[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 261132
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1115 UTC

...THE ITCZ...

ITCZ AXIS IS CENTERED ALONG 6N10W 4N20W 2N30W 1N40W EQUATOR AT
43W INTO NE BRAZIL. SCATTERED MODERATE CONVECTION IS FROM 1N-4N
BETWEEN 24W-29W. SCATTERED SHOWERS ARE WITHIN 180 NM EITHER SIDE
OF AXIS BETWEEN 30W-35W.

...DISCUSSION...

GULF OF MEXICO...
MAIN WEATHER FEATURE IN THE GULF CONTINUES TO BE A COLD FRONT
WHICH EXTENDS FROM A WEAK 1017 MB LOW LOCATED NEAR 28N92W SW TO
23N95W. AT THIS POINT...THE FRONT BECOMES STATIONARY EXTENDING
NWD ALONG THE E SLOPES OF THE SIERRA MADRE MOUNTAINS IN MEXICO.
PERSISTENT LOW CLOUDS BANKING UP AGAINST THE MOUNTAINS INDICATES
THE PRESENCE OF THIS FRONTAL BOUNDARY. A WARM FRONT ALSO EXTENDS
EWD FROM THE LOW TO NEAR 29N85W. THIS WEAK LOW CURRENTLY OVER
THE NW PORTION OF THE GULF WILL MOVE EWD REACHING NORTH FLORIDA
LATE TONIGHT. HIGH PRES WILL GRIP THE AREA IN THE WAKE OF THE
FRONT. AS A RESULT...EXPECT NLY WINDS OF 15 TO 20 KT AND SEAS UP
TO 7 FT BEHIND THE FRONT ON SUN...BUT MAINLY ACROSS THE EASTERN
GULF. SCATTERED SHOWERS ARE TSTMS COVER A LARGE PORTION OF THE N
GULF STATES FROM SE LOUISIANA TO GEORGIA AND N FLORIDA 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 AMPLIFIES OVER
U.S. AND DIGS SE DRIVING THE FRONT THROUGH THE ENTIRE REGION BY
SUNDAY. THIS FRONT ALSO PROMISES TO REACH HISPANIOLA ON MONDAY
AND PUERTO RICO LATE MONDAY.

CARIBBEAN SEA...
THE CARIBBEAN REMAINS QUIET EARLY THIS MORNING 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 AND OVER THE LESSER ANTILLES. FRAGMENTS OF LOW LEVEL
CLOUDS ARE ALSO AFFECTING CENTRAL AMERICA WHERE THE LOW LEVEL
FLOW IS SLIGHTLY CONFLUENT. THE FRONTAL ZONE THAT WAS AFFECTING
CUBA HAS DISSIPATED...HOWEVER SOME CLOUDINESS WITH MAINLY LIGHT
SHOWERS CONTINUES TO MOVE ACROSS THE ISLAND UNDER A NELY WIND
FLOW. MODERATE TO STRONG TRADE WINDS OF 20-30 KT ARE BLOWING
ACROSS THE CENTRAL CARIBBEAN WITH THE STRONGEST WINDS...AS USUAL
JUST OFFSHORE THE COLOMBIAN COAST.

ATLANTIC...
LARGE MID TO UPPER TROUGH OFF THE U.S. EASTERN SEABOARD IS
SUPPORTING A COLD FRONT THAT ENTERS THE AREA NEAR 31N52W AND
EXTENDS SW ACROSS THE SE BAHAMAS TO THE EXTREME EASTERN CUBA.
SCATTERED SHOWERS AND TSTMS ARE WITHIN 130 NM AHEAD OF THE FRONT
N OF 26N. A DIFFLUENT PATTERN ALOFT BETWEEN THE LARGE UPPER
TROUGH AND A NARROW AMPLIFIED RIDGE ALONG 45W IS ENHANCING THIS
CONVECTIVE ACTIVITY. A WIDE BAND OF BROKEN TO OVERCAST LOW
CLOUDS DEFINES THE FRONTAL BOUNDARY E OF THE SE BAHAMAS.
ABUNDANT COLD AIR STRATOCUMULUS CLOUDS ARE FOUND BEHIND THE
FRONT COVERING MOST OF THE W ATLC AND THE CENTRAL AND SE
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 40N22W EXTENDING TO A SMALLER UPPER CYCLONE
NEAR 27N32W. SCATTERED SHOWERS ARE ROTATING AROUND THIS SRN
UPPER LOW WITHIN 180 NM OF THE CENTER. A SURFACE TROUGH...
REFLECTION OF THIS UPPER FEATURE CONTINUES TO LINGER OVER THE
EASTERN ATLC WITH AXIS ALONG 28W/29W FROM 20N-30N. THE SFC
TROUGH SHOWS UP NICELY ON A QUIKSCAT PASS FROM AROUND 07Z. A JET
STREAM BRANCH AROUND THE BASE OF THE UPPER-LEVEL TROUGH IS
ADVECTING ABUNDANT UPPER-LEVEL MOISTURE FROM N SOUTH AMERICA TO
TO THE AFRICAN COAST. THIS JET PASSES THROUGH THE CAPE VERDE
ISLANDS.

$$
GR




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