[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 051742
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST WED DEC 05 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 4N10W 3N20W 2N40W EQ44W 2S48W.
SCATTERED MODERATE CONVECTION IS WITHIN 120 NM OF THE AXIS
BETWEEN 34W-40W. ISOLATED MODERATE IS WITHIN 180 NM N OF THE
AXIS BETWEEN 10W-32W.

DISCUSSION...

THE GULF OF MEXICO...
WEAK SFC PRES GRADIENT DOMINATES THE GULF WITH A 1017 MB HIGH
ALONG THE MEXICAN COAST BETWEEN TAMPICO AND VERACRUZ. A SFC
TROUGH IS ANALYZED OVER THE EASTERN GULF ALONG 85W FROM 24N-30N.
THIS TROUGH WILL MOVE SE THIS AFTERNOON AND DISSIPATE TONIGHT
WHILE WEAK HIGH PRES BUILDS OVER THE NRN GULF. GOES-10 SATELLITE
IMAGERY SHOWS SOME CLOUDINESS BETWEEN THIS FEATURE AND THE WEST
COAST OF FLORIDA AS WELL AS COLD AIR STRATOCUMULUS CLOUDS OVER
THE CENTRAL AND NE PORTIONS OF THE GULF. ALOFT...A WELL DEFINED
CUT-OFF LOW IS SPINNING OVER CENTRAL MEXICO LIKELY ADVECTING A
PLUME OF CLOUDINESS INTO THE WRN GULF. THE REMAINDER OF THE
REGION IS UNDER W TO NW UPPER FLOW INDUCING STABLE CONDITIONS.
THE NEXT COLD FRONT WILL MOVE INTO THE NORTHERN GULF WATERS
TONIGHT AND THU.

THE CARIBBEAN SEA...
WEAK SFC PRES GRADIENT ALSO COVERS THE CARIBBEAN SEA. A SFC
RIDGE FROM THE ATLC CLIPS THE NE CARIBBEAN. SCATTERED SHOWERS
AND ISOLATED TSTMS ARE SEEN OVER THE SW PORTION OF THE SEA DUE
TO THE PRESENCE OF THE COLOMBIAN/PANAMANIAN LOW AND THE CLOSE
PROXIMITY OF THE EPAC ITCZ. A 1011 MB LOW IS NEAR 10N80W.
TYPICAL PATCHES OF LOW LEVEL MOISTURE DOT THE AREA. THE SAN JUAN
DOPPLER RADAR SHOWS SCATTERED SHOWERS AND ISOLATED TSTMS MAINLY
SOUTH OF THE ISLAND. WINDS REMAINS LIGHT ACROSS THE ENTIRE
REGION DUE TO THE WEAK PRES PATTERN BROUGHT ABOUT BY THE FRONTAL
BOUNDARY N OF THE AREA. STRONG HIGH PRES MOVING EAST ACROSS THE
EASTERN SEABOARD LATE THU THROUGH FRI WILL BRING INCREASING
WINDS AND BUILDING SEAS TO THE ENTIRE BASIN THROUGH THE REST
OF THE WEEK.

THE ATLANTIC OCEAN...
A WEAK LOW PRES HAS DEVELOPED OVER THE W ATLC JUST N OF THE NW
BAHAMAS. A COLD FRONT RUNS FROM THE LOW ACROSS THE BAHAMAS INTO
THE STRAITS OF FLORIDA. A WARM FRONT ALSO EXTENDS WWD FROM THE
LOW TO NEAR 26N72W AND CONTINUES AS COLD FRONT BEYOND 31N58W. A
THIN BAND OF LOW TO MID CLOUDS AND ISOLATED SHOWERS ARE
ASSOCIATED WITH THE FRONTAL BOUNDARY. THE LOW IS EXPECTED TO
MERGE WITH ANOTHER LOW PRES SYSTEM LOCATED JUST OFFSHORE THE
CAROLINAS. A QUIKSCAT PASS FROM THIS MORNING REVEALED 20-25 KT
SW WINDS WITHIN 180 NM AHEAD OF THE FRONT N OF 27N. FARTHER
E...A PERSISTENT 1014 MB LOW IS STILL SPINNING IN THE CENTRAL
ATLC NEAR 27N51W...WHERE THE LOWEST PRES WAS FOUND. THIS LOW HAS
BEEN MEANDERING FOR THE PAST FEW DAYS...BUT NOW APPEARS TO BE
PULLING NWD AND MAY EVENTUALLY MERGE WITH THE APPROACHING FRONT.
SCATTERED SHOWERS AND ISOLATED TSTMS ARE NOTED JUST N OF THE LOW
ALONG AN ASSOCIATED TROUGH AXIS. ANOTHER WEAK NEARLY STATIONARY
SFC TROUGH IS ALONG 58W FROM 11N-19N. A BATCH OF CLOUDS WITH
POSSIBLE SHOWERS IS FROM 12N-16N BETWEEN 54W-60W.  A SFC RIDGE
DOMINATES THE REMAINDER OF THE FORECAST AREA ANCHORED ON A 1032
MB HIGH LOCATED WEST AND CLOSE TO THE MADEIRA ISLANDS.  IN THE
MID AND UPPER LEVELS ABOVE THE CENTRAL AND E ATLC...A HIGHLY
AMPLIFIED RIDGE/TROUGH PATTERN EXISTS IN THE SUBTROPICS AND
MID-LATITUDES. THESE FEATURES ARE ENHANCING STRONG ZONAL FLOW IN
THE TROPICS WHICH IS ADVECTING A CONSIDERABLE AMOUNT OF UPPER
LEVEL MOISTURE. WV IMAGERY SHOWS A WIDE BAND OF TRANSVERSE HIGH
CLOUDS STRETCHING BETWEEN THE LESSER ANTILLES AND THE WEST COAST
OF AFRICA SOUTH OF 20N...AND CROSSING THE CAPE VERDE ISLANDS.

$$
GR





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