[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 120001
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT WED MAR 11 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...

A GALE WARNING REMAINS IN EFFECT FOR THE COASTAL WATERS OF
COLOMBIA FROM 11N TO 13.5N BETWEEN 74W AND 77W. SCATTEROMETER
DATA CONFIRM THE PRESENCE OF THESE WINDS WHILE ALTIMETER DATA
INDICATE SEA HEIGHTS FROM 11 TO 16 FT IN THE WARNING AREA. THESE
HIGH WINDS ARE THE RESULT OF A STRONG PRESSURE GRADIENT BETWEEN
A 1006 MB LOW ON NW COLOMBIA/E PANAMA COASTAL WATERS AND A 1029
MB HIGH PRES LOCATED EAST OF BERMUDA NEAR 36N44W. GALE
CONDITIONS ARE FORECAST THROUGH THU MORNING...RESUMING AGAIN THU
NIGHT AND CONTINUING THROUGH FRIDAY AFTERNOON. SEE LATEST NWS
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 05N09W TO 03N12W WHERE THE ITCZ BEGINS AND
CONTINUES ALONG 01N25W TO THE EQUATOR NEAR 35W TO THE COAST OF
NORTHERN BRAZIL NEAR 01S44W. SCATTERED MODERATE CONVECTION IS
FROM 04S TO 04N W OF 27W.

...DISCUSSION...

GULF OF MEXICO...

A TROUGH ALOFT STRETCHES FROM THE GREAT LAKES SW TO AN UPPER LOW
OVER CENTRAL MEXICO TO A BASE OVER E PACIFIC WATERS AND PROVIDES
SOUTHWESTERLY FLOW ACROSS THE GULF OF MEXICO. TROUGHING ALOFT
CONTINUES TO SUPPORT A FRONTAL SYSTEM ANALYZED AS A STATIONARY
FRONT FROM A 1019 MB LOW OVER NE ALABAMA SW TO SOUTHERN ALABAMA
NEAR 30N88W TO A 1012 MB LOW OVER THE NW GULF NEAR 25N93W. FROM
THE LOW...A COLD FRONT EXTENDS S-SW ALONG 22N92W TO THE BAY OF
CAMPECHE NEAR 18N94W. LOW LEVEL MOISTURE CONVERGENCE ASSOCIATED
WITH THE LOW PRESSURE ALONG WITH MOISTURE INFLOW FROM THE
CARIBBEAN SUPPORT SCATTERED MODERATE CONVECTION WITHIN 75 NM OFF
THE COAST FROM SOUTHERN TEXAS TO SOUTHERN-CENTRAL LOUISIANA. IN
ADDITION...A LINE OF SHOWERS AND TSTMS IS OBSERVED WITHIN 120 NM
AHEAD OF THE STATIONARY FRONT AND THE LOW PRESSURE. SEA FOG IS
BEING REPORTED N AND NW OF THE LOW PRESSURE CENTER...COINCIDING
WITH MODERATE TO HIGH GOES-13 IFR FOG PROBABILITIES. NORTH-
NORTHWESTERLY FLOW OF 20 TO 25 KT CONTINUES TO DOMINATE BEHIND
THE FRONT WHILE THE INFLUENCE OF ATLC SURFACE RIDGING PROVIDES
SOUTHEASTERLY FLOW OF 10 TO 15 KT EAST OF THE FRONT. THE LOW
WILL DRIFT N-NW TO INLAND SE TEXAS BY THU MORNING...RESULTING IN
THE SLOW PROGRESSION OF THE COLD FRONT TOWARDS THE CENTRAL BASIN
DURING THE NIGHT HOURS THAT DAY. ON FRIDAY MORNING THE LOW
ALREADY INLAND WILL TAKE A TURN TO THE N-NE AND THE FRONT IS
FORECAST TO DISSIPATE OVER THE GULF FRIDAY NIGHT...WHILE A
SURFACE TROUGH DEVELOPS NW OF THE YUCATAN PENINSULA.

