[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 211025
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT TUE APR 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE TROPICAL
ATLANTIC NEAR 07N12W TO 04N13W WHERE THE ITCZ BEGINS AND
CONTINUES ALONG 00N26W THEN S OF THE EQUATOR NEAR 38W. SCATTERED
MODERATE CONVECTION IS FROM 03N TO S OF THE EQUATOR BETWEEN 18W-
38W.

...DISCUSSION...

GULF OF MEXICO...

A BROAD UPPER-LEVEL RIDGE ANCHORED IN THE EPAC EXTENDS E
REACHING THE WESTERN HALF OF THE GULF. AN UPPER-LEVEL TROUGH
COVERS THE E CONUS SUPPORTING A FRONTAL SYSTEM THAT PREVAILS
ACROSS THE NORTHERN GULF. IT BEGINS AS A STATIONARY FRONT FROM
25N97W TO 26N91W THEN IT TRANSITIONS INTO A COLD FRONT THROUGH
30N85W. ISOLATED CONVECTION IS OBSERVED IN THE VICINITY OF THE
FRONTS MAINLY N OF 25N. A SURFACE TROUGH EXTENDS ACROSS THE
SOUTHERN GULF W OF THE YUCATAN PENINSULA FROM 24N89W TO 20N90W.
NO SIGNIFICANT CONVECTION IS RELATED TO THIS FEATURE. LIGHT TO
GENTLE NE FLOW PREVAILS ACROSS THE BASIN W OF 90W WHILE A GENTLE
NW FLOW IS OBSERVED IN SCATTEROMETER DATA AND CURRENT
OBSERVATIONS E OF 90W AND N OF THE COLD FRONT. EXPECT OVER THE
NEXT 24-48 HOURS FOR THE STATIONARY FRONT TO WEAKEN ACROSS THE
NW GULF. THE COLD FRONT WILL CONTINUE MOVING SE ENHANCING
CONVECTION ACROSS THE W GULF AND THE FLORIDA PENINSULA. A WEAK
HIGH PRESSURE WILL BUILD IN THE WAKE OF THE COLD FRONT.

CARIBBEAN SEA...

THE UPPER-LEVEL RIDGE THAT EXTENDS FROM THE EPAC INTO THE GULF
ALSO REACHES THE W CARIBBEAN. TO THE E OF THIS...AN UPPER-LEVEL
TROUGH EXTENDS ITS AXIS ACROSS THE CENTRAL CARIBBEAN FROM 12N83W
TO 18N71W. SATELLITE WATER VAPOR IMAGERY SHOWS STRONG SUBSIDENCE
AND DRY STABLE AIR ACROSS THE CARIBBEAN IN THE AREA DOMINATED BY
THE UPPER-LEVEL TROUGH. DESPITE THIS...LOW-LEVEL MOISTURE IS
ALSO PRESENT ACROSS THE BASIN GENERATING ISOLATED CONVECTION.
LIGHT TO GENTLE TRADES PREVAIL ACROSS THE BASIN EXCEPT N OF
COLOMBIA FROM 12N-16N BETWEEN 69W-76W WHERE GENTLE TO MODERATE
FLOW IS OBSERVED IN SCATTEROMETER DATA. THERE IS ALSO A SMALL
AREA N OF HONDURAS MAINLY S OF 17N WHERE A MODERATE FLOW IS
DEPICTED. EXPECT A SIMILAR WEATHER PATTERN OVER THE NEXT 24-48
HOURS.

HISPANIOLA...

CLEAR SKIES AND FAIR WEATHER PREVAILS ACROSS THE AREA. LOW-LEVEL
MOISTURE COUPLED WITH THE EASTERLY TRADE WINDS WILL CONTINUE TO
GENERATE ISOLATED CONVECTION ACROSS THE ISLAND MAINLY IN THE
AFTERNOON OVER THE NEXT IN 24 HOURS.

ATLANTIC OCEAN...

A 1013 MB SURFACE LOW IS CENTERED OVER THE W ATLANTIC NEAR
30N77W. A SURFACE TROUGH EXTENDS FROM THE LOW TO 28N78W. A
SQUALL LINE IS E OF THE LOW AND TROUGH EXTENDING FROM 30N73W TO
27N78W. SCATTERED MODERATE CONVECTION IS N OF 26N BETWEEN 68W-
76W. A FRONTAL SYSTEM CONTINUES ACROSS THE CENTRAL
ATLANTIC...BEGINNING AS A STATIONARY FRONT FROM 28N57W TO 28N45W
THEN TRANSITIONING INTO A COLD FRONT TO 31N39W. ISOLATED
CONVECTION PREVAILS ALONG THE COLD FRONT MAINLY N OF 30N. A PAIR
OF SURFACE HIGH PRESSURE CENTERS LOCATED NEAR 24N50W AND 38N25W
EXTEND ACROSS THE REMAINDER OF THE BASIN WITH FAIR WEATHER.
EXPECT OVER THE NEXT 24-48 HOURS FOR THE COLD FRONT...CURRENTLY
OVER THE GULF OF MEXICO...TO REACH THE W ATLANTIC WITH
CONVECTION. THE SQUALL LINE AND LOW PRESSURE OVER THE W ATLANTIC
WILL DISSIPATE. THE FRONTAL SYSTEM OVER THE CENTRAL ATLANTIC
WILL WEAKEN.

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

$$

ERA


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