[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 210524
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT TUE APR 21 2009

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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 0515 UTC.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 6N10W 3N14W CROSSING THE EQUATOR
NEAR 19W TO 4S33W TO 2S45W. ISOLATED MODERATE CONVECTION IS S OF
3N BETWEEN 13W-22W.

...DISCUSSION...

THE GULF OF MEXICO...
A LARGE UPPER TROUGH OVER THE ERN CONUS IS SUPPORTING A COLD
FRONT THAT EXTENDS FROM NEAR THE TAMPA AREA TO THE NW YUCATAN
PENINSULA. UPPER DIFFLUENCE TO THE E OF THE TROUGH AXIS COUPLED
WITH LOW-LEVEL CONVERGENCE ALONG THE FRONT IS PRODUCING A SWATH
OF MOISTURE OVER THE SE GULF AND FLORIDA. DOPPLER RADAR AND
LIGHTNING DATA ONLY SUGGEST EMBEDDED ISOLATED SHOWER AND TSTM
ACTIVITY. A FASTER MOVING SECONDARY SURGE IS NOTED ON SATELLITE
IMAGERY OVER THE FLORIDA PANHANDLE ADVECTING DRIER AIR BEHIND
IT. THESE BOUNDARIES ARE EXPECTED TO CROSS THE REMAINDER OF THE
AREA BY THIS AFTERNOON. W OF THE FRONT...N WINDS LIKELY PEAKED
AROUND 25-30 KT OVER THE TOPOGRAPHICALLY ENHANCED SW PORTION OF
THE BAY OF CAMPECHE MON. WINDS ARE DIMINISHING TONIGHT AS WEAK
HIGH PRES HAS BUILT E OVER THE WRN GULF...WEAKENING THE PRESSURE
GRADIENT. THIS HIGH IS FORECAST TO CONTINUE ITS E DRIFT ACROSS
THE GULF OVER THE NEXT COUPLE OF DAYS.

THE CARIBBEAN SEA...
A LARGE AREA OF CONVECTIVE ACTIVITY IS LOCATED INLAND OVER
COLOMBIA TRIGGERED BY A SWLY UPPER JET AND LIKELY ENHANCED BY
LOCAL FLOWS AND USUAL SFC LOW PRES. LATEST QUIKSCAT PASS REVEALS
20-25 KT NE/E WINDS BETWEEN THE COAST OF COLOMBIA AND HISPANIOLA
WITH 15-20 KT TRADES ELSEWHERE E OF 80W. WINDS ARE LIGHT AND
VARIABLE OVER THE W PORTION DUE TO THE PRESENCE OF A WEAK
PREFRONTAL TROUGH ALONG 83W/84W. SOME MOISTURE...LIKELY
CONTAINING ONLY ISOLATED SHOWERS AND TSTMS...HAS MOVED INTO THE
FAR NW CARIBBEAN AHEAD OF A COLD FRONT OVER THE E GULF. THIS
FRONT MAY MOVE INTO THE AREA BUT SHOULD HAVE LITTLE SIGNIFICANT
WEATHER IMPACTS.

THE ATLANTIC OCEAN...
SCATTERED SHOWERS AND TSTMS ARE WITHIN 240 NM E OF THE N FLORIDA
AND GEORGIA COASTS TRIGGERED BY AN UPPER DIFFLUENT FLOW AND A
COLD FRONT OVER FLORIDA. SEE GULF OF MEXICO SECTION FOR MORE
DETAILS. SLY WINDS HAVE INCREASED TO 20-25 KT NEAR THE N BORDER
W OF 74W AND WILL LIKELY INCREASE TO 30 KT OVER THE NEXT 6-12
HOURS AS THE FRONT NEARS. OVER THE CENTRAL ATLC...DEEP LAYER
TROUGHING REMAINS WELL DEFINED PROVIDING LIMITED SUPPORT FOR A
WEAK BOUNDARY FROM 32N46W TO 22N60W. A WEAK SMALL SCALE LOW IS
POSITIONED W OF THE FRONT NEAR 27N55W PRODUCING LITTLE
SIGNIFICANT WEATHER. A MORE AMPLIFIED TROUGH...SUPPORTING
ANOTHER FRONT...IS EXPECTED TO SWEEP SE AND ABSORB OR MERGE WITH
THE WEAK LOW/FRONT OVER THE NEXT COUPLE OF DAYS. A NARROW SWATH
OF SCATTERED SHOWERS AND TSTMS ARE LOCATED IN THE UPPER
DIFFLUENT ZONE N OF 24N BETWEEN 37W-42W. AN UPPER JET EXTENDING
NE FROM THE WINDWARD ISLANDS TO 20N40W IS LIKELY PRODUCING
SCATTERED SHOWERS AND TSTMS WITHIN 300 NM E OF THE JET AXIS.
OTHERWISE...THE E ATLC IS DOMINATED BY A STRONG AZORES HIGH.

$$
CANGIALOSI



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