[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 210551
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0545 UTC.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS ACROSS AFRICA TO THE COAST OF SENEGAL
AND THE EXTENDS OVER THE EASTERN TROPICAL ATLANTIC ALONG 13N17W
TO 06N23W. THE ITCZ BEGINS FROM THERE AND CONTINUES JUST S OF
THE EQUATOR WEST OF 35W TO THE NORTHERN COAST OF BRAZIL NEAR
01S46W. SCATTERED MODERATE CONVECTION EXISTS WITHIN 120 NM OF
THE ITCZ WEST OF 35W.  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
WITH A WEAK 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 WEST CENTRAL GULF AS UPPER-LEVEL
DEBRIS CLOUDINESS FROM LATE AFTERNOON AND EARLY EVENING DEEP
CONVECTION OVER CENTRAL MEXICO.  OVER THE NEXT COUPLE OF
DAYS...THE WINDS WILL DROP OFF EVEN MORE AS THE WEAK SURFACE
HIGH DRIFTS SOUTHWESTWARD INTO THE CENTRAL GULF.  NO SIGNIFICANT
DEEP CONVECTION OR SHOWERS ARE EXPECTED FOR THE NEXT
DAY...THOUGH LATE TUESDAY 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.  SCATTERED MODERATE ISOLATED
STRONG CONVECTION EXISTED OVER EASTERN CUBA AND THE EASTERN
BAHAMAS EARLIER...THOUGH THIS IS CURRENTLY DISSIPATING.  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
ALSO...POSSIBLY AN EARLY SEASON WEAK TROPICAL WAVE...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 SHOWER 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...
THE DEEP CONVECTION THAT OCCURRED OVER THE HIGH TERRAIN OF HAITI
AND DOMINICAN REPUBLIC EARLIER TODAY HAS DIMINISHED.  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 SOUTH OF NORTH
CAROLINA NEAR 31N75W 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
100 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 ON
MONDAY...THOUGH THE POTENTIAL FOR DEEP CONVECTION WITH THIS
APPEARS MINIMAL AND WINDS REMAIN LIGHT ACROSS THE FRONT.
ELSEWHERE...THE REMAINDER OF THE ATLANTIC IS DOMINATED BY A
SURFACE RIDGE ANCHORED BY A 1025 MB HIGH NEAR 30N45W WHICH IS
EXPECTED TO DRIFT EASTWARD OVER THE NEXT TWO DAY.  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


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