[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 132344
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST SUN FEB 13 2011

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...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND
RADAR.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2300 UTC.

...ITCZ...

THE ITCZ IS ANALYZED FROM SIERRA LEONE AT 8N13W ALONG 2N20W
CROSSING THE EQUATOR NEAR 30N TO THE NE BRAZIL COAST NEAR 3S43W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 1N-6N
BETWEEN 7W-11W. SIMILAR ACTIVITY IS FROM 4S-1N BETWEEN 24W-32W.
ISOLATED MODERATE/STRONG CONVECTION IS S OF 3N INTO INLAND
BRAZIL BETWEEN 32W-52W...WITH STRONGER ACTIVITY ALONG THE
COASTLINE AND INLAND.

...DISCUSSION...

GULF OF MEXICO...
SURFACE RIDGING AROUND A PAIR OF 1027 MB HIGHS LOCATED S OF
MOBILE ALABAMA AND IN THE SW BAY OF CAMPECHE CONTINUE TO
DOMINATE THE GULF OF MEXICO PROVIDING MOSTLY FAIR CONDITIONS.
WEAK ANTI-CYCLONIC FLOW IS AROUND THE HIGH S OF MOBILE WITH WIND
SPEEDS INCREASING WITH DISTANCE FROM THE CENTER REACHING UP TO
20 KTS ACROSS THE SE GULF. AS OF 2100 UTC...A SURFACE TROUGH IS
ANALYZED BETWEEN THE TWO RIDGES IN THE SE BAY OF CAMPECHE WHERE
THE SURFACE FLOW TURNS CYCLONICALLY AROUND THE WRN SIDE OF THE
YUCATAN PENINSULA. THIS AREA OF SURFACE CONVERGENCE IS
SUPPORTING DENSE LOW-LEVEL CLOUDS S OF 21N BETWEEN 92W-95W WITH
POSSIBLE ISOLATED SHOWERS. AREAS OF LOW-LEVEL STRATOCUMULUS
CLOUDS ARE NOTED ACROSS PORTIONS OF THE SE PART OF THE BASIN.
ALOFT...AN UPPER LEVEL RIDGE EXTENDS FROM TEXAS TO THE GREAT
LAKES REGION SUPPORTING THE SURFACE RIDGE ACROSS THE AREA. AN
ELONGATED AND TILTED UPPER TROUGH EXTENDS OFF THE ERN SEABOARD
ENTERING THE GULF NEAR NE FLORIDA CONTINUING TO THE SW BAY OF
CAMPECHE. WATER VAPOR IMAGERY INDICATES A CLEAR LINE OF
EXTREMELY DRY AIR PUSHING SWD ALONG THIS TROUGH AXIS WITH STRONG
SUBSIDENCE BEHIND IT WHICH IS FURTHER SUPPORTING THE FAIR
WEATHER AND CLEAR SKIES ACROSS MUCH OF THE BASIN. EXPECT THE
UPPER TROUGH TO PUSH EWD ALLOWING THE UPPER AND SURFACE RIDGES
TO SHIFT EWD ACROSS THE BASIN PROVIDING FAIR WEATHER
THROUGHOUT.

CARIBBEAN SEA...
A STATIONARY FRONT CONTINUES TO SIT ACROSS THE NW CARIBBEAN
EXTENDING FROM CENTRAL CUBA TO NW HONDURAS ALONG 21N78W 18N87W
16N88W. SCATTERED SHOWERS ARE WITHIN 120 NM NW...60 NM...SE OF
THE BOUNDARY. THE FRONT IS SUPPORTED BY AN UPPER LEVEL TROUGH
ACROSS THE WRN ATLC THAT EXTENDS INTO THE SRN GULF OF MEXICO.
THE REMAINDER OF THE BASIN IS UNDER A DRY AND STABLE AIR MASS
AROUND AN UPPER LEVEL RIDGE EXTENDING FROM COLOMBIA TO
HISPANIOLA SUPPORTING MOSTLY FAIR WEATHER. A WEAK UPPER TROUGH
EXTENDS FROM PUERTO RICO TO VENEZUELA...BUT DUE TO THE DRY
CONDITIONS IT IS ONLY SUPPORTING A FEW ISOLATED SHOWERS FROM
13N-16N BETWEEN 70W-74W. A FEW ISOLATED SHOWERS ARE ALSO ALONG A
LINE FROM JAMAICA TO THE PANAMA/COSTA RICA BORDERS DUE TO THE
NATURAL BROAD CYCLONIC FLOW AROUND THE TIP OF COLOMBIA. EXPECT
THE FRONTAL BOUNDARY TO GRADUALLY DISSIPATE OVER THE NEXT 24 HRS.

ATLANTIC OCEAN...
A COLD FRONT ENTERS THE DISCUSSION AREA NEAR 32N52W STRETCHING
SW WHERE IT BECOMES STATIONARY NEAR 29N59W TO THE SE BAHAMAS AND
INTO THE NW CARIBBEAN. DEEP CLOUDS AND SCATTERED SHOWERS EXTEND
WITHIN 200 NM BEHIND THE FRONT...90 NM AHEAD OF THE FRONT. THIS
SYSTEM IS SUPPORTED BY AN UPPER LEVEL TROUGH OFF THE ERN UNITED
STATES COAST. SURFACE RIDGING AROUND A 1029 MB HIGH NEAR 29N35W
DOMINATES THE REMAINDER OF THE BASIN PROVIDING MOSTLY FAIR
WEATHER ACROSS THE CENTRAL AND ERN ATLC. THE SURFACE RIDGE IS
SUPPORTED BY A WIDESPREAD UPPER RIDGE ANCHORED NEAR 23N40W. AN
UPPER LEVEL TROUGH IS THE E EXTENDING FROM SPAIN ACROSS NW
AFRICA AND THE CAPE VERDE ISLANDS INTO THE TROPICAL ATLC NEAR
17N35W. EXPECT THE NRN PORTION OF THE FRONT TO CONTINUE TO MOVE
EWD OVER THE NEXT 24 HOURS BEFORE STALLING ACROSS THE CENTRAL
ATLC.

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

$$
WALTON







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