[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 182327
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST WED FEB 18 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...SPECIAL FEATURES...

...GALE WARNING FOR THE W ATLC...

A GALE WARNING IS IN EFFECT N OF 28.5N WITHIN 90 NM SE OF A COLD
FRONT THAT EXTENDS FROM 31N71W TO 23N81W. THE GALE FORCE WINDS
ARE FORECAST TO SHIFT EAST AHEAD OF THE EASTWARD MOVING COLD
FRONT UNTIL 0000 UTC FRIDAY...WHEN WINDS ARE EXPECTED TO
DECREASE BELOW GALE FORCE. 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 WEST AFRICA INTO THE TROPICAL
ATLC NEAR 10N14W TO 6N19W TO WHERE THE ITCZ BEGINS AND CONTINUES
TO 2S44W AT THE COAST OF SOUTH AMERICA. WIDELY SCATTERED
MODERATE CONVECTION EXISTS WITHIN 180 NM OF THE ITCZ WEST OF
25W. SCATTERED MODERATE CONVECTION IS OBSERVED NORTH OF THE
EQUATOR AND EAST OF 0W TO THE WEST AFRICAN COAST.

...DISCUSSION...

GULF OF MEXICO...

A 1029 MB HIGH IS CENTERED OVER THE COAST OF TEXAS NEAR 29N95W.
COLD AIR ADVECTION DOMINATES THE GULF BEHIND A STRONG FRONT
WHICH NOW EXTENDS FROM THE ATLANTIC INTO THE NW CARIBBEAN.
NORTHERLY WINDS HAD DROPPED BELOW GALE FORCE AS OF 18 UTC AND
NOW PEAK AT 25 KT IN BOTH THE NE AND SW GULF. IN THE UPPER
LEVELS...THE BASE OF A STRONG TROUGH REACHES THE CENTRAL GULF
WITH AN AXIS ALONG 88W. SUBSTANTIAL LOW-LEVEL MOISTURE AND
CLOUDINESS REMAIN ACROSS THE SOUTHERN THIRD OF THE GULF. ON
THURSDAY...COLD AIR ADVECTION WILL STILL PREVAIL OVER THE
GULF...WHILE ON FRIDAY SOUTHERLY RETURN FLOW SETS UP IN THE
WESTERN HALF OF THE GULF.

CARIBBEAN SEA...

A STRONG COLD FRONT EXTENDS FROM CUBA NEAR 23N81W WEST-
SOUTHWESTWARD ACROSS THE NW CARIBBEAN TO 20N87W ALONG THE
YUCATAN OF MEXICO.  A PRE-FRONTAL TROUGH EXTENDS FROM 22N81W TO
16N86W. SCATTERED MODERATE CONVECTION IS PRESENT OVER CENTRAL
CUBA IN THE VICINITY OF THE FRONT AND WITHIN 60 NM OF THE TROUGH
NORTH OF 20N...AS SEEN FROM THE GRAND CAYMAN AND CAMAGUEY RADAR.
25 KT N TO NW WINDS ARE NW OF THE FRONT. 15-25 KT TRADEWINDS ARE
OVER THE REMAINDER OF CARIBBEAN SEA WITH MOSTLY FAIR WEATHER. IN
THE UPPER LEVELS...THE SOUTHEASTERN SIDE OF A MID-LATITUDE
TROUGH REACHES INTO THE NW CARIBBEAN AND IS HELPING TO ENHANCE
THE CONVECTION.  ELSEWHERE...RIDGING WITH STRONG SUBSIDENCE
DOMINATES THE CARIBBEAN. ON THURSDAY...THE COLD FRONT SHOULD
CONTINUE TO ADVANCE SOUTHEASTWARD WITH SIGNIFICANT CHANCE FOR
SHOWERS AND DEEP CONVECTION.  BY FRIDAY...THE COLD FRONT SHOULD
BE DISSIPATING THOUGH WITH CONTINUED CHANCES FOR SHOWERS AND
DEEP CONVECTION IN THE CENTRAL AND SOUTHWESTERN CARIBBEAN.

...HISPANIOLA...

MOSTLY FAIR WEATHER IS OVER HISPANIOLA TODAY AS STRONG UPPER
LEVEL SUBSIDENCE COVERS THE ISLAND. OVER THE NEXT 24 HOURS...
SOME SHOWERS MAY DEVELOP OVER HISPANIOLA AS THE PRE-FRONTAL
TROUGH AND COLD FRONT APPROACH. ON THURSDAY NIGHT AND FRIDAY...A
MORE SIGNIFICANT CHANCE FOR SHOWERS AND THUNDERSTORMS IS LIKELY
AS THE DISSIPATING COLD FRONTAL BOUNDARY SHOULD BE NEAR OR OVER
THE ISLAND.

ATLANTIC OCEAN...

A STRONG COLD FRONT EXTENDS OVER THE W ATLANTIC FROM 32N70W
ACROSS THE NORTHERN BAHAMAS TO CUBA NEAR 23N81W. GALE CONDITIONS
ARE CURRENTLY E OF FRONT. SEE ABOVE. SCATTERED TO NUMEROUS
MODERATE CONVECTION IS OBSERVED WITHIN 120 NM EAST OF THE FRONT.
A STRONG 1036 MB HIGH IS CENTERED NORTH OF OUR AREA NEAR 37N26W
WITH RIDGING EXTENDING SOUTHWESTWARD TO THE GREATER ANTILLES.
TRADEWINDS ARE GENERALLY 10-20 KT ACROSS THE TROPICAL NORTH
ATLANTIC. IN THE UPPER LEVELS...THE GULF OF MEXICO UPPER TROUGH
IS PRODUCING A CONDUCIVE DIVERGENCE PATTERN OVER THE FRONT
HELPING TO ENHANCE THE CONVECTION.  EXPECT IN 24 HOURS...THE
ATLANTIC COLD FRONT SHOULD EXTEND FROM 32N63W TO EASTERN CUBA
WITH A SIGNIFICANT CHANCE OF ASSOCIATED SHOWERS AND DEEP
CONVECTION.  AT THE SAME TIME...A SECONDARY COLD FRONT WILL PUSH
OFF OF THE SE UNITED STATES COAST AND ENHANCED THE NORTHWESTERLY
FLOW BEHIND IT.  ON FRIDAY...THE TWO FRONTS SHOULD MERGE AND
CONTINUE PRESSING EASTWARD WITH THE TAIL OF THE FRONT REACHING
HISPANIOLA.

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

$$
LANDSEA


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