[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 061738
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST TUE JAN 06 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...THE ITCZ...

THE ITCZ IS PRETTY ACTIVE TODAY. IT IS CENTERED ALONG 6N10W
6N20W 4N30W 4N40W INTO NE BRAZIL NEAR 1S51W. SCATTERED MODERATE
TO ISOLATED STRONG CONVECTION IS FROM 2N-6N BETWEEN 17W-32W...
AND FROM 3N-7N BETWEEN 35W-47W.

...DISCUSSION...

GULF OF MEXICO...
AS OF 1500 UTC...THE SFC LOW THAT WAS PREVIOUSLY ALONG THE
FRONTAL BOUNDARY OVER THE NW CORNER OF THE GULF HAS DISSIPATED.
PRESENTLY...A STATIONARY FRONT EXTENDS FROM SOUTH-CENTRAL
LOUISIANA TO THE COAST OF MEXICO JUST N OF TAMPICO. DOPPLER
RADAR SHOWS A BAND OF SHOWERS AND ISOLATED TSTMS EXTENDING FROM
SE TEXAS TO THE CAROLINAS ASSOCIATED WITH THE FRONT. AHEAD OF
THIS SYSTEM...MODERATE RETURN FLOW AND MOSTLY FAIR WEATHER
PREVAIL DUE TO THE PRESENCE OF A SFC AND UPPER LEVEL RIDGE. A
RECENT QSCAT PASS SHOWED NW WINDS OF 15-25 KT BEHIND THE FRONT.
OVER THE NEXT 24 HOURS...EXPECT MODERATE TO STRONG WINDS OF 20
TO 30 KT TO FOLLOW THE FRONT AS IT MOVES MORE RAPIDLY ACROSS THE
REGION LATE TODAY THROUGH WED. THE FRONT IS EXPECTED TO REACH
SOUTH FLORIDA AND THE YUCATAN PENINSULA LATE WED BRINGING SOME
SHOWER ACTIVITY.

CARIBBEAN SEA...
A MID-UPPER LEVEL RIDGE DOMINATES THE MAJORITY OF THE CARIBBEAN
EXTENDING NW FROM AN UPPER HIGH NEAR 14N79W. AN UPPER-LEVEL
TROUGH FROM THE CENTRAL ATLC DIGS INTO THE TROPICS REACHING THE
WINDWARD ISLANDS. THIS PATTERN CONTINUES TO PRODUCE MODERATE TO
STRONG UPPER LEVEL SUBSIDENCE AND IMPLIED DRY AIR MASS IS NOTED
WITHIN THE RIDGE. HOWEVER...LOW-LEVEL INSTABILITY IS PRODUCING
PATCHES OF LOW CLOUDS WITH EMBEDDED LIGHT SHOWERS MOSTLY OVER
THE LEEWARD ISLANDS AND PARTS OF JAMAICA. HIGH PRES N OF AREA
COMBINED WITH THE COLOMBIAN OR PANAMANIAN LOW IS GENERATING
MODERATE TO FRESH TRADE WINDS ACROSS THE BASIN WITH THE
STRONGEST WINDS OF 20 TO 30 KT NEAR THE COAST OF COLOMBIA. A
WEAKENING COLD FRONT IS FORECAST TO APPROACH THE YUCATAN CHANNEL
AND WESTERN CUBA LATE WEDNESDAY INTO EARLY THURSDAY.

ATLANTIC OCEAN...
A RIDGE/TROUGH/RIDGE/TROUGH PATTERN DOMINATES THE FORECAST AREA.
AN AREA OF MULTILAYERED CLOUDS WITH EMBEDDED SHOWERS IS FROM
20N-26N BETWEEN 43W AND 56W. THIS ACTIVITY IS AHEAD OF AN
UPPER-LEVEL TROUGH OVER THE CENTRAL ATLC WHICH DIPS INTO THE
DEEP TROPICS TO NEAR THE WINDWARD ISLANDS. A JET STREAM BRANCH
WITH CORE WINDS OF 90-110 KT ROUNDS THE BASE OF THIS TROUGH AND
EXTENDS MAINLY EWD ALONG 18N40W 18N20W ENTERING WEST AFRICA NEAR
18N16W. AT THE SURFACE...A RIDGE DOMINATES THE ENTIRE DISCUSSION
AREA ANCHORED BY A 1028 MB HIGH CENTERED NEAR 32N32W. THIS
SYSTEM IS PRODUCING A BELT OF MODERATE TO STRONG NELY WINDS
ACROSS THE TROPICS PARTICULARLY WEST OF 35W. THIS AREA OF WINDS
IS EXPECTED TO SPREAD EWD AS HIGH PRES CURRENTLY N OF REGION
MOVES INTO THE FORECAST AREA IN ABOUT 24 HOURS.

$$
GR





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