000
AXNT20 KNHC 211103
TWDAT
TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT MON APR 21 2014
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
1145 UTC.
...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS ACROSS AFRICA TO THE COAST OF SENEGAL
AND THE EXTENDS OVER THE EASTERN TROPICAL ATLANTIC ALONG 14N17W
TO 06N21W. THE ITCZ BEGINS FROM THERE AND CONTINUES JUST S OF
THE EQUATOR WEST OF 35W TO THE NORTHERN COAST OF BRAZIL NEAR
03S40W. SCATTERED MODERATE ISOLATED STRONG CONVECTION EXISTS
SOUTH OF WEST AFRICA EAST OF 10W.
...DISCUSSION...
GULF OF MEXICO...
A 1021 MB SURFACE HIGH IS ANALYZED ALONG THE FLORIDA PANHANDLE-
ALABAMA BORDER WITH A WEAK NORTH-SOUTH SURFACE PRESSURE GRADIENT
ACROSS THE GULF OF MEXICO. CORRESPONDINGLY...SURFACE WINDS ARE
GENERALLY GENTLE TO MODERATE BREEZE CONDITIONS OUT OF THE
NORTHEAST IN THE EASTERN GULF AND SOUTHEAST IN THE WESTERN GULF.
NO SIGNIFICANT DEEP CONVECTION OR SHOWERS ARE CURRENTLY
OCCURRING. RELATIVELY THICK CIRRUS IS BLOWING EASTWARD ACROSS
THE WESTERN GULF AS UPPER-LEVEL DEBRIS CLOUDINESS FROM DEEP
CONVECTION OVER CENTRAL MEXICO LATE YESTERDAY. OVER THE NEXT
COUPLE OF DAYS...THE WINDS WILL DROP OFF EVEN MORE AS THE WEAK
SURFACE HIGH DRIFTS SOUTHWESTWARD INTO THE NORTH CENTRAL GULF.
NO SIGNIFICANT DEEP CONVECTION OR SHOWERS ARE EXPECTED FOR THE
NEXT DAY...THOUGH LATE TUESDAY AND EARLY WEDNESDAY SOME
CONVECTION COULD DEVELOP IN THE NORTHERN GULF OF MEXICO AHEAD OF
AN ADVANCING COLD FRONT.
CARIBBEAN SEA...
THE TAIL END OF A COLD FRONT EXTENDS ACROSS THE CENTRAL BAHAMAS
TO EASTERN CUBA WITH A DISSIPATING COLD FRONT INDICATED FROM
THERE TO NEAR THE CAYMAN ISLANDS. A MODERATE NORTH-SOUTH
SURFACE PRESSURE GRADIENT EXISTS ACROSS THE CARIBBEAN AND THE
EASTERLY TRADEWINDS ARE GENTLE TO FRESH BREEZE CONDITIONS...WITH
THE USUAL EXCEPTION OF STRONGER NE WINDS OF 25 KT NORTH OF
COLOMBIA. OVER THE NEXT COUPLE OF DAYS...THE SURFACE PRESSURE
GRADIENT WEAKENS AND WINDS FURTHER SLACKEN. ENHANCED TOTAL
PRECIPITABLE WATER IS OBSERVED WITH THE TPW IMAGERY ACROSS THE
EASTERN BAHAMAS...EASTERN CUBA...AND THE NORTHWESTERN CARIBBEAN.
ADDITIONALLY...A WEAK MAXIMA IN MOISTURE...POSSIBLY AN EARLY
SEASON WEAK TROPICAL WAVE...ALSO IS REACHING THE WINDWARD
ISLANDS. WHILE THE FRONTAL BOUNDARY SHOULD DISSIPATE NEAR THE
BAHAMAS SHORTLY...THE RESIDUAL MOISTURE AND CONVERGENCE MAY
CONTINUE TO AID THE DEVELOPMENT OF SCATTERED DEEP CONVECTION IN
THE EASTERN BAHAMAS...EASTERN CUBA...HISPANIOLA...AND JAMAICA
DURING THE NEXT COUPLE OF DAYS. ADDITIONALLY...THE WEAK MAXIMA
IN MOISTURE IS SUGGESTED BY THE GFS TO MOVE NORTHWESTWARD AND
MAY ENHANCE SHOWERS AND WIDELY SCATTERED DEEP CONVECTION OVER
THE LESSER ANTILLES AND PUERTO RICO. HOWEVER...SUCH CONVECTIVE
ACTIVITY IS NOT EXPECTED TO BE WIDESPREAD...AS SUBSIDENT UPPER-
LEVEL WESTERLY FLOW COVERS THE CARIBBEAN AS IS TYPICAL FOR THIS
TIME OF YEAR.
