Tropical Weather Discussion
Issued by NWS

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000
AXNT20 KNHC 281120
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST WED JAN 28 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
1115 UTC.

...GALE WARNING IN W ATLC...

A GALE WARNING IS IN EFFECT FOR AN AREA N OF 28N AND E OF FRONT
THAT EXTENDS FROM 31N70W TO 27N80W TO 66W. GALE FORCE WINDS ARE
EXPECTED TO SUBSIDE LATER THIS MORNING. SEE HIGH SEAS FORECAST
UNDER AWIPS/WMO HEADERS MIAHSFAT2/FZNT02 KNHC FOR MORE
INFORMATION.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL
ATLC NEAR 08N13W TO 02N21W WHERE THE ITCZ BEGINS AND CONTINUES
ALONG 02N33W INTO SOUTH AMERICA NEAR 00N46W. SCATTERED MODERATE
CONVECTION IS FROM 00N-03N BETWEEN 16W-40W.

...DISCUSSION...

GULF OF MEXICO...

A SHARP UPPER-LEVEL TROUGH EXTENDS FROM NEW ENGLAND OVER W
ATLANTIC AND INTO THE FAR NE GULF OF MEXICO SUPPORTING A PAIR OF
COLD FRONTS THAT ARE ACROSS THE W ATLANTIC. A BROAD UPPER-LEVEL
RIDGE EXTENDS FROM MEXICO INTO THE PLAIN STATES GIVING THE
REMAINDER OF THE GULF NEAR ZONAL WESTERLY FLOW ALOFT. A SURFACE
RIDGE COVERS THE GULF ANCHORED BY A 1023 MB HIGH CENTERED NEAR
25N95W. LATEST SATELLITE WATER VAPOR IMAGERY DEPICTS STRONG
SUBSIDENCE AND DRY STABLE AIR DOMINATING THE BASIN. A SLIGHT
ANTICYCLONIC FLOW PREVAILS W OF 90W WHILE A GENTLE TO MODERATE
NORTHERLY FLOW IS DEPICTED IN SCATTEROMETER DATA E OF 90W. OVER
THE NEXT 24 HOURS...EXPECT FOR THE SURFACE RIDGE CURRENTLY OVER
THE W GULF TO DRIFT E BEFORE DISSIPATING. A HIGH PRESSURE OVER
THE SE CONUS WILL DOMINATE THE BASIN AFTER THAT.

CARIBBEAN SEA...

AN UPPER-LEVEL TROUGH OVER THE W ATLANTIC SUPPORTS A COLD FRONT
THAT EXTENDS FROM THE W CENTRAL ATLANTIC INTO HAITI. A SHEAR
LINE EXTENDS S FROM THE FRONT THROUGH THE CARIBBEAN FROM 19N74W
TO 10N81W. ISOLATED SHOWERS ARE POSSIBLE ALONG THE SHEARLINE
AFFECTING THE ADJACENT WATERS W OF HAITI...E OF JAMAICA AND N OF
COSTA RICA AND PANAMA. A SURFACE TROUGH EXTENDS FROM THE
ATLANTIC ACROSS DOMINICAN REPUBLIC INTO THE CENTRAL CARIBBEAN
WATERS FROM 18N69W TO 15N72W WITH ISOLATED TO SCATTERED
CONVECTION AFFECTING LA MONA PASSAGE AND DOMINICAN REPUBLIC. A
BROAD UPPER-LEVEL RIDGE COVERS THE CARIBBEAN ANCHORED OVER
COLOMBIA AND EXTENDING A RIDGE AXIS NE OVER THE E CARIBBEAN AND
S CENTRAL ATLANTIC. STRONG SUBSIDENCE AND DRY STABLE AIR
DOMINATE THE REMAINDER OF THE BASIN E OF THE SHEAR LINE WHICH
KEEPS THE AREA UNDER A FAIR WEATHER REGIME. SLIGHT TO GENTLE
TRADES PREVAIL E OF THE SHEAR LINE WHILE GENTLE TO MODERATE
NORTHERLY FLOW PREVAILS W OF THE SHEARLINE. OVER THE NEXT 24
HOURS...EXPECT FOR THE COLD FRONT OVER HAITI TO WEAKEN. FRESH TO
STRONG WINDS WILL PERSIST NEAR THE COAST OF NICARAGUA AND COSTA
RICA.

...HISPANIOLA...

SCATTERED SHOWERS ARE ACROSS THE ISLAND DUE TO THE PROXIMITY OF
A COLD FRONT CURRENTLY OVER HAITI AND A SURFACE TROUGH OVER E
DOMINICAN REPUBLIC. THE MOISTURE ASSOCIATED WITH THESE FEATURES
WILL PERSIST ACROSS THE AREA ENHANCING CONVECTION AS THE FRONT
AND TROUGH MERGE WITHIN THE NEXT 24 HOURS AND STALL.

ATLANTIC OCEAN...

A SHARP UPPER-LEVEL TROUGH EXTENDS FROM NEW ENGLAND TO OVER THE
W ATLANTIC AND THE FAR NE GULF OF MEXICO SUPPORTING A PAIR OF
COLD FRONTS. THE FIRST ONE EXTENDS FROM THE FLORIDA PENINSULA
NEAR 26N80W TO 32N69W. THE SECOND FRONT EXTENDS FROM 19N73W TO
32N61W. LATEST SCATTEROMETER DATA DEPICTS GALE FORCE WINDS IN
THE PROXIMITY OF THESE FRONTS THEREFORE A GALE WARNING IS IN
EFFECT FOR THIS AREA. FOR MORE INFORMATION PLEASE REFER TO THE
SPECIAL FEATURES SECTION ABOVE. TO THE E OF THE FRONTS...A PRE-
FRONTAL TROUGH EXTENDS FROM THE CARIBBEAN INTO THE CENTRAL
ATLANTIC FROM 19N69W TO 24N63W. SCATTERED MODERATE CONVECTION IS
N OF 21N BETWEEN 56W-68W. THE REMAINDER OF THE BASIN IS
DOMINATED BY A 1042 MB SURFACE HIGH CENTERED NEAR 39N30W. THE
REFLECTION OF AN UPPER-LEVEL LOW IS DEPICTED AS A SURFACE TROUGH
EXTENDING FROM 24N36W TO 28N36W. EXPECT OVER THE NEXT 24 HOURS
FOR THE COLD FRONT THAT EXTENDS FROM THE ATLANTIC TO HAITI TO
MERGE WITH THE PRE-FRONTAL TROUGH AND STALL. THE COLD FRONT
BEHIND THIS ONE WILL CONTINUE MOVING E MERGING WITH THE STALLED
FRONT IN 48 HOURS.

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

$$
ERA



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