURES. A NEW COLD FRONT WILL BE ENTERING THE SW N
ATLC WATERS ON THU.

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

$$
NR


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