[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 112344
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT TUE MAR 11 2008

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
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 7N12W 3N20W CROSSING THE EQUATOR
NEAR 24W THEN ALONG 3S30W TO 3S40W. CLUSTERS OF SCATTERED
MODERATE/STRONG CONVECTION ARE FROM EQUATOR TO THE COAST OF SW
AFRICA BETWEEN THE PRIME MERIDIAN AND 14W. SIMILAR CONVECTION IS
SEEN OVER NE BRAZIL.

...DISCUSSION...

GULF OF MEXICO...
A WEAK SHORTWAVE TROUGH OVER THE LOWER MISSISSIPPI VALLEY
SUPPORTS A COLD FRONT THAT IS MOVING EWD ACROSS THE CENTRAL
GULF. AT 2100 UTC...THE FRONT EXTENDS FROM A 1013 MB LOW LOCATED
NEAR 28N87W THROUGH THE CENTRAL GULF INTO THE BAY OF CAMPECHE.
THE COLD FRONT SHOULD ONLY MAKE SLOW SEWD PROGRESS TONIGHT AND
EARLY WED...UNTIL A SECOND SOUTHERN STREAM SHORTWAVE MOVING
THROUGH THE SOUTHERN PLAINS REACHES THE GULF COAST EARLY WED AND
DRIVES THE FRONT THROUGH THE REMAINDER OF THE GULF AND SOUTH
FLORIDA LATE WED. HIGH PRES CURRENTLY OVER TEXAS WILL BUILD IN
GIVING THE AREA LIGHT TO MODERATE NLY FLOW. MEANWHILE...A
DISSIPATING FRONTAL BOUNDARY REMAINS NEARLY STATIONARY ACROSS
SOUTH FLORIDA AND THE KEYS GENERATING SOME CLOUDINESS. DOPPLER
RADAR SHOWS SCATTERED SHOWERS AND TSTMS OVER THE STRAITS OF
FLORIDA JUST SOUTH OF THE FLORIDA KEYS AS WELL AS SOME SHOWER
ACTIVITY OVER THE NE CORNER OF THE GULF AND THE FLORIDA
PANHANDLE ASSOCIATED WITH THE ABOVE MENTIONED SFC LOW.
ADDITIONAL SHOWERS AND ISOLATED TSTMS ARE DEVELOPING OVER THE
YUCATAN PENINSULA AND REGIONAL WATERS ASSOCIATED WITH A SFC
TROUGH THAT RUNS FROM 24N87W TO 19N89W. ALOFT...NEARLY WLY UPPER
LEVEL WINDS DOMINATES THE ENTIRE GULF. A JET STREAM BRANCH WITH
CORE WINDS OF 90-110 KT EXTENDS ACROSS THE N GULF WATERS AND N
FLORIDA INTO THE W ATLC.

CARIBBEAN SEA...
A MID TO UPPER-LEVEL RIDGE ANCHORED ON A HIGH LOCATED JUST SOUTH
OF JAMAICA AT UPPER LEVELS CONTINUES TO DOMINATE THE WEATHER
PATTERN ACROSS THE CARIBBEAN SEA AND CENTRAL AMERICA...WITH AN
AXIS ALONG 15N-16N. AN UPPER TROUGH FROM THE CENTRAL ATLC
EXTENDS INTO THE FAR SE CARIBBEAN AND CENTRAL VENEZUELA. STRONG
SUBSIDENCE IS ASSOCIATED WITH THESE UPPER FEATURES. AS USUAL...
PATCHES OF LOW LEVEL MOISTURE EMBEDDED IN THE TRADE WIND FLOW
ARE MOVING ACROSS THE AREA PRODUCING ISOLATED TO SCATTERED
PASSING SHOWERS PARTICULARLY OVER JAMAICA AND COASTAL WATERS.
SIMILAR CLOUDINESS IS OBSERVED OVER CENTRAL AMERICA BETWEEN WEST
PANAMA AND NE HONDURAS. WEAK ATLC HIGH PRES WILL MAINTAIN MAINLY
LIGHT TO MODERATE TRADES THROUGH FRI. THE GULF FRONT DESCRIBED
ABOVE SHOULD REACH THE YUCATAN CHANNEL EARLY WED.

ATLANTIC OCEAN...
A DEEP LAYERED TROUGH IS OVER THE WESTERN ATLC WITH THE
ATTENDANT COLD FRONT ENTERING THE FORECAST AREA NEAR 32N50W THEN
CONTINUES SW TO NEAR 28N60W. AT THIS POINT...THE FRONT BECOMES
STATIONARY CROSSING AS A DIFFUSE FRONTAL BOUNDARY THE NW BAHAMAS
AND SOUTH FLORIDA. A BROKEN BAND OF LOW/MID CLOUDS IS RELATED TO
THE FRONT MAINLY EAST OF 70W. A WEAK 1022 MB HIGH IS BEHIND THE
FRONT...WEST OF BERMUDAS NEAR 32N68W. THIS HIGH WILL MOVE EWD AS
A COLD FRONT ENTERS THE W ATLC WED MORNING. FARTHER EAST...A
WEAK SFC TROUGH...REFLECTION OF AN UPPER TROUGH OVER THE
CENTRAL ATLC EXTENDS FROM 32N44W TO 23N48W. LITTLE OR NO SHOWER
ACTIVITY IS ASSOCIATED WITH THE TROUGH DUE TO THE DRY AND STABLE
ENVIRONMENT OVER THE AREA. A 1026 MB HIGH CENTERED E OF THE
AZORES EXTENDS A RIDGE ACROSS THE E ATLC. THE COMBINATION OF
THIS HIGH AND LOWER PRES OVER AFRICA IS PRODUCING A SWATH OF NE
WINDS UP TO 25 KT BETWEEN THE CANARY/CAPE VERDE ISLANDS AND THE
WEST COAST OF AFRICA. ELSEWHERE...MID TO UPPER LEVEL HIGH
PRESSURE OVER THE CARIBBEAN THIS EVENING SHOULD BUILD EWD INTO
THE TROPICAL ATLC MIDDLE AND LATE WEEK...REPLACING THE CURRENT
SHORTWAVE TROUGH LYING FROM 27N37W TO 11N62W. A BROAD RIDGE
REMAINS OVER THE EASTERN ATLC WITH A HIGH LOCATED SW OF THE CAPE
VERDE ISLANDS. STRONG SWLY UPPER FLOW BETWEEN THESE UPPER
FEATURES IS ADVECTING ABUNDANT UPPER LEVEL MOISTURE FROM N SOUTH
AMERICA ALL THE WAY NE BEYOND 30N25W.

$$
GR



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