[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 191043
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SUN APR 19 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...ITCZ...
THE ITCZ IS CENTERED ALONG 5N9W ...CROSSING THE EQUATOR NEAR 15W
TO 1S20W 3S30W AND INTO NE BRAZIL NEAR 3S40W. NO SIGNIFICANT
CONVECTION IS OBSERVED IN THE DISCUSSION AREA.

...DISCUSSION...

GULF OF MEXICO...
MOIST WESTERLY FLOW ALOFT IS OBSERVED OVER THE GULF REGION AS A
DEEP LAYER TROUGH PROGRESSES ACROSS THE CENTRAL CONUS. THE
RETURN FLOW AROUND A 1021 MB SURFACE HIGH CENTERED OVER THE W
ATLC NEAR 31N79W IS RESULTING IN SE WINDS OF 15 TO 20 KT ACROSS
MUCH OF THE GULF REGION THIS MORNING. THESE WINDS ARE ADVECTING
ABUNDANT LOW-LEVEL MOISTURE ACROSS THE GULF REGION...RESULTING
IN INCREASED INSTABILITY ACROSS MUCH OF THE NRN GULF. THIS
INSTABILITY AND A SURFACE TROUGH ANALYZED FROM ERN TEXAS THROUGH
CORPUS CHRISTI TO NE MEXICO IS COMBINING WITH MIDDLE TO UPPER
LEVEL ATMOSPHERIC DIFFLUENCE ACROSS THE NW AND N/CENTRAL GULF TO
SUPPORT SCATTERED SHOWERS AND TSTMS N OF 26N W OF 88W. ACROSS
THE E AND SE GULF...STABLE ATMOSPHERIC CONDITIONS ARE RESULTING
IN GENERALLY FAIR WEATHER CONDITIONS. A SURFACE COLD FRONT
ASSOCIATED WITH THE CENTRAL CONUS DEEP LAYER TROUGH IS FORECAST
TO MOVE OFF THE TEXAS COAST MIDDAY SUNDAY...AND EXTEND FROM THE
FLORIDA BIG BEND TO THE BAY OF CAMPECHE BY MONDAY. INCREASED NLY
WINDS AND RELATIVELY COOLER AND DRIER CONDITIONS ARE FORECAST
ACROSS THE NW GULF WITH THE PASSAGE OF THIS FRONT.

CARIBBEAN SEA...
A SURFACE RIDGE LOCATED OVER THE W ATLC IS FORECAST TO MAINTAIN
FRESH NE TO E TRADE WINDS ACROSS THE CARIBBEAN SEA THROUGH
WEDNESDAY. GENERALLY FAIR WEATHER IS PRESENT ACROSS THE
CARIBBEAN...WHERE DEEP LAYER DRY AIR AND SUBSIDENCE IS RESULTING
FROM CONFLUENT WESTERLY FLOW ALOFT. HOWEVER...LOW LEVEL
CONVERGENCE IS SUPPORTING SCATTERED SHOWERS WITHIN 90 NM EITHER
SIDE OF A WEAKENING SURFACE COLD FRONT IN THE N/CENTRAL
CARIBBEAN THAT EXTENDS FROM THE W ATLC N OF THE MONA PASSAGE TO
ACROSS SE HISPANIOLA NEAR 19N69W TO 18N72W. SCATTERED SHOWERS
ARE N OF 17N BETWEEN 64W-73W...INCLUDING PUERTO RICO AND THE
SURROUNDING ADJACENT COASTAL WATERS.

ATLANTIC OCEAN...
SUBSIDENCE IN NW FLOW ALOFT ACROSS THE W ATLC IS ASSOCIATED WITH
A 1021 MB SURFACE HIGH CENTERED NEAR 31N79W. A SURFACE RIDGE
EXTENDS S-SE FROM THIS HIGH INTO THE SW NORTH ATLC...WHERE
GENERALLY FAIR WEATHER CONDITIONS ARE PRESENT. FARTHER TO THE
E...AN UPPER LEVEL TROUGH OVER THE W AND CENTRAL ATLC WITH AXIS
ALONG 60W IS ASSOCIATED WITH A SURFACE STATIONARY FRONT THAT
EXTENDS FROM NE OF THE DISCUSSION AREA TO 32N50W SW INTO A 1014
MB SURFACE LOW NEAR 26N59W. A COLD FRONT CONTINUES SW FROM THE
LOW ALONG 20N65W TO ACROSS SE HISPANIOLA NEAR 19N69W. LOW LEVEL
CONVERGENCE AND ATMOSPHERIC INSTABILITY ARE SUPPORTING SCATTERED
SHOWERS WITHIN 120 NM EITHER SIDE OF THIS FRONT S OF 26N WITH
NUMEROUS SHOWERS AND ISOLATED TSTMS WITHIN 150 NM EITHER SIDE OF
THIS FRONT N OF 25N. W OF THE FRONT...A WEAK 1013 MB SURFACE LOW
IS CENTERED NEAR 30N57W WITH A COLD FRONT EXTENDING ALONG 28N60W
TO 27N64W. LOW LEVEL CONVERGENCE IS SUPPORTING ISOLATED SHOWERS
WITHIN 60 NM EITHER SIDE OF THE FRONTAL BOUNDARY. ACROSS THE E
ATLC...SUBSIDENCE ASSOCIATED WITH A SURFACE RIDGE IS RESULTING
IN GENERALLY FAIR WEATHER CONDITIONS. THIS SURFACE RIDGE IS
ANCHORED BY A 1026 MB SURFACE HIGH NEAR 33N27W. ACROSS THE
TROPICAL ATLC...AN UPPER LEVEL RIDGE IS S OF 15N E OF 60W WITH
THE UPPER LEVEL HIGH CENTERED NEAR 4N49W. UPPER LEVEL DIVERGENCE
ASSOCIATED WITH THIS FEATURE IS ENHANCING CONVECTION...MAINLY
SOUTH OF THE EQUATOR...ASSOCIATED WITH THE ITCZ.

$$
HUFFMAN





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