[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 211735
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST TUE DEC 21 2010

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...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND
RADAR.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1715 UTC.

...THE ITCZ...

ITCZ AXIS IS CENTERED FROM LIBERIA NEAR 5N9W ALONG 3N27W 3N40W
1N53W. NUMEROUS MODERATE/SCATTERED STRONG CONVECTION IS FROM
1S-3N BETWEEN 8W-12W...AND FROM 2N-7N BETWEEN 12W-18W. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS FROM 3N-5N BETWEEN
23W-27W. ISOLATED MODERATE/STRONG CONVECTION IS FROM 3N-7N
BETWEEN 42W-48W. NUMEROUS MODERATE/STRONG CONVECTION IS FROM
EQ-5N BETWEEN 50W-53W.

...DISCUSSION...

GULF OF MEXICO...
MAINLY NWLY FLOW ALOFT COVERS THE GULF OF MEXICO TODAY AROUND
THE ERN HALF OF AN UPPER LEVEL RIDGE COVERING MUCH OF THE
CENTRAL UNITED STATES. THE UPPER RIDGE SUPPORTS A SURFACE RIDGE
ANCHORED BY A 1023 MB HIGH OVER NRN FLORIDA AND SRN GEORGIA NEAR
31N83W. WEAK ANTI-CYCLONIC FLOW IS AROUND THE RIDGE WITH
STRONGER SLY WINDS UP TO 15 KTS ALONG THE TEXAS COASTLINE. DRY
AIR AND SUBSIDENCE ALOFT ARE MAINTAINING MOSTLY CLEAR SKIES
ACROSS THE BASIN WITH THE EXCEPTION OF AN AREA OF STRATOCUMULUS
CLOUDS IN THE N CENTRAL GULF N OF 27N BETWEEN 86W-95W. EXPECT
SURFACE RIDGING TO DOMINATE THE BASIN FOR THE NEXT SEVERAL DAYS
KEEPING CONDITIONS FAIR.

CARIBBEAN SEA...
DRY AIR AND SUBSIDENCE ALOFT THAT COVERS THE GULF OF MEXICO IS
ALSO IMPACTING MUCH OF THE WRN CARIBBEAN KEEPING CONDITIONS
FAIR. A LONGWAVE UPPER TROUGH OVER THE W ATLC SUPPORTS A COLD
FRONT THAT CROSSES THE NRN LEEWARD ISLANDS NEAR ANTIGUA ALONG
17N61W TO 16N65W WHERE IT CONTINUES AS A SURFACE TROUGH ALONG
15N67W 13N67W. SCATTERED SHOWERS/POSSIBLE THUNDERSTORMS ARE
WITHIN 45 NM EITHER SIDE OF THE AXIS. A SECOND SURFACE TROUGH IS
FARTHER W ALONG 17N72W TO 13N70W...AS INDICATED BY A WINDSAT
SCATTEROMETER PASS. THE PASS REVEALS N-NE WINDS UP TO 20 KTS ARE
NE OF THE TROUGH AXIS WITH WEAKER WINDS TO THE SW. CONVERGENCE
NEAR THE TROUGH IS SUPPORTING SCATTERED SHOWERS/POSSIBLE
THUNDERSTORMS WITHIN 45 NM EITHER SIDE OF THE AXIS. POSSIBLE
ISOLATED SHOWERS ARE ALSO N OF 16N BETWEEN 63W-69W. EXPECT
SHOWER ACTIVITY TO CONTINUE ACROSS PORTIONS OF THE ERN
CARIBBEAN...AS WELL AS ACROSS THE SRN WINDWARD ISLANDS AS A LOW
PRESSURE SYSTEM SE OF BARBADOS MOVES WWD OVER THE NEXT 24 HRS.

ATLANTIC OCEAN...
SURFACE RIDGING CENTERED OVER NRN FLORIDA/SRN GEORGIA EXTENDS
OVER THE FAR W ATLC KEEPING CONDITIONS FAIR. A DEEP LAYER TROUGH
IS TO THE E SUPPORTING A BROAD LOW PRESSURE SYSTEM CENTERED OFF
THE NEW ENGLAND COAST WITH AN ASSOCIATED COLD FRONT ENTERING THE
DISCUSSION AREA NEAR 32N51W CONTINUING TO THE NRN LEEWARD
ISLANDS ALONG 25N53W 17N62W. SCATTERED SHOWERS/POSSIBLE
THUNDERSTORMS ARE WITHIN 250 NM AHEAD OF THE FRONT N OF
23N...AND WITHIN 120 NM AHEAD OF THE FRONT S OF 23N. GALE FORCE
WINDS ARE BOTH AHEAD OF AND BEHIND THE FRONT WITH A LARGE AREA
OF STRATOCUMULUS CLOUDS ALSO BEHIND THE FRONT. TO THE S...A 1010
MB LOW IS LOCATED NEAR BARBADOS AT 12N59W WITH A SURFACE TROUGH
EXTENDING THROUGH THE CENTER ALONG 16N56W TO 9N62W. AN AREA OF
STRONG SHOWERS/THUNDERSTORMS ARE W OF THE SYSTEM WITHIN 100
NM...AND SHOULD BEGIN IMPACTING THE WINDWARD ISLANDS SHORTLY AS
THE SYSTEM PROGRESSES WWD. ACROSS THE ERN ATLC...A BROAD UPPER
LEVEL RIDGE ALONG 39W SUPPORTS A SURFACE RIDGE ANCHORED BY A
1020 MB HIGH NEAR 25N37W PROVIDING GENERALLY FAIR WEATHER ACROSS
THIS PORTION OF THE BASIN. AN UPPER LEVEL TROUGH IS TO THE E
ACROSS THE CANARY ISLANDS TO THE CAPE VERDE ISLANDS SUPPORTING A
LOW PRESSURE SYSTEM N OF THE DISCUSSION AREA THAT IS GENERATING
CYCLONIC SURFACE FLOW N OF 25N. A SURFACE TROUGH DEPICTS THE
SHIFTING CYCLONIC WINDS ALONG 31N16W TO 24N27W.

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

$$
WALTON





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