CARIBBEAN SEA...

TRADES OF 20 TO 25 KT ARE ACROSS THE CENTRAL AND EASTERN BASIN
INCREASING TO GALE FORCE WINDS NEAR THE COAST OF COLOMBIA.
PLEASE SEE SPECIAL FEATURES SECTION FOR DETAILS. TRADES RANGE
BETWEEN 10 TO 15 KT ON THE NW CARIBBEAN SEA. ALOFT...RIDGING AND
DRY AIR CONTINUE TO DOMINATE ACROSS THE ENTIRE REGION...THUS
FAVORING A STABLE ENVIRONMENT THAT HINDERS THE DEVELOPMENT OF
CONVECTION. HOWEVER...AT THE LOWER LEVELS...SSMI TPW IMAGERY
CONTINUE TO SHOW PATCHES OF LOW LEVEL MOISTURE EMBEDDED IN THE
TRADES...SOME OF THEM NOW CROSSING THE UK/US VIRGIN ISLANDS...
PUERTO RICO...HISPANIOLA AND JAMAICA. A HIGHER MOISTURE
CONCENTRATION IS OVER THE SW BASIN ASSOCIATED WITH A LOW
PRESSURE CENTERED OFF THE E PANAMA AND NW COLOMBIA COASTS. THIS
MOISTURE IS ENHANCING PASSING TO SCATTERED SHOWERS LIKELY TO
PERSIST DURING THE NIGHT HOURS. LITTLE CHANGE IN THE WEATHER
PATTERN IS EXPECTED DURING THE NEXT TWO DAYS.

...HISPANIOLA...

PATCHES OF SHALLOW MOISTURE CONTINUE TO MOVE ACROSS THE ISLAND
EMBEDDED IN THE TRADE WIND FLOW. THIS MOISTURE IS SUPPORTING
CLOUDINESS WITH POSSIBLE ISOLATED SHOWERS LIKELY TO CONTINUE
DURING THE NIGHT HOURS. ALOFT...THE INFLUENCE OF A RIDGE AND DRY
AIR FAVOR A STABLE ENVIRONMENT THAT HINDERS THE DEVELOPMENT OF
CONVECTION. SIMILAR WEATHER CONDITIONS ARE FORECAST TO PERSIST
THROUGH AT LEAST FRIDAY MORNING.

ATLANTIC OCEAN...

THE DOMINANT SURFACE FEATURE ACROSS THE ATLANTIC CONTINUES TO BE
RIDGING BEING ANCHORED BY A 1029 MB HIGH PRES CENTER LOCATED NE
OF BERMUDA NEAR 36N44W. VARIABLE WINDS OF 20 TO 25 KT ARE N OF
20N W OF A LINE FROM 30N48W SW TO 20N70W AND OVER THE E ATLC
FROM 17N TO 27N E OF 25W. VARIABLE WINDS OF 5 TO 15 KT DOMINATE
ELSEWHERE. A SURFACE TROUGH EXTENDS FROM 30N41W TO
26N51W...THOUGH NO SIGNIFICANT WEATHER IS CURRENTLY ASSOCIATED
WITH THIS FEATURE. IN THE UPPER LEVELS...A CUT OFF LOW IS
CENTERED NEAR 21N41W. SCATTERED TO ISOLATED SHOWERS ARE
ASSOCIATED WITH THIS FEATURE MAINLY FROM 18N TO 25N BETWEEN 34W
AND 46W. DURING THE NEXT COUPLE OF DAYS...THE UPPER-LEVEL LOW
WILL DRIFT SLOWLY EASTWARD AND OCCASIONALLY PRODUCE SOME
SHOWERS...BUT NO SIGNIFICANT SURFACE FEATURES ARE ANTICIPATED TO
FORM.

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

$$
RAMOS

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