[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 190539
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...ITCZ...
THE ITCZ IS CENTERED ALONG 5N8W 2N15W...CROSSING THE EQUATOR
NEAR 20W TO 3S30W AND INTO NE BRAZIL NEAR 3S40W. NO SIGNIFICANT
CONVECTION IS OBSERVED IN THE DISCUSSION AREA.

...DISCUSSION...

GULF OF MEXICO...
MOIST WESTERLY FLOW ALOFT CONTINUES TO INCREASE ACROSS THE GULF
REGION AHEAD OF A DEEP LAYER TROUGH OVER THE CENTRAL CONUS. THE
RETURN FLOW AROUND A 1021 MB SURFACE HIGH CENTERED OVER THE W
ATLC NEAR 33N76W IS RESULTING IN E TO SE WINDS OF 15 TO 20 KT
ACROSS MUCH OF THE GULF REGION. THESE WINDS ARE ADVECTING
ABUNDANT LOW-LEVEL MOISTURE ACROSS THE GULF REGION...RESULTING
IN INCREASED INSTABILITY ACROSS THE NRN GULF. THIS INSTABILITY
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 90W. 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
EARLY SUNDAY...AND EXTEND FROM THE FLORIDA BIG BEND TO THE BAY
OF CAMPECHE ON MONDAY. INCREASED NLY WINDS AND RELATIVELY COOLER
AND DRIER CONDITIONS ARE FORECAST N OF THIS FRONT.

CARIBBEAN SEA...
A SURFACE RIDGE BUILDING 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 NRN CARIBBEAN THAT
EXTENDS FROM THE W ATLC ACROSS HISPANIOLA NEAR 19N70W TO 18N77W
17N82W TO 20N87W. SCATTERED SHOWERS ARE ALSO NOTED SE OF THE
FRONT OVER 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 33N76W. 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 61W IS ASSOCIATED WITH A SURFACE COLD FRONT THAT EXTENDS
FROM NE OF THE DISCUSSION AREA TO 32N50W TO 25N58W TO NW OF
HISPANIOLA NEAR 20N67W. LOW LEVEL CONVERGENCE AND ATMOSPHERIC
INSTABILITY ARE SUPPORTING SCATTERED SHOWERS WITHIN 75 NM EITHER
SIDE OF THIS FRONT S OF 25N WITH NUMEROUS SHOWERS AND ISOLATED
TSTMS WITHIN 120 NM EITHER SIDE OF THIS FRONT N OF 25N. W OF
THIS FRONT...A TRIO OF WEAK 1014 MB SURFACE LOWS EXTEND ALONG A
STATIONARY FRONT THAT LIES WITHIN A LINE FROM 30N56W SW TO
25N65W. A COLD FRONT EXTENDS FROM THE SWRN LOW NEAR 25N65W TO
23N70W TO 25N73W. LOW LEVEL CONVERGENCE IS SUPPORTING SCATTERED
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 1028 MB SURFACE HIGH NEAR 33N25W. ACROSS
THE TROPICAL ATLC...AN UPPER LEVEL RIDGE IS S OF 10N E OF 60W
WITH UPPER LEVEL HIGHS CENTERED NEAR 5N11W AND 4N50W. UPPER
LEVEL DIVERGENCE ASSOCIATED WITH THESE FEATURES IS ENHANCING THE
CONVECTION ASSOCIATED WITH THE ITCZ OF WHICH IS LOCATED MAINLY S
OF THE EQUATOR.

$$
HUFFMAN



This weather bulletin was brought to you by:
www.nashvilleweather.net