[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 260557
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST SAT JAN 26 2008

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
0515 UTC

...THE ITCZ...

ITCZ AXIS IS CENTERED ALONG 6N10W 4N20W 2N30W 1N40W EQUATOR AT
44W INTO NE BRAZIL. SCATTERED MODERATE CONVECTION IS WITHIN 120
NM SOUTH OF THE AXIS BETWEEN 18W-29W...AND WITHIN 160  NM N OF
AXIS BETWEEN 30W-33W.

...DISCUSSION...

GULF OF MEXICO...
MAIN FEATURE IN THE GULF CONTINUES TO BE A FRONTAL BOUNDARY
WHICH HAS BEEN DRAPED ACROSS THE REGION FOR THE PAST FEW DAYS.
THE EAST GULF AND FLORIDA ARE UNDER THE INFLUENCE OF A RIDGE
ANCHORED ON A HIGH OVER THE E CONUS WHICH IS USHERING A COOL AIR
MASS. AS OF 03Z...THE FRONT TRANSITIONS TO STATIONARY AND THEN
WARM FROM WESTERN CUBA TO A 1020 MB LOW SITUATED OFF THE TEXAS
COAST NEAR 28N94W. THIS LOW SHOWS UP NICELY IN THE NEARBY
BUOY/SHIP DATA. A SLOW MOVING COLD FRONT CONTINUES SWD FROM THE
LOW TO 23N95W. AT THIS POINT...THE FRONT BECOMES STATIONARY
EXTENDING NWD ALONG THE E SLOPES OF THE SIERRA MADRE MOUNTAINS
IN MEXICO. SCATTERED SHOWERS ARE TSTMS COVER A LARGE PORTION OF
THE N GULF STATES FROM LOUISIANA TO GEORGIA AND THE FLORIDA
PANHANDLE AS NOTED IN DOPPLER RADAR AND LIGHTNING DATA. DENSE
MULTILAYERED CLOUDINESS AND SCATTERED SHOWERS ARE OVER THE GULF
WATERS N AND W OF THE FRONT MOSTLY W OF 90W. MODEL GUIDANCE
SHOWS THE FRONT FINALLY GET A GOOD PUSH SWD AS AN UPPER
SHORTWAVE OVER THE DAKOTAS AMPLIFIES AND DIGS SE DRIVING THE
FRONT THROUGH THE ENTIRE REGION BY SUNDAY.

CARIBBEAN SEA...
THE CARIBBEAN REMAINS QUIET TONIGHT BENEATH A WEAK UPPER
SHORTWAVE OVER THE NW PORTION AND A MODEST MID TO UPPER RIDGE
ELSEWHERE. WV IMAGERY SHOWS MODERATE TO STRONG SUBSIDENCE ACROSS
ENTIRE REGION THAT IS SUPPRESSING THE DEVELOPMENT OF DEEP
CONVECTION. HOWEVER...PATCHES OF LOW LEVEL CLOUDS WITH EMBEDDED
SHOWERS ARE SEEN ACROSS THE BASIN...MORE CONCENTRATED NEAR THE
ABC ISLANDS. FRAGMENTS OF LOW LEVEL CLOUDS ARE ALSO AFFECTING
CENTRAL AMERICA WHERE THE LOW LEVEL FLOW IS SLIGHTLY CONFLUENT.
A COLD FRONT FROM THE ATLC CROSSES EASTERN CUBA THE CONTINUES W
AND NW ACROSS WESTERN CUBA AND THE GULF OF MEXICO. THIS FRONT IS
GENERATING SOME CLOUDINESS WITH MAINLY LIGHT SHOWERS OVER PARTS
OF CUBA AND IS FORECAST TO DISSIPATE LATE TODAY. TRADE WINDS ARE
QUITE BRISK 20-25 KT...EXCEPT TO 30 KT JUST OFFSHORE THE
COLOMBIAN COAST. A QUIKSCAT PASS FROM AROUND 00Z CONFIRMED THESE
WINDS.

ATLANTIC...
LARGE MID TO UPPER TROUGH OFF THE U.S. EASTERN SEABOARD IS
SUPPORTING A COLD FRONT THAT ENTERS THE AREA NEAR 32N56W AND
EXTENDS SW ACROSS THE SE BAHAMAS TO THE N SHORE OF EASTERN CUBA.
SCATTERED SHOWERS AND TSTMS ARE WITHIN 120 NM AHEAD OF THE FRONT
N OF 25N. A DIFFLUENT PATTERN ALOFT BETWEEN THE LARGE UPPER
TROUGH AND A NARROW AMPLIFIED RIDGE ALONG 45W IS ENHANCING THIS
ACTIVITY. A BAND OF BROKEN TO OVERCAST LOW CLOUDS DEFINES THE
FRONTAL BOUNDARY S OF 25N TO EASTERN CUBA. ABUNDANT COLD AIR
STRATOCUMULUS CLOUDS ARE FILTERING SWD BEHIND THE FRONT COVERING
MOST OF THE W ATLC AND THE BAHAMAS.

THE WEATHER PATTERN IN THE CENTRAL AND EASTERN ATLC HAS CHANGED
LITTLE OVER THE PAST FEW DAYS. A LARGE HIGHLY ELONGATED MID TO
UPPER TROUGH CONTINUES TO DOMINATE MUCH OF THE REGION ANCHORED
BY AN UPPER LOW NEAR 40N20W EXTENDING TO A SMALLER UPPER CYCLONE
NEAR 27N32W. SCATTERED SHOWERS ARE ROTATING AROUND THIS SRN
UPPER LOW WITHIN 180 NM OF THE CENTER. AN ASSOCIATED SFC TROUGH
CONTINUES TO LINGER OVER THE EASTERN ATLC...ANALYZED ALONG
26W/27W FROM 20N-30N. AN EARLIER ASCAT PASS SHOWED THE WIND
SHIFT ASSOCIATED WITH THIS TROUGH. STRONG W TO SW UPPER-LEVEL
FLOW AROUND THE BASE OF THE TROUGH IS ADVECTING ABUNDANT
UPPER-LEVEL MOISTURE FROM THE LESSER ANTILLES TO THE AFRICAN
COAST.

$$
GR/JC



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