[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 120606
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT MON MAR 12 2012

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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS W AFRICA INTO THE E TROPICAL
ATLC NEAR 8N13W TO 6N17W WHERE THE ITCZ AXIS CONTINUES ALONG
3N22W 2N30W S OF THE EQUATOR NEAR 36W INTO SOUTH AMERICA NEAR
3S41W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION
ARE FROM 6N TO THE EQUATOR BETWEEN 13W-26W. CLUSTERS OF
SCATTERED MODERATE CONVECTION ARE FROM 2N TO THE EQUATOR BETWEEN
4W-10W AND BETWEEN 30W-39W.

...DISCUSSION...

GULF OF MEXICO...
A STRONG UPPER LOW IS OVER THE CENTRAL PLAIN STATES WITH THE
UPPER TROUGH EXTENDING S TO THE W LOUISIANA/E TEXAS COAST
SUPPORTING A COLD FRONT THAT AT 12/0300 UTC IS INLAND OVER
ARKANSAS AND LOUISIANA WITH A STATIONARY FRONT ENTERING THE GULF
NEAR THE LOUISIANA/TEXAS BORDER CONTINUING ALONG 26N95W TO
23N96W WHERE A SURFACE TROUGH CONTINUES INTO THE W BAY OF
CAMPECHE TO NEAR 19N96W. SCATTERED SHOWERS/THUNDERSTORMS ARE
WITHIN 120 NM E OF THE FRONT N OF 26N. AN UPPER RIDGE DOMINATES
THE GULF WATERS WITH THE MEAN AXIS EXTENDING THROUGH THE YUCATAN
CHANNEL TO INLAND OVER THE SE GULF STATES NEAR PENSACOLA
FLORIDA. THIS UPPER RIDGE IS DRAWING MOISTURE ALOFT ACROSS THE
SW GULF GENERATING SCATTERED SHOWERS W OF THE FRONT/SURFACE
TROUGH TO INLAND OVER MEXICO S OF 25N. A SURFACE RIDGE EXTENDS
FROM THE W ATLC AND A 1033 MB HIGH ALONG THE VIRGINIA/NORTH
CAROLINA COAST TO SE LOUISIANA. THE SE RETURN OVER THE E GULF IS
PRODUCING SCATTERED SHOWERS NE OF A LINE FROM THE STRAITS OF
FLORIDA NEAR 23N80W ALONG 28N85W TO THE MISSISSIPPI/LOUISIANA
BORDER. THIS IS LEAVING THE REMAINDER OF THE GULF UNDER MOSTLY
CLEAR SKIES TONIGHT. FRONT/SURFACE TROUGH OVER THE W GULF WILL
SHIFT W OF AREA TODAY AS THE SURFACE RIDGE BUILDS W FROM THE W
ATLC ACROSS GULF OF MEXICO THROUGH FRI.

CARIBBEAN SEA...
WEAK UPPER TROUGH EXTENDS FROM THE W ATLC ACROSS HAITI TO
JAMAICA AMPLIFYING AN UPPER RIDGE THAT EXTENDS FROM THE E GULF
OF HONDURAS THROUGH THE YUCATAN CHANNEL INTO THE GULF OF MEXICO.
A BROAD UPPER RIDGE OVER THE TROPICAL ATLC DOMINATES THE
CARIBBEAN E OF 70W WITH NEAR ZONAL WESTERLY FLOW OVER THE SW
CARIBBEAN. MODERATE/STRONG SUBSIDENCE AND DRY STABLE AIR ARE W
OF A LINE FROM THE LEEWARD ISLANDS NEAR 17N63W TO COLOMBIA NEAR
11N74W AND S OF 20N W OF 75W. AFTERNOON SHOWERS/THUNDERSTORMS
THAT HAD DEVELOPED INLAND OVER HAITI AND JAMAICA HAVE SHIFTED
WSW INTO THE CARIBBEAN WATERS DOTTING THE AREA WITHIN 75 NM OF
LINE FROM 17N80W TO OVER HAITI NEAR 19N82W. THE UPPER RIDGE OVER
THE E CARIBBEAN IS DRAWING MOISTURE ALOFT AND IS GENERATING
SCATTERED SHOWERS SE OF LINE FROM THE LEEWARD ISLANDS NEAR
17N63W TO COLOMBIA NEAR 12N71W INCLUDING THE WINDWARD AND ABC
ISLANDS. THE TIGHT PRESSURE GRADIENT IS PRODUCING FRESH TO
STRONG NE TO E TRADE WINDS ACROSS THE BASIN. LITTLE CHANGE IS
EXPECTED THROUGH FRI.

ATLANTIC OCEAN...
A SURFACE RIDGE COVERS THE W ATLC W OF 60W ANCHORED BY A 1033 MB
HIGH ALONG THE VIRGINIA/NORTH CAROLINA COAST. THE TIGHT PRESSURE
GRADIENT OVER THE W ATLC IS GENERATING FRESH NW TRADE WINDS
ACROSS THE W ATLC. A BROAD UPPER TROUGH EXTENDS INTO THE W ATLC
THROUGH 32N56W ALONG 24N8W NARROWING AS IT ENTERS THE CARIBBEAN
OVER HAITI SUPPORTING A 1012 MB SURFACE LOW NEAR 32N51W WITH A
DISSIPATING COLD FRONT EXTENDING SW ALONG 29N56W TO 26N64W AND A
SHEAR AXIS ANALYZED ALONG 25N72W TO THE N BAHAMA ISLANDS NEAR
25N78W. A DEVELOPING COLD FRONT IS TO THE E EXTENDING FROM THE
SURFACE LOW ALONG 28N54W TO 25N58W. SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS ARE N OF 26N E OF THE DEVELOPING COLD FRONT TO
48W. BROAD UPPER RIDGE COVERS THE TROPICAL ATLC S OF 25N BETWEEN
30W-70W WITH A NARROW RIDGE EXTENDING FROM 25N43W TO BEYOND
32N39W WITH NEAR ZONAL WESTERLY FLOW ALOFT E OF 30W. A SURFACE
RIDGE DOMINATES THE E ATLC ANCHORED BY A 1027 MB HIGH BOUT 400
NM SW OF THE AZORES AND A 1025 MB HIGH ABOUT 550 NM E OF THE
AZORES. THE LAST VISIBLE SATELLITE IMAGES SHOW AN AREA OF
AFRICAN DUST COVERING THE E TROPICAL ATLC FROM 7N-30N E OF 36W
WHILE THE UW-CIMSS IMAGERY INDICATES THE DUST HAS REACHED AS FAR
AS 40W. THE DEVELOPING COLD FRONT WILL MOVE INTO THE CENTRAL
ATLC TUE WHERE IT WILL STALL AND WEAKEN THROUGH WED NIGHT AND
DISSIPATE BY EARLY FRI. SURFACE RIDGE OVER THE W ATLC WILL
WEAKEN MON AND TUE WITH E TO W RIDGE BUILDING ALONG THE NORTHERN
PERIPHERY THROUGH FRI.

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

$$
PAW





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