[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 202318
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST SUN DEC 20 2009

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2230 UTC.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 9N8W 7N21W 5N37W 1N53W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM EQ-6N
BETWEEN 31W-42W.

...DISCUSSION...

GULF OF MEXICO...
SURFACE RIDGING CONTINUES TO DOMINATE THE GULF OF MEXICO
ANCHORED BY A 1028 MB SURFACE HIGH OVER NE MEXICO...AND A 1027
MB HIGH NEAR NE LOUISIANA. MAINLY N-NE WINDS ARE ACROSS THE
BASIN. IN THE UPPER LEVELS...MOIST SWLY FLOW COVERS THE AREA
AROUND THE E SIDE OF AN UPPER LEVEL TROUGH EXTENDING DOWN THE
TEXAS COASTLINE INTO CENTRAL MEXICO. THE MID-UPPER LEVEL
TROPICAL MOISTURE BEING DRAWN N-NE ACROSS THE BASIN IS
SUPPORTING POSSIBLE ISOLATED SHOWERS ACROSS THE SW GULF. EXPECT
THE SURFACE RIDGE TO GRADUALLY SHIFT EWD AS RETURN FLOW
INCREASES ACROSS THE NW GULF AHEAD OF THE NEXT COLD FRONT
FORECAST TO ENTER THE BASIN LATE WED.

CARIBBEAN SEA...
A STATIONARY FRONT EXTENDS ACROSS THE CARIBBEAN THIS EVENING
FROM THE WINDWARD PASSAGE ACROSS JAMAICA INTO THE SW CARIBBEAN
TO NRN COSTA RICA. A SURFACE TROUGH IS AHEAD OF THE FRONT
EXTENDING ACROSS HAITI TO NRN COLOMBIA. N-NE WINDS UP TO 25 KTS
ARE BEHIND THE FRONT. THE FRONT IS SUPPORTED BY AN UPPER LEVEL
LOW OFF THE NE UNITED STATES COAST. HOWEVER...MOST OF THE
CARIBBEAN IS COVERED BY AN UPPER LEVEL RIDGE WITH AXIS FROM
VENEZUELA ACROSS THE LEEWARD ISLANDS. MOIST SWLY FLOW AROUND THE
W SIDE OF THE RIDGE IS DRAWING TROPICAL MOISTURE ACROSS THE NW
CARIBBEAN AND CENTRAL AMERICA. THIS ALONG WITH SURFACE
CONVERGENCE NEAR THE FRONT/TROUGH AXIS ARE SUPPORTING SCATTERED
SHOWERS WITHIN 120 NM OF THE FRONT AXIS...AND ISOLATED SHOWERS
WITHIN 60 NM OF THE SURFACE TROUGH. POSSIBLE ISOLATED SHOWERS
ARE ELSEWHERE W OF 73W. DRY AIR AND SUBSIDENCE COVER THE E
CARIBBEAN NOTED IN WATER VAPOR IMAGERY BRINGING GENERALLY FAIR
WEATHER TO THAT PORTION OF THE BASIN. EXPECT THE FRONT TO REMAIN
STATIONARY OVER THE NEXT 24 HRS WITH CONTINUED PRECIPITATION
BECOMING DIFFUSE BY TUE.

ATLANTIC OCEAN...
AN OCCLUDED 968 MB LOW IS LOCATED OFF THE NEW ENGLAND COAST NEAR
41N66W WITH A COLD FRONT ENTERING INTO THE DISCUSSION AREA NEAR
32N54W CONTINUING ALONG 25N64W TO JUST E OF TURKS AND CAICOS
NEAR 21N70W BECOMING STATIONARY TO THE WINDWARD PASSAGE AND INTO
THE CARIBBEAN. SCATTERED SHOWERS ARE WITHIN 120 NM OF THE
FRONT...AND FARTHER E N OF 26N BETWEEN 41W-58W. A LARGE AREA OF
STRATOCUMULUS CLOUDS AND STRONG W-NW WINDS ARE BEHIND THE
FRONT. A WEAK 1017 MB HIGH IS LOCATED IN THE CENTRAL ATLC NEAR
21N46W SANDWICHED BETWEEN THE AFOREMENTIONED COLD FRONT AND A
SECOND COLD FRONT EXTENDING FROM E OF THE CANARY ISLANDS ALONG
32N16W 23N26W BECOMING A DYING STATIONARY FRONT NEAR 21N35W TO
20N43W. THE WEAK SURFACE RIDGE IS SUPPORTED BY AN UPPER LEVEL
RIDGE EXTENDING FROM THE CARIBBEAN ACROSS THE LEEWARD ISLANDS TO
NEAR 33N50W. THE SECOND COLD FRONT IN THE E ATLC IS SUPPORTED BY
AN UPPER LEVEL TROUGH CENTERED NEAR THE AZORES ISLANDS. ISOLATED
SHOWERS ARE WITHIN 60 NM OF THE FRONT AXIS..WITH SCATTERED
SHOWERS/POSSIBLE THUNDERSTORMS W OF THE FRONT N OF 24N BETWEEN
21W-34W.

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

$$
WALTON






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