AXNT20 KNHC 191134
TWDAT 

TROPICAL WEATHER DISCUSSION   
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST WED NOV 19 2008

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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1115 UTC.

...TROPICAL WAVES...
A TROPICAL WAVE IS ALONG 43W S OF 17N MOVING W 10-15 KT. THIS 
TROPICAL WAVE COINCIDES WITH A DEEP LAYER MOISTURE MAXIMUM BASED 
ON TOTAL PRECIPITABLE WATER PRODUCT FROM CIMSS. ALSO...CIMSS 
WAVETRAK PRODUCT INDICATES A MAXIMUM IN LOW LEVEL CYCLONIC 
CIRCULATION ALONG THE WAVE AXIS. SCATTERED MODERATE CONVECTION 
IS FROM 7N-15N BETWEEN 41W-49W.

A TROPICAL WAVE IS ALONG 73W/74W S OF 16N MOVING W 10-15 KT. A 
MAXIMUM IN DEEP LAYER MOISTURE COINCIDES WITH THIS WAVE. 
ALSO...UPPER AIR TIME-HEIGHT ANALYSIS FOR CURACAO...LOCATED IN 
THE NETHERLANDS ANTILLES NEAR 12N69W...DEPICTS VEERING OF MEAN 
LOW/MID-LEVEL FLOW FROM NE TO SE OVER THE LAST DAY SUGGESTING 
WAVE PASSAGE. SCATTERED MODERATE CONVECTION IS WITHIN 150 NM 
EITHER SIDE OF THIS WAVE S OF 12N...INCLUDING PORTIONS OF N 
COLOMBIA AND NW VENEZUELA.

...THE ITCZ...
THE ITCZ AXIS IS ANALYZED ALONG 9N12W 6N22W 6N36W 10N51W 8N60W. 
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 150 NM 
EITHER SIDE OF THE ITCZ AXIS BETWEEN 26W-34W. SCATTERED MODERATE 
CONVECTION IS FROM 9N-14N BETWEEN 53W-60W.

...DISCUSSION...

GULF OF MEXICO...
STRONG WEST-NORTHWESTERLY FLOW ALOFT AND DEEP LAYER DRY AIR ARE 
PRESENT OVER MUCH OF THE GULF REGION. ALSO...A MODIFIED 
CONTINENTAL POLAR AIRMASS PERSISTS ACROSS THE GULF REGION. AS A 
RESULT... TEMPERATURES ACROSS THE GULF REGION ARE BELOW SEASONAL 
AVERAGES. THIS RELATIVELY COOLER AND DRIER AIRMASS IS BEING 
REINFORCED BY A SURFACE COLD FRONT THAT EXTENDS FROM THE SE 
TEXAS COAST NEAR 29N95W TO 24N85W TO S OF FLORIDA NEAR 24N82W. 
WITH INCREASED N TO NE WINDS SUPPORTING LOW-LEVEL COLD AIR 
ADVECTION IN THE WAKE OF THE COLD FRONT...FREEZE WARNINGS AND 
WIND CHILL ADVISORIES ARE IN EFFECT FOR THIS MORNING...WITH 
FREEZE WATCHES IN EFFECT FOR LATE TONIGHT THROUGH THURSDAY 
MORNING...FOR PORTIONS OF FLORIDA. ALSO...A 1029 MB SURFACE HIGH 
IS CENTERED OVER NE MEXICO NEAR 25N99W...WITH AN ASSOCIATED 
SURFACE RIDGE EXTENDING INTO THE W GULF. AS THE COOLER AIR IS 
BEING ADVECTED OVER THE RELATIVELY WARMER GULF WATERS...WEAK LOW 
LEVEL INSTABILITY IS SUPPORTING SCATTERED STRATOCUMULUS CLOUDS 
ACROSS THE GULF. HOWEVER...SUBSIDENCE AND STABLE ATMOSPHERIC 
CONDITIONS HIGHER IN THE ATMOSPHERE ARE INHIBITING DEEP 
CONVECTION ACROSS THE GULF REGION. ADDITIONALLY...STRONG 
NORTHERLY SURFACE WINDS ARE BLOWING THROUGH THE ISTHMUS OF 
TEHUANTEPEC RESULTING IN STORM FORCE WINDS IN THE E PACIFIC 
REGION.

CARIBBEAN SEA...
ACROSS THE NW CARIBBEAN...A SURFACE STATIONARY FRONT EXTENDS 
FROM W OF HAITI NEAR 20N74W TO 16N80W TO N COSTA RICA NEAR 
11N85W. LOW LEVEL CONVERGENCE NEAR THIS FRONT IS INTERACTING 
WITH DEEP MOISTURE OVER THE W CARIBBEAN TO GENERATE SCATTERED 
SHOWERS AND THUNDERSTORMS S OF 17N W OF 73W. THIS ACTIVITY IS 
BEING ENHANCED BY UPPER LEVEL DIVERGENCE IN THE VICINITY OF AN 
UPPER RIDGE PRESENT OVER THE W CARIBBEAN...WITH THE AXIS OF THIS 
UPPER RIDGE EXTENDING FROM N COLOMBIA NEAR 11N73W TO 15N79W TO 
18N83W. THIS ACTIVITY IS ALSO BEING ENHANCED BY THE TROPICAL 
WAVE ALONG 73W/74W. OVER THE E CARIBBEAN...AN UPPER LEVEL RIDGE 
EXTENDS FROM N VENEZUELA NEAR 10N66W TO 16N64W TO 18N63W TO THE 
SW ATLC...WITH UPPER LEVEL DIVERGENCE SUPPORTING SCATTERED 
SHOWERS OVER THE E CARIBBEAN S OF 15N E OF 70W.

ATLANTIC OCEAN...
A VIGOROUS UPPER TROUGH IS OVER THE E CONUS AND THE W ATLC... 
WHICH IS SUPPORTING A SURFACE STATIONARY FRONT AND TWO SURFACE 
COLD FRONTS. THE STATIONARY FRONT EXTENDS FROM W OF HAITI NEAR 
20N74W TO 27N64W TO 31N61W AND EXTENDS FARTHER TO THE NE AS A 
DISSIPATING SURFACE STATIONARY FRONT. ISOLATED SHOWERS ARE 
WITHIN 60 NM EITHER SIDE OF THE STATIONARY FRONT. TO THE W OF 
THIS STATIONARY FRONT...A MODIFIED CONTINENTAL POLAR AIRMASS IS 
IN PLACE...WITH TEMPERATURES BELOW SEASONAL AVERAGES ACROSS 
FLORIDA. THIS RELATIVELY COOLER AND DRIER AIRMASS IS BEING 
REINFORCED BY A SURFACE COLD FRONT THAT EXTENDS FROM S OF 
FLORIDA NEAR 24N82W TO 27N70W TO 32N65W TO NE OF THE DISCUSSION 
AREA...WITH SCATTERED STRATOCUMULUS CLOUDS BETWEEN THIS FRONT 
AND THE COAST OF THE SE CONUS. ANOTHER SURFACE COLD FRONT 
EXTENDS FROM 31N69W TO 32N68W TO NE OF THE DISCUSSION AREA. 
FARTHER TO THE E...A 1016 MB SURFACE HIGH IS CENTERED NEAR 
27N54W...WHICH IS BEING SUPPORTED BY AN UPPER LEVEL RIDGE WITH 
AN AXIS EXTENDING FROM 18N63W TO 23N58W TO 32N51W TO N OF THE 
DISCUSSION AREA. FARTHER TO THE E...AN UPPER LOW IS CENTERED 
NEAR 32N39W THAT IS ACCOMPANIED BY AN UPPER TROUGH N OF 22N 
BETWEEN 24W-40W. THIS UPPER LOW AND UPPER TROUGH ARE ACCOMPANIED 
A 1010 MB SURFACE LOW NEAR 30N42W...ANOTHER 1010 MB SURFACE LOW 
CENTERED NEAR 29N47W...AND A SURFACE TROUGH EXTENDING FROM 
22N35W TO 26N33W TO 31N34W. LOW LEVEL CONVERGENCE NEAR THESE TWO 
SURFACE LOWS AND THE SURFACE TROUGH IS SUPPORTING SCATTERED 
SHOWERS N OF 21N BETWEEN 24W-32W...WITH ISOLATED SHOWERS N OF 
28N BETWEEN 33W-48W. OVER THE TROPICAL ATLC...AN UPPER RIDGE IS 
S OF 6N BETWEEN 21W-39W. UPPER LEVEL DIVERGENCE IN THE VICINITY 
OF THIS UPPER RIDGE IS ENHANCING THE CONVECTION ASSOCIATED WITH 
THE ITCZ...AS WELL AS THE CONVECTION ASSOCIATED WITH THE 
TROPICAL WAVE ALONG 43W.

$$
COHEN