[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 231749
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST MON JAN 23 2012

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1700 UTC.

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH PASSES THROUGH THE SRN COAST OF LIBERIA NEAR
5N9W TO 7N16W. THE ITCZ CONTINUES FROM 7N16W ALONG 3N25W 2N37W
CROSSING THE EQUATOR AT 48W TO 1S50W. SCATTERED MODERATE/STRONG
CONVECTION IS S OF THE MONSOON AXIS FROM EQ-3N BETWEEN 3W-13W.
SCATTERED MODERATE CONVECTION IS WITHIN 75 NM OF THE AXIS
BETWEEN 25W-30W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION
IS FROM 1S-4N BETWEEN 39W-52W.

...DISCUSSION...

THE GULF OF MEXICO...
AN UPPER LEVEL TROUGH WHICH IS RAPIDLY MOVING OVER THE GREAT
LAKES REGION SUPPORTS A COLD FRONT MOVING ACROSS THE ERN CONUS
WHICH ENTERS THE GULF OF MEXICO OVER SE LOUISIANA NEAR 29N91W.
THE FRONT CONTINUES TO THE SRN TIP OF TEXAS NEAR 26N97W TO
25N100W...AS OF 1500 UTC. ISOLATED SHOWERS ARE ALONG THE FRONT
AXIS WITH STRONGER ACTIVITY FARTHER INLAND. THE REMAINDER OF THE
BASIN IS IMPACTED BY A SURFACE RIDGE EXTENDING FROM THE W ATLC.
DRY AIR ALOFT AROUND AN UPPER LEVEL RIDGE OVER THE
CARIBBEAN...GULF AND W ATLC IS HELPING SUPPORT THE SURFACE RIDGE
AND MAINTAIN FAIR SURFACE CONDITIONS. BESIDES NEAR THE
FRONT...SKIES ARE MOSTLY CLEAR WITH ANTI-CYCLONIC FLOW OF 10-15
KTS. THE FRONT IS EXPECTED TO CONTINUE TO MOVE SE ACROSS THE
BASIN THROUGH TONIGHT BEFORE STALLING AND RETREATING BACK TO THE
NW. ANOTHER FRONT IS EXPECTED TO MOVE INTO THE BASIN LATER IN
THE WEEK.

THE CARIBBEAN SEA...
MOSTLY FAIR CONDITIONS ARE ACROSS THE CARIBBEAN TODAY DUE TO
SIGNIFICANT DRY AIR ALOFT AROUND AN UPPER LEVEL RIDGE COVERING
THE WRN HALF OF THE BASIN. AN UPPER LEVEL TROUGH DIGS INTO THE
ERN CARIBBEAN ALONG 67W...BUT IS ACCOMPANIED BY DRY AIR.
TRADEWIND FLOW OF 15-20 KTS IS ACROSS MUCH OF THE BASIN. A FEW
PATCHES OF CLOUDS WITH POSSIBLE ISOLATED SHOWERS ARE EMBEDDED
WITHIN THE FLOW. A SHEAR AXIS...REMNANTS OF A FRONTAL BOUNDARY
IN THE CENTRAL ATLC...EXTENDS ACROSS THE FAR SE CORNER FROM
11N62W TO 12N67W SUPPORTING AN AREA OF MORE CONCENTRATED
SHOWERS. EXPECT THE SHEAR AXIS TO DISSIPATE WHILE THE REMAINDER
OF THE BASIN REMAINS UNDER SIMILAR CONDITIONS.

THE ATLANTIC OCEAN...
AN UPPER LEVEL RIDGE COVERS THE FAR WRN ATLC ALONG 75W PROVIDING
FAIR WEATHER ACROSS FLORIDA AND MUCH OF THE BAHAMAS. A SHORTWAVE
UPPER LEVEL TROUGH TO THE E ALONG 65W SUPPORTS A SURFACE TROUGH
ALONG 29N69W TO 22N73W. A FEW CLUSTERS OF SHOWERS/THUNDERSTORMS
ARE NEAR THE AXIS WITH UPPER LEVEL CLOUDINESS TO THE E AROUND
THE E SIDE OF THE UPPER TROUGH. WEAK SURFACE RIDGING COVERS THE
REMAINDER OF THE W ATLC AROUND A 1026 MB HIGH NEAR 32N62W. A
NARROW UPPER LEVEL TROUGH IS OVER THE CENTRAL ATLC ALONG 44W
SUPPORTING A DISSIPATING STATIONARY FRONT ALONG 32N41W 21N41W
14N47W. A SHEAR AXIS CONTINUES FROM THE TAIL END OF THE FRONT TO
JUST N OF VENEZUELA NEAR 11N61W. SCATTERED SHOWERS/POSSIBLE
THUNDERSTORMS ARE WITHIN 200 NM E OF THE AXIS TO THE N OF 27N.
ISOLATED SHOWERS ARE WITHIN 60 NM EITHER SIDE THE AXIS ELSEWHERE
ALONG THE FRONT AND THE SHEAR AXIS. A SURFACE TROUGH IS W OF THE
FRONT ALONG 32N45W 26N45W 22N49W WITH NO ASSOCIATED SHOWER
ACTIVITY. THE REMAINDER OF THE E ATLC IS DOMINATED BY SURFACE
RIDGING ANCHORED BY A 1031 MB HIGH NEAR 36N27W. THE RIDGE IS
SUPPORTED BY AN UPPER LEVEL RIDGE ALONG 28W. EXPECT THE FRONTAL
BOUNDARY IN THE CENTRAL ATLC TO CONTINUE TO DISSIPATE STILL
LEAVING BEHIND SOME LOWER PRESSURES AND TROUGHING.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
WALTON








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