[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 130535
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST SUN JAN 13 2008

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC

...THE ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 8N13W 3N25W 1N140W CROSSING THE
EQUATOR NEAR 45W TO 1S47W. SCATTERED MODERATE TO STRONG CONVECTION
IS WITHIN 45-60 NM OF THE AXIS BETWEEN 21W AND 24W. SCATTERED
MODERATE CONVECTION IS WITHIN 90 NM OF THE AXIS BETWEEN 28W-32W AND
FROM THE EQUATOR TO 3N BETWEEN 10W-18W.

...DISCUSSION...

THE GULF OF MEXICO...
A WEAK FRONTAL BOUNDARY REMAINS STALLED FROM CEDAR KEY FLORIDA
THROUGH 26N90W TO THE EAST COAST OF MEXICO NEAR TAMPICO.
COMBINATION OF MOSAIC DOPPLER RADAR AND LIGHTNING DATA SUGGEST
SCATTERED SHOWERS AND TSTMS ARE WITHIN 60 NM N OF THE STATIONARY
FRONT. THE FRONT HAS LITTLE UPPER SUPPORT AT THE MOMENT AS WATER
VAPOR IMAGES AND DERIVED UPPER WINDS SHOW WIDESPREAD SWLY FLOW
AREA-WIDE. HOWEVER...SUPPORT IS ON THE WAY AS A LARGE UPPER TROUGH
OVER THE SOUTH-CENTRAL U.S. SHIFTS E. THIS TROUGH IS SUPPORTING A
COLD FRONT WHICH HAS NOW MOVED OFF THE CENTRAL TEXAS COAST. MODEL
GUIDANCE SHOWS THESE BOUNDARIES MERGING AND SWEEPING THROUGH THE
MAJORITY OF THE AREA WITHIN THE NEXT 24-36 HOURS BRINGING COOLER
CONDITIONS TO THE REGION.

THE CARIBBEAN SEA...
LARGE SUBSIDENT MID TO UPPER RIDGE LIES ABOVE THE ENTIRE ZONE
LIMITING THE DEVELOPMENT OF CONVECTION OR DEEP CLOUDINESS. PATCHES
OF LOW LEVEL CLOUDS ARE STREAMING FROM W TO E ACROSS THE AREA IN
MODERATE TRADE WIND FLOW. THE MOST CONCENTRATED PATCHES ARE S OF 17N
E OF 70W AND FROM 14N-20N BETWEEN 80W-84W AND MOVING ONSHORE OVER NE
NICARAGUA AND FAR EASTERN HONDURAS. OVERALL...LITTLE CHANGE IS
EXPECTED UNTIL A FRONT MOVES INTO THE NW CORNER ON MON.

THE ATLANTIC OCEAN...
A WEAK 1013 MB LOW PRES SYSTEM IS DRIFTING N AND WAS CENTERED NEAR
27N60W. WHILE THE LOW-LEVEL CIRCULATION IS EASILY EVIDENT...THE
SYSTEM IS DEVOID OF DEEP CONVECTION. A 0044 UTC ASCAT PASS CAPTURED
THE CIRCULATION WELL REVEALING WINDS OF UP TO 20 KT MAINLY IN THE
EASTERN SEMICIRCLE. NWP MODELS SHOW A CONTINUED NORTH-NORTHWEST
DRIFT AS IT OPENS INTO A TROUGH OVER THE NEXT DAY OR TWO...
EVENTUALLY BEING ABSORBED BY A MUCH LARGER EXTRATROPICAL LOW.
OVERCAST MULTILAYERED CLOUDS WITH EMBEDDED SCATTERED SHOWERS/
ISOLATED TSTMS LIE WELL TO THE E OF THE SFC LOW FROM 22N-30N
BETWEEN 45W-51W IN AN UPPER DIFFLUENT ZONE.

THE W ATLC W OF 65W IS UNDER SWLY UPPER FLOW AND WEAK SFC RIDGING.
THIS PATTERN IS PRODUCING SCATTERED LOW CLOUDS NE OF THE BAHAMAS.
RADAR AND LIGHTNING DATA INDICATES THAT A LINE OF SCATTERED
THUNDERSTORMS HAVE DEVELOPED WITHIN 60-75 NM E OF THE FLORIDA E
COAST FROM VERO BEACH TO JACKSONVILLE. FURTHER E...MUCH STRONGER SFC
RIDGING LIES OVER THE E ATLC WITH A FAIRLY WELL DEFINED TROUGH ALOFT
EXTENDING FROM THE MADEIRA ISLANDS NEAR 32N17W TO 25N35W. SWIFT MID
TO UPPER ZONAL FLOW LIES OVER THE TROPICAL BELT. THIS OVERALL
PATTERN IS ALSO NOT AMOUNTING TO MUCH SENSIBLE WEATHER WITH ONLY A
SWATH OF MID-HIGH LEVEL CLOUDS AND POSSIBLE SHOWERS FROM 10N-16N E
OF 50W.

$$
COBB


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