...HISPANIOLA...
NO SIGNIFICANT DEEP CONVECTION IS OCCURRING OVER HAITI AND
DOMINICAN REPUBLIC. ENHANCED TOTAL PRECIPITABLE WATER IS
OBSERVED WITH THE TPW IMAGERY ACROSS THE EASTERN
BAHAMAS...EASTERN CUBA...AND THE NORTHWESTERN CARIBBEAN. WHILE
THE FRONTAL BOUNDARY SHOULD DISSIPATE NEAR THE BAHAMAS
SHORTLY...THE RESIDUAL MOISTURE AND CONVERGENCE MAY CONTINUE TO
AID THE DEVELOPMENT OF SCATTERED DEEP CONVECTION IN HISPANIOLA
DURING THE NEXT COUPLE OF DAYS. HOWEVER...SUCH CONVECTIVE
ACTIVITY IS NOT EXPECTED TO BE WIDESPREAD...AS SUBSIDENT UPPER-
LEVEL WESTERLY FLOW COVERS THE CARIBBEAN AS IS TYPICAL FOR THIS
TIME OF YEAR.
ATLANTIC OCEAN...
A 1009 MB SURFACE LOW IS SOUTHEAST OF NORTH
CAROLINA NEAR 32N73W WITH A COLD FRONT EXTENDING SOUTHWARD TO
EASTERN CUBA AND A SECONDARY TROUGH EXTENDING SOUTHWESTWARD TO
THE NORTHWESTERN BAHAMAS. A PRE-FRONTAL SQUALL LINE IS ABOUT
120 NM AHEAD OF THE FRONT NORTH OF 25N. SURFACE WINDS REACH UP
TO 30 KT IN THE NORTHERLY FLOW JUST OFFSHORE OF NORTHEASTERN
FLORIDA. ALL OF THIS IS SUPPORTED BY A VIGOROUS UPPER-LEVEL
CUTOFF LOW AT ABOUT THE SAME LOCATION AS THE SURFACE LOW. THE
UPPER-LEVEL LOW SHOULD LIFT OUT AND BECOME AN OPEN TROUGH AS IT
QUICKLY MOVES NORTHEASTWARD. WHILE THE BAROCLINICITY OF THE
COLD FRONT WEAKENS SOME...LARGE AMOUNTS OF MOISTURE AND UPPER-
LEVEL FORCING SHOULD CONTINUE TO PROVIDE THE POTENTIAL FOR AT
LEAST SCATTERED DEEP CONVECTION AHEAD AND ALONG THE FRONT FOR
THE NEXT COUPLE OF DAYS. WHILE THE NORTHERLY FLOW BEHIND THE
FRONT SHOULD GRADUALLY WEAKEN...THE SOUTHWESTERLY WINDS AHEAD OF
THE FRONT SHOULD STRENGTHEN UP TO STRONG BREEZE OR NEAR GALE
CONDITIONS FOR THE NEXT TWO DAYS. FARTHER TO THE EAST...A
ANOTHER COLD FRONT MAY JUST REACH AROUND 30N EAST OF 40W LATE
TODAY...THOUGH THE POTENTIAL FOR DEEP CONVECTION WITH THIS FRONT
APPEARS MINIMAL AND WINDS REMAIN LIGHT ACROSS THE FRONT.
ELSEWHERE...THE REMAINDER OF THE ATLANTIC IS DOMINATED BY A
SURFACE RIDGE ANCHORED BY A 10253 MB HIGH NEAR 29N51W WHICH IS
EXPECTED TO DRIFT EASTWARD OVER THE NEXT TWO DAYS. FAIR WEATHER
IS OVER THE CENTRAL AND EASTERN ATLANTIC BEING SUPPORTED BY DRY
AIR SUBSIDENCE FROM THE MIDDLE LEVELS.
FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE
$$
LANDSEA
