Tropical Weather Discussion
Issued by NWS

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000
AXNT20 KNHC 191034
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SUN APR 19 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
1030 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE TROPICAL
ATLANTIC NEAR 06N10W TO 03N13W WHERE THE ITCZ BEGINS AND
CONTINUES ALONG 00N25W THEN S OF THE EQUATOR NEAR 40W. SCATTERED
MODERATE CONVECTION IS FROM 02N TO S OF THE EQUATOR BETWEEN 29W-
40W.

...DISCUSSION...

GULF OF MEXICO...

AN UPPER-LEVEL LOW OVER THE CENTRAL PLAINS EXTENDS ITS
ASSOCIATED TROUGH S REACHING THE NW GULF. TO THE E...A BROAD
UPPER-LEVEL RIDGE ANCHORED IN THE E PACIFIC EXTENDS ACROSS THE
EASTERN HALF OF THE YUCATAN PENINSULA REACHING THE E GULF AND
ADVECTING UPPER-LEVEL MOISTURE TO THE AREA. A DIFFLUENT FLOW
PREVAILS ACROSS THE NORTHERN GULF BETWEEN THE UPPER-LEVEL TROUGH
AND RIDGE PREVIOUSLY MENTIONED SUPPORTING SCATTERED MODERATE
CONVECTION MAINLY N OF 24N BETWEEN 88W-93W. THIS CONVECTION IS
ALSO ENHANCED BY A SURFACE TROUGH THAT EXTENDS FROM 24N93W TO
28N89W. A WEAKER SURFACE TROUGH IS OVER THE NW GULF EXTENDING
FROM 27N94W TO 29N93W. NO SIGNIFICANT CONVECTION IS RELATED TO
THIS BOUNDARY. A THIRD SURFACE TROUGH WAS DEPICTED IN
OBSERVATIONS AND SCATTEROMETER DATA ACROSS THE SW GULF
...EXTENDING FROM 24N91W TO 19N92W. ISOLATED CONVECTION PREVAILS
ALONG THIS FEATURE. LIGHT TO GENTLE SE FLOW PREVAILS ACROSS THE
BASIN EXCEPT N OF 27N AND W OF 91W WHERE A NW FLOW DOMINATES.
OVER THE NEXT 24-48 HOURS...EXPECT FOR THE CONVECTION ACROSS THE
NORTHERN GULF TO DIMINISH. A FRONTAL BOUNDARY IS EXPECTED TO
ENTER THE NW GULF WITH CONVECTION. A WEAK HIGH PRESSURE WILL
BUILD IN THE WAKE OF THIS FRONT.

CARIBBEAN SEA...

A SURFACE HIGH PRESSURE LOCATED OVER THE CENTRAL ATLANTIC
EXTENDS SW REACHING THE CARIBBEAN. AN UPPER-LEVEL RIDGE COVERS
THE NW CARIBBEAN WHILE A BROAD UPPER-LEVEL TROUGH EXTENDS FROM
THE CENTRAL ATLANTIC ACROSS HISPANIOLA AND THE CENTRAL
CARIBBEAN. CURRENT WATER VAPOR IMAGERY DEPICTS STRONG SUBSIDENCE
AND DRY AIR PREVAILING ACROSS MOST OF THE BASIN. LOW-LEVEL
MOISTURE TRANSPORTED BY THE LIGHT TO GENTLE TRADES IS GENERATING
ISOLATED CONVECTION ACROSS THE BASIN. ACROSS THE E CARIBBEAN S
OF 17 AND E OF 70W...AN UPPER-LEVEL SW FLOW IS BRINGING MOIST
AIR INTO THE AREA. AS MENTIONED BEFORE...LIGHT TO GENTLE TRADES
ARE OBSERVED IN SCATTEROMETER DATA ACROSS MOST OF THE BASIN
EXCEPT S OF 15N BETWEEN 69W-74W...WHERE MODERATE TO FRESH WINDS
ARE DEPICTED. THERE IS ALSO ANOTHER AREA OF MODERATE TO FRESH
WINDS NOTED N OF HONDURAS BETWEEN 84W-87W. EXPECT SIMILAR
WEATHER CONDITIONS OVER THE NEXT 24-48 HOURS.

HISPANIOLA...

AN UPPER-LEVEL TROUGH EXTENDS FROM THE CENTRAL ATLANTIC ACROSS
THE WESTERN PORTION OF THE ISLAND INTO THE CARIBBEAN. LOW-LEVEL
MOISTURE COUPLED WITH THE TRADE WINDS WILL CONTINUE SUPPORTING
ISOLATED CONVECTION ACROSS THE ISLAND THROUGH THE NEXT 24 HOURS.

ATLANTIC OCEAN...

A FRONTAL SYSTEM EXTENDS ACROSS MOST OF THE BASIN. IT BEGINS AS
A STATIONARY FRONT ACROSS THE W ATLANTIC FROM 29N80W TO A 1013
MB LOW CENTERED NEAR 32N69W. A WEAKENING STATIONARY FRONT WAS
ANALYZED FROM 32N69W TO ANOTHER 1013 MB LOW CENTERED NEAR
33N56W. FROM THIS POINT...THE WEAKENING STATIONARY FRONT
CONTINUES TO 24N44W. A COLD FRONT IS FROM 24N44W TO 31N23W.
ISOLATED CONVECTION IS OBSERVED ALONG THESE BOUNDARIES. AN UPPER-
LEVEL TROUGH EXTENDS ALONG 65W SUPPORTING SCATTERED CONVECTION N
OF 29N BETWEEN 57W-63W. THE REMAINDER OF THE BASIN IS DOMINATED
BY A BROAD 1029 MB SURFACE HIGH CENTERED NEAR 36N37W. OVER THE
NEXT 24 HOURS...EXPECT FOR THE STATIONARY FRONT ACROSS THE W
ATLANTIC TO TRANSITION INTO A COLD FRONT MOVING E WITH
CONVECTION. ANOTHER COLD FRONT WILL MOVE OFFSHORE THE UNITED
STATES COAST AND STALL ACROSS THE W ATLANTIC IN 48 HOURS.

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

$$

ERA



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