[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 130001
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT TUE MAR 12 2013

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...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL
ANALYSIS.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE GUINEA COAST IN AFRICA NEAR
10N14W TO 06N17W TO 04N19W. THE INTERTROPICAL CONVERGENCE ZONE
AXIS EXTENDS FROM 03N19W THEN ALONG 1N21W 1S30W TO THE NORTHERN
COAST OF BRAZIL NEAR 2S40W. SCATTERED MODERATE CONVECTION IS
FROM 04N-07N BETWEEN 10W-20W AS WELL AS FROM 02S-04N BETWEEN 20W-
29W.

...DISCUSSION...

GULF OF MEXICO...
A BROAD MIDDLE TO UPPER LEVEL LONGWAVE TROUGH EXTENDS FROM
CENTRAL USA TO THE EASTERN CONUS SUPPORTING A COLD FRONT THAT AS
OF 21 UTC ENTERS THE GULF BY FORT MYERS FLORIDA AND EXTENDS
ALONG 24N83W 21N85W THEN ALONG THE EASTERN COAST OF THE YUCATAN
PENINSULA TO 16N87W. MOSAIC DOPPLER RADAR IMAGERY INDICATE
WIDELY SCATTERED SHOWERS  OCCURRING IN THE STRAITS OF FLORIDA.
METAR OBSERVATIONS OVER WESTERN CUBA AND PENINSULA OF YUCATAN
INDICATE THAT RAINSHOWERS ARE OCCURRING IN THE YUCATAN CHANNEL.
NORTH-NORTHEASTERLY WIND FLOW SPREADS W OF 85W AND NORTHWESTERLY
WIND COVERS THE REMAINDER OF THE GULF WEST OF THE COLD FRONT. IN
TERMS OF WIND MAGNITUDE 5-10 KT WINDS SPREAD W OF 91W WHEREAS 15
KT WINDS DOMINATE W OF THAT MERIDIAN. THE FRONT IS EXPECTED TO
WEAKEN AND SWEEP EAST OF THE BASIN WITHIN 24 HOURS WHILE
NORTHEASTERLY WINDS WILL BE DOMINATING THE ENTIRE BASIN.

CARIBBEAN SEA...
AS OF 21 UTC...A PORTION OF THE COLD FRONT OVER THE EASTERN GULF
EXTENDS ALONG THE YUCATAN CHANNEL FROM 21N85W TO 20N86W AND
CONTINUES ALONG THE COASTAL WATERS OF THE EASTERN YUCATAN
PENINSULA TO 16N87W. ALSO NEAR THE COASTAL WATERS OF THE EASTERN
YUCATAN PENINSULA...A PREFRONTAL TROUGH EXTENDS FROM 20N86W TO
16N86W. METAR OBSERVATIONS OVER WESTERN CUBA AND THE YUCATAN
PENINSULA INDICATE SHOWERS ARE OCURRING ALONG THE FRONTAL
BOUNDARY AND COULD BE EXTENDING APPROXIMATELY 100 NM EAST OF THE
FRONT. IN THE MIDDLE TO UPPER LEVELS WESTERLY FLOW IS ACROSS THE
ENTIRE BASIN. WATER VAPOR IMAGERY INDICATE GENERALLY DRY AND
STABLE AIR ALOFT FOR THE REMAINDER OF THE CARIBBEAN WHICH IS
FAVORING FAIR WEATHER CONDITIONS. E-NE TRADEWINDS IN THE RANGE
OF 15-20 KT SPREAD OVER THE EASTERN...CENTRAL AND SOUTHERN
CARIBBEAN WHILE LIGHTER SOUTHEASTERLY WINDS DOMINATE THE WESTERN
CARIBBEAN AHEAD OF THE FRONT. OVER THE COURSE OF 24 HOURS...THE
FRONT WILL CONTINUE TO MOVE SLOWLY OVER THE NW CARIBBEAN WHILE
IT WEAKENS. RAINSHOWERS WILL CONTINUE OVER THE NW CARIBBEAN AND
EASTERLY TRADEWINDS OVER THE REST OF THE BASIN.

ATLANTIC OCEAN...
BROKEN TO OVERCAST SKIES ALONG WITH SCATTERED SHOWERS COVER THE
WEST ATLC N OF 24N W OF 74W. THIS PRECIPITATION IS ASSOCIATED TO
A COLD FRONT THAT AS OF 2100 UTC IS EXTENDING FROM 30N80W TO
29N81W AND THEN ACROSS FLORIDA TO THE YUCANTAN PENINSULA.
MOISTURE FROM THE E PACIFIC BEING ADVECTED BY UPPER LEVEL
WESTERLY FLOW IS ENHANCING THIS CONVECTION. TWO SURFACE TROUGHS
ARE OVER THE CENTRAL ATLC...THE WESTERNMOST TROUGH EXTENDS FROM
A 1000 MB LOW N OF THE DISCUSSION AREA TO 30N47W 26N48W 23N52W.
ISOLATED SHOWERS ARE UP TO 250 NM EAST OF THIS TROUGH AND 160 NM
WEST OF IT. THE EASTERNMOST TROUGH EXTENDS FROM 30N38W TO 21N44W
14N55W. NUMEROUS SHOWERS ARE OCCURING N OF 21N BETWEEN 33W AND
44W. SURFACE RIDGING IS OVER THE E ATLC N OF 15 E OF 37W
ANCHORED BY A 1018 MB HIGH LOCATED NEAR 27N23W. WITHIN 24
HOURS...THE FRONT ACROSS FLORIDA AND THE E GULF IS EXPECTED TO
WEAKEN AND MOVE OVER THE WEST ATLC.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
NR


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