[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 272351
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SAT APR 27 2013

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
2315 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS THE COAST OF SIERRA LEONE AT
8N13W TO 4N20W. THE ITCZ BEGINS AT 4N20W AND CONTINUES ALONG
3N30W EQ40W 3S50W. SCATTERED MODERATE CONVECTION IS FROM 4N-6N
BETWEEN 16W-20W...AND FROM 3N-5N BETWEEN 31W-35W.

...DISCUSSION...

GULF OF MEXICO...
BROAD UPPER RIDGING CONTINUES TO COVER THE GULF OF MEXICO
SUPPORTING SURFACE RIDGING EXTENDING FROM A 1029 MB HIGH OFF THE
COAST OF NEW JERSEY NEAR 39N74W. THIS PATTERN IS PROVIDING EAST
TO SOUTHEAST SURFACE FLOW OF 10-15 KT. DRY AIR ALOFT IS HELPING
CLEAR SKIES THROUGHOUT. HOWEVER...A BURST OF
SHOWERS/THUNDERSTORMS HAS FORMED JUST INLAND OVER EASTERN TEXAS
NEAR THE LOUISIANA BORDER. THIS ACTIVITY IS SE OF A FRONTAL
BOUNDARY THROUGH CENTRAL TEXAS. THE FRONT WILL LIKELY STAY NORTH
OF THE DISCUSSION AREA...BUT SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE ALONG THE NORTHERN GULF COAST OVER THE NEXT COUPLE OF
DAYS.

CARIBBEAN SEA...
THE BROAD UPPER RIDGE ACROSS THE GULF OF MEXICO CONTINUES INTO
THE WESTERN CARIBBEAN WHILE BROAD UPPER TROUGHING COVERS THE
REMAINDER OF THE BASIN WITH AXIS NEAR 75W. MOSTLY DRY AIR ALOFT
IS PROVIDING FAIR SURFACE CONDITIONS WITH CLEAR SKIES EXCEPT FOR
A FEW PATCHES OF CLOUDS AND POSSIBLE SHOWERS SOUTH OF PUERTO
RICO AND HAITI. A FEW PATCHES OF CLOUDS ARE ALSO MOVING THROUGH
THE NW CARIBBEAN AND INTO HONDURAS AND NICARAGUA. A LARGE AREA
OF SHOWERS/THUNDERSTORMS REMAINS EAST OF WINDWARD ISLANDS. MODEL
GUIDANCE CONTINUES TO SHOW A GRADUAL SHIFT WEST OF THIS MOISTURE
BY EARLY NEXT WEEK...WHICH MAY BRING HEAVY SHOWERS AND
THUNDERSTORMS TO THE SE CARIBBEAN. TRADEWIND FLOW OF 10-15 KT IS
CURRENTLY PRESENT ACROSS THE MAJORITY OF THE BASIN WITH LITTLE
CHANGE EXPECTED OVER THE NEXT 24 HOURS.

ATLANTIC OCEAN...
UPPER LEVEL RIDGING OVER THE SE CONUS SUPPORTS SURFACE RIDGING
ACROSS THE WEST ATLC ANCHORED BY A 1029 MB HIGH OFF THE COAST OF
NEW JERSEY NEAR 39N74W. A NARROW UPPER LEVEL TROUGH TO THE EAST
ALONG 60W SUPPORTS A COLD FRONT NORTH OF THE AREA WHICH
TRANSITIONS INTO A SURFACE TROUGH ALONG 31N64W 28N67W. A SECOND
SURFACE TROUGH IS TO THE SE ALONG 30N59W TO 25N55W WITH POSSIBLE
ISOLATED SHOWERS WITHIN 90 NM EAST OF THE AXIS. A WEAK THIRD
SURFACE TROUGH IS FARTHER SOUTH ACROSS THE SE BAHAMAS AND
HISPANIOLA ALONG 23N72W TO 18N69W WITH NO ASSOCIATED SHOWER
ACTIVITY EXCEPT FOR A FEW POSSIBLE SHOWERS OVER HISPANIOLA. A
LARGE AREA OF SHOWERS/POSSIBLE THUNDERSTORMS ARE EAST OF THE
WINDWARD ISLANDS FROM 8N-13N BETWEEN 53W-61W. THE ACTIVITY IS
LIKELY LINKED TO MOIST SOUTHWESTERLY FLOW ALOFT AROUND A BROAD
UPPER TROUGH ACROSS THE CARIBBEAN. FARTHER NORTH...AN UPPER
LEVEL LOW NEAR 36N38W CONTINUES TO SUPPORT 1007 MB SURFACE LOW
NEAR 35N37W. A DISSIPATING COLD FRONT EXTENDS INTO THE
DISCUSSION AREA ALONG 31N25W 24N28W 22N33W. POSSIBLE ISOLATED
SHOWERS ARE ALONG THE AXIS. A BROAD UPPER RIDGE COVERS THE
REMAINDER OF THE EASTERN TROPICAL ATLC PROVIDING MOSTLY FAIR
CONDITIONS ACROSS THE AREA.

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

$$
WALTON


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