[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 140003
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT FRI MAR 13 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2345 UTC.

...SPECIAL FEATURES...

...GALE WARNING FOR THE SW CARIBBEAN...

GALE WINDS DIMINISHED OVER COLOMBIA COASTAL WATERS THIS
AFTERNOON...HOWEVER ARE FORECAST TO RESUME TONIGHT CONTINUING
THROUGH SATURDAY AFTERNOON...THEN RESUMING AGAIN SATURDAY NIGHT.
THE HIGH WINDS ARE BEING CAUSED BY THE STRONG PRESSURE GRADIENT
BETWEEN A 1007 MB LOW OVER NORTHERN COLOMBIA AND A SURFACE RIDGE
OVER THE W ATLC...IN COMBINATION WITH THE TYPICAL TOPOGRAPHICAL
WIND ENHANCEMENTS NORTH OF COLOMBIA. PLEASE SEE THE LATEST HIGH
SEAS FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/FZNT02 KNHC FOR
MORE DETAILS.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE TROPICAL
ATLANTIC NEAR 10N14W TO 03N17W WHERE THE ITCZ BEGINS AND
CONTINUES ALONG THE EQUATOR NEAR 30W TO THE COAST OF NORTHERN
BRAZIL NEAR 01S48W. SCATTERED MODERATE TO STRONG CONVECTION IS S
OF THE MONSOON TROUGH FROM 01N-05N BETWEEN 08W-15W. SCATTERED TO
ISOLATED MODERATE CONVECTION IS WITHIN 150 NM EITHER SIDE OF THE
ITCZ.

...DISCUSSION...

GULF OF MEXICO...

A 1013 MB LOW IS CENTERED OVER SE LOUISIANA ACCOMPANIED BY A
STATIONARY FRONT EXTENDING S-SW TO THE WEST COAST OF NORTHERN
YUCATAN PENINSULA NEAR 21N90W. SCATTERED MODERATE AND ISOLATED
STRONG CONVECTION IS OBSERVED AHEAD OF THE FRONT E OF 88W N OF
26N BASED UPON GEOSTATIONARY IMAGERY...LIGHTNING DATA...AND THE
U.S. WSR-88D RADAR NETWORK. THE CONVECTION IS SUPPORTED BY
FORCING FROM A HIGH AMPLITUDE MID-TO UPPER-LEVEL LONGWAVE TROUGH
CENTERED OVER MEXICO. A 1017 MB HIGH IS BEHIND THE FRONT
CENTERED NEAR 24N94W...WHICH IS PROVIDING VARIABLE WINDS OF 5 TO
10 KT S OF 27N...WESTERLY FLOW OF 15 KT DOMINATES N OF 27N WEST
OF THE FRONT. A SURFACE RIDGE OVER THE W ATLC EXTENDS SW ACROSS
THE FLORIDA PENINSULA TO THE EASTERN GULF AND PROVIDES SE FLOW
OF 15 TO 25 KT E OF THE STATIONARY FRONT...AS SEEN IN AN EARLIER
ASCAT SCATTEROMETER PASS. OVER THE NEXT TWO DAYS...THE PORTION
OF THE FRONT OVER THE NORTHERN GULF WILL TRANSITION TO A COLD
FRONT WHILE THE SOUTHERN PORTION OF IT WILL SLOWLY RETROGRADE TO
THE WESTERN BASIN AS A STATIONARY FRONT. THE ADVECTION OF
ABUNDANT MOISTURE ALONG WITH FORCING BY THE UPPER-LEVEL TROUGH
SHOULD CONTINUE TO PROVIDE THE POTENTIAL FOR CONVECTION DURING
THE NEXT COUPLE OF DAYS IN THE WESTERN AND CENTRAL GULF OF
MEXICO INCLUDING THE COAST OF MEXICO FROM THE BAY OF CAMPECHE TO
THE U.S. GULF COAST FROM TEXAS TO THE FLORIDA PANHANDLE.

CARIBBEAN SEA...

OUTSIDE NEAR GALE CONDITIONS ALONG THE COAST OF COLOMBIA
REFERENCED ON THE SPECIAL FEATURES SECTION...THE CARIBBEAN SEA
HAS NO SURFACE FEATURES OF INTEREST NOR IS THERE ANY ORGANIZED
DEEP CONVECTION. A BROAD HIGH AMPLITUDE UPPER RIDGE COVERS THE
CARIBBEAN WITH AN AXIS ALONG 74W...WHICH IS PROMOTING SUBSIDENCE
OVER THE CARIBBEAN. THE AFOREMENTIONED STRONG PRESSURE GRADIENT
FORCING NEAR GALE CONDITIONS ON COLOMBIA ADJACENT WATERS ARE
ALSO FORCING E TO NE TRADEWINDS OF 20 TO 25 KT ACROSS THE
EASTERN AND CENTRAL CARIBBEAN. TRADES OF 15 KT DOMINATE OVER THE
NW BASIN. LITTLE CHANGE IS EXPECTED DURING THE NEXT TWO DAYS.

...HISPANIOLA...

GENERALLY FAIR SKIES WITH POSSIBLE ISOLATED PASSING SHOWERS
DOMINATE THE ISLAND THIS EVENING. WINDS ALONG THE COASTS WILL BE
A BRISK 20-25 KT OUT OF THE EAST-NORTHEAST. THESE CONDITIONS
WILL PERSIST THROUGH AT LEAST SUNDAY MORNING.

ATLANTIC OCEAN...

A COLD FRONT EXTENDS FROM 30N47W TO 25N59W TO 25N72W WITH
POSSIBLE SCATTERED TO ISOLATED SHOWERS WITHIN 60 NM EITHER SIDE
OF THE FRONT. WINDS BEHIND THE FRONT ARE FROM THE N-NE OF 15-20
KT...AS OBSERVED BY AN EARLIER SCATTEROMETER PASS. THE FRONT
WILL CONTINUE TO MOVE EASTWARD THE NEXT TWO DAYS...TRANSITIONING
TO A STATIONARY FRONT S OF 26N W OF 50W BY SATURDAY MORNING.
ELSEWHERE...THE ATLANTIC CONTINUES TO BE DOMINATED BY RIDGING
EXTENDING FROM A 1036 MB HIGH NEAR 40N71W SOUTHWARD TO A
RIDGELINE ALONG 23N AND ANOTHER RIDGE OVER THE E ATLC ANCHORED
BY A 1032 MB HIGH NEAR 49N09W. TRADEWINDS ARE GENERALLY NE 15-20
KT ACROSS MOST OF THE REGION E AND S OF THE FRONT.

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

$$
NR

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