[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 222353
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SAT MAR 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2345 UTC.

...THE ITCZ/THE MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE TROPICAL ATLC
NEAR 7N11W SW TO 2N20W. THE ITCZ AXIS EXTENDS FROM 2N20W TO
2N30W TO THE EQUATOR AT 25W THEN TO THE COAST OF SOUTH AMERICA
NEAR 2S43W. SCATTERED MODERATE CONVECTION WAS NOTED WITHIN 60-90
NM OF THE ITCZ BETWEEN 30W-43W...AND ELSEWHERE S OF 3N W OF 40W.

...DISCUSSION...

GULF OF MEXICO...
UPPER LEVEL FLOW OVER THE GULF REMAINED ANTICYCLONIC WITH A FLAT
RIDGE AXIS ALONG 90W. SUBSIDING AIR PREVAILED OVER THE SOUTHERN
THIRD OF THE GULF WITH MID TO UPPER LEVEL MOISTURE NOTED N OF
24N. THIS MOISTURE WAS BEING ADVECTED BY STRONG WESTERLY WINDS.
GRIDDED WINDS AT 250 MB FROM THE GFS MODEL WERE ON THE ORDER OF
100-110 KT OVER THE GULF COAST. GLOBAL MODEL GUIDANCE INDICATES
A NARROW EAST-WEST RIBBON OF MID-LEVEL VORTICITY STRETCHING FROM
WEST TEXAS TO THE MISSISSIPPI RIVER DELTA WHICH SUPPORTED A
SURFACE TROUGH EXTENDING FROM NEAR GALVESTON TEXAS ESE THROUGH
28N90W TO 27N85W. THE TROUGH SEPARATED LIGHT ENE WINDS FROM
SOUTHERLY WINDS. BROKEN TO OVERCAST LOW CLOUDS WERE NOTED WITHIN
60-120 NM N OF THE TROUGH WITH SCATTERED SHOWERS CONCENTRATED
WITHIN 60 NM OF 27N86.5W. AS OF 2100 UTC A 1017 MB SFC HIGH WAS
NOTED NEAR 28N85W. MOSTLY FAIR CONDITIONS PREVAILED ELSEWHERE S
OF THE TROUGH. THE SURFACE TROUGH IS EXPECTED TO GRADUALLY
BECOME DIFFUSE OVERNIGHT INTO SUNDAY AS THE NEXT FRONTAL
BOUNDARY APPROACHES THE TEXAS AND LOUISIANA COAST. THIS FRONT IS
FORECAST TO EMERGE OFF THE COAST SUNDAY AFTERNOON INTO THE
EVENING HOURS. WINDS BEHIND THE FRONT WILL SHIFT NORTHEASTERLY
AND REMAIN IN THE RANGE OF 15 TO 20 KT DUE TO THE OVERALL LACK
OF MIDDLE TO UPPER LEVEL FORCING DYNAMICS. A STRONGER SECONDARY
COLD FRONT IS EXPECTED EARLY TUESDAY.

CARIBBEAN...
A BROAD FLAT UPPER RIDGE COVERS THE WESTERN AND CENTRAL
CARIBBEAN WHILE A WEAK TROUGH EXTENDS SOUTHWARD ALONG 58W...JUST
E OF THE WINDWARD ISLANDS. GENERALLY WEST TO NORTHWEST UPPER
LEVEL WINDS PREVAIL OVER MUCH OF THE CARIBBEAN BASIN WITH WATER
VAPOR IMAGERY INDICATING DRY STABLE AIR AT THE MID AND UPPER
LEVELS ACROSS THE ENTIRE BASIN WHICH IS SUPPRESSING THE
DEVELOPMENT OF ANY DEEP CONVECTION. HOWEVER...A SMALL PORTION OF
THE NORTH-CENTRAL CARIBBEAN...INCLUDING WESTERN HISPANIOLA...THE
WINDWARD PASSAGE...AND JAMAICA IS UNDER THE INFLUENCE OF A
REMNANT FRONTAL BOUNDARY NOW ANALYZED AS A SURFACE TROUGH
EXTENDING FROM THE CENTRAL ATLC TO THE ENTRANCE OF THE WINDWARD
PASSAGE. ISOLATED SHOWERS ARE POSSIBLE WITHIN 60 NM EITHER SIDE
OF A LINE FROM 21N72W TO 18N78W. THE BOUNDARY IS EXPECTED TO
DISSIPATE OVER THE NEXT 24 HOURS. FINALLY...THE OTHER
SIGNIFICANT IMPACT IS STRONG TRADE WINDS OCCURRING ACROSS THE
SOUTH-CENTRAL CARIBBEAN S OF 15N BETWEEN 67W-78W. THESE TRADES
RANGE FROM 20 TO 25 KT AND ARE EXPECTED TO PERSIST THROUGH
TUESDAY.

HISPANIOLA...
LATE DAY VISIBLE SATELLITE IMAGERY SHOWED SCATTERED LOW CLOUDS
ACROSS THE ISLAND WITH ISOLATED SHOWERS/THUNDERSTORM ALONG THE N
FACING SLOPES OF THE ISLANDS ON THE BORDER OF HAITI AND THE
DOMINICAN REPUBLIC. THIS CLOUDINESS IS BEING SUPPORTED BY
LINGERING MOISTURE ASSOCIATED WITH A SURFACE TROUGH JUST TO THE
NW OF THE ISLAND. OTHERWISE... NORTHWESTERLY WINDS ALOFT PREVAIL
AND WILL MAINTAIN A FAIRLY DRY AND STABLE ENVIRONMENT OVER THE
NEXT FEW DAYS. WITH THE BOUNDARY IN PLACE AND TRENDING TOWARD
DISSIPATION...THE THREAT OF PRECIPITATION GRADUALLY DECREASES
THROUGH THE OVERNIGHT HOURS INTO SUNDAY.

ATLANTIC...
WEST-NORTHWESTERLY FLOW ALOFT IS NOTED OVER THE SW NORTH ATLC
WITH WATER VAPOR IMAGERY INDICATING A FAIR AMOUNT OF
PROGRESSIVE MIDDLE TO UPPER LEVEL CLOUDINESS AND MOISTURE
CONTINUING TO MOVE EAST N OF 28N. MOST OF THIS MOISTURE IS ABOVE
A FAIRLY BROAD SURFACE RIDGE ANCHORED BY A 1024 MB HIGH CENTERED
W OF BERMUDA NEAR 32N68W. WITH RETURN FLOW ON THE WESTERN
PERIPHERY OF THE RIDGING...LOW-LEVEL MOISTURE CONVERGENCE AND
AID FROM MARGINAL MID-LEVEL DYNAMICS ARE GENERATING WIDELY
SCATTERED SHOWERS AND ISOLATED TSTMS WITHIN 90-120 NM EAST OF A
SURFACE TROUGH WHICH EXTENDS FROM SAVANNAH GEORGIA SOUTHWARD
ALONG THE FLORIDA E COAST TO NEAR NAPLES. AS OF 21 UTC...A WEAK
1014 MB LOW DEVELOPED OVER EXTREME NE FLORIDA NEAR DAYTONA
BEACH. FARTHER EAST...A MIDDLE TO UPPER LEVEL TROUGH AXIS
EXTENDS SOUTHWARD ALONG 53W TO A BASE NEAR 20N. THIS TROUGHING
SUPPORTS A COLD FRONT ANALYZED FROM 32N51W TO 28N60W AND A PRE-
FRONTAL SURFACE TROUGH FROM 31N50W SW TO 25N60W TO THE ENTRANCE
OF THE WINDWARD PASSAGE. ISOLATED SHOWERS ARE OCCURRING WITHIN
120 NM EITHER SIDE OF BOTH THE COLD FRONT AND SURFACE TROUGH
BOUNDARIES. FINALLY...THE EASTERN ATLC IS UNDER THE INFLUENCE OF
A SURFACE RIDGE ANCHORED BY A 1030 MB HIGH CENTERED WELL SW OF
THE AZORES NEAR 31N32W.

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

$$
COBB

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