[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 271741
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT TUE MAR 27 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 8N10W 3N20W ALONG THE EQUATOR FROM
28W-40W THEN ALONG 2N45W 1N51W. CLUSTERS OF SCATTERED MODERATE
TO ISOLATED STRONG CONVECTION ARE WITHIN 120/150 NM OF THE AXIS
W OF 23W TO INLAND OVER SOUTH AMERICA.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL LOW OVER NE TEXAS IS MOVING OUT TO THE NE WITH
THE UPPER TROUGH EXTENDING SW ACROSS THE NW CORNER OF THE GULF.
THE LOW IS PRODUCING SHOWERS WITH SCATTERED THUNDERSTORMS INLAND
MAINLY OVER E TEXAS AND NW LOUISIANA. UPPER RIDGE EXTENDS FROM
THE E PACIFIC REGION ACROSS S MEXICO AND THE YUCATAN PENINSULA
INTO THE E HALF OF THE GULF AND THE FLORIDA PENINSULA. WV
IMAGERY SHOWS A PLUME OF UPPER LEVEL MOISTURE CROSSING CENTRAL
MEXICO AND THE GULF TO OVER THE SE US GENERATING ISOLATED
SHOWERS MAINLY OVER THE NE QUADRANT OF THE GULF. MODERATE/STRONG
EASTERLY SURFACE WINDS FROM THE W ATLC ACROSS THE STRAITS OF
FLORIDA AND SE GULF CONTINUE TO BRING IN ISOLATED SHOWERS OVER
EXTREME S FLORIDA...THE FLORIDA KEYS AND THROUGH THE STRAITS OF
FLORIDA E OF 83W. SURFACE RIDGE DOMINATES THE GULF WITH A 1025
MB HIGH OVER THE SE US. THIS WEATHER PATTERN IS FORECAST TO
PERSIST MOST OF THE WORK WEEK. A COLD FRONT WILL MOVE OFF THE TX
COAST FRI NIGHT.

CARIBBEAN...
UPPER RIDGE IN THE GULF OF MEXICO EXTENDS OVER THE NW CARIBBEAN
AND CENTRAL AMERICA W OF 80W. AN UPPER LOW IS JUST N OF
HISPANIOLA NEAR 20N72W WITH THE UPPER TROUGH CONTINUING S TO
NEAR 12N76W. STRONG SUBSIDENCE/DRY AIR IS FOUND W OF THE TROUGH
AXIS WHILE ABUNDANT UPPER LEVEL MOISTURE IS BEING TRANSPORTED
FROM NORTH SOUTH AMERICA INTO THE E CARIBBEAN BY A STRONG SW
UPPER FLOW AHEAD OF THE TROUGH. A SURFACE REFLECTION IN THE FORM
OF A SURFACE TROUGH EXTENDS FROM 22N68W TO 15N70W TO N COLOMBIA.
THIS FEATURE IS PRODUCING AREAS OF SHOWERS WITH EMBEDDED TSTMS
OVER PUERTO RICO AND THE VIRGIN/LEEWARD ISLANDS AND JUST N OF
HISPANIOLA. THE SAN JUAN DOPPLER RADAR SHOWS MOST OF THE
CONVECTIVE ACTIVITY OVER THE VIRGIN ISLANDS. ACCORDING TO THE
GFS MODEL...A BAND OF MOISTURE WILL PERSIST OVER THE NE
CARIBBEAN DURING THE NEXT SEVERAL DAYS KEEPING THE LIKELIHOOD OF
RAIN OVER PUERTO RICO AND THE VIRGIN/LEEWARD ISLANDS. REMAINDER
OF THE CARIBBEAN AND THE WINDWARD ISLANDS ARE UNDER A BROAD
UPPER RIDGE THAT IS ANCHORED IN THE TROPICAL ATLC NEAR 4N4OW.
HIGH PRES N OF THE AREA IS GENERATING STRONG EASTERLY WINDS N OF
15N W OF 75W WHILE THE REMAINDER OF THE CARIBBEAN IS UNDER
LIGHT/MODERATE SURFACE WINDS.

ATLANTIC...
UPPER RIDGE IN THE GULF OF MEXICO EXTENDS OVER THE FAR W ATLC W
OF 75W. E OF RIDGE...A DEEP UPPER TROUGH EXTENDS SOUTHWEST FROM
30N65W ACROSS HISPANIOLA AND THE CENTRAL CARIBBEAN SEA TO
PANAMA. THIS TROUGH WILL MOVE EAST AND WEAKEN DURING THE NEXT 24
HOURS. THE ASSOCIATED COLD FRONT ENTERS THE REGION NEAR 31N42W
EXTENDING SW ALONG 26N50W TO 21N58W. EARLIER QUIKSCAT PASS
SHOWED CLEARLY THE WIND SHIFT ASSOCIATED WITH THE FRONT.
STRATOCUMULUS CLOUDS ARE NW OF FRONT. SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS ARE WITHIN 200 NM E OF THE FRONT N OF 27N. THE
SURFACE TROUGH MENTIONED IN THE CARIBBEAN SECTION IS ALSO
GENERATING SOME SHOWERS OVER THE E BAHAMAS AND THE REGIONAL
COASTAL WATERS. BROAD SURFACE RIDGE DOMINATES THE E ATLC E OF
THE COLD FRONT WITH A 1031 MB HIGH LOCATED S OF THE AZORES. AN
UPPER HIGH SITUATED NEAR 4N40W EXTENDS A RIDGE MAINLY NWD TO
BEYOND 32N35W COVERING THE TROPICAL ATLC AND THE SE CARIBBEAN.
UNDER THE INFLUENCE OF THIS SYSTEM...THE REMAINDER OF THE ATLC
REMAINS RATHER TRANQUIL WITH FAIR WEATHER CLOUDS. AN UPPER
TROUGH ENTERS THE FORECAST AREA SOUTH OF THE MADEIRA ISLANDS
THEN CONTINUES SW TO JUST N OF THE CAPE VERDE ISLANDS. UPPER DRY
AIR/SUBSIDENCE IS N OF 20N E OF 27W TO THE AFRICAN COAST.
VISIBLE SATELLITE IMAGERY AND THE SAHARAN AIR LAYER ANALYSIS
FROM CIMSS SHOW AN AREA OF AFRICAN DUST REACHING 50W.

$$
GR






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