[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 240003
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST SAT DEC 23 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
2315 UTC.

...THE ITCZ...
7N11W 4N24W 1N32W EQ53W. SCATTERED MODERATE SHOWERS AND ISOLATED
STRONG THUNDERSTORMS WITHIN 180 NM OF AXIS BETWEEN 18W AND 27W.

...DISCUSSION...
THE GULF OF MEXICO...
DEEPENING UPPER TROUGH IS DIGGING THROUGH WEST TEXAS AND N
CENTRAL MEXICO THIS EVENING...PROVIDING SUPPORT TO A 1010 MB
SURFACE IN NE MEXICO NEAR MMMY. SWLY FLOW IN THE MID AND UPPER
LEVELS AHEAD OF THE ADVANCING TROUGH IS FLOW ACROSS WARM FRONT
BOUNDARY EXTENDING FROM LOW CENTER THROUGH S TEXAS AND INTO THE
CENTRAL GULF NEAR 26N88W AS A STATIONARY FRONT. WHILE DEEP LAYER
MOISTURE IS NOT ESPECIALLY MOIST...WITH PRECIPITABLE WATER
VALUES LESS THAN AN INCH OVER S TEXAS...THE OVERRUNNING SW FLOW
IS PROVIDING STRONG ISENTROPIC LIFT AND PROMOTING SHOWER GROWTH
OVER MUCH OF TEXAS AND IN THE W CENTRAL GULF. SMALL CLUSTER OF
SHOWERS AND THUNDERSTORMS NEAR 24N94W ALONG THE BOUNDARY...AIDED
BY RIGHT REAR QUADRANT OF EXITING 90 KT JET AXIS. OVER THE
EASTERN GULF...COLD FRONT IS EXTENDS FROM CENTRAL FLORIDA NORTH
OF TAMPA TO 26N88W WHERE IT BECOMES STATIONARY. FOR TONIGHT AND
SUN...UPPER TROUGH WILL SHIFT FROM NRN MEXICO AND INTO THE N
CENTRAL GULF...PUSHING ASSOCIATED SURFACE LOW TOWARD THE FLORIDA
PANHANDLE. WINDS WILL INCREASE TO GALE FORCE BEHIND THE TRAILING
COLD FRONT. WET PATTERN WILL SET UP OVER THE CENTRAL AND EASTERN
GULF REGIONS AS WARM FRONT PUSHES N AHEAD OF THE SURFACE LOW.
STRONG NLY WINDS WILL PERSIST OVER THE ENTIRE GULF THROUGH EARLY
NEXT WEEK AS HIGH PRES BUILDS BEHIND THE FRONT.

THE CARIBBEAN SEA...
STRONG SURFACE HIGH PRES OVER THE WESTERN ATLC IS MAINTAINING
STRONG E TO SE WINDS ACROSS THE CARIBBEAN BASIN. ANIMATED
VISIBLE IMAGERY SHOWS ONLY STREAKS OF CUMULUS IN THE ELY
FLOW...WITH NO MAJOR CONVECTION NOTED EXCEPT N OF WESTERN PANAMA
WHERE WEAK CONVERGENCE IS SUPPORTING SCATTERED SHOWERS AND
THUNDERSTORMS. ALOFT...MID AND UPPER LEVELS REMAIN FAIRLY DRY.
UPPER RIDGE EXTENDS FROM HONDURAS TO CENTRAL CUBA. UPPER TROUGH
EXTENDS E-W ALONG 15N OVER THE EASTERN AND CENTRAL CARIBBEAN. 70
TO 90 KT WLY WINDS ARE BRINGING BROKEN CIRRUS DECKS OVER NRN S
AMERICA...BETWEEN UPPER TROUGH TO THE N...AND WEAKENING UPPER
RIDGE ALONG 5N. NO MAJOR CHANGES ARE EXPECTED THROUGH THE MIDDLE
OF NEXT WEEK...AS HIGH PRES TO THE N CONTINUES TO PROMOTE FRESH
TO STRONG ELY WINDS ACROSS THE CARIBBEAN. THE EXCEPTION WILL BE
A COLD FRONT PUSHING INTO THE EXTREME NW CARIBBEAN NEAR THE
YUCATAN MON...FOLLOWED BY STRONG NLY WINDS THROUGH MID WEEK.

THE ATLANTIC OCEAN...
UPPER RIDGE AXIS EXTENDS FROM 32N61W THROUGH CENTRAL CUBA. 1030
MB SURFACE HIGH CENTERED N OF THE AREA NEAR 37N54W MAINTAINING
FRESH TO STRONG ELY WINDS OVER SUBTROPICAL ATLC W OF 50W.
STALLING COLD FRONT IS SLOWLY EMERGING OFF THE NE COAST OF
FLORIDA. THIS FEATURE WILL STALL OVERNIGHT AND RETREAT NWD AS A
WARM FRONT...AHEAD OF STRONG BAROCLINIC SYSTEM PUSHING THROUGH
THE GULF OF MEXICO. FURTHER E...ORIENTED UPPER TROUGH EXTENDS
N-S ALONG 36W. FROM THE BASE OF THIS TROUGH...ANOTHER UPPER
TROUGH EXTENDS MORE E-W INTO THE CARIBBEAN BASIN. AFTERNOON
QUIKSCAT IMAGERY OUTLINES A COLD FRONT IS PUSHING THROUGH THE N
CENTRAL ATLC ASSOCIATED WITH THE UPPER TROUGH...WHICH WILL
QUICKLY ABSORB A COUPLE OF WEAK BOUNDARIES AHEAD OF
IT...INCLUDING A WEAK TROUGH NEAR 34W. TO THE E...LARGE FIELD OF
STRATO CUMULUS CLOUDS OFF IBERIAN AND MOROCCAN
COASTLINES...ASSOCIATED WITH STABLE AIRMASS UNDER UPPER RIDGE
AXIS ALONG 18W. OVER THE TROPICAL ATLC S OF 20N...UPPER LEVEL
ANTICYCLONIC DIFFLUENCE ALONG 5N IS ENHANCING SCATTERED
CONVECTION ALONG THE ITCZ AS NOTED ABOVE. QUIKSCAT IMAGERY SHOWS
MAINLY LIGHT TO MODERATE NELY FLOW ACROSS THE REGION.

$$
CHRISTENSEN




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