[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 220515
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EST TUE APR 22 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
0515 UTC.

...THE ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH PASSES THROUGH COASTAL SECTIONS OF SENEGAL
NEAR 12N16W TO 4N23W. THE ITCZ CONTINUES FROM THERE CROSSING THE
EQUATOR ALONG 38W TO 2S45W NEAR THE COAST OF BRAZIL. NUMEROUS
MODERATE SCATTERED STRONG CONVECTION WAS NOTED SOUTH OF THE
TROUGH BETWEEN 15W AND 23W.

...DISCUSSION...

...THE GULF OF MEXICO...

A BROAD 1018 MB SURFACE HIGH IS CENTERED SOUTH OF COASTAL
ALABAMA AT 28N88W.  WITH A FLAT PRESSURE GRADIENT...SURFACE
WINDS ACROSS THE GULF ARE AT GENTLE BREEZE OR WEAKER.  ISOLATED
DEEP CONVECTION FIRED UP OVER THE HIGH TERRAIN OF MEXICO DURING
THE LATE AFTERNOON DIURNAL MAXIMUM.  FORCING FOR THIS DEEP
CONVECTION NORTH OF 25N MAY BE DUE IN PART TO A MID TO UPPER
LEVEL TROUGH MOVING ACROSS TEXAS. SOME THUNDERSTORMS ARE STILL
OCCURRING ALONG THE EASTERN FLANK OF THE SIERRA MADRE
MOUNTAINS...THOUGH THESE SHOULD DIMINISH OVERNIGHT.  ELSEWHERE
ACROSS THE GULF...NO SIGNIFICANT DEEP CONVECTION OR SHOWERS ARE
OCCURRING.  OVER THE NEXT TWO DAYS...THE WEAK HIGH SHOULD REMAIN
RELATIVELY STATIONARY OVER THE GULF.  A WEAK COOL FRONT WILL
APPROACH THE U.S. GULF COAST LATE ON TUESDAY AND MAY BARELY
REACH THE NORTHERN GULF.  DEEP CONVECTION MAY OCCUR IN
ASSOCIATION WITH THIS WEAK FRONT...BUT WITH LITTLE TO NO MOIST
SOUTHERLY RETURN FLOW IN ADVANCE...EXPECT THE EXTENT OF
THUNDERSTORMS TO BE RATHER LIMITED.

...THE CARIBBEAN SEA...

A DISSIPATING COLD FRONT EXTENDS FROM THE EASTERN BAHAMAS TO
EASTERN CUBA WITH A REMNANT TROUGH FROM EASTERN CUBA TO THE
NORTHWESTERN CARIBBEAN SEA.  LITTLE BAROCLINICITY REMAINS WITH
THE BOUNDARIES...THOUGH THEY DID PROMOTE DEVELOPMENT OF ISOLATED
DEEP CONVECTION IN ASSOCIATION WITH AFTERNOON HEATING OVER
EASTERN CUBA...JAMAICA...THE EASTERN BAHAMAS...AND HISPANIOLA
LATE ON MONDAY. WITH THE NORTH-SOUTH PRESSURE GRADIENT RATHER
FLAT...EASTERLY TRADES ACROSS THE CARIBBEAN ARE MODERATE TO
GENTLE BREEZES...WITH THE EXCEPTION OF FRESH BREEZE
NORTHEASTERLIES JUST NORTH OF COLOMBIA.  IF ANYTHING...THE
PRESSURE GRADIENT AND ASSOCIATED TRADEWINDS MAY WEAKEN EVEN MORE
DURING THE NEXT TWO DAYS. AS THE FRONTAL BOUNDARY AND TROUGH ARE
EXPECTED TO DISSIPATE IN THE NEXT DAY OR SO...THIS MAY REDUCE
CHANCES OF DEEP CONVECTION OVER THE NEXT TWO DAYS OVER THE
CARIBBEAN...WHICH IS OVERLAID BY SUBSIDENT UPPER LEVEL
WESTERLIES TYPICAL FOR THIS TIME OF YEAR.

...HISPANIOLA...

A DISSIPATING COLD FRONT EXTENDS FROM THE EASTERN BAHAMAS TO
EASTERN CUBA .  LITTLE BAROCLINICITY REMAINS WITH THIS
BOUNDARY...THOUGH IT DID PROMOTE DEVELOPMENT OF ISOLATED DEEP
CONVECTION IN ASSOCIATION WITH AFTERNOON HEATING OVER HISPANIOLA
LATE ON MONDAY. AS THE FRONTAL BOUNDARY IS EXPECTED TO DISSIPATE
IN THE NEXT DAY OR SO...THIS MAY REDUCE CHANCES OF DEEP
CONVECTION OVER THE NEXT TWO DAYS OVER HISPANIOLA...WHICH IS
OVERLAID BY SUBSIDENT UPPER LEVEL WESTERLIES TYPICAL FOR THIS
TIME OF YEAR.

...THE ATLANTIC OCEAN...

A 1005 MB SURFACE LOW WAS LOCATED A COUPLE HUNDRED MILES EAST-
SOUTHEAST OF NORTH CAROLINA NEAR 33N69W.  A COLD FRONT FROM THE
LOW EXTENDS SOUTHWESTWARD IN OUR AREA FROM 32N66W TO THE EASTERN
BAHAMAS WHERE IT BECOMES A DISSIPATING COLD FRONT.  ISOLATED
DEEP CONVECTION EXISTS WITHIN 60 NM OF THE FRONT NORTH OF 25N.
SURFACE SOUTHWESTERLY WINDS AHEAD OF FRONT ARE FRESH TO STRONG
BREEZE CONDITIONS...BUT ARE WEAKER BEHIND THE FRONT.  A SURFACE
TROUGH ALSO IS PRESENT FROM THE LOW SOUTHWESTWARD TO THE
NORTHWESTERN BAHAMAS...THOUGH THIS FEATURE HAS NO SIGNIFICANT
CONVECTION OR WINDS WITH IT.  THE LOW IS VERTICALLY STACKED WITH
AN UPPER LOW OBSERVED IN THE WATER VAPOR IMAGERY AT THE SAME
LOCATION.  THE UPPER LOW IS STARTING TO OPEN UP INTO A TROUGH
AND BE ADVECTED QUICKLY TOWARD THE WEST.  THE COLD FRONT
ASSOCIATED WITH THE LOW HAS LIMITED BAROCLINICITY...BUT IT WILL
CONTINUE TO INITIATE ISOLATED TO SCATTERED DEEP CONVECTION ALONG
AND JUST EAST OF THE FRONT.  IN A COUPLE OF DAYS...THE LOW AND
THE FRONT WILL BE ABSORBED WITHIN A NEWLY DEVELOPING
EXTRATROPICAL LOW AND MORE VIGOROUS COLD FRONT...THE LATTER WILL
REACH OUR NORTHERN BORDER LATE WEDNESDAY.

FARTHER EAST...A COLD FRONT STRADDLES THE NORTHERN BORDER FROM
32N47W TO 31N40W TO 32N33W.  THIS FRONT IS WELL-DEFINED...THOUGH
SURFACE WINDS IN ASSOCIATION WITH IT ONLY REACH FRESH BREEZE
CONDITIONS.  THE FRONT WILL PROGRESS EASTWARD...BUT NOT MUCH
FARTHER EQUATORWARD...AND HAVE LIMITED TO NO ASSOCIATED DEEP
CONVECTION.

ELSEWHERE...A 1023 MB SURFACE HIGH IS LOCATED AT 27N43W WITH
ASSOCIATED RIDGING EXTENDING ZONALLY ACROSS MOST OF THE ATLANTIC
AROUND 27N.  THE MODEST PRESSURE GRADIENT EQUATORWARD OF THE
RIDGE IS PRODUCING TRADEWINDS OF AT MOST FRESH BREEZE
CONDITIONS.  LITTLE CHANGE IS EXPECTED FOR THE NEXT COUPLE OF
DAYS.

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

$$
LANDSEA


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