[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 122350
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU MAY 12 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...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL
ANALYSIS.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2345 UTC.

...ITCZ...

THE ITCZ AXIS IS ANALYZED FROM THE COAST OF SIERRA LEONE NEAR
7N12W SOUTHWESTWARD ALONG 4N20W 1N30W EQ40W TO NE BRAZIL ALONG
1S50W. SCATTERED MODERATE CONVECTION IS WITHIN 150 NM ON EITHER
SIDE OF THE AXIS W OF 30W.

...DISCUSSION...

GULF OF MEXICO...
A MESOSCALE CONVECTIVE SYSTEM IS EMERGING OFF THE TEXAS COAST
THIS EVENING. THIS SYSTEM IS AHEAD OF A FRONTAL BOUNDARY MOVING
ACROSS EASTERN TEXAS. THE LEADING EDGE OF CONVECTION IS
ASSOCIATED TO A SQUALL LINE ANALYZED ALONG 29N94W 27N94W 26N97W.
THIS LINE IS EXPANDING EASTWARD AT ABOUT 18 KT GENERATING HEAVY
RAIN WITH POSSIBLE HAIL...STRONG STRAIGHT LINE WINDS...FREQUENT
LIGHTNING...AND WATERSPOUTS W OF 94W N OF 26N. THIS SYSTEM WILL
CONTINUE TO EXPAND ESE OVER THE NEXT 6 HOURS WITH CONVECTION...
THEN LOOSE MOMENTUM AND DISSIPATE. IN THE MEAN TIME...THE NEXT
COLD FRONT IS FORECAST TO EMERGE OFF THE TEXAS COAST FRIDAY LATE
AFTERNOON. ELSEWHERE ACROSS THE GULF...WATER VAPOR IMAGERY
INDICATES DRY AIR ALOFT ACROSS THE AREA. AT SURFACE...A 1016 MB
HIGH IS OVER THE FAR NE BASIN NEAR 29N85W. WHILE LIGHT AND
VARIABLE WINDS ARE OBSERVED NEAR THE HIGH CENTER...ESE FLOW IS
ELSEWHERE ACROSS THE AREA RANGING FROM 10 TO 20 KT. THE HIGH
PRESSURE RIDGE IS FORECAST TO REMAIN NEARLY STATIONARY OVER THE
NEXT 24 HOURS. A NEARLY STATIONARY TROUGH LINES THE CENTRAL
FLORIDA PENINSULA ENHANCED BY SEA BREEZE CONVERGENCE IS
GENERATING A FEW ISOLATED SHOWERS MOVING OFF THE SW FLORIDA
COAST INTO THE STRAITS AND THE NW COAST OF CUBA S OF 25N E OF
84W. THIS ACTIVITY WILL PERSIST THROUGH THE NEXT 6-8 HOURS.

CARIBBEAN SEA...
WATER VAPOR IMAGERY INDICATES DRY AIR AND SUBSIDENCE ACROSS THE
NW BASIN N OF 15N W OF 74W SUPPRESSING ANY CONVECTION IN THIS
REGION. BROAD CYCLONIC TURNING COVERS THE REMAINDER OF THE
CENTRAL AND EASTERN CARIBBEAN...UNDER THE INFLUENCE OF A BROAD
AREA OF MODERATE TO STRONG SOUTHWESTERLY FLOW ALOFT AND DEEP
TROUGHINESS SUPPORTING SCATTERED SHOWERS AND THUNDERSTORMS
WITHIN 55 NM ON EITHER SIDE OF A SURFACE TROUGH ANALYZED FROM
THE ATLC BASIN ACROSS PUERTO RICO ALONG 18N67W...EXTENDING SW TO
THE COAST OF COLOMBIA NEAR 11N74W. GLOBAL MODEL GUIDANCE
INDICATES THIS SYNOPTIC SETUP WILL REMAIN IN PLACE OVER THE NEXT
FEW DAYS. TOTAL PRECIPITABLE WATER VALUES REMAIN ELEVATED OVER
THE FAR SW BASIN...WHERE LOW LEVEL CONVERGENCE ASSOCIATED TO
MONSOONAL CONVECTION OVER THE FAR EAST TROPICAL PACIFIC IS
GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS WITHIN 70 NM
ALONG THE COASTS OF PANAMA...COSTA RICA...NICARAGUA AND COLOMBIA
BETWEEN 74W AND THE COAST OF NICARAGUA S OF 12N. THIS AREA OF
CONVECTION IS EXPECTED TO LINGER OVER THE NEXT 24 HOURS.

ATLANTIC OCEAN...
AN UPPER LEVEL RIDGE OF HIGH PRESSURE CONTINUES TO BUILD OVER
THE WEST ATLC. AHEAD OF THIS RIDGE...A OCCLUDED DEEP LAYERED LOW
IS OVER THE NW ATLC ROTATING AROUND 34N61W. THIS SYSTEM SUPPORTS
A COLD FRONT ENTERING THE DISCUSSION AREA NEAR 30N50W CONTINUING
SW AS A STATIONARY FRONT ALONG 26N54W 22N60W 20N67W. SE OF THIS
FRONT...A SURFACE TROUGH IS ANALYZED FROM 21N59W INTO THE
CARIBBEAN ACROSS PUERTO RICO ALONG 18N67W. THESE BOUNDARIES ARE
SUPPORTED ALOFT BY A BROAD AND ELONGATED AREA OF DIFFLUENCE FLOW
ALOFT ASSOCIATED TO A FAIRLY STRONG 110 KT UPPER LEVEL JET
STREAK WITH AXIS FROM 18N67W TO 30N46W. A SECONDARY SURFACE
TROUGH IS ANALYZED WEST OF THE STATIONARY FRONT ALONG 27N58W
24N64W 24N72W. SCATTERED WEAK SHOWERS ARE WITHIN 20 NM ON EITHER
SIDE OF THE TROUGH. SURFACE RIDGING COVERS THE REMAINDER OF THE
EASTERN ATLC. A WEAK SURFACE TROUGH ANALYZED FROM 25N41W TO
19N43W IS EMBEDDED WITHIN THE SURFACE RIDGE GENERATING SCATTERED
SHOWERS FROM 21N-25N BETWEEN 38W-44W. A 1007 MB LOW IS JUST E OF
THE CANARY ISLANDS GENERATING ISOLATED SHOWERS AND TSTMS FROM S
OF 31N E OF 15W. THIS LOW IS EXPECTED TO MOVE NW IN THE NEXT 24
HOURS WITH CONVECTION AFFECTING MOSTLY THE COASTAL WATERS NEAR
THE CANARY ISLANDS.

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

$$

GARCIA




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