[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 130003
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU MAR 12 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 ALONG THE COAST OF COLOMBIA THIS
AFTERNOON...HOWEVER ARE FORECAST TO RESUME TONIGHT CONTINUING
THROUGH FRIDAY AFTERNOON...THEN RESUMING AGAIN SATURDAY MORNING.
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 06N10W TO 02N15W WHERE THE ITCZ BEGINS AND
CONTINUES TO THE EQUATOR ALONG 40W TO THE COAST OF NORTHERN
BRAZIL NEAR 01S46W. SCATTERED MODERATE CONVECTION AND TSTMS ARE
WITHIN 100 NM EITHER SIDE OF THE ITCZ.

...DISCUSSION...

GULF OF MEXICO...

A 1013 MB LOW IS CENTERED AT 28N94W IN THE NORTHWESTERN GULF OF
MEXICO ACCOMPANIED BY A COLD FRONT EXTENDING SOUTHWARD TO THE
WESTERN YUCATAN PENINSULA AND A STATIONARY FRONT EXTENDING
NORTHEASTWARD TO THE WEST LOUISIANA COAST. SCATTERED MODERATE
AND ISOLATED STRONG CONVECTION IS OBSERVED WITHIN 300 NM WEST OF
THE COLD FRONT AND N OF 25N BETWEEN THE FLORIDA PANHANDLE AND SE
LOUISIANA BASED UPON GEOSTATIONARY IMAGERY...LIGHTNING
DATA...AND THE U.S. WSR-88D RADAR NETWORK. THE CONVECTION
CONTINUES TO BE SUPPORTED BY FORCING FROM A HIGH AMPLITUDE MID-
TO UPPER-LEVEL LONGWAVE TROUGH CENTERED NEAR 98W WITH A BASE
OVER THE EAST PACIFIC WATERS NEAR 10N. SURFACE WINDS PEAK WEST
OF THE COLD FRONT AT 15 KT. WINDS IN THE EASTERN HALF OF THE
GULF ARE GENERALLY 15 KT FROM THE SE...EXCEPT N OF 27N BETWEEN
87W AND 91W. THE COLD FRONT WILL CONTINUE TO MOVE SLOWLY
EASTWARD AND STALL IN THE CENTRAL GULF WHILE THE WEAK LOW MOVES
NORTHWARD AND REACHES EASTERN TEXAS FRIDAY MORNING. THE FRONT IS
FORECAST TO DISSIPATE SATURDAY MORNING AS THE LOW CONTINUES TO
WEAKEN INLAND. 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 NORTHERN GULF OF MEXICO.

CARIBBEAN SEA...

GALE FORCE WINDS ALONG THE COAST OF COLOMBIA DIMINISHED THIS
AFTERNOON BUT ARE RESUMING TONIGHT. SEE THE SPECIAL FEATURES
SECTION FOR DETAILS. OTHERWISE...THE CARIBBEAN SEA HAS NO
SURFACE FEATURES OF INTEREST NOR IS THERE ANY ORGANIZED DEEP
CONVECTION. THE CONTINUATION OF A STRONG PRESSURE GRADIENT
BETWEEN A LOW OVER NW COLOMBIA AND THE RIDGE OVER THE ATLC
SUPPORT TRADES OF 20 TO 25 KT BETWEEN 65W AND 83W. TRADES OF 10
TO 15 KT DOMINATE ELSEWHERE. ALOFT...A BROAD HIGH AMPLITUDE
UPPER RIDGE COVERS THE CARIBBEAN WITH AN AXIS ALONG 75W...WHICH
IS PROMOTING SUBSIDENCE OVER THE CARIBBEAN. LITTLE CHANGE IS
EXPECTED DURING THE NEXT TWO DAYS.

...HISPANIOLA...

DEEP LAYER DRY AIR OVER THE ISLAND CONTINUE TO SUPPORT FAIR
SKIES. HOWEVER...PASSING SHOWERS ARE POSSIBLE AS PATCHES OF
SHALLOW MOISTURE CONTINUE TO MOVE WESTWARD WITH THE TRADES
ACROSS THE CARIBBEAN. THESE CONDITIONS ARE FORECAST TO PERSIST
THROUGH AT LEAST SATURDAY MORNING.

ATLANTIC OCEAN...

THE MAIN SURFACE FEATURE ACROSS THE ATLANTIC IS RIDGING
EXTENDING SE FROM A 1039 MB HIGH NEAR 55N118W TO A 1025 MB HIGH
OVER THE SW N ATLC NEAR 26N95W...AND ANOTHER RIDGE EXTENDING
FROM A 1030 MB HIGH NEAR 47N22W SW TO NEAR 27N48W. A BROAD MID-
TO UPPER-LEVEL TROUGH OVER THE WESTERN AND CENTRAL ATLC WITH
BASE NEAR 30N CONTINUE TO SUPPORT A COLD FRONT WITH TAIL
REACHING COASTAL WATERS OF SE GEORGIA. THE HIGH PRESSURE CENTER
OVER THE SW N ATLC IS FORECAST TO DISSIPATE WITHIN THE NEXT
SEVERAL HOURS GIVING THE SPACE FOR THE COLD FRONT TO ENTER THE
AREA OF DISCUSSION FRIDAY MORNING. A SURFACE TROUGH EXTENDS FROM
27N72W TO 19N80W...THOUGH NO SIGNIFICANT WEATHER IS CURRENTLY
ASSOCIATED WITH THIS FEATURE. VARIABLE WINDS OF 5 TO 15 KT
DOMINATE THE BASIN W OF 30W N OF 22N...A TIGHTER PRESSURE
GRADIENT SUPPORT WINDS OF 20 KT ALONG THE NW COAST OF AFRICA AND
NORTHERN COASTAL WATERS OF THE GREATER ANTILLES. IN THE UPPER
LEVELS...A CUT OFF LOW IS CENTERED NEAR 12N25W. SCATTERED
SHOWERS ARE OCCURRING FROM 18N TO 23N BETWEEN 34W AND 40W IN
ASSOCIATION WITH THE LOW...THOUGH NO SURFACE COMPONENT TO THE
FEATURE IS CURRENTLY PRESENT.

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

$$
RAMOS

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