[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 072351
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST THU DEC 07 2006

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...
CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...
NORTHEASTERN SECTIONS OF SOUTH AMERICA...AND THE 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
2345 UTC.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 7N11W 5N30W 4N50W. CLUSTERS OF
SCATTERED MODERATE TO ISOLATED STRONG CONVECTION ARE SEEN WITHIN
60 NM OF THE AXIS BETWEEN 29W-47W.

...DISCUSSION...
THE GULF OF MEXICO...
ZONAL UPPER FLOW IS CARRYING ABUNDANT UPPER MOISTURE AND HIGH
CLOUDS E ACROSS MUCH OF THE GULF THIS EVENING. THIS IS MAKING IT
DIFFICULT TO FIND THE EXACT PLACEMENT OF THE COLD FRONT MOVING
THROUGH. AS OF 2100 UTC...THE COLD FRONT EXTENDS E FROM THE
TAMPA AREA TO 27N84W. THE FRONT IS WARM FROM THIS POINT TO THE
SFC LOW NEAR 26N85W...AND COLD THROUGH THE WRN GULF TO 24N96W.
THIS BOUNDARY IS GENERALLY AT THE LEADING EDGE OF A STRONG 1045
MB HIGH BUILDING INTO THE NRN GULF FROM KANSAS. THE LOW IN THE
EAST CENTRAL GULF HAS NOT BEEN HANDLED WELL BY THE MODELS...AND
LIKELY CONTAINS SCATTERED TO NUMEROUS SHOWERS ESPECIALLY IN THE
NRN AND ERN SEMICIRCLES OUT 150 NM AS ESTIMATED BY SATELLITE
IMAGERY. A GALE WARNING IS IN EFFECT FOR THE WRN GULF N OF 22N
WITH RAPIDLY INCREASING NE WINDS AND WIND WAVES. THESE
CONDITIONS GRADUALLY SUBSIDE THROUGH THE WEEKEND AS THE HIGH
WEAKENS AND SHIFTS E. BROWNSVILLE RADAR SHOWING A FAIRLY
WIDESPREAD REGION OF LIGHT RAIN IN THE AREA...WITH SOME WEAK SFC
TROUGHING AND ISENTROPIC LIFT OVER THE WRN GULF. MODEL CONSENSUS
SUGGESTS THE WRN GULF/COASTAL MEXICO WILL CONTINUE TO SEE THE
PRECIP MAXIMA OVER THE GULF INTO THE WEEKEND...WITH WEAK
TROUGHING PERSISTING.

CARIBBEAN SEA...
DRY MID TO UPPER AIR CONTINUES TO DOMINATE MUCH OF THE CARIBBEAN
THIS EVENING. THE LARGE SCALE UPPER PATTERN OVER THE CARIBBEAN
IS DOMINATED BY AN UPPER RIDGE OVER MUCH OF THE CENTRAL AND WRN
PORTION...WITH THE AXIS EXTENDING FROM THE SW PORTION THROUGH
HISPANIOLA. A WEAK UPPER TROUGH CONTINUES TO EXTEND THROUGH THE
LEEWARD ISLANDS INTO THE NE CARIBBEAN. SCATTERED LOW CLOUDS WITH
ISOLATED SHOWERS CONTINUED TO BE ADVECTED W THROUGH THE
CARIBBEAN WITH THE TRADES...WHICH ARE GENERALLY IN THE 15 TO 25
KT RANGE. NE FLOW EXPECTED TO INCREASE OVER THE NW PORTION FRI
EVENING INTO SAT AS STRONGER HIGH PRESSURE BUILDS N OF THE AREA.
THE SFC TROUGH THAT IS ALONG 12N75W 29N75W WILL LIKELY BE
REMOVED FROM THE CARIBBEAN AT 00Z...AS THE CYCLONIC TURNING IN
THE AREA SEEMS MORE ASSOCIATED WITH THE NATURAL TRADE FLOW
THROUGH THE AREA AND AROUND THE COLOMBIAN LOW.

THE ATLANTIC OCEAN...
A COLD FRONT IS PUSHING INTO THE SW NORTH ATLC JUST OFF THE
COAST OF NE FLORIDA. STRONG HIGH PRESSURE WILL BUILD INTO THE
AREA BEHIND THE FRONT FRIDAY AND SATURDAY...ALLOWING NE WINDS
AND WIND WAVES TO INCREASE. A GALE WARNING IS IN EFFECT FOR THIS
STARTING LATE TONIGHT OFF THE COAST OF N FLORIDA...SEE MIAHSFAT2
FOR DETAILS. SCATTERED MODERATE CONVECTION IS AHEAD OF THE FRONT
N OF 26N BETWEEN 69W-74W...WHICH SEEMS ALIGNED WITH A PREFRONTAL
TROUGH. THIS AREA ALSO SUPPORTED BY UPPER DIFFLUENT AIR BETWEEN
THE LARGE SCALE TROUGHING OVER THE ERN US WITH THE UPPER RIDGE
EXTENDING NE THROUGH HISPANIOLA AND INTO THE CENTRAL ATLC. A
PRONOUNCED UPPER LOW IS SEEN SPINNING NEAR 19N36W. ABUNDANT
UPPER MOISTURE IS S AND SE OF THIS FEATURE...WITH SCATTERED
SHOWERS POSSIBLE FROM 9N-22N BETWEEN AFRICA AND 35W. THE SFC
PATTERN IN THE E AND CENTRAL ATLC DOMINATED BY THE SOUTH SIDE OF
HIGH PRESSURE...WITH A 1030 MB CENTER NEAR 32N31W. WLY JET OVER
THE DEEP TROPICS CONTINUES TO SHEAR THE CONVECTION OVER THE ITCZ
TO THE E.

$$
WILLIS


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