[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 151118
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST SAT DEC 15 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1045 UTC

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 6N8W 5N27W 6N38W 3N51W. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 150 NM S OF THE
ITCZ AXIS FROM 30W-46W...WITHIN 90 NM N OF THE ITCZ AXIS FROM
30W-35W...AND WITHIN 150 NM N OF THE ITCZ AXIS 35W-44W. CLUSTERS
OF SCATTERED MODERATE CONVECTION ARE WITHIN 90 NM OF THE ITCZ
AXIS FROM 17W-30W.

DISCUSSION...
GULF OF MEXICO...
A DISSIPATING STATIONARY FRONT IS ALONG THE N GULF COAST
EXTENDING ACROSS SE GEORGIA INTO THE GULF JUST E OF PANAMA CITY
FLORIDA S OF LOUISIANA COAST INTO E TEXAS NEAR HOUSTON AS A WARM
FRONT. THIS FRONT REMAINS EMBEDDED WITHIN SOME RATHER DRY AIR SO
NO SHOWER ACTIVITY IN THE GULF. HOWEVER...A FRONTAL BOUNDARY
INLAND OVER S TEXAS IS APPROACHING THE TEXAS COAST WITH SOME
ISOLATED SHOWERS WITHIN 60 NM OF THE TEXAS COAST AND NE MEXICO N
OF 25N. THE REMNANTS OF OLGA ARE IN THE W CARIBBEAN ALONG THE
COAST OF THE YUCATAN EXTENDING A SURFACE TROUGH NNE THROUGH THE
YUCATAN CHANNEL NEAR 22N86W OVER FLORIDA NEAR TAMPA GENERATING A
BROAD AREA OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 29N
E OF 90W ACROSS FLORIDA. A BROAD UPPER RIDGE EXTENDS FROM THE W
CARIBBEAN THROUGH THE YUCATAN CHANNEL AND ACROSS FLORIDA INTO
THE W ATLC COVERING THE ENTIRE GULF ENHANCING THE ACTIVITY
ASSOCIATED WITH THE SURFACE TROUGH ABOVE.

CARIBBEAN SEA...
THE REMNANTS OF OLGA...A 1006 MB LOW...IS IN THE W CARIBBEAN
ALONG THE COAST OF THE YUCATAN NEAR 20.5N86.5W EXTENDING A
SURFACE TROUGH NNE INTO THE GULF OF MEXICO THROUGH THE YUCATAN
CHANNEL NEAR 22N86W GENERATING SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS N OF 19N W OF 84W. THIS LOW IS EXPECTED TO
CONTINUE TO MOVE NW AND IS CURRENTLY MOVING INTO THE GULF OF
MEXICO AND WILL MERGE WITH AN APPROACHING FRONTAL BOUNDARY LATE
TODAY INTO TONIGHT. AN UPPER HIGH IS INLAND OVER CENTRAL AMERICA
EXTENDING AN UPPER RIDGE THROUGH THE YUCATAN CHANNEL INTO THE
GULF OF MEXICO COVERING THE W CARIBBEAN W OF 78W. AN UPPER
TROUGH EXTENDS FROM PUERTO RICO SW TO AN UPPER LOW ALONG THE N
COAST OF COLOMBIA COVERING THE REMAINDER OF THE CARIBBEAN. THE
UPPER AIR OVER MOST OF THE CARIBBEAN IS MAINLY DRY WITH SOME
WEAK UPPER DIVERGENCE GENERATING SCATTERED SHOWERS WITHIN 75 NM
OF LINE FROM 12N81W TO 20N85W AND SOME SCATTERED SHOWERS/
ISOLATED THUNDERSTORMS S OF 11N FROM COLOMBIA TO COSTA RICA.

ATLANTIC OCEAN...
AN UPPER RIDGE ANCHORED OVER CENTRAL AMERICA EXTENDS ACROSS
FLORIDA INTO THE W ATLC TO NEAR 28N74W COUPLED WITH A FRONTAL
BOUNDARY JUST N OF THE REGION IS GENERATING SCATTERED SHOWERS N
OF 27N W OF 71W TO THE COAST OF FLORIDA/GEORGIA. THE UPPER
TROUGH THAT EXTENDS FROM PUERTO RICO COVERS THE REMAINDER OF THE
W ATLC WITH DRY STABLE AIR. BROAD UPPER TROUGH COVERS THE
CENTRAL AND E ATLC E OF 45W WITH THE SURFACE TROUGH EXTENDING
INTO THE E ATLC THROUGH 32N29W SW TO 23N45W. A 1015 MB SURFACE
LOW IS EMBEDDED WITHIN THIS UPPER TROUGH W OF THE CANARY ISLANDS
NEAR 27N21W WITH A SURFACE TROUGH EXTENDING SW TO 21N31W AND E
ACROSS THE CANARY ISLANDS TO OVER S MOROCCO AFRICA BUT DUE TO
THE DRY STABLE AIR ONLY WIDELY ISOLATED LOW LEVEL SHOWERS ARE
WITHIN 120 NM SE OF THE SURFACE LOW. UPPER WESTERLY ZONAL FLOW
COVERS THE TROPICS AND A JET STREAM WITH ESTIMATED WINDS OF 80
TO 100 KT EXTENDING ALONG 15N45W TO THE CAPE VERDE ISLANDS THEN
NE TO OVER AFRICA NEAR 21N16W. OTHERWISE THE ATLC REMAINS RATHER
TRANQUIL TONIGHT WITH SURFACE RIDGE DOMINATING THE AREA FROM
40W-75W ANCHORED BY A 1026 MB HIGH NEAR 29N56W.

$$
WALLACE



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