[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 112335
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT WED APR 11 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN
SECTIONS OF SOUTH AMERICA...AND THE 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 5N10W 4N25W 2N35W CROSSING THE
EQUATOR AT 44W INTO NE BRAZIL. WIDELY SCATTERED MODERATE
CONVECTION IS WITHIN 120NM N AND 80NM S OF THE AXIS BETWEEN
22W-32W. CLUSTERS OF MODERATE TO STRONG CONVECTION ARE OVER SW
AFRICA BETWEEN 6N-12N JUST WEST OF THE PRIME MERIDIAN AND NEAR
8N10W. SIMILAR CONVECTION IS OVER NE BRAZIL.

...DISCUSSION...

GULF OF MEXICO...
AS OF 21Z...A COLD FRONT IS ENTERING THE NW CORNER OF THE GULF.
THIS FEATURE WILL EXTEND FROM FLORIDA PANHANDLE TO S TEXAS LATE
TONIGHT THEN STALL FROM TAMPA BAY TO S TEXAS THU AND DISSIPATE.
A PREFRONTAL TROUGH LIES ALONG 29N86W 25N90W TO THE MEXICAN
COAST JUST N OF TAMPICO. A NARROW LINE OF LOW CLOUDS AND A SW TO
NW WIND SHIFT DEFINE THIS SFC TROUGH. AN AREA OF SHOWERS AND
TSTMS IS DEVELOPING OVER THE NE CORNER OF THE GULF. MORE
NUMEROUS SHOWERS/TSTMS ARE NOTED ACROSS THE STRAIT OF FLORIDA
AND BETWEEN CENTRAL CUBA AND THE BAHAMAS...ASSOCIATED WITH
DYNAMICS AHEAD OF A FLATTENING MID TO UPPER SHORTWAVE TROUGH
LOCATED OVER THE FAR WEST ATLC. A DRIER AND MORE STABLE
ATMOSPHERE IS GRIPPING THE FLORIDA PENINSULA BEHIND THE SHORT
WAVE TROUGH WHILE A ZONAL FLOW DOMINATES THE GULF. ANOTHER COLD
FRONT...THIS ONE EXPECTED TO BE MUCH STRONGER...IS FORECAST TO
MOVE INTO THE NW GULF EARLY SAT INCREASING THE CHANCE OF RAIN
AHEAD OF IT AND BRINGING ABOUT A MUCH COOLER AIRMASS THIS
WEEKEND. WINDS/SEAS WILL ALSO BE STRONGER BOTH IN ADVANCE AND
BEHIND THIS NEXT FRONT.

THE CARIBBEAN SEA...
A BROAD MID TO UPPER LEVEL RIDGE COVERS THE REGION ANCHORED BY
AN UPPER HIGH CENTERED OVER THE SW CARIB NEAR 12N75W. DIFFLUENCE
ON THE W SIDE OF THIS UPPER ANTICYCLONE IS ENHANCING SCATTERED
SHOWERS/TSTMS OVER PARTS OF NICARAGUA AND COSTA RICA WITH A
CLUSTER A MODERATE CONVECTION OVER THE NW PORTION OF COSTA RICA.
ELSEWHERE AT THE SFC...HIGH PRES NE OF THE AREA IS PRODUCING
MODERATE TO FRESH ELY TRADES ACROSS THE E AND CENTRAL CARIB
VEERING TO THE SE IN THE NW CARIB AROUND THE SW PORTION OF THE
RIDGE. VIS SAT IMAGERY SHOWS VERY WELL DEFINED LOW LEVELS CLOUDS
LINES OVER THE NW CARIBBEAN MOVING INTO CUBA...UNDER THE SE WIND
FLOW. AN AREA OF SHOWERS/TSTMS IS AFFECTING CENTRAL CUBA. THE
KEY WEST DOPPLER RADAR IS SHOWING RAINFALL AMOUNTS BETWEEN 2-3
INCHES (50-75 MM) IN SOME SPOTS. AS MENTIONED BEFORE...A SHORT
WAVE TROUGH IS SUPPORTING THIS CONVECTIVE ACTIVITY OVER CUBA. A
SFC TROUGH IS ANALYZED JUST AHEAD OF THIS SHOWER/TSTMS ACTIVITY
AND GOES FROM 26N72W TO CENTRAL CUBA NEAR 22N78W. THE ATLC RIDGE
NE OF AREA WILL MAINTAIN THE TRADE WINDS THROUGH FRI.

ATLANTIC OCEAN...
AS WAS PREDICTED BY THE COMPUTER MODELS...A 1008 MB SFC LOW
FORMED OFF THE COAST OF NRN FLORIDA THIS MORNING. AS OF 21Z...IT
IS LOCATED 31N78W. A FRONTAL SYSTEM EXTENDS EWD FROM THE LOW
ALONG 31N WEST OF 60W...THEN CONTINUES NE AS A COLD FRONT OVER
THE ATLC OCEAN TO A 996 MB SFC LOW SITUATED WELL N OF THE
FORECAST AREA. UPPER DIFFLUENCE BETWEEN THE SHORTWAVE TROUGH
EXTENDING OVER THE FAR W ATLC AND THE RIDGING EXTENDING N FROM
THE CARIBBEAN IS SUPPORTING A BROAD AREA OF CONVECTION OVER THE
WRN ATLC...INCLUDING ALSO THE BAHAMAS AND CENTRAL CUBA. MUCH OF
THE REMAINDER OF THE E AND CENTRAL ATLC SFC PATTERN IS DOMINATED
BY A 1025MB HIGH S OF THE AZORES NEAR 35N26W. THIS IS PRODUCING
LIGHT TO MODERATE TRADES AND FAIR WEATHER OVER MUCH OF THE AREA
E OF 60W. UPPER TROUGHING EXTENDING SW FROM THE CANARY ISLANDS
TO THE DEEP TROPICS NEAR 10N35W IS INTERACTING WITH RIDGING
OVER AFRICA TO PRODUCE A SWLY JET SE OF THE CAPE VERDE ISLANDS.
DRY AIR IS PRESENT ALONG THE TROUGH AXIS WITH A BROAD BAND OF
UPPER LEVEL MOISTURE SPREADING NE FROM NE SOUTH AMERICA TO
WESTERN AFRICA.

$$
GR




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