[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 161148
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST THU DEC 16 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1115 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 09N13W 04N30W 01N50W. SCATTERED
MODERATE CONVECTION IS FROM 04N-07N BETWEEN 10W-14W...AND FROM
02N-10N BETWEEN 17W-28W. ISOLATED STRONG CONVECTION IS FROM THE
EQUATOR TO 03N BETWEEN 48W-52W.

...DISCUSSION...

GULF OF MEXICO...
WATER VAPOR IMAGERY INDICATES VERY DRY AIR IS PRESENT ALOFT OVER
THE GULF WITH WESTERLY ZONAL FLOW PROVIDING FOR AN OVERALL
STABLE ATMOSPHERE THIS MORNING. AT THE SURFACE...THE WESTERN
PERIPHERY OF A RIDGE REMAINS IN CONTROL ANCHORED BY A 1020 MB
HIGH CENTERED OVER THE NORTHERN FLORIDA PENINSULA. THE RIDGE IS
FORECAST TO SLIDE E-SE INTO THE W ATLC THROUGH THE DAY ON
THURSDAY. S TO SW WINDS TO 25 KT ARE EXPECTED THURSDAY ACROSS
MUCH OF THE GULF E OF 85W AHEAD OF THE NEXT FRONTAL BOUNDARY
FORECAST TO EMERGE OFF THE TEXAS COAST EARLY FRIDAY. THE WEAK
FRONT WILL SWEEP ACROSS THE GULF THROUGH THE WEEKEND INTRODUCING
N-NE WINDS OVER THE GULF BY EARLY SUNDAY.

CARIBBEAN SEA...
VERY STRONG SUBSIDENCE AND DRY AIR ALOFT IS NOTED ACROSS THE NW
CARIBBEAN THAT CONTINUES TO SUPPORT A SURFACE RIDGE EXTENDING
FROM THE FLORIDA PENINSULA OVER MUCH OF THE NW CARIBBEAN N OF
17N AND W OF 78W. OVERALL STABLE CONDITIONS PERSIST AS A
RESULT...WITH MOSTLY BROKEN STRATOCUMULUS CLOUDS NOTED ON
SATELLITE IMAGERY THIS MORNING. OVER THE EASTERN AND CENTRAL
CARIBBEAN...A SHEAR LINE IS ANALYZED FROM ANTIGUA TO 15N73W THEN
TO THE NORTHERN COLOMBIA COAST NEAR 11N75W. AN EARLIER 16/0224
UTC ASCAT PASS CAPTURED STRONGER NORTHEASTERLY WINDS S OF
HISPANIOLA TO THE SHEAR LINE ALONG 16N...THEN LIGHTER EASTERLY
TRADES SOUTH OF THE SHEAR LINE AXIS. LOW-LEVEL SPEED CONVERGENCE
IN VICINITY OF THIS BOUNDARY IS PROVIDING FOCUS FOR WIDELY
SCATTERED SHOWERS WITHIN 120 NM EITHER SIDE OF THE SHEAR LINE.
ELSEWHERE...ISOLATED SHOWERS LINGER OVER THE REMAINDER OF THE NE
CARIBBEAN N OF 17N E OF 73W...INCLUDING HISPANIOLA...PUERTO
RICO...AND THE US/UK VIRGIN ISLANDS. FINALLY...A SURFACE TROUGH
IS ANALYZED FROM THE TROPICAL NORTH ATLC NEAR 19N58W TO SAINT
LUCIA ALONG THE WESTERN COASTS OF THE WINDWARD ISLANDS TO THE
GULF OF PARIA NEAR 10N62W. LOW-LEVEL CONVERGENCE IN THE VICINITY
OF THE SURFACE TROUGH AND ELEVATED TOTAL PRECIPITABLE WATER
VALUES IS ENHANCING ISOLATED SHOWERS WITHIN 90 NM EITHER SIDE OF
THE BOUNDARY.

ATLANTIC OCEAN...
BROAD UPPER LEVEL TROUGHING IS EVIDENT ON WATER VAPOR IMAGERY
OVER THE W ATLC WATERS REMAINING MAINLY N OF 27N AND W OF 53W
THAT SUPPORTS A COLD FRONT ENTERING THE DISCUSSION AREA NEAR
32N49W AND EXTENDING SW ALONG 27N53W TO 18N60W THEN BECOMING A
SHEAR LINE TO ANTIGUA NEAR 17N62W AND INTO THE NE CARIBBEAN SEA.
SCATTERED SHOWERS ARE OCCURRING FROM 21N-32N BETWEEN THE FRONT
AND 44W. ISOLATED SHOWERS ARE ELSEWHERE OVER THE ATLC WATERS S
OF 21N BETWEEN THE FRONT AND 73W...INCLUDING HISPANIOLA AND
PUERTO RICO. A SURFACE TROUGH EXTENDS FROM THE COLD FRONT NEAR
19N58W TO SAINT LUCIA WITH ISOLATED SHOWERS FROM 13N-21N BETWEEN
THE BOUNDARY AND 47W. THE STRONGER CONVECTION EAST OF THE FRONT
IS LIKELY ENHANCED DUE TO DIFFLUENCE BETWEEN THE UPPER LEVEL
TROUGH AND AN UPPER LEVEL RIDGE WITH AXIS ALONG 45W. THE
REMAINDER OF THE W ATLC IS UNDER THE INFLUENCE OF A SURFACE
RIDGE BUILDING IN ANCHORED BY A 1020 MB HIGH CENTERED OVER THE
NORTHERN FLORIDA PENINSULA CENTERED NEAR 29N82W. FARTHER
EAST...AN UPPER LEVEL LOW CENTERED NEAR 34N27W CONTINUES TO
IMPACT MUCH OF THE EASTERN ATLC E OF 35W DRIVING A COMPLEX AREA
OF LOW PRESSURE NORTH OF THE DISCUSSION AREA. THE MOST
IMPRESSIVE SURFACE FEATURE WITHIN THIS COMPLEX AREA IS A 999 MB
LOW CENTERED NEAR 31N25W THAT EXTENDS A SURFACE TROUGH FROM THE
LOW ALONG 32N23W 30N22W 26N25W 24N33W. ISOLATED SHOWERS ARE
MAINLY OCCURRING WITHIN 90 NM EITHER SIDE OF THE SURFACE TROUGH
S OF 31N. A SHIELD OF SCATTERED SHOWERS AND POSSIBLE ISOLATED
TSTMS IS ALSO OCCURRING FROM 31N-35N BETWEEN 17W-27W.

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

$$
HUFFMAN




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