[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 312347
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST WED JAN 31 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...
CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...
NORTHEASTERN 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 5N5W 3N10W CROSSING THE EQUATOR AT
20W...2S30W TO 3N50W IN NE BRAZIL. CLUSTERS OF SCATTERED
MODERATE CONVECTION ARE WITHIN 120 NM N OF THE AXIS FROM
10W-20W. WIDELY SCATTERED MODERATE CONVECTION IS FROM 3S-4N
BETWEEN 22W-34W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG
CONVECTION ARE OVER NE BRAZIL ALONG THE ITCZ AXIS.

...DISCUSSION...
GULF OF MEXICO...
A BROAD UPPER LEVEL RIDGE DOMINATES THE ENTIRE GULF OF MEXICO
WITH VERY DRY AIR...RESULTING IN MODERATE TO STRONG SUBSIDENCE.
AN UPPER LEVEL TROUGH IS OVER NW MEXICO. BROAD SUBTROPICAL JET
WITH WINDS OF 110 TO 130 LIES SE OF THIS TROUGH AND EXTENDS
ACROSS MEXICO OVER THE SE US AND N GULF EXTENDING INTO THE W
ATLC. AT THE SURFACE...A WARM FRONT IN THE NORTHERN GULF OF
MEXICO EXTENDS FROM 27N86W TO A 1010 MB LOW PRES LOCATED OVER
THE NW CORNER OF THE GULF NEAR 27N96W. THE LOW WILL MOVE INTO SE
LOUISIANA LATER TONIGHT AND THE WARM FRONT MOVE NORTH INTO THE
SE US. WINDS WILL BECOME SLY ACROSS THE ENTIRE GULF BY THU
MORNING. A SFC TROUGH ALSO EXTENDS SWD FROM THE LOW TO NEAR
22N97W. COLD AIR IS ALREADY BANKING UP AGAINST THE E SLOPE OF
THE SIERRA MADRE MOUNTAINS AND STATIONARY FRONT IS ANALYZED
THERE. ANOTHER SFC LOW IS EXPECTED TO DEVELOP OVER NE MEXICO THU
MORNING...THEN WILL MOVE NE ALONG THE N GULF COAST DURING THE
REST OF THE DAY. THE TRAILING COLD FRONT WILL ENTER THE NW GULF
IN THE AFTERNOON AND WILL EXTEND FROM THE FLORIDA PANHANDLE TO
THE BAY OF CAMPECHE FRIDAY MORNING. HIGH PRESSURE LOCATED OVER
THE SE US WILL MOVE E INTO THE W ATLC THROUGH THE CAROLINAS OVER
THE NEXT 12 HOURS. PATCHES OF LOW LEVEL MOISTURE ARE SEEN OVER
THE GULF WITH MAINLY LIGHT SHOWERS/RAIN NORTH OF THE WARM FRONT.

CARIBBEAN SEA...
NO SIGNIFICANT FEATURES ARE OBSERVED OVER THE CARIBBEAN THIS
EVENING. BROAD UPPER RIDGE COVERS THE CARIBBEAN AND CENTRAL
AMERICA EXTENDING INTO THE W AND CENTRAL ATLC ACROSS THE GREATER
ANTILLES. THIS FEATURE IS GIVING THE NW CARIBBEAN WESTERLY FLOW
AND THE SE CARIBBEAN EASTERLY FLOW. VERY DRY MID/UPPER AIR
CONTINUES TO DOMINATE THE ENTIRE AREA. TYPICAL PATCHES OF LOW
LEVEL MOISTURE WITH SHORT-LIVE SHOWERS ARE SEEN ACROSS THE
REGION... PARTICULARLY OVER THE NW QUADRANT OF THE BASIN/YUCATAN
CHANNEL  AND OVER E CARIBBEAN SOUTH OF PUERTO RICO. MODERATE TO
STRONG EASTERLY TRADE WINDS REMAIN ACROSS THE AREA WITH THE
HIGHEST WINDS ALONG THE COAST OF COLOMBIA. BRISK TRADE WINDS
WILL CONTINUE TO BLOW ACROSS THE AREA THROUGH THE UPCOMING
WEEKEND.

ATLANTIC OCEAN...
BROAD UPPER RIDGE DOMINATES THE W AND CENTRAL ATLC W OF 40W. A
DEEP LAYERED TROUGH IS OVER THE E ATLC AND RUNS FROM OVER THE
MADEIRA ISLANDS TO THE CAPE VERDE ISLANDS. AN AREA OF SHOWERS
AND ISOLATED TSTMS IS AHEAD OF THIS TROUGH AFFECTING THE CANARY
ISLANDS. THE TROUGH IS ALSO DRAWING TROPICAL MOISTURE NORTHWARD
ACROSS WESTERN AFRICA. ANOTHER UPPER LEVEL TROUGH IS NORTH OF
27N WITH THE AXIS ALONG 52W. THE ATTENDANT FRONTAL BOUNDARY
ENTERS THE AREA NEAR 32N38W THEN CONTINUES SW TO 27N50W. A SFC
TROUGH...REMNANT OF A COLD FRONT...GOES FROM THIS POINT TO THE
SOUTHERN BAHAMAS. ANOTHER SURFACE TROUGH RUNS FROM 30N70W TO THE
NORTHERN BAHAMAS. COLD AIR STRATOCUMULUS CLOUDS ARE BEHIND THE
SECOND TROUGH. IN BETWEEN...THERE IS A BAND OF BROKEN
MULTILAYERED CLOUDS WITH SCATTERED SHOWERS.  AN AREA OF MODERATE
TO ISOLATED STRONG CONVECTION ENHANCED BY UPPER LEVEL DIFFLUENT
IS FROM 27N-32N BETWEEN 53W-59W. A SURFACE RIDGE DOMINATES THE
ATLC E OF 50W WITH A WEAKENING 1022 MB HIGH NEAR 31N35W. AN
UPPER RIDGE IS MOSTLY INLAND OVER AFRICA.

$$
GR




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