[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 121135
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST SAT 12 FEB 2005

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN SECTIONS
OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM
THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON
SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND
METEOROLOGICAL ANALYSIS.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1115 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 3N0 2N5W 3N20W 4S43W. NUMEROUS
STRONG CONVECTION WITHIN 75 NM OF THE AXIS E OF 10W. ISOLATED
MODERATE UP TO 250 NM N OF THE AXIS BETWEEN 10W-25W. ISOLATED
SHOWERS/TSTMS UP TO 200 NM N OF THE AMAZON DELTA. SCATTERED
MODERATE OVER COLOMBIA AND FAR W VENEZUELA NEAR LAKE MARACAIBO.

...DISCUSSION...

GULF OF MEXICO...
COOL DRY WEATHER HAS OVERSPREAD THE ENTIRE GULF OF MEXICO AND FL
WITH THE RESPONSIBLE COLD FRONT HAVING MOVED ALL THE WAY INTO
THE NW CARIBBEAN. HIGH PRES IS CENTERED OVER COASTAL AREAS OF
LOUISIANA AND HAS MAINTAINED ITS STRENGTH OVER THE PAST 6 HRS
WITH A PRES OF 1028 MB. THE LIGHT WINDS AND CLEAR SKIES NEAR THE
HIGH HAVE FOSTERED STRONG RADIATIONAL COOLING OVER LAND DURING
THE NIGHT AND TEMPERATURES HAVE EVEN DROPPED INTO THE UPPER 30S
F OVER PARTS OF THE EVERGLADES IN S FLORIDA. PART OF THE
COLD FRONT IS STILL HUNG UP ALONG THE E SLOPES OF THE SIERRA
MADRES AND THE ASSOCIATED LOW CLOUDS/DRIZZLE HAVE PUSHED INLAND
AS FAR W AS A LINE ALONG 17N95W 20N97W 22N101W 25N100W 27N101W.
THE AIR MASS WILL MODIFY RATHER QUICKLY BEGINNING ON SAT AS THE
SFC HIGH SCOOTS OFF THE E AND LOW PRES DEVELOPS OVER THE CNTRL
PLAINS WITH RETURN FLOW DEVELOPING OVER THE W GULF. A WEAK COLD
FRONT ASSOCIATED WITH THIS LOW WILL MOVE OFF THE TX COAST SUN
NIGHT PRECEDED BY SCATTERED SHOWERS/TSTMS BUT THEN THE BOUNDARY
SHOULD WEAKEN OVER THE N GULF WATERS MON NIGHT AND TUE AS ITS
MID-LEVEL SUPPORT DISSIPATES IN FAST ZONAL FLOW.

CARIBBEAN...
A LARGE AREA OF MODERATE/STRONG SUBSIDENCE COVERS MOST OF THE
CARIBBEAN WATERS AS UPPER LEVEL FLOW CONVERGES BETWEEN A TROF
AND RIDGE. THE WEAKENING TROF EXTENDS FROM E CUBA ACROSS
HONDURAS TO A UPPER LOW OVER THE PACIFIC WATERS WHILE THE BROAD
RIDGE EXTENDS N OF VENEZUELA. A COLD FRONT EXTENDS FROM HAITI SW
TO 13N80W WWD THRU NICARAGUA THEN ALONG THE MOUNTAINS TO
GUATEMALA AND SE MEXICO. HOWEVER...THE AIR MASS IS SO DRY THAT
THE ONLY SIGNIFICANT WEATHER IS PATCHY LOW CLOUDS AND DRIZZLE
OVER LAND BETWEEN THE FRONT IN CNTRL AMERICA. ELSEWHERE...THE
HEAVY RAINS AND FLOODING THAT AFFECTED THE COAST OF VENEZUELA
NEAR CARACAS A COUPLE DAYS AGO HAVE COMPLETELY DISSIPATED AND
NOW THE STRONGEST CONVECTIVE ACTIVITY HAS SHIFTED TO OVER W
VENEZUELA AND COLOMBIA. A WEAK SFC TROF IS LOCATED OVER THE
LESSER ANTILLES FROM 13N61W TO 20N61W AND IS PRODUCING A PATCH
OF LOW CLOUDS AND A FEW LIGHT SHOWERS FROM 12N-21N BETWEEN
58W-63W.

WEST/CENTRAL ATLANTIC...
A STRONG COLD FRONT IS SWEEPING ACROSS THE W ATLC WATERS FROM
32N56W SW TO THE N COAST OF HAITI AND IS FOLLOWED BY A BROKEN
STRATOCUMULUS FIELD BACK TO WITHIN 150 NM OF THE FLORIDA/SE U.S.
COAST. A BAND OF LOW CLOUDS/WIDELY SCATTERED SHOWERS IS LOCATED
WITHIN 90 NM OF THE FRONT PRIMARILY N OF 26N WITH THE STRONGEST
UPPER LEVEL DIVERGENCE N OF THE AREA. THE ASSOCIATED UPPER TROF
HAS BECOME RATHER BROAD AND IS CENTERED BETWEEN 55W-80W WITH A
STRONG VORT MAX CENTERED NEAR 33N68W. THIS FEATURE IS SUPPORTING
A POST-FRONTAL TROF ALONG 32N68W 29N76W WHICH IS REINFORCING THE
COLD AIR ADVECTION AND STRATOCUMULUS OVER THE W ATLC WATERS. AN
UPPER RIDGE IS LOCATED DOWNSTREAM ALONG 20N54W 32N46W AND IS
PRODUCING ONLY A FEW PATCHY CLOUDS WITHIN THE SLY FLOW PRECEDING
THE FRONT.

EAST ATLANTIC...
A LARGE AND ELONGATED UPPER LEVEL LOW IS CENTERED JUST W OF THE
CANARY ISLANDS NEAR 29N20W WITH ASSOCIATED TROF EXTENDING SW TO
15N41W. THE LOW IS UNDERLAIN BY A BROAD SFC RIDGE STRETCHING
FROM A 1040 MB HIGH NEAR THE AZORES SW INTO THE CNTRL ATLC NEAR
20N53W. THE HIGH IS PRODUCING A TIGHT PRES GRADIENT OVER THE
SUBTROPICAL WATERS AND IS RESULTING IN OCCASIONAL GALE
CONDITIONS OFF THE MOROCCAN COAST S OF THE CANARY ISLANDS. THIS
STRONG EASTERLY FLOW HAS ADVECTED A DENSE PLUME OF DUST AND SAND
OFFSHORE FROM 20N-29N E OF 30W OVER THE ATLC WATERS. SEVERAL
SITES IN THE CANARY ISLANDS...WHICH LIES ON THE EDGE OF THE
PLUME...ARE REPORTING VISIBILITIES REDUCED TO 4-5 MILES AND IS
IT LIKELY THAT VISIBILITIES ARE EVEN LOWER WITHIN THE MAIN PART
OF THE PLUME. ZONAL WESTERLY UPPER FLOW EXTENDS ACROSS THE
ENTIRE TROPICAL REGION WITH AN ACTIVE 100 KT JET ALONG 12N40W
14N24W PULLING MID/UPPER LEVEL MOISTURE FROM THE ITCZ NEWD
TOWARDS SENEGAL AND MAURITANIA. A SFC LOW IS EXPECTED TO FORM
OFF THE COAST OF WESTERN SAHARA WITHIN THE NEXT 24 HRS AND WILL
TAP INTO THIS MOISTURE SOURCE...POSSIBLY BRINING PERIODS OF RAIN
OVER THE CANARY ISLANDS AND WESTERN SAHARA THRU MONDAY.

$$
BERG



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