[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 112351
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST MON FEB 11 2013

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 12N16W TO
05N21W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
05N21W TO 02N26W TO 01N35W TO THE EQUATOR NEAR 42W. WIDELY
SCATTERED MODERATE CONVECTION IS FROM 01N-07N BETWEEN 47W-55W.

...DISCUSSION...

GULF OF MEXICO...
A MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH EMBEDDED WITHIN A
LARGER UPPER LEVEL CYCLONIC CIRCULATION CENTERED OVER THE GREAT
LAKES REGION HAS CONTINUED TO WEAKEN THIS EVENING...BUT OVERALL
ATMOSPHERIC TROUGHING ALOFT IS NOTED OVER THE EASTERN CONUS.
THIS TROUGHING SUPPORTS A COLD FRONT ANALYZED ACROSS THE FLORIDA
PANHANDLE AND INTO THE NORTHERN GULF FROM 30N87W TO 29N92W TO
27N96W WHERE THE BOUNDARY BECOMES STATIONARY ACROSS EXTREME
SOUTHERN TEXAS AND NORTHEASTERN MEXICO. MOSAIC DOPPLER RADAR
IMAGERY AND LIGHTNING DATA INDICATE WIDESPREAD SHOWERS AND
ISOLATED TSTMS ARE OCCURRING ALONG AND NORTH OF THE FRONT OVER A
MAJORITY OF THE SE CONUS. SOUTH OF THE FRONT...THE WESTERN
PERIPHERY OF A SURFACE RIDGE ANCHORED OVER THE SW NORTH ATLC IS
PROVIDING FOR SOUTH-SOUTHEASTERLY WINDS IN THE RANGE OF 10 TO 20
KT. SKIES REMAIN GENERALLY CLEAR WITH CLOUDINESS INCREASING IN
THE VICINITY OF THE FRONT. THE FRONT IS FORECAST TO BECOME
STATIONARY ACROSS THE NORTHERN GULF WATERS AND LIFT NORTHWARD AS
A WARM FRONT BY LATE TUESDAY AS SURFACE LOW PRESSURE DEVELOPS
OVER EASTERN TEXAS AND MOVES EASTWARD ACROSS THE SE CONUS INTO
WEDNESDAY. WITH CYCLOGENESIS ANTICIPATED...THE ASSOCIATED COLD
FRONT IS EXPECTED TO EMERGE OFF THE TEXAS AND LOUISIANA COAST
LATE TUESDAY INTRODUCING NORTHERLY WINDS IN WAKE OF THE FRONT
FOR THE NW AND WEST-CENTRAL PORTIONS OF THE GULF.

CARIBBEAN SEA...
NORTHWESTERLY UPPER LEVEL FLOW DOMINATES OVER THE CARIBBEAN WITH
WATER VAPOR IMAGERY INDICATING VERY DRY AIR AND STRONG
SUBSIDENCE KEEPING SKIES FAIR AND CONDITIONS TRANQUIL ACROSS A
MAJORITY OF THE BASIN THIS EVENING. THE EXCEPTION TO AN OVERALL
QUIET EVENING IS THE PRESENCE OF A SHEAR LINE ANALYZED FROM THE
CENTRAL ATLC NEAR 20N60W TO 19N66W TO EASTERN CUBA NEAR 21N76W.
THE SHEAR LINE IS PROVIDING FOCUS FOR WIDELY SCATTERED SHOWERS N
OF 17N BETWEEN 60W-78W....INCLUDING PUERTO RICO...THE US/UK
VIRGIN ISLANDS...AND PORTIONS OF HISPANIOLA. OTHERWISE...TRADES
REMAIN BRISK IN THE RANGE OF 15 TO 25 KT WITH HIGHER SPEEDS
FORECAST IN CLOSE PROXIMITY TO THE COAST OF COLOMBIA. LOOKING
AHEAD...THE SHEAR LINE IS EXPECTED TO SLOWLY DRIFT SOUTHWARD AND
BECOME DIFFUSE OVER THE NEXT 24 TO 36 HOURS WHILE CONTINUING TO
PROVIDE INCREASED PROBABILITY OF PRECIPITATION ACROSS THE
EASTERN CARIBBEAN.

ATLANTIC OCEAN...
MIDDLE TO UPPER LEVEL RIDGING EXTENDS FROM OVER CENTRAL AMERICA
NEAR 15N87W NORTHEASTWARD TO BEYOND 32N71W IN THE SW NORTH ATLC.
THE RIDGING IS PROVIDING SUPPORT FOR A 1028 MB SURFACE HIGH
CENTERED WEST OF BERMUDA NEAR 33N67W. FAIR SKIES AND CONDITIONS
ARE NOTED N OF 20N W OF 55W IN ASSOCIATION WITH THE HIGH.
FARTHER EAST...AN MIDDLE TO UPPER LEVEL TROUGH WITH AXIS ALONG
49W DIPS SOUTHWARD INTO THE CENTRAL ATLC AND SUPPORTS A COLD
FRONT ANALYZED FROM 32N44W TO 24N52W WHICH THEN BECOMES A SHEAR
LINE TO 20N60W TO 19N66W TO EASTERN CUBA NEAR 21N76W. WIDELY
SCATTERED SHOWERS ARE OCCURRING WITHIN 150 NM EITHER SIDE OF THE
COLD FRONT AND WITHIN 90 NM EITHER SIDE OF THE SHEAR LINE. A
PRE-FRONTAL SURFACE TROUGH IS ALSO LOCATED SOUTHEAST OF THE COLD
FRONT FROM 16N50W TO 26N47W AND CONTINUES TO PROVIDE FOCUS FOR
ISOLATED SHOWERS FROM 14N-26N BETWEEN 44W-51W. OTHERWISE THE
REMAINDER OF THE EASTERN ATLC IS DOMINATED BY A SURFACE RIDGE
ANCHORED BY A 1030 MB HIGH CENTERED EAST OF THE AZORES NEAR
38N24W.

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

$$
HUFFMAN




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