[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 110526
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST SUN NOV 11 2007

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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0445 UTC.

...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 55W/56W S OF 13N MOVING W 15-20 KT. WAVE
REMAINS EMBEDDED WITHIN A SURGE OF AFRICAN DUST AND IS MOVING
OVER EASTERN PORTION OF SOUTH AMERICA. SCATTERED SHOWERS/
ISOLATED THUNDERSTORMS ARE FROM 7N-10N BETWEEN 55W-61W.

TROPICAL WAVE IS ALONG 68W S OF 14N BASED ON SURFACE
OBSERVATIONS MOVING W NEAR 10 KT. WAVE IS MOSTLY INLAND OVER
SOUTH AMERICA AND HAS NO ASSOCIATED SHOWERS/CONVECTION.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 9N10W 6N20W 7N32W 6N41W 4N52W.
SCATTERED MODERATE/STRONG CONVECTION COVERS THE AREA FROM 2N-9N
BETWEEN 17W-34W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG
CONVECTION ARE FROM 1N-8N BETWEEN 3W-13W INCLUDING THE COASTAL
REGIONS OF SW AFRICA AND WITHIN 120 NM N OF THE ITCZ AXIS FROM
34W-28W.

DISCUSSION...

GULF OF MEXICO...
BROAD UPPER RIDGE EXTENDING ALONG THE E COAST OF MEXICO AND THE
W GULF ALONG 97W TO INLAND OVER THE CENTRAL US. UPPER LEVEL
TROUGH IS MOSTLY IN THE W ATLC BUT COVERS THE E GULF E OF 87W.
DRY STABLE AIR COVERS THE ENTIRE GULF. A SURFACE RIDGE EXTENDS
OVER THE GULF INTO THE W ATLC ANCHORED OVER WEST VIRGINIA GIVING
THE W GULF RETURN FLOW AND PRODUCING SOME LOW LEVEL ISOLATED
SHOWERS...THUS MOSTLY FAIR SKIES DOMINATE THE GULF TONIGHT.

CARIBBEAN SEA...
THE MAIN FOCUS OF THE NIGHT IS A 1008 MB LOW IN THE SW CARIBBEAN
NEAR 11N79W WITH A SURFACE TROUGH EXTENDING NW TO JUST S OF THE
CAYMAN ISLANDS NEAR 18N81W. A SURFACE TROUGH FROM THE W/CENTRAL
ATLC EXTENDS ACROSS HAITI TO S OF JAMAICA 17N76W. THIS IS GIVING
THE AREA SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 120 NM
OF A LINE FROM ACROSS HISPANIOLA NEAR 19N71W ALONG 15N78W TO THE
COAST OF PANAMA AND COSTA RICA NEAR 9N82W. BROAD UPPER RIDGE
COVERS THE W CARIBBEAN ANCHORED NEAR 13N75W WHILE AN UPPER RIDGE
COVERS THE E CARIBBEAN ANCHORED IN THE W TROPICAL ATLC NEAR
16N60W. THIS IS PRODUCING AN UPPER LEVEL INVERTED TROUGH OVER
THE CENTRAL CARIBBEAN ALONG 70W/71W. ALTHOUGH THE SURFACE
LOW/TROUGH ARE SHOWING A FEW SIGNS OF ORGANIZATION...NO
SIGNIFICANT DEVELOPMENT IS ANTICIPATED BEFORE IT MOVES INLAND
OVER CENTRAL AMERICA IN THE NEXT DAY OR TWO. HOWEVER...IT COULD
PRODUCE LOCALLY HEAVY RAINFALL OVER PORTIONS OF PANAMA...COSTA
RICA...AND NICARAGUA DURING THE NEXT FEW DAYS.

ATLANTIC OCEAN...
BROAD UPPER TROUGH COVERS THE W ATLC WITH THE UPPER LOW OVER THE
CANADIAN MARITIMES AND EXTENDING W INTO THE E GULF OF MEXICO.
THE ASSOCIATED COLD FRONT EXTENDS ACROSS BERMUDA TO 29N69W. DUE
TO THE DRY AIR OVER THE AREA FROM 22N-30N W OF 65W...LITTLE IN
THE WAY OF SHOWERS CAN DEVELOP. A SECOND SURGE IN THE FORM OF A
SURFACE TROUGH EXTENDS ALONG 32N70W SW TO 28N77W WITH OVERCAST
LOW/MID CLOUDS WITH POSSIBLE ISOLATED SHOWERS ARE WITHIN 75 NM
EITHER SIDE OF THE SURFACE TROUGH. A JET STREAM WITH WINDS
ESTIMATED TO BE 70 TO 100 KT EXTENDS ALONG THE EASTERN EDGE OF
THE UPPER TROUGH FROM NEAR 22N73W TO BEYOND 32N54W. A REMNANT
COLD FRONT FROM AN UPPER SYSTEM THAT IS WELL N OF THE REGION
EXTENDS INTO THE W/CENTRAL ATLC NEAR 32N48W SW TO 24N60W
CONTINUING AS A SURFACE TROUGH ALONG 20N70W THEN ACROSS HAITI
INTO THE CARIBBEAN. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE
WITHIN 180 NM OF THE COLD FRONT WITH SOME SCATTERED SHOWERS S OF
21N TO OVER HISPANIOLA BETWEEN 68W-72W. AN UPPER HIGH IS IN THE
W TROPICAL ATLC NEAR 16N60W EXTENDING AN UPPER RIDGE NE ALONG
21N53W TO BEYOND 32N37W. A WEAK UPPER LOW IS UNDERCUTTING THE
UPPER RIDGE ABOVE CENTERED NEAR 14N45W. A NARROW UPPER TROUGH IS
OVER THE FAR E ATLC N OF 23N E OF 25W TO THE COAST OF W AFRICA
WITH NO ASSOCIATED SURFACE FEATURES. ZONAL WESTERLY UPPER FLOW
DOMINATES THE REMAINDER OF THE TROPICAL ATLC S OF 18N E OF 40W.
BROAD AREA OF AFRICAN DUST COVERS MOST OF THE TROPICS N OF THE
ITCZ AND IS SPREADING ACROSS WITH WINDWARD ISLANDS TONIGHT
ALTHOUGH IT IS BECOMING LESS DENSE E OF THE CAPE VERDE ISLANDS.

$$
WALLACE




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