[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 160545
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT MON APR 16 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 AFRICA INTO THE E TROPICAL
ATLC NEAR 6N10W 3N13W 2N22W WHERE THE ITCZ AXIS CONTINUES ALONG
1N27W THEN S OF THE EQUATOR NEAR 31W. SCATTERED CLUSTERS OF
SCATTERED MODERATE/STRONG CONVECTION ARE FROM 4N TO THE EQUATOR
E OF 22W TO ACROSS THE PRIME MERIDIAN. CLUSTERS OF SCATTERED
MODERATE/ISOLATED STRONG CONVECTION ARE S OF 9N TO INLAND OVER
SOUTH AMERICA BETWEEN 50W-55W.

...DISCUSSION...

GULF OF MEXICO...
BROAD UPPER RIDGE DOMINATES THE GULF N OF 24N ANCHORED OVER NE
FLORIDA AND EXTENDS INTO THE W ATLC. THIS UPPER RIDGE IS BEING
AMPLIFIED N BY A STRONG UPPER TROUGH OVER THE CENTRAL PLAIN
STATES. THIS UPPER TROUGH IS SUPPORTING A NOW STATIONARY FRONT
INLAND OVER TEXAS GENERATING SCATTERED TO HEAVY SHOWERS WITH
SCATTERED TO NUMEROUS THUNDERSTORMS INLAND OVER TEXAS THROUGH NE
LOUISIANA TO OVER THE MISSISSIPPI VALLEY. THESE SHOWERS/
THUNDERSTORMS ARE MOVING INTO THE GULF ALONG THE IMMEDIATE TEXAS
COASTLINE. A SECOND UPPER RIDGE EXTENDS FROM THE E PACIFIC
REGION ACROSS S MEXICO AND THE BAY OF CAMPECHE TO 24N94W. A
SURFACE RIDGE ANCHORED IN THE W ATLC EXTENDS ALONG THE N GULF
COAST TO SE LOUISIANA GIVING THE GULF SOUTHERLY RETURN FLOW N OF
25N. STRONG SUBSIDENCE AND DRY STABLE AIR DOMINATES THE GULF
WATERS. HOWEVER THE SOUTHERLY RETURN FLOW IS USHERING IN SOME
LOW LEVEL MOISTURE AND SUBSEQUENT ISOLATED SHOWERS MAINLY
DOTTING THE E GULF E OF 89W LEAVING THE REMAINDER OF THE GULF
WITH CLEAR SKIES TONIGHT. THE SOUTHERLY RETURN FLOW WILL
DIMINISH FROM THE W TO E ON MON AS THE NOW STATIONARY FRONT
BECOMES A COLD AND WILL MOVE E AGAIN ON TUE REACHING FROM THE
FLORIDA PANHANDLE TO THE CENTRAL WATERS TUE NIGHT THEN DRIFTING
E ACROSS THE NE GULF WED AND WED NIGHT. REMNANTS OF THE FRONT
WILL DISSIPATE OVER N FLORIDA ON THU AS AN E TO W RIDGE DEVELOPS
ACROSS THE NORTHERN COASTAL PLAINS. THE RIDGE WILL SHIFT S TO
ALONG 28N ON FRI.

CARIBBEAN SEA...
NEAR ZONAL WESTERLY FLOW ALOFT DOMINATES THE ENTIRE CARIBBEAN. A
RELATIVELY TIGHT PRESSURE GRADIENT AS THE SURFACE RIDGE OVER THE
W ATLC EXTENDS S TO ACROSS THE GREATER ANTILLES OVER THE N
CARIBBEAN AND IS GENERATING FRESH TO MODERATE EASTERLY TRADE
WINDS ACROSS THE BASIN. MODERATE TO STRONG SUBSIDENCE AND DRY
AIR ALOFT COVERS THE CARIBBEAN. A SHEAR AXIS EXTENDS FROM
CENTRAL ATLC FRONT OVER GUADALOUPE IN THE LESSER ANTILLES TO
NEAR 13N73W. THIS SHEAR AXIS IS PROVING LIFT FOR SOME LOW LEVEL
MOISTURE THAT REMAINS ACROSS THE E CARIBBEAN TO GENERATE
SCATTERED SHOWERS WITHIN 120 NM N AND 90 NM S OF THE SHEAR AXIS.
A SECOND BAND OF LOW LEVEL MOISTURE WITH SCATTERED SHOWERS
EXTENDS WITHIN 75 NM OF A LINE FROM OVER HISPANIOLA ALONG 18N74W
17N80W TO 20N86W INCLUDING JAMAICA. THIS IS LEAVING THE
REMAINDER OF THE CARIBBEAN WITH FAIR WEATHER TONIGHT. THE SHEAR
AXIS WILL CONTINUE TO WEAKEN AS IT MOVES E INTO THE TROPICAL
ATLC WATERS THROUGH WED. THE W ATLC SURFACE RIDGE WILL GRADUALLY
INCREASE THE NORTHERLY FLOW THROUGH MON WITH THE GRADIENT
BEGINNING TO RELAX SOME BY LATE TUE. THE LOW LEVEL FLOW WILL
BECOME SE OVER THE NW WATERS LATE IN THE WEEK.

ATLANTIC OCEAN...
A BROAD UPPER RIDGE IS ANCHORED OVER NE FLORIDA COVERING THE W
ATLC W OF 67W INTO THE GULF OF MEXICO. A SURFACE RIDGE DOMINATES
THE W ATLC N OF 18N W OF 50W AND ANCHORED BY A 1029 MB HIGH JUST
W OF BERMUDA. AN UPPER TROUGH CONTINUES TO MOVE ACROSS THE
CENTRAL ATLC N OF 20N BETWEEN 43W-67W SUPPORTING A COLD FRONT
THAT EXTENDS FROM A 1011 MB LOW NEAR 32N48W ALONG 27N48W TO
20N55W WHERE IT DISSIPATES TO OVER GUADALOUPE IN THE LESSER
ANTILLES BECOMING A SHEAR AXIS OVER THE CARIBBEAN WATERS.
SCATTERED TO NUMEROUS SHOWERS WITH POSSIBLE ISOLATED
THUNDERSTORMS ARE WITHIN 200 NM E OF THE FRONT N OF 25N WITH
SCATTERED SHOWERS WITHIN 120 NM E OF THE FRONT BETWEEN 20N-25N
AND ISOLATED SHOWERS WITHIN 90 NM EITHER SIDE OF THE REMAINDER
OF THE FRONT. A LARGE UPPER RIDGE DOMINATES MUCH OF THE NE ATLC
N OF 28N. A SMALL UPPER LOW IS TO THE S CENTERED NEAR 26N24W
EXTENDING AN UPPER TROUGH INT THE TROPICS TO NEAR 8N20W AND
GENERATING SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS
WITHIN 120/150 NM OF A LINE FROM THE CAPE VERDE ISLANDS TO THE
COAST OF AFRICA NEAR 19N16W. A SURFACE RIDGE DOMINATES THE E
ATLC N OF 10N E OF 45W ANCHORED BY A 1035 MB HIGH JUST N OF THE
AZORES. THIS IS LEAVING THE REMAINDER OF THE ATLC WITH FAIR
WEATHER TONIGHT. W ATLC SURFACE RIDGE WILL WEAKEN AS A COLD
FRONT PASSES THROUGH THE NW WATERS S OF BERMUDA MON NIGHT AND
TUE. THE RIDGE WILL SHIFT SLOWLY S ACROSS THE W ATLC WED THROUGH
FRI.

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

$$
PAW